阅读说明：本技术 位置判定系统 (Position determination system ) 是由 三治健一郎 冈部信康 池田正和 角谷祐次 于 2020-03-09 设计创作，主要内容包括：本发明的位置判定系统通过与由车辆的用户携带的便携终端使用1GHz以上的电波相互无线通信来判定便携终端相对于车辆的位置。位置判定系统具备：车室外通信机(12β、12L、12M、12N),具有用于接收从便携终端发送的无线信号的天线(121)；和位置判定部(F4),基于车室外通信机中的来自便携终端的无线信号的接收状况,判定便携终端的位置。位置判定部基于车室外通信机以第一模式进行工作时的来自便携终端的无线信号的接收状况判定在车室外距车辆规定的工作工作距离以内的区域即室外工作区域是否存在便携终端,使用车室外通信机以第二模式进行工作时的来自便携终端的无线信号的接收状况判定便携终端是否存在于车室内。(A position determination system determines the position of a portable terminal relative to a vehicle by mutually wireless communication with the portable terminal carried by a user of the vehicle using a radio wave of 1GHz or more. The position determination system includes: an outside-vehicle communication device (12 beta, 12L, 12M, 12N) having an antenna (121) for receiving a wireless signal transmitted from a portable terminal; and a position determination unit (F4) for determining the position of the portable terminal based on the reception status of the wireless signal from the portable terminal in the vehicle-outside communication device. The position determination unit determines whether or not the portable terminal is present in an outdoor operation area, which is an area within a predetermined operation distance from the vehicle outdoors based on a reception status of the wireless signal from the portable terminal when the vehicle outdoor communication device operates in the first mode, and determines whether or not the portable terminal is present in the vehicle indoors using a reception status of the wireless signal from the portable terminal when the vehicle outdoor communication device operates in the second mode.)

1. A position determination system for a vehicle for determining the position of a portable terminal carried by a user of the vehicle with respect to the vehicle by mutual wireless communication using a radio wave of 1GHz or higher with the portable terminal,

the position determination system includes:

an outside-vehicle communication device (12 β, 12L, 12M, 12N) that is provided on an outer surface portion of the side surface portion or the rear surface portion of the vehicle and that has an antenna (121) for receiving a wireless signal transmitted from the portable terminal; and

a position determination unit (F4) for determining the position of the portable terminal based on the reception status of the wireless signal from the portable terminal by the vehicle-outside communication device,

the outside communication device has a first mode and a second mode as operation modes,

in the first mode, a linearly polarized wave is radiated in a direction parallel to the outer surface portion on which the vehicle exterior communication device is mounted, an electric field vibration direction of the linearly polarized wave being perpendicular to the outer surface portion,

in the second mode, a linearly polarized wave whose electric field vibration direction is parallel to the outer surface portion is radiated,

the position determination unit is configured to determine a position of the movable body,

determining whether or not the portable terminal is present in an outdoor operation area, which is an area outside the vehicle and within a predetermined operation distance from the vehicle, based on a reception status of a wireless signal from the portable terminal when the communication device outside the vehicle operates in the first mode,

And determining whether the portable terminal is present in the vehicle interior using a reception status of the wireless signal from the portable terminal when the vehicle exterior communication device operates in the second mode.

2. The position determination system according to claim 1,

the antenna of the vehicle exterior communication device is configured to radiate a linearly polarized wave in a direction perpendicular to the outer surface portion to which the vehicle exterior communication device is attached in the second mode, and an electric field vibration direction of the linearly polarized wave is parallel to the outer surface portion.

3. The position determination system according to claim 1 or 2,

the outside-vehicle communication means is constituted so that,

operating in the first mode at a predetermined first frequency belonging to a frequency band used for wireless communication with the portable terminal,

the mobile terminal operates in the second mode at a predetermined second frequency that is different from the first frequency and that belongs to a frequency band used for wireless communication with the mobile terminal.

4. The position determination system according to claim 3,

the antenna is provided with:

a bottom plate (51) which is a flat plate-shaped conductor member;

a counter conductor plate (53) which is a flat plate-shaped conductor member provided at a predetermined interval from the bottom plate, the counter conductor plate being provided with a power feeding point (531) electrically connected to a power feeding line; and

A short-circuit section (54) provided in a central region of the opposing conductor plate and electrically connecting the opposing conductor plate and the chassis,

the bottom plate is disposed asymmetrically with respect to the opposite conductor plate,

the antenna is configured to perform parallel resonance at the first frequency using a capacitance formed by the opposing conductor plate and the bottom plate and an inductance provided in the short-circuit portion,

the vehicle exterior communication device is mounted on the outer surface portion in a posture in which the floor panel faces the outer surface portion.

5. The position determination system according to claim 4,

the base plate of the antenna includes a symmetry maintaining section (512) which is rectangular and is disposed concentrically with the opposing conductor plate, and an asymmetric section (511) which is disposed on a side of the symmetry maintaining section,

the symmetry maintaining section and the asymmetry section are connected via a switch (513),

the outside-vehicle communication means is configured to operate in the first mode when the switch is turned off, and to operate in the second mode when the switch is turned off.

6. The position determination system according to claim 4 or 5,

In the antenna, the short-circuit portion is formed at a position offset by a predetermined amount from the center of the opposite conductor plate.

7. The position determination system according to claim 3,

the antenna is provided with:

a bottom plate (51) which is a flat plate-shaped conductor member;

a counter conductor plate (53) which is a flat plate-shaped conductor member provided at a predetermined interval from the bottom plate, the counter conductor plate being provided with a power feeding point (531) electrically connected to a power feeding line; and

a short-circuit section (54) provided in a central region of the opposing conductor plate and electrically connecting the opposing conductor plate and the chassis,

the opposing conductor plates are formed in a line-symmetrical shape with respect to each of two mutually orthogonal straight lines,

an electrical length of the opposing conductor plate in a direction along a first axis of symmetry which is either one of two axes of symmetry of the opposing conductor plate is half a wavelength of the radio wave of the second frequency,

the feeding point is disposed on a straight line passing through the center of the opposing conductor plate and parallel to the first axis of symmetry,

the antenna is configured to perform parallel resonance at the first frequency using a capacitance formed by the opposing conductor plate and the bottom plate and an inductance provided in the short-circuit portion,

The vehicle exterior communication device is mounted on the outer surface portion in a posture in which the floor panel faces the outer surface portion.

8. The position determination system according to claim 7,

in the vehicle outdoor communication device, the antenna is connected to a transmission/reception circuit (122) via an impedance variable element (591) configured to have a variable capacitance or inductance,

an operation mode switching unit (125) for switching the operation mode of the vehicle exterior communication device by changing the capacitance or inductance of the impedance variable element,

the position determination unit is configured to determine a position of the movable body,

when it is determined whether or not the portable terminal is present in the outdoor operation area, the external communication device is operated in the first mode in cooperation with the operation mode switching unit,

and a second mode switching unit configured to switch between a first mode in which the portable terminal is located and a second mode in which the portable terminal is located.

9. The position determination system according to claim 7,

the opposing conductor plate includes a first feeding point for transmitting and receiving a signal of the first frequency and a second feeding point as the feeding point for transmitting and receiving a signal of the second frequency,

The second feeding point is disposed on a straight line passing through the center of the opposing conductor plate and parallel to the first axis of symmetry,

the position determination unit is configured to determine a position of the movable body,

determining whether the portable terminal is present in the outdoor working area using the reception strength of the signal from the portable terminal acquired via the first power feeding point, and,

and determining whether the portable terminal is present in the vehicle interior using the reception intensity of the signal from the portable terminal acquired via the second power feeding point.

10. The position determination system according to any one of claims 3 to 9,

the outside-vehicle communication device is provided with an intensity detection unit (124) for detecting the reception intensity of the wireless signal received by the antenna,

the position determination system is provided with an in-vehicle communication device (12 alpha) which is provided in the vehicle interior of the vehicle, receives a wireless signal transmitted from the portable terminal, and detects the reception intensity of the received wireless signal,

the position determination unit is configured to determine a position of the movable body,

determining that the portable terminal is present in the outdoor operating area based on the reception intensity of the signal of the first frequency detected by the vehicle-outdoor communication device being equal to or greater than a predetermined operating threshold value,

The mobile terminal is determined to be present in the vehicle interior based on the reception intensity of the signal of the second frequency detected by the vehicle interior communication device being greater than the reception intensity of the signal of the second frequency detected by the vehicle exterior communication device by a predetermined threshold or more.

11. The position determination system according to any one of claims 3 to 10,

the outside-vehicle communication device is provided with an intensity detection unit (124) for detecting the reception intensity of the wireless signal received by the antenna,

the position determination system is provided with an in-vehicle communication device (12 alpha) which is provided in the vehicle interior of the vehicle, receives a wireless signal transmitted from the portable terminal, and detects the reception intensity of the received wireless signal,

the position determination unit is configured to determine a position of the movable body,

determining that the portable terminal is present in the outdoor operating area based on the reception intensity of the signal of the first frequency detected by the vehicle-outdoor communication device being equal to or greater than a predetermined operating threshold value,

and determining that the portable terminal is present in the vehicle interior based on the reception intensity of the signal of the second frequency detected by the vehicle interior communication device being equal to or greater than a predetermined vehicle interior equivalent value.

12. The position determination system according to any one of claims 1 to 11,

the outside-vehicle communication device is provided on a window frame portion of a side window of the vehicle.

Technical Field

The present disclosure relates to a position determination system mounted on a vehicle and used for estimating a relative position of a portable terminal carried by a user with respect to the vehicle based on a reception state of a wireless signal transmitted from the portable terminal using a radio wave of 1GHz or more.

Background

Various position determination systems have been proposed that estimate the position of a portable terminal relative to a vehicle by performing wireless communication with the portable terminal carried by a user of the vehicle. For example, patent document 1 discloses the following structure: the response request signal is transmitted from the vehicle to the portable terminal using an LF (Low Frequency) band radio wave, and whether or not the portable terminal is present in the vicinity of the vehicle outside the vehicle (hereinafter, an outdoor work area) is determined based on the fact that the response signal to the response request signal can be received.

The outdoor operation area corresponds to an area in which the portable terminal is allowed to automatically unlock the vehicle door by wireless communication with the portable terminal. Generally, the outdoor working area is often set to within 1m or within 0.7m from the vehicle. The reason why the radio wave in the LF band is used for signal transmission from the vehicle to the portable device is that the range of arrival of the radio signal is easily limited to the vicinity of the vehicle. In a vehicle, the transmission power of an antenna for transmitting radio waves in the LF band is adjusted so that radio signals reach only the outdoor operating area.

Such a position determination system is used in an electronic key system for a vehicle that performs predetermined vehicle control according to the position of a portable terminal. The electronic key system for a vehicle includes a keyless entry and start system (hereinafter, PEPS system) that automatically controls a locked state of a door of the vehicle and an operation state of a drive source according to a position of the portable terminal.

There are cases where a portable information processing terminal such as a smartphone or a wearable terminal is intended to function as a key of a vehicle. Accordingly, there is a demand for a configuration that can determine the position of the portable terminal relative to the vehicle using the reception intensity of a high-frequency radio wave used for short-range communication such as Bluetooth instead of a radio wave in the LF band. This is because a smartphone generally does not have a function of transmitting and receiving radio waves in the LF band, and on the other hand, a smartphone is often equipped with a short-range communication function such as Bluetooth (registered trademark) or Wi-Fi (registered trademark) as a standard.

Patent document 2 discloses an in-vehicle device that estimates the position of a portable terminal relative to a vehicle by performing wireless communication conforming to the Bluetooth standard with the portable terminal carried by a user of the vehicle. The in-vehicle device disclosed in patent document 1 periodically transmits a request signal requesting a return response signal to the portable terminal from a communication device (hereinafter, an in-vehicle communication device) installed on a floor surface in a vehicle interior such as a vicinity of a foot of a driver's seat. When receiving a request Signal from the in-vehicle communication device, the portable terminal returns a response Signal including an RSSI (Received Signal Strength Indication) of the request Signal. The in-vehicle device stores the RSSI included in the response signal returned from the portable terminal in the memory. When the average value of the RSSI values stored in the memory for the last 5 times exceeds a predetermined threshold value, the in-vehicle device determines that the portable terminal is present in the vehicle interior. On the other hand, when the average value of the RSSI values of the last 5 times is equal to or less than the threshold value, it is determined that the vehicle exists outside the vehicle.

Hereinafter, communication according to a predetermined wireless communication standard such as Bluetooth having a communication range of, for example, several tens of meters is referred to as short-range communication. For short-range communication, for example, radio waves of 1GHz or more (hereinafter, high-frequency radio waves) such as 2.4GHz are used. Such a high-frequency radio wave has a property of being more straight-traveling and easily reflected by a metal body such as a vehicle body of a vehicle than a radio wave in an LF band.

Patent document 1: japanese patent No. 5438048;

patent document 2: japanese patent No. 6313114.

Patent document 2 does not directly mention a method of determining whether a portable terminal is present in an outdoor working area outside a vehicle or in an prohibited area. As a configuration related to the above-described determination, there is disclosed a method of limiting the communication area of the in-vehicle device to within 1m from the vehicle by adjusting the output of the antenna for short-range communication provided in the vehicle interior. However, high-frequency radio waves used for near field communication such as Bluetooth have properties of being more straightforward and easily reflected by a metal plate of a vehicle body or the like than radio waves in the LF band. Therefore, it is sometimes difficult to actually set the communication area outside the vehicle to 1m while maintaining the signal intensity at a sufficiently high level over the entire area inside the vehicle. That is, in the configuration disclosed in patent document 1, it is not possible to distinguish whether the mobile terminal is present in the outdoor operation area or the prohibited area.

As one solution, a configuration may be considered in which whether the portable terminal is present in an outdoor working area outside the vehicle or in an prohibited area is determined using the reception intensity of the signal from the vehicle at the portable terminal, as in the case of determining whether the portable terminal is present in the vehicle. However, there is no structure such as a vehicle body of the vehicle between the outdoor working area outside the vehicle compartment and the prohibited area. Radio waves from an antenna installed in a vehicle interior are continuously attenuated from an outdoor working area toward a prohibited area. In addition, since the antenna in the vehicle interior is located outside the field of view on the back side of the door module (i.e., below the outdoor work area), the reception intensity of the portable terminal is low. Therefore, there are cases where an intentional difference in the strength of the signal transmitted from the antenna in the vehicle interior does not occur between the lower side of the outdoor work area and the prohibited area.

Therefore, it is actually difficult to determine whether the portable terminal is present in an outdoor working area outside the vehicle or in an prohibited area based on the reception intensity of the signal transmitted from the communication device installed in the vehicle interior in the portable terminal. It is possible that the determination result is erroneously determined to be in the prohibited area although the determination result is in the outdoor operation area. Of course, if it is erroneously determined that the portable terminal is present in the prohibited area, the door is not unlocked, and thus the convenience of the user may be impaired.

In order for a user to utilize a vehicle without stress, it is necessary to detect the presence at least in an outdoor work area with high accuracy. In order to ensure the safety of the vehicle, it is necessary to reduce the possibility that the vehicle is erroneously determined to be present in the outdoor work area although it is present in the prohibited area. In order to improve the accuracy of determination of the presence in the outdoor operating area, it is sometimes preferable to provide an antenna on the outer surface of the vehicle so that the outdoor operating area is a strong electric field area without omission and a weak electric field level is achieved in an area located at a distance from or above the vehicle.

Based on the above-described concept, the inventors have conducted various tests and found that if the dipole antenna is mounted in a posture perpendicular to the side surface of the vehicle, the outdoor working area can be made a strong electric field area without omission, and the electric field intensity in the prohibited area can be suppressed to a sufficiently low level. This is considered to be because, according to the system in which the dipole antenna is mounted in the above-described posture, an electric field whose electric field starting direction is perpendicular to the side surface portion is radiated in a direction parallel to the side surface portion of the vehicle. The electric wave whose electric field vibration direction is perpendicular to the metal surface propagates along the metal surface. Therefore, the outdoor operating region can be set to a strong electric field region without omission.

Since the electric wave whose electric field vibration direction is perpendicular to the metal surface propagates along the metal surface, the electric field vibration may be a strong electric field region in the vehicle interior as well as the outdoor work area. In a structure in which the dipole antenna is mounted in a posture perpendicular to the side surface of the vehicle, a difference in electric field intensity between the inside of the vehicle and the outside work area is not easily generated, and therefore, it is sometimes difficult to determine whether the portable terminal is present in the inside of the vehicle or the outside work area.

Disclosure of Invention

An object of the present disclosure is to provide a position determination system capable of improving the detection rate of the presence of a portable terminal in an outdoor work area and reducing the possibility of erroneously determining that the portable terminal is present outside the vehicle (mainly, in an external outdoor work area) despite being present inside the vehicle.

A position determination system according to one aspect of the present disclosure is a vehicle position determination system that determines the position of a portable terminal relative to a vehicle by performing mutual wireless communication with the portable terminal carried by a user of the vehicle using radio waves of 1GHz or more. The position determination system includes: an outside-vehicle communication device provided on an outer surface portion of a side surface portion or a rear surface portion of a vehicle and having an antenna for receiving a wireless signal transmitted from a portable terminal; and a position determination unit that determines the position of the portable terminal based on the reception status of the wireless signal from the portable terminal in the vehicle-outside communication device. The vehicle exterior communication device includes, as operation modes, a first mode in which a linearly polarized wave having an electric field vibration direction perpendicular to an outer surface portion is radiated in a direction parallel to the outer surface portion to which the vehicle exterior communication device is attached, and a second mode in which a linearly polarized wave having an electric field vibration direction parallel to the outer surface portion is radiated. The position determination unit is configured to determine whether or not the portable terminal is present in an outdoor operation area, which is an area within a predetermined operation distance from the vehicle outdoors, based on a reception status of a wireless signal from the portable terminal when the vehicle outdoor communication unit operates in the first mode, and to determine whether or not the portable terminal is present in the vehicle interior using a reception status of a wireless signal from the portable terminal when the vehicle outdoor communication unit operates in the second mode.

A linearly polarized wave in which the vibration direction of the electric field is perpendicular to the surface of the metal tends to propagate along the metal. Therefore, when the communication device outside the vehicle compartment operates in the first mode, the vicinity of the vehicle outside the vehicle compartment can be set as a strong electric field region without omission. Therefore, in the determination of whether or not the portable terminal is present in the outdoor operation area, the detection rate of the presence of the portable terminal in the outdoor operation area can be increased by using the reception state of the wireless signal from the portable terminal when operating in the first mode.

The linearly polarized wave to be transmitted and received by the vehicle exterior communication device in the first mode is likely to enter the vehicle interior along the metal providing the side surface of the vehicle. Therefore, in the first mode, the interior of the vehicle compartment may be a strong electric field region. Since the propagation path of the radio signal is reversible, the above trend indicates that the signal from the portable terminal existing in the vehicle interior is easily received when the vehicle exterior communication device operates in the first mode.

The linearly polarized wave to be transmitted and received by the external communication device in the second mode is less likely to be diffracted into the vehicle interior. This is because a linearly polarized wave in which the vibration direction of the electric field is parallel to the metal that provides the outer surface portion of the vehicle is easily bounced back by the metal. As a result, the electric field level in the vehicle interior in the second mode becomes low. As described above, since the propagation path of the radio signal is reversible, the above tendency indicates that it is difficult to receive a signal from a portable terminal existing in the vehicle interior when the vehicle exterior communication device operates in the second mode.

Therefore, in the determination of whether or not the portable terminal is present in the vehicle interior, by using the reception state of the wireless signal from the portable terminal when the vehicle exterior communication device is operated in the second mode, it is possible to reduce the possibility that the portable terminal is erroneously determined to be present in the outdoor operation area although the portable terminal is present in the vehicle interior. That is, according to the above configuration, it is possible to improve the detection rate of the presence of the mobile terminal in the outdoor work area and reduce the possibility of erroneously determining that the mobile terminal is present in the outdoor work area although the mobile terminal is present in the vehicle interior.

Drawings

Fig. 1 is a diagram for explaining a schematic configuration of an electronic key system for a vehicle.

Fig. 2 is a diagram for explaining the structure of the vehicle.

Fig. 3 is a block diagram showing a schematic configuration of the in-vehicle system.

Fig. 4 is a schematic diagram showing an example of a mounting position of the in-vehicle communication device.

Fig. 5 is a block diagram showing a schematic configuration of the in-vehicle communication device.

Fig. 6 is a diagram showing an example of the configuration of the vehicle-exterior communication device.

Fig. 7 is an external perspective view showing the structure of the circuit board.

Fig. 8 is a sectional view taken along line VIII-VIII of fig. 7.

Fig. 9 is a diagram for explaining a positional relationship between the opposing conductor plate and the bottom plate.

Fig. 10 is a diagram showing current, voltage, and electric field distributions in the zero-order resonance mode.

Fig. 11 is a diagram showing radiation characteristics in the zero-order resonance mode.

Fig. 12 is a diagram showing radiation characteristics in the zero-order resonance mode.

Fig. 13 is a diagram for explaining the operation principle of the backplane excitation mode.

Fig. 14 is a diagram for explaining the operation principle of the backplane excitation mode.

Fig. 15 is a diagram showing an example of frequency characteristics of the gain in each operation mode.

Fig. 16 is a diagram showing an example of frequency characteristics of the gain in each operation mode.

Fig. 17 is a diagram showing an example of the installation position and installation posture of the outdoor left-side communication device.

Fig. 18 is a diagram showing the directivity and polarized wave for each operation mode of the vehicle exterior communication device as the side communication device.

Fig. 19 is a diagram showing radiation characteristics of the vehicle-exterior communication device as a side communication device.

Fig. 20 is a diagram showing the distribution of the electric field intensity when the outdoor left-side communication device operates in the zero-order resonance mode.

Fig. 21 is a diagram showing the distribution of the electric field intensity when the outdoor left-side communication device operates in the backplane excitation mode.

Fig. 22 is a diagram for explaining the function of the smart ECU.

Fig. 23 is a flowchart for explaining the connection-related processing.

Fig. 24 is a flowchart for explaining the position determination process.

Fig. 25 is a diagram for explaining the elements of the electronic key system for a vehicle.

Fig. 26 is a diagram showing a modification of the structure of the vehicle-exterior communication device.

Fig. 27 is a diagram showing a modification of the structure of the vehicle-exterior communication device.

Fig. 28 is a diagram showing a modification of the structure of the vehicle exterior antenna.

Fig. 29 is a diagram showing a current distribution in the opposite conductive plate in a case where the short-circuited portion is formed in the center of the opposite conductive plate.

Fig. 30 is a diagram showing a current distribution in the opposite conductive plate and an action thereof in a case where a short-circuited portion is formed at a position deviated from the center of the opposite conductive plate.

Fig. 31 is a diagram showing the electric field intensity distribution when the vehicle exterior antenna shown in fig. 28 operates in the zero-order resonance mode.

Fig. 32 is a diagram showing a modification of the structure of the vehicle exterior antenna.

Fig. 33 is a diagram showing an external antenna configured to be capable of switching operation modes.

Fig. 34 is a diagram showing a modification of the smart ECU and the vehicle-exterior communication device.

Fig. 35 is a diagram showing a modification of the vehicle exterior antenna.

Fig. 36 is a diagram showing a modification of the configuration for switching the operation mode of the vehicle outdoor communication device.

Detailed Description

Hereinafter, an example of an embodiment of a position determination system according to the present disclosure will be described with reference to the drawings. Fig. 1 is a diagram showing an example of a schematic configuration of an electronic key system for a vehicle to which a position determination system according to the present disclosure is applied. As shown in fig. 1, the vehicle electronic key system includes an in-vehicle system 1 mounted on a vehicle Hv, and a mobile terminal 2, which is a communication terminal carried by a user of the vehicle Hv.

(general overview of the entirety)

The in-vehicle system 1 is a vehicle-side device/system constituting a vehicle electronic key system, such as a keyless entry and start system (hereinafter, PEPS system). The in-vehicle system 1 performs wireless communication using a radio wave of a predetermined frequency band with the mobile terminal 2, thereby performing predetermined vehicle control according to the position of the mobile terminal 2. For example, the in-vehicle system 1 locks or unlocks the doors on the condition that the presence of the portable terminal 2 in the outdoor work area Rx set in advance for the vehicle Hv can be confirmed.

The outdoor work area Rx corresponds to an area outside the vehicle cabin where the execution of the vehicle control by the in-vehicle system 1 is permitted. Here, the outdoor work area Rx is set to an area that allows locking and unlocking of the doors of the vehicle by the in-vehicle system 1, for example. The outdoor working area Rx is defined in the vicinity of the vehicle Hv. In the present embodiment, as an example, an area outside the vehicle compartment within a predetermined operating distance (for example, 0.7 m) from the outside door handles provided in the driver's seat door, the passenger seat door, and the trunk door, respectively, is set as the outdoor operating area Rx. The working distance defining the size of the outdoor working area Rx may be 1m or 1.5 m. The working distance may be set to be smaller than a prohibition distance (2m) defining the size of a prohibition area, which will be described later. The outside door handle is a gripping member for opening and closing the door, which is provided on the outer side surface of the door. The outside door handle may also be of the type stored in a door panel, such as a flashing handle, a pop-up handle, etc.

The in-vehicle system 1 and the portable terminal 2 according to the present embodiment are each configured to be capable of performing communication (hereinafter, referred to as short-range communication) according to a predetermined short-range wireless communication standard in which a communication distance can be set to about 10 meters. As the short-range wireless communication standard here, for example, Bluetooth Low Energy (Bluetooth is a registered trademark), Wi-Fi (registered trademark), ZigBee (registered trademark), or the like can be used. The short-range wireless communication standard may provide a communication distance of about several meters to several tens of meters, for example. As an example, the in-vehicle system 1 and the portable terminal 2 according to the present embodiment are configured to perform wireless communication in accordance with the Bluetooth Low Energy standard.

The portable terminal 2 is a device that functions as an electronic key for the vehicle Hv in association with the in-vehicle system 1. The portable terminal 2 may be any device that can be carried by the user and that has the near field communication function described above. For example, a smartphone can be used as the mobile terminal 2. Of course, the mobile terminal 2 may be a tablet terminal, a wearable device, a portable music player, a portable game machine, or the like. The signal transmitted by the mobile terminal 2 as the near field communication includes the transmission source information. The source information is, for example, unique identification information (hereinafter, referred to as a terminal ID) assigned to the mobile terminal 2. The terminal ID functions as information for identifying another communication terminal and the mobile terminal 2.

The mobile terminal 2 notifies the presence of itself (i.e., advertisement) to the surrounding communication terminals having the short-range communication function by wirelessly transmitting a communication packet including the transmission source information at a predetermined transmission interval. Hereinafter, a communication packet periodically transmitted for the purpose of advertisement is referred to as an advertisement packet.

The in-vehicle system 1 receives a signal (for example, an advertisement packet) transmitted from the portable terminal 2 by the near field communication function described above, and detects that the portable terminal 2 is present in a range in which near field communication with the in-vehicle system 1 is possible. Hereinafter, a range in which the in-vehicle system 1 can perform data communication with the portable terminal 2 by the short-range communication function is also referred to as a communication area.

In the present embodiment, the in-vehicle system 1 is configured to detect the presence of the mobile terminal 2 in the communication area by receiving advertisement packets sequentially transmitted from the mobile terminal 2, as an example, but the present invention is not limited thereto. As another mode, the in-vehicle system 1 may be configured to sequentially transmit advertisement packets and detect that the mobile terminal 2 is present in the communication area based on establishment of a communication connection (so-called connection) with the mobile terminal 2.

(Structure of vehicle Hv)

The structure of the vehicle Hv will be described with reference to fig. 2. The vehicle Hv is, for example, a car with 5 occupants. Here, the vehicle Hv includes a front seat and a rear seat, and a driver's seat (in other words, a steering wheel) is provided on the left side, as an example. The vehicle Hv may be a vehicle provided with a driver's seat on the right side. Or a vehicle without a rear seat. The vehicle Hv may be a truck such as a truck. The vehicle Hv may be a taxi or a camper. The vehicle Hv may be a vehicle for a vehicle rental service (so-called rental car) or a vehicle for a vehicle sharing service (so-called shared car). Also included in the shared automobile is a vehicle used in a service of lending to another person during a period in which a manager of the vehicle does not use a vehicle owned by an individual. In the case where the vehicle Hv is a vehicle for the above-described service (hereinafter, a service vehicle), a person who makes a contract for utilizing these services may become a user. A person having the right to use the vehicle Hv may become the user.

The body of the vehicle Hv is mainly realized using metal parts. The vehicle body herein includes a vehicle body panel in addition to a frame that provides a vehicle body main body portion, such as a B pillar. The body panels include side body panels, roof panels, rear end panels, hood panels, door panels, and the like. Here, as an example, a portion of the door panel that overlaps the B pillar 42B or a portion that functions as a window frame portion is formed of resin.

Since the metal plate has a property of reflecting radio waves, the vehicle body of the vehicle Hv reflects radio waves. That is, the vehicle body of the vehicle Hv is configured to block the direct propagation of the radio wave. The radio wave here is a radio wave of a frequency band used for wireless communication between the in-vehicle system 1 and the portable terminal 2 (hereinafter, the system uses a radio wave). The system-use radio wave herein refers to a radio wave in a 2.4GHz band. The blocking here is ideally a reflection, but is not limited to this. A configuration capable of attenuating a radio wave by a predetermined level or more (hereinafter, a target attenuation level) corresponds to a configuration for blocking propagation of a radio wave. The target attenuation level may be set to, for example, 10dB, as long as the signal intensity of the radio wave is intentionally different between the inside and the outside of the vehicle. The target attenuation level can be set to any value of 5dB or more (e.g., 10dB, 20 dB).

The vehicle Hv has a roof 41 provided by a roof panel, and includes a plurality of pillars 42 for supporting the roof panel. The vehicle Hv includes an a pillar 42A, B and a C pillar 42C as the pillars 42. The a-pillar 42A corresponds to a pillar 42 provided in front of the front seat. The B pillar 42B corresponds to the pillar 42 provided between the front seat and the rear seat. The C-pillar 42C corresponds to the pillar 42 provided diagonally rearward of the rear seat. A part or the whole of each strut 42 is realized by using a metal member such as a high tensile steel plate. In another embodiment, the support column 42 may be made of carbon fiber or resin. And, it can be realized by combining various materials.

The vehicle Hv is configured such that, when all the doors are closed, the system enters the vehicle interior from the outside of the vehicle interior only through the window 43 using radio waves, or leaks from the inside of the vehicle interior to the outside of the vehicle interior. That is, the window 43 is configured to function as a channel through which radio waves are used by the system. Here, the window portion 43 is a front window, a window (so-called side window) provided in a side portion of the vehicle Hv, a rear window, or the like.

As another mode, a window glass provided in a door or the like of the vehicle Hv may be configured to block the direct propagation of the radio wave used in the system. The window glass here is a transparent member disposed in the window portion 43 provided in the vehicle Hv, and may not be glass in a strict sense. For example, acrylic resin or the like may be used. That is, the window glass here is a transparent member that functions as a windshield.

(construction of the vehicle-mounted System 1)

Next, the configuration and operation of the in-vehicle system 1 will be described. As shown in fig. 3, the in-vehicle system 1 includes a smart ECU11, a plurality of in-vehicle communication devices 12, a door button 13, a start button 14, an engine ECU15, and a vehicle body ECU 16. Further, the ECU in the names of the components is an abbreviation of Electronic Control Unit, indicating an Electronic Control device.

The smart ECU11 is an Electronic Control Unit (ECU) that performs vehicle Control such as locking and unlocking of doors, and starting of an engine by performing wireless communication with the portable terminal 2. The smart ECU11 is implemented using a computer. That is, the smart ECU11 includes a CPU111, a flash memory 112, a RAM113, an I/O114, a bus connecting these components, and the like. The CPU111 is an arithmetic processing device that executes various arithmetic processes. The flash memory 112 is a rewritable nonvolatile storage medium. The RAM113 is a volatile storage medium. The I/O114 is a circuit module that functions as an interface for allowing the smart ECU11 to communicate with another device mounted on the vehicle Hv, such as the on-vehicle communication device 12. The I/O114 may be implemented using analog circuit elements, ICs, etc.

The flash memory 112 has a terminal ID assigned to the mobile terminal 2 owned by the user registered therein. The flash memory 112 stores a program (hereinafter, a position determination program) for causing the computer to function as the smart ECU11, and the like. In addition, the above-described location determination program may be stored in a non-transitory storage medium. The CPU111 executes the position determination program corresponding to a method of executing the position determination program.

In addition, the in-vehicle equivalent value Pin, the operation threshold value Prx, and the intensity difference threshold value Pg are stored in the flash memory 112 as threshold values (hereinafter, determination threshold values) for the smart ECU11 to determine the position of the mobile terminal 2 based on the reception intensity of the signal from the mobile terminal 2. The vehicle interior equivalent value Pin is a threshold value for determining that the mobile terminal 2 is present in the vehicle interior. The operation threshold Prx is a threshold for determining that the mobile terminal 2 is present in the outdoor operation area Rx outside the vehicle. The in-vehicle equivalent value Pin corresponds to the in-vehicle determination value. The technical significance, setting method, and smart ECU11 of the vehicle interior equivalent value Pin and the operating threshold value Prx will be described later in detail.

The in-vehicle communication device 12 is a communication module mounted on the vehicle Hv for performing short-range communication. Each of the on-vehicle communication devices 12 is configured to be able to transmit and receive 2400MHz to 2500MHz radio waves (i.e., radio waves in the 2.4GHz-ISM band). Each of the in-vehicle communicators 12 is communicably connected to the smart ECU11 with each other via a dedicated communication line or an in-vehicle network. A unique communication device number is set in each in-vehicle communication device 12. The communication device number is information corresponding to the terminal ID of the mobile terminal 2. The communicator number functions as information for identifying the plurality of in-vehicle communicators 12.

As shown in fig. 4, the in-vehicle system 1 of the present embodiment includes at least one in-vehicle communication device 12 α and a plurality of out-vehicle communication devices 12 β as the in-vehicle communication devices 12. The in-vehicle communication device 12 α is an in-vehicle communication device 12 installed in the vehicle interior, and the out-vehicle communication device 12 β is an in-vehicle communication device 12 disposed on the outer surface portion of the vehicle Hv. The outer surface portion here is a vehicle body portion that contacts the vehicle exterior space in the vehicle Hv, and includes a side surface portion, a rear surface portion, and a front surface portion of the vehicle Hv. The in-vehicle system 1 of the present embodiment includes an outdoor left-side communicator 12L, an outdoor right-side communicator 12M, and an outdoor rear-side communicator 12N as an outdoor-side communicator 12 β.

Each in-vehicle communication device 12 plays a role of providing the smart ECU11 with the reception intensity of the signal transmitted from the portable terminal 2. The in-vehicle communication device 12 α also functions as a data communication device that plays a role of transmitting and receiving data to and from the portable terminal 2 by the smart ECU 11. Fig. 4 is a schematic plan view of the vehicle Hv, which is shown through the roof portion 41 to explain the installation positions of the various in-vehicle communication devices 12.

Fig. 5 schematically shows the electrical configuration of the in-vehicle communicator 12. As shown in fig. 5, the in-vehicle communication device 12 includes an antenna 121, a transmission/reception circuit 122, and a communication microcomputer 123.

The antenna 121 is an antenna for transmitting and receiving radio waves in a frequency band used for wireless communication with the mobile terminal 2 (hereinafter, a system use frequency band). The system here uses a 2.4GHz band from 2400MHz to 2500 MHz. The system usage frequency band corresponds to the operating frequency band of the antenna 121. The frequency band used in the system according to the present embodiment may include 2400MHz to 2480MHz used in compliance with the Bluetooth standard. The upper limit frequency and the lower limit frequency of the system use frequency band can be appropriately changed according to the communication standard with the mobile terminal 2.

The antenna 121 is electrically connected to the transceiver circuit 122. The specific structure of the antenna 121 will be described later. The transceiver circuit 122 demodulates the signal received by the antenna 121 and supplies the demodulated signal to the communication microcomputer 123. The transceiver circuit 122 modulates a signal input from the smart ECU11 via the communication microcomputer 123, outputs the signal to the antenna 121, and radiates the signal as a radio wave. The transceiver circuit 122 and the communication microcomputer 123 are communicably connected to each other.

The transmission/reception circuit 122 includes a reception intensity detector 124 that sequentially detects the intensity of the signal received by the antenna 121. The reception intensity detecting section 124 can be implemented by various circuit configurations. The reception intensity detected by the reception intensity detecting unit 124 is sequentially supplied to the communication microcomputer 123 in association with the terminal ID included in the reception data and the channel number used for reception of the data. The channel number indicates a frequency used for communication with the mobile terminal 2. The reception intensity may be expressed by a unit of power [ dBm ], for example. Data associating the reception intensity, the terminal ID, and the channel number is referred to as reception intensity data. The reception intensity detector 124 corresponds to an intensity detector.

The communication microcomputer 123 is a microcomputer that controls the operation of the transmission/reception circuit 122. From another point of view, the communication microcomputer 123 corresponds to a microcomputer that controls data transmission and reception with the smart ECU 11. The communication microcomputer 123 associates the reception data input from the transceiver circuit 122 with the reception intensity and supplies the same to the smart ECU 11. The communication microcomputer 123 has the following functions: the terminal ID of the portable terminal 2 is authenticated, and cryptographic communication is performed with the portable terminal 2 based on a request from the smart ECU 11. As the encryption method, various methods such as a method specified by Bluetooth can be cited. As the ID authentication method, various methods such as a method specified by Bluetooth can be cited.

The door button 13 is a button for unlocking and locking the door of the vehicle Hv by the user. The door button 13 is provided at or near an outside door handle of the vehicle Hv. When the door button 13 is pressed by the user, an electric signal indicating the pressing is output to the smart ECU 11. The door button 13 corresponds to a structure for the smart ECU11 to receive an unlock instruction and a lock instruction from a user. Further, as a configuration for receiving at least one of an unlocking instruction and a locking instruction by a user, a touch sensor may be employed.

The start button 14 is a push switch for a user to start a drive source (e.g., an engine). When the user performs a pressing operation, the start button 14 outputs an electric signal indicating the pressing operation to the smart ECU 11. Here, the vehicle Hv is a vehicle provided with an engine as a power source, as an example, but is not limited thereto. The vehicle Hv may be an electric vehicle or a hybrid vehicle. When the vehicle Hv is a vehicle including a motor as a drive source, the start button 14 is a switch for starting the motor for driving.

Engine ECU15 is an ECU that controls the operation of an engine mounted on vehicle Hv. For example, when the engine ECU15 acquires a start instruction signal instructing the start of the engine from the smart ECU11, the engine is started.

The vehicle body ECU16 is an ECU that controls the in-vehicle actuators 17 based on a request from the smart ECU 11. The vehicle body ECU16 is communicably connected to various vehicle-mounted actuators 17 and various vehicle-mounted sensors 18. The in-vehicle actuator 17 is, for example, a door lock motor constituting a lock mechanism of each door, an actuator for adjusting a seat position (hereinafter, a seat actuator), or the like. The in-vehicle sensor 18 here is a door courtesy switch or the like disposed in each door. The door courtesy switch is a sensor that detects opening and closing of a door. The vehicle body ECU16 locks or unlocks each door by outputting a predetermined control signal to a door lock motor provided in each door of the vehicle Hv, for example, in response to a request from the smart ECU 11.

(function and Structure of the vehicle interior communication machine 12. alpha.)

The in-vehicle communication device 12 α is disposed at a predetermined position in the vehicle interior so that the vehicle interior becomes a strong electric field region. The strong electric field region here is a region in which a signal transmitted from the in-vehicle communication device 12 propagates with an intensity equal to or higher than a predetermined threshold (hereinafter, a strong electric field threshold). The strong electric field threshold is set to a level sufficiently strong as a signal for near field communication. For example, the strong electric field threshold is-35 dBm (-0.316 μ W). From another viewpoint, the strong electric field region is also a region in which the reception intensity of the signal transmitted from the mobile terminal 2 in the in-vehicle communication device 12 is equal to or higher than a predetermined threshold because the propagation path of the radio signal is reversible.

The in-vehicle communication device 12 α can be installed at any position in the vehicle interior. However, it is sometimes preferable that the in-vehicle communication device 12 α functioning also as a data communication device be disposed at a position where the vicinity of the door inside and outside the vehicle room can be seen. The position in the vehicle interior and in the vicinity of the door outside the vehicle interior can be seen, for example, the roof in the vehicle interior. Here, the in-vehicle communication device 12 α is disposed in the center of the upper end of the windshield (i.e., in the vicinity of the rear view mirror), as an example. The installation position of the in-vehicle communication device 12 α may be the center portion in the vehicle width direction of the instrument panel 49, the overhead console, the center portion of the roof portion, or the like. Even when the portable terminal 2 is present outside the field of view of the in-vehicle communication device 12 α, the portable terminal 2 and the in-vehicle communication device 12 α can perform wireless communication due to reflection of a structure or the like. Therefore, the in-vehicle communication device 12 α may be installed outside the vehicle interior, such as the center console 48, the feet of the driver's seat, and the floor, to be out of sight.

The area within the field of view of a certain on-vehicle communication device 12 is an area that can be directly reached by a signal transmitted from the on-vehicle communication device 12. Since the propagation path of the radio signal is reversible, the area within the field of view of a certain in-vehicle communication device 12, in other words, the area in which the in-vehicle communication device 12 can directly receive the signal transmitted from the portable terminal 2, corresponds to. The outside of the field of view of a certain in-vehicle communication device 12 refers to an area where a signal transmitted from the in-vehicle communication device 12 does not directly reach. Since the propagation path of the radio signal is reversible, the field of view of a certain in-vehicle communication device 12 corresponds to an area in which the in-vehicle communication device 12 cannot directly receive the signal transmitted from the mobile terminal 2. Further, the signal transmitted from the portable terminal 2 can be reflected by various structures and can reach the outside of the field of view.

The terminal information is stored in a nonvolatile memory provided in the in-vehicle communication device 12 α as a data communication device. The terminal information is, for example, an authentication key, a terminal ID, and the like. The terminal information may be registered by the user performing an operation of performing a key exchange protocol (so-called pairing). In addition, when the vehicle Hv is a service vehicle, the terminal information may be distributed from an external server that manages the use (for example, a reservation situation, a running situation) of the service vehicle by the user. When the vehicle Hv is used by a plurality of users, the terminal information of the portable terminal 2 held by each user is stored.

When the in-vehicle communication device 12 α as a data communication device receives the advertisement packet from the portable terminal 2, it automatically establishes a communication connection with the portable terminal 2 using the stored terminal information. The smart ECU11 transmits and receives data to and from the mobile terminal 2. When the in-vehicle communication device 12 α establishes a communication connection with the mobile terminal 2, the terminal ID of the mobile terminal 2 to which the communication connection is made is supplied to the smart ECU 11.

According to the Bluetooth standard, encrypted data communication is implemented by a frequency hopping method. The frequency hopping scheme is a communication scheme in which channels used for communication are sequentially switched in time. Specifically, in the Bluetooth standard, data communication is performed by a Frequency Hopping and Spectrum spreading method (FHSS). In Bluetooth Low Energy (hereinafter, Bluetooth LE), 40 channels from No. 0 to No. 39 are prepared, and 37 channels from No. 0 to No. 36 are available for data communication. Further, 3 channels from 37 to 39 are channels for transmission and reception of advertisement packets (hereinafter, advertisement channels).

When the communication connection with the mobile terminal 2 is established, the in-vehicle communication device 12 α sequentially changes 37 channels and performs data transmission and reception with the mobile terminal 2. At this time, the in-vehicle communication device 12 α sequentially provides the smart ECU11 with information indicating a channel used for communication with the mobile terminal 2 (hereinafter, channel information). The channel information may be a specific channel number or a parameter (so-called hopincment) indicating a transition rule for using a channel. HopIncrement is a number from 5 to 16 that is randomly decided upon communication connection. The channel information sometimes preferably includes the current channel number and hopsegment.

There may be a plurality of the in-vehicle communicators 12 α. The number of the in-vehicle communicators 12 α may be two, three, or four or more. For example, the in-vehicle communication device 12 α may include two in-vehicle communication devices 12 α, i.e., the in-vehicle communication device 12 disposed near the foot of the driver's seat and the in-vehicle communication device 12 disposed at the floor of the trunk area. The in-vehicle communication devices 12 α may be disposed one on each of the indoor surfaces of the left and right B-pillars 42B. The in-vehicle communication device 12 α may be disposed on an indoor side surface of a door for a rear seat and a floor surface of a rear seat. The in-vehicle communication device 12 α, which does not also function as a data communication device, may be preferably installed outside the vehicle to be out of view. One or more in-vehicle communication devices 12 α may be disposed at predetermined positions so that most (more preferably, the entire) of the interior of the vehicle becomes a strong electric field region.

As the antenna 121 constituting the in-vehicle communication device 12 α, various antenna structures such as a patch antenna, a dipole antenna, a monopole antenna, a linear/plate-shaped inverted F antenna, an inverted L antenna, and a zero-order resonant antenna can be used. The antenna 121 of the in-vehicle communication device 12 α may be a chassis extension type zero-order resonance antenna, a half-wavelength type zero-order resonance antenna, or the like, which will be described later. The installation position, installation posture (installation position), and the number of the in-vehicle communication devices 12 α can be appropriately designed in consideration of the directivity of the built-in antenna 121 and the shape in the vehicle interior.

(Structure of vehicle outdoor communication machine 12 beta)

Next, the structure of the vehicle-exterior communication device 12 β will be explained. The outdoor left-side communicator 12L, the outdoor right-side communicator 12M, and the outdoor rear-side communicator 12N, which are the vehicle outdoor-side communicators 12 β, have the same antenna structure. Hereinafter, the wavelength (hereinafter, also referred to as a target wavelength) of the center frequency (here, 2.45GHz) of the system use band is represented by "λ". For example, "λ/2" and "0.5 λ" refer to the length of half of the subject wavelength, "λ/4" and "0.25 λ" refer to the length of a quarter of the subject wavelength. The wavelength (i.e., λ) of a radio wave of 2.45GHz in vacuum and air is 122 mm.

As shown in fig. 6, the vehicle outdoor communication device 12 β includes a circuit board 5 and a housing 6. The circuit board 5 includes a bottom plate 51, a support plate 52, a counter conductor plate 53, a short-circuit portion 54, and a circuit portion 55. The structure in which the bottom plate 51, the opposing conductor plate 53, and the short-circuit portion 54 are combined corresponds to the antenna 121 (hereinafter, also referred to as an external antenna 121 β) of the external communication device 12 β. Fig. 7 is an external perspective view of the circuit board 5. Fig. 8 is a sectional view taken along line VIII-VIII shown in fig. 7. In fig. 7 and 8, illustration of the housing 6 is omitted. Hereinafter, the side where the opposite conductive plate 53 is provided with respect to the bottom plate 51 will be described as the upper side of the vehicle exterior communication device 12 β. That is, the direction from the bottom plate 51 toward the opposite conductor plate 53 corresponds to the upward direction of the vehicle exterior communication device 12 β. The direction from the opposite conductor plate 53 toward the bottom plate 51 corresponds to the downward direction of the vehicle exterior communication device 12 β.

The bottom plate 51 is a plate-shaped conductor member made of a conductor such as copper. The bottom plate 51 is provided along the lower side of the support plate 52. The plate shape here also includes a film shape such as a metal foil. That is, the bottom plate 51 may be formed on the surface of a resin plate such as a printed wiring board by patterning such as plating. The base plate 51 is electrically connected to an outer conductor of the coaxial cable or a ground layer provided in the support plate 52, and supplies a ground potential (in other words, a ground potential) in the vehicle exterior communication device 12 β.

The bottom plate 51 is formed in a rectangular shape. The length of the short side of the bottom plate 51 is set to a value electrically equivalent to 0.4 λ, for example. The length of the long side of the bottom plate 51 is set to be electrically 1.2 λ. The electrical length here is an effective length in consideration of a fringe electric field, a wavelength shortening effect due to a dielectric, and the like. In the case where the support plate 52 is formed using a dielectric having a relative permittivity of 4.3, the wavelength on the surface of the base plate 51 becomes about 60mm due to the wavelength shortening effect of the dielectric serving as the support plate 52. Therefore, the length electrically equivalent to 1.2 λ is 72 mm.

The X axis shown in fig. 6 and the like indicates the longitudinal direction of the base plate 51, the Y axis indicates the short side direction of the base plate 51, and the Z axis indicates the vertical direction. A three-dimensional coordinate system (hereinafter, antenna coordinate system) including these X, Y, and Z axes is a concept for explaining the configuration of the vehicle-exterior communication device 12 β. In the case where the bottom plate 51 is square as another embodiment, a direction along any one side can be defined as the X axis. When the bottom plate 51 is circular, any direction parallel to the bottom plate 51 can be set as the X axis. The Y axis may be parallel to the base plate 51 and orthogonal to the X axis. When the bottom plate 51 has a shape having a long side direction and a short side direction, such as a rectangle or an oblong, the long side direction can be set to the X-axis direction. The Z axis is set such that the upward direction of the antenna 121 becomes the positive direction.

The bottom plate 51 may preferably have a line-symmetrical shape (hereinafter, a bidirectional line-symmetrical shape) with each of two mutually orthogonal straight lines as a symmetry axis. The bidirectional line-symmetric shape is a figure that is symmetric about a straight line as a symmetry axis and is also line-symmetric about another straight line orthogonal to the straight line. The two-way line symmetric shape corresponds to, for example, an ellipse, a rectangle, a circle, a square, a regular hexagon, a regular octagon, a rhombus, or the like. It is sometimes preferable that the bottom plate 51 is formed larger than a circle having a diameter of 1 wavelength. The planar shape of a certain member means a shape of the member as viewed from above.

The support plate 52 is a rectangular flat plate member. The support plate 52 serves to dispose the base plate 51 and the opposing conductive plate 53 to face each other with a predetermined gap therebetween. The support plate 52 is formed to have substantially the same size as the bottom plate 51 in a plan view. The support plate 52 is implemented using a dielectric having a prescribed relative permittivity. As the support plate 52, for example, a printed circuit board using a glass epoxy resin or the like as a base material can be used. Here, as an example, the support plate 52 is realized using a glass epoxy-based resin having a relative dielectric constant of 4.3 (in other words, FR 4: Flame Retardant Type 4).

In the present embodiment, the support plate 52 is formed to have a thickness of, for example, 1.5mm, as an example. The thickness of the support plate 52 corresponds to the distance between the base plate 51 and the opposite conductor plate 53. By adjusting the thickness of the support plate 52, the distance between the opposing conductor plate 53 and the bottom plate 51 can be adjusted. The specific value of the thickness of the support plate 52 can be determined appropriately by simulation and experiment. The thickness of the support plate 52 may be 2.0mm, 3.0mm, or the like. Further, the wavelength on the support plate 52 is about 60mm due to the wavelength shortening effect of the dielectric. Thus, a value of 1.5mm in thickness corresponds to a forty-first (i.e., λ/40) wavelength of the electrical target. In the present embodiment, the space between the bottom plate 51 and the opposite conductor plate 53 is filled with the resin serving as the support plate 52, but the present invention is not limited to this. The space between the bottom plate 51 and the opposing conductive plate 53 may be hollow or vacuum. Further, the above-described structures may be combined.

The opposite conductive plate 53 is a plate-shaped conductive member made of a conductor such as copper. The plate shape here also includes a film shape such as a copper foil as described above. The opposing conductor plate 53 is disposed to face the base plate 51 via the support plate 52. The opposite conductor plate 53 may be patterned on the surface of a resin plate such as a printed wiring board, as in the case of the bottom plate 51. The parallelism as referred to herein is not limited to being perfectly parallel. And can be inclined by a few degrees to about ten degrees. That is, a substantially parallel state (so-called substantially parallel state) may be included.

By disposing the opposite conductive plate 53 and the bottom plate 51 to face each other, a capacitance corresponding to the area of the opposite conductive plate 53 and the distance between the opposite conductive plate 53 and the bottom plate 51 is formed. The opposing conductive plate 53 is formed to have a size such that it forms a capacitance that resonates in parallel with the inductance of the short-circuit portion 54 at a predetermined first frequency. The first frequency is an arbitrary frequency belonging to a frequency band used by the system. For example, the first frequency is 2420 MHz. Alternatively, the first frequency may be set to an advertisement channel of 2402MHz, 2426MHz, 2480MHz, or the like. Hereinafter, even when it is necessary to distinguish the wavelength of the radio wave of the first frequency from the target wavelength, the wavelength of the radio wave of the first frequency is hereinafter referred to as "λ₁". However, lambda in air₁The difference from λ is about 1.5mm, and in the present embodiment, the difference is negligible.

The area of the opposite conductor plate 53 may be appropriately designed to provide a desired capacitance (and thus operate at the first frequency). For example, the opposing conductive plate 53 is formed in a square shape having one side of 12mm electrically. The wavelength on the surface of the opposite conductive plate 53 is about 60mm due to the wavelength shortening effect of the support plate 52, and therefore a value of 12mm corresponds to electrically 0.2 λ. Of course, the length of one side of the opposite conductive plate 53 may be changed as appropriate, and may be 14mm, 15mm, 20mm, 25mm, or the like.

Here, the opposing conductive plate 53 is formed in a square shape as an example, but the planar shape of the opposing conductive plate 53 may be a circle, a regular octagon, a regular hexagon, or the like as another configuration. The opposite conductor plate 53 may be rectangular, oblong, or the like. It is sometimes preferable that the counter conductor plate 53 has a bidirectional line-symmetric shape. It is sometimes more preferable that the opposing conductive plate 53 has a point-symmetric pattern such as a circle, a square, a rectangle, or a parallelogram.

The opposing conductive plate 53 may be provided with a slit or chamfered at a corner portion. The edge portion of the opposite conductor plate 53 may be formed in a zigzag shape partially or entirely. The two-way line-symmetric shape also includes a shape in which a minute (about several mm) unevenness is provided at the edge portion. The irregularities provided at the edge portion of the opposite conductive plate 53 to such an extent that they do not affect the operation can be ignored. The technical idea regarding the planar shape of the opposing conductor plate 53 is the same for the base plate 51 described above.

The opposite conductor plate 53 is connected to the circuit portion 55 using a microstrip line 551. The connection portion between the opposite conductor plate 53 and the microstrip line 551 corresponds to the feeding point 531 of the antenna 121. The microstrip line 551 corresponds to a power supply line. As a power feeding method for feeding power to the opposite conductor plate 53, various methods such as a direct coupling power feeding method and an electromagnetic coupling method can be used. The electromagnetic coupling method is a power feeding method using electromagnetic coupling with the opposite conductor plate 53 by a microstrip line for power feeding or the like. The feeding point 531 may be provided at a position where the input/output impedance of the antenna 121 is matched as viewed from the circuit unit 55. In other words, the feeding point 531 may be provided at a position where the return loss becomes a predetermined allowable level. The feeding point 531 can be disposed at an arbitrary position such as an edge portion or a central region of the opposite conductor plate 53.

As shown in fig. 9, the opposing conductive plate 53 is disposed to face the bottom plate 51 in a posture in which one pair of opposing sides is parallel to the X axis and the other pair of opposing sides is parallel to the Y axis. However, the center thereof is arranged offset from the center of the bottom plate 51 by a predetermined amount in the X-axis direction. Specifically, the opposing conductor plate 53 is disposed such that the center thereof is located at a position electrically shifted by one twenty-fifth of the target wavelength (i.e., 0.04 λ) from the center of the bottom plate 51 in the X-axis direction. From another viewpoint, this structure corresponds to a structure in which the bottom plate 51 is disposed asymmetrically with respect to the opposite conductor plate 53.

The distance between the center of the bottom plate 51 (hereinafter, bottom plate center) and the center of the opposing conductor plate 53 in the X-axis direction (hereinafter, bottom plate offset Δ Sa) is not limited to 0.04 λ. The floor offset Δ Sa may also be 0.05 λ, 0.08 λ, 0.25 λ, etc. The floor offset Δ Sa may also be set to 0.125 λ (═ λ/8). The floor offset amount Δ Sa can be appropriately changed within a range in which the opposing conductor plate 53 does not protrude outside the floor 51 in a plan view. The opposing conductor plate 53 is disposed so as to face the base plate 51 over at least the entire region (in other words, the entire surface). The floor offset amount Δ Sa corresponds to the amount of deviation between the center of the floor 51 and the center of the opposite conductor plate 53. The floor offset Δ Sa is designed such that the floor 51 functions as a radiation element at a second frequency, which will be described later.

In fig. 9, the support plate 52 is made transparent (that is, not shown) in order to clearly show the positional relationship between the bottom plate 51 and the opposite conductor plate 53. A chain line Lx1 shown in fig. 9 represents a straight line passing through the center of the bottom plate 51 and parallel to the X axis, and a chain line Ly1 represents a straight line passing through the center of the bottom plate 51 and parallel to the Y axis. The two-dot chain line Ly2 indicates a straight line passing through the center of the opposite conductor plate 53 and parallel to the Y axis. From another point of view, the straight line Lx1 corresponds to the symmetry axis of the bottom plate 51 and the opposite conductor plate 53. The line Ly1 corresponds to the axis of symmetry of the bottom plate 51. The straight line Ly2 corresponds to the axis of symmetry of the opposing conductor plate 53.

Since the opposite conductor plate 53 is disposed offset by a predetermined amount in the X-axis direction from a position concentric with the bottom plate 51, the dashed-dotted line Lx1 also passes through the center of the opposite conductor plate 53. That is, the chain line Lx1 corresponds to a straight line parallel to the X axis and passing through the centers of the bottom plate 51 and the opposite conductor plate 53. The intersection of the straight line Lx1 and the straight line Ly1 corresponds to the bottom plate center, and the intersection of the straight line Lx1 and the straight line Ly2 corresponds to the center of the opposing conductive plate 53 (hereinafter, conductive plate center). The center of the conductive plate corresponds to the center of gravity of the opposing conductive plate 53. In the present embodiment, since the opposing conductive plate 53 is square, the center of the conductive plate corresponds to the intersection of two diagonal lines of the opposing conductive plate 53. The concentric arrangement of the bottom plate 51 and the opposing conductive plate 53 corresponds to an arrangement in which the center of the opposing conductive plate 53 and the center of the bottom plate 51 overlap each other in a plan view.

The short-circuit portion 54 is a conductive member electrically connecting the bottom plate 51 and the opposite conductive plate 53. The short-circuit portion 54 may be a linear member having one end electrically connected to the bottom plate 51 and the other end electrically connected to the opposite conductive plate 53. The short-circuit portion 54 is realized, for example, by using a through hole provided in a printed circuit board serving as the support plate 52. The short-circuit portion 54 may be realized by using a conductive pin. The inductance of the short-circuit portion 54 can be adjusted by adjusting the length and diameter of the short-circuit portion 54.

The short-circuit portion 54 is provided, for example, at the center of the conductor plate. The position of the short-circuit portion 54 does not need to be exactly aligned with the center of the conductive plate. The short-circuit portion 54 may be offset by about several mm from the center of the conductive plate. The short-circuit portion 54 may be formed in the central region of the opposite conductive plate 53. The central region of the opposite conductive plate 53 is a region located inward of a line connecting points separated by 1: 5 from the center to the edge of the conductive plate. From another point of view, the central region corresponds to a region where the opposing conductive plate 53 is similarly narrowed to overlap in a concentric pattern of about one sixth.

The circuit unit 55 is a circuit module including the transmission/reception circuit 122, the communication microcomputer 123, the power supply circuit, and the like. The circuit portion 55 is an electrical assembly of various components such as an IC, an analog circuit element, and a connector. The circuit portion 55 is formed on the surface of the support plate 52 on the side where the opposite conductive plate 53 is arranged (hereinafter, the substrate upper surface 52 a). For example, the circuit portion 55 is formed on the substrate upper surface 52a using a region located above the asymmetric portion 511. The microstrip line 551 is a linear conductor for supplying power to the opposite conductor plate 53. One end of the microstrip line 551 is connected to the opposite conductor plate 53, and the other end is connected to the circuit portion 55. The microstrip line 551 may be formed inside the support plate 52.

The housing 6 is configured to house the circuit board 5. The housing 6 is configured by combining an upper housing and a lower housing configured to be separable in the vertical direction, for example. The case 6 is formed using, for example, Polycarbonate (PC) resin. As a material of the housing 6, various resins such as a synthetic resin obtained by mixing a PC resin with an acrylonitrile butadiene styrene copolymer (so-called ABS) and polypropylene (PP) can be used.

The housing 6 includes a housing bottom portion 61, a housing side wall portion 62, and a housing top portion 63. The housing bottom 61 is a structure that provides the bottom of the housing 6. The case bottom portion 61 is formed in a flat plate shape. In the housing 6, the circuit board 5 is disposed such that the bottom plate 51 faces the housing bottom portion 61 via a rib (hereinafter, lower rib) 611 formed on the housing bottom portion 61. The lower rib 611 is a convex structure integrally formed from a predetermined position of the housing bottom portion 61 toward the upper side. The lower rib 611 plays a role of regulating the position of the circuit substrate 5 in the housing 6. The lower rib 611 is provided to abut against an edge portion of the bottom plate 51. The lower rib 611 is formed such that the distance between the bottom plate 51 and the housing bottom 61 is λ/25 or less (i.e., 5mm or less). The lower rib 611 may be formed to protrude from the inner surface of the side wall 62 toward the inside of the case. The lower rib 611 may be configured to support the circuit substrate 5 from below, or may be formed integrally with the side wall 62.

The case side wall portion 62 is a structure that provides a side surface of the case 6, and is provided upright from an edge portion of the case bottom portion 61 toward the upper side. The height of the case side wall portion 62 is designed so that the distance between the inner surface of the case top portion 63 and the opposing conductor plate 53 is λ/25 or less. The housing top 63 is a structure that provides an upper surface portion of the housing 6. The case top 63 of the present embodiment is formed in a flat plate shape. As the shape of the housing top 63, various shapes such as a dome shape can be adopted. The housing top 63 has an inner surface facing the substrate upper surface 52a (and thus the facing conductive plate 53). An upper rib 631 is formed on the inner surface of the housing top 63.

The upper rib 631 is formed in a convex shape downward from a predetermined position on the inner surface of the case top 63. The upper rib 631 is provided to abut against an edge portion of the opposite conductor plate 53. The upper rib 631 is integrally formed with the housing 6. The upper rib 631 restricts the position of the support plate 52 in the housing 6. A metal pattern such as a copper foil may be applied to the upper rib 631 on a vertical surface (i.e., an outer surface) connected to the edge of the opposite conductive plate 53. The upper rib 631 is an arbitrary element and may not be provided.

The inside of the case 6 is filled with, for example, a sealing material 7. The sealing material 7 corresponds to a sealing material. As the sealing material 7, various materials such as urethane resin (more specifically, urethane prepolymer), epoxy resin, and silicone resin can be used. The structure in which the case 6 is filled with the sealing material 7 can also improve water resistance, dust resistance, and vibration resistance. Further, according to the configuration in which the case 6 is filled with the sealing material 7, the sealing material 7 located above the opposite conductive plate 53 suppresses the propagation of the vertically polarized wave of the backplane from the end of the opposite conductive plate 53 to the upper side of the opposite conductive plate 53, and thus the radiation gain in the parallel direction of the backplane is improved. The bottom plate parallel direction here means a direction from the center of the opposite conductor plate 53 toward the edge portion thereof. From another viewpoint, the base plate parallel direction is a direction perpendicular to a perpendicular line to the base plate 51 passing through the center of the opposite conductor plate 53. The floor parallel direction corresponds to the lateral direction (in other words, the side direction) of the vehicle exterior communication device 12 β. The sealing material 7 is an arbitrary element, and is not an essential element. In fig. 6, hatching of the sealing material 7 is omitted for the sake of ensuring visibility of the drawing.

The upper rib 631 and the sealing member 7 are configured to play a role of suppressing a vertical electric field radiated in a zero-order resonance mode (described later) from being detoured from the edge portion of the opposite conductive plate 53 to the upper side (hereinafter, referred to as a wave blocker). The configuration disclosed in the present embodiment corresponds to a configuration in which a radio wave blocker configured using a conductor or a dielectric is disposed above the opposite conductor plate 53. Further, it is preferable that the case 6 including the upper rib 631 and the sealing member 7 have a high relative dielectric constant and a low dielectric loss tangent. For example, it is preferable that the relative permittivity is 2.0 or more and the dielectric loss tangent is 0.03 or less in some cases. When the dielectric loss tangent is high, the amount of radiation energy lost as heat loss increases. Therefore, it may be preferable to realize the housing 6 and the sealing member 7 by using materials having smaller dielectric loss tangents. The case 6 and the sealing material 7 function to suppress the entry of an electric field as the dielectric constant is higher. In other words, the higher the dielectric constants of the case 6 and the sealing material 7 are, the more the effect of increasing the gain in the direction parallel to the chassis becomes stronger. Therefore, it is sometimes preferable to use a dielectric having a high dielectric constant as the material of the case 6 and the sealing material 7.

(working of the vehicle outdoor communication machine 12 beta)

The operation of the vehicle outdoor communication device 12 β configured as described above will be described. In the vehicle outdoor communication device 12 β, the opposing conductive plate 53 is short-circuited to the bottom plate 51 by the short-circuit portion 54 provided in the central region thereof, and the area of the opposing conductive plate 53 is an area where a capacitance that resonates in parallel with the inductance of the short-circuit portion 54 at the first frequency is formed.

At the first frequency and its vicinity, parallel resonance (so-called LC parallel resonance) occurs by energy exchange between the inductance and the capacitance, and an electric field perpendicular to the bottom plate 51 and the opposite conductive plate 53 is generated between the bottom plate 51 and the opposite conductive plate 53. The vertical electric field propagates from the short-circuit portion 54 toward the edge portion of the opposite conductive plate 53, and propagates spatially as a backplane vertically polarized wave at the edge portion of the opposite conductive plate 53. Here, the bottom plate vertically polarized wave refers to a radio wave in which the vibration direction of the electric field is perpendicular to the bottom plate 51 and the opposing conductive plate 53. When the vehicle exterior communication device 12 β is used in a posture parallel to the horizontal plane, the backplane vertically polarized wave is a polarized wave perpendicular to the ground (i.e., a normal vertically polarized wave).

As shown in fig. 10, the propagation direction of the vertical electric field is symmetrical about the short-circuit portion 54. Therefore, as shown in fig. 11, there is no directivity (in other words, all the directivity) with respect to the radiation characteristic in the direction parallel to the bottom plate. Therefore, when the floor panel 51 is disposed horizontally, the vehicle exterior communication device 12 β functions as an antenna having a main beam in the horizontal direction. The base plate parallel surface here means a plane parallel to the base plate 51 and the opposing conductor plate 53.

Since the short-circuit portion 54 is disposed at the center of the conductive plate, the current flowing through the opposite conductive plate 53 is symmetrical about the short-circuit portion 54. Therefore, in the opposite conductive plate 53, the radio wave in the antenna height direction emitted by the current flowing in a certain direction from the center of the conductive plate is cancelled by the radio wave emitted by the current flowing in the opposite direction. That is, the current excited by the opposite conductor plate 53 does not contribute to radiation of the radio wave. Therefore, as shown in fig. 12, no radio wave is radiated in a direction perpendicular to the bottom plate 51 (hereinafter, the bottom plate perpendicular direction). The vertical direction of the bottom plate corresponds to the positive direction of the Z axis in the drawing. Hereinafter, a mode in which the resonance is caused by LC parallel resonance between the capacitance formed between the bottom plate 51 and the opposite conductor plate 53 and the inductance of the short-circuit portion 54 is referred to as a zero-order resonance mode. The vehicle exterior antenna 121 β as the zero-order resonance mode corresponds to a voltage system antenna. The antenna having the above-described configuration corresponds to an antenna configured to resonate in parallel at a predetermined first frequency using a capacitance formed by the opposing conductor plate 53 and the bottom plate 51 and an inductance provided by the short-circuit portion 54. In addition, the resonant frequency of the zeroth order resonant mode can also be adjusted using the matching element.

Since the bottom plate 51 is formed asymmetrically as viewed from the opposite conductor plate 53, the vehicle exterior antenna 121 β also radiates a radio wave from the bottom plate 51. Specifically, the following is described. In the vehicle outdoor communication device 12 β of the present embodiment, the opposing conductor plate 53 is disposed at a position electrically shifted by 0.04 λ in the X-axis direction from a position concentric with the bottom plate 51. In the mode of setting the floor offset Δ Sa to 0.04 λ, the region within 0.08 λ from the end in the X-axis direction becomes the asymmetric portion 511 of the opposite conductive plate 53. Here, the asymmetric portion 511 is a region of the bottom plate 51 that is asymmetric when viewed from the opposite conductive plate 53. The length of the asymmetric portion 511 in the X-axis direction (hereinafter, asymmetric portion width W) can be appropriately changed. The asymmetry portion width W may be set to 0.1 λ, 0.125 λ, 0.25 λ, 0.5 λ, or the like. The asymmetrical portion width W corresponds to 2 times the floor offset amount Δ Sa. Therefore, the configuration in which the asymmetric portion width W is 0.25 λ corresponds to the configuration in which the floor offset amount Δ Sa is set to 0.125 λ.

In fig. 13 and 14, in order to clearly show this region, the asymmetric portion 511 is hatched in a dot pattern. The largest region of the bottom plate 51 having symmetry when viewed from the opposite conductive plate 53 is also referred to as a symmetry maintaining section 512. The symmetry maintaining portion 512 is provided to include a part of the edge portion of the bottom plate 51. The length in the X-axis direction from the center region to the end of the symmetry maintaining portion 512 is L/2- Δ Sa. The center of the symmetry maintaining portion 512 coincides with the center of the opposite conductive plate 53 in a plan view.

Fig. 13 is a diagram schematically showing the current flowing in the bottom plate 51. As a result of the simulation, it was confirmed that the current flowing in the bottom plate 51 by the LC parallel resonance mainly flows along the edge portion of the bottom plate 51. In fig. 13, the size of the arrow indicates the amplitude of the current. In fig. 13, the support plate 52 is made transparent (i.e., illustration is omitted).

The current flowing from the opposite conductor plate 53 to the bottom plate 51 through the short-circuit portion 54 flows from the short-circuit portion 54 to both ends of the bottom plate 51 in the X axis direction. The short-circuit portion 54 serving as a current inlet/outlet of the bottom plate 51 is located at the center of the symmetry maintaining portion 512. Therefore, in the symmetry maintaining portion 512, the directions of currents flowing from the short-circuit portion 54 toward both ends in the X-axis direction are opposite and equal in magnitude. Therefore, as shown in fig. 14, an electromagnetic wave generated by a current flowing in a certain direction (for example, the positive X-axis direction) from the center of the symmetry maintaining unit 512 is cancelled (i.e., canceled) by an electromagnetic wave generated by a current flowing in the opposite direction (for example, the negative X-axis direction). Therefore, radio waves are not substantially radiated from the symmetry maintaining unit 512.

Radio waves emitted by the current flowing through the asymmetric portion 511 are not canceled but remain. In other words, the edge of the asymmetric portion 511 functions as a radiation element (actually, a wire antenna). The radio wave radiated from the bottom plate 51 becomes a linearly polarized wave (hereinafter, bottom plate parallel polarized wave) in which an electric field vibrates in a direction parallel to the bottom plate 51. Specifically, the radio wave radiated from the bottom plate 51 becomes a linearly polarized wave whose vibration direction of the electric field is parallel to the X axis (hereinafter, X-axis parallel polarized wave). The backplane parallel polarized wave radiates in a direction orthogonal to the X-axis. That is, the chassis-parallel polarized wave is also radiated in the upward direction of the vehicle exterior communication device 12 β (hereinafter, the chassis vertical direction).

Hereinafter, an operation mode using a linear current flowing in the edge portion of the asymmetric portion 511 of the bottom plate 51 is referred to as a bottom plate excitation mode. The bottom plate excitation mode corresponds to an operation mode of a linearly polarized wave in which an electric field is radiated in a direction perpendicular to the edge portion and vibrates in a direction (X-axis direction in this case) in which the asymmetry portion 511 and the symmetry maintaining portion 512 are connected. The vehicle exterior communication device 12 β as the floor excitation mode corresponds to a current system antenna that radiates an electric wave by an induced current. When the vehicle exterior communication device 12 β is used in a posture parallel to the horizontal plane, the backplane parallel polarized wave corresponds to a linearly polarized wave (i.e., a horizontally polarized wave) in which the electric field vibration direction is parallel to the ground.

By having the above-described structure, the vehicle exterior communication device 12 β of the present embodiment can simultaneously operate in two modes, i.e., a zero-order resonance mode in which a beam is formed in the floor-parallel direction and a floor excitation mode in which a beam is formed in the floor-perpendicular direction. The gain in the chassis excitation mode can be adjusted by the asymmetry width W. Accordingly, the ratio of the gain in the vertical direction of the chassis to the gain in the parallel direction of the chassis also varies according to the asymmetry portion width W. The asymmetry portion width W can be appropriately adjusted to obtain a desired gain ratio.

The ratio of the gain in the floor vertical direction to the gain in the floor parallel direction is affected not only by the asymmetry portion width W but also by the distance between the metal (e.g., the B-pillar 42B) present on the rear surface of the vehicle exterior communication device 12 β and the floor 51. In the present embodiment, the asymmetry portion width W is adjusted to a value at which the gain in the chassis excitation mode is superior to the gain in the zero-order resonance mode at the predetermined second frequency. The second frequency is a different frequency from the first frequency in the system use band. For example the second frequency is 2480 MHz. Alternatively, the second frequency may be set to 2402MHz, 2426MHz, 2450MHz, or the like.

It is sometimes preferable for the first frequency and the second frequency to diverge by more than 20MHz (more than 10 channels). Hereinafter, when it is necessary to distinguish the wavelength of the radio wave of the second frequency from the target wavelength, the wavelength of the radio wave of the second frequency is also referred to as "λ" below₂". However, lambda in air₂The difference from λ is about 1.5mm, and this difference is negligible in the present embodiment. Further, the relative bandwidth of the frequency band used by the system is less than 25% (specifically about 3.3%). The first frequency and the second frequency correspond to frequencies in the frequency region having a distance smaller than a quarter (actually, 3.3% or less) of the center frequency. The position determination system of the present disclosure corresponds to a position determination system applicable to a wireless communication system in which the relative bandwidth is set to be less than 25% of the center frequency, such as 5%, 10%, or the like.

Fig. 15 shows a result of simulation of radiation gain in each operation mode for each frequency in the case where the floor shift amount Δ Sa is set to an arbitrary value (for example, 0.08 λ). The first frequency corresponds to a frequency at which the gain in the zeroth-order resonance mode is superior to the gain in the chassis excitation mode. The second frequency corresponds to a frequency at which the gain in the chassis excitation mode becomes dominant over the gain in the zero-order resonance mode. That is, the first frequency corresponds to a frequency at which the antenna 121 operates mainly in the zeroth-order resonance mode, and the second frequency corresponds to a frequency at which the antenna 121 operates mainly in the bottom-plate excitation mode.

In the example shown in fig. 15, an example is shown in which the gain in the floor excitation mode at the second frequency is higher than the gain in the zeroth order resonance mode at the first frequency, but is not limited thereto. The respective operating principles of the zeroth order resonant mode and the backplane excitation mode are different, and therefore the respective resonant frequencies can be determined independently. For example, the frequency characteristics of the chassis excitation mode can be changed by adjusting the gap between the chassis 51 and the metal on the back surface and the asymmetric portion width W. The frequency characteristic of the zeroth-order resonance mode can also be appropriately changed by adjusting the area of the opposite conductive plate 53, the diameter of the short-circuit portion 54, and the like. For example, as shown in fig. 16, the gain in the zeroth-order resonance mode at the first frequency can be made equal to the gain in the floor excitation mode at the second frequency. The peak value of the gain in the bottom plate excitation mode and the peak value in the zero-order resonance mode in the frequency band used by the system can be made to coincide with each other. The vehicle exterior antenna 121 β may be configured to operate in the zero-order resonance mode on the low frequency side of the predetermined switching frequency and to operate in the floor excitation mode on the high frequency side of the switching frequency. Of course, it may have its opposite radiation characteristics.

The first frequency and the second frequency may be determined by inverting the frequency characteristics of each operation mode of the antenna 121. The second frequency may be a frequency at which the gain in the chassis excitation mode is more dominant than the gain in the zero-order resonance mode and at which the same gain as the gain in the zero-order resonance mode at the first frequency is obtained. In the present embodiment, the first frequency is set to a frequency at which the gain of the zeroth-order resonance mode is higher by 3dB or more (for example, about 5 dB) than the gain in the floor excitation mode, for example. The second frequency is set to a frequency at which the gain in the chassis excitation mode is more dominant than the gain in the zero-order resonance mode, and the same gain as the gain in the zero-order resonance mode at the first frequency is obtained. The zeroth order resonance mode corresponds to the first mode and the bottom plate excitation mode corresponds to the second mode. The first mode also includes a state in which the zeroth-order resonance mode and the bottom plate excitation mode coexist, but the antenna 121 is considered to be mainly (in other words, substantially) operated in the zeroth-order resonance mode in accordance with the relationship of the gain difference. For example, a state in which the gain of the zeroth-order resonance mode is higher by 3dB or more than the gain in the bottom-plate excitation mode corresponds to the first mode. The same point can be applied to the second mode.

The operation when the vehicle outdoor communication device 12 β transmits (radiates) a radio wave and the operation when it receives a radio wave have mutual reversibility. That is, according to the above-described vehicle exterior communication device 12 β, it is possible to receive the backplane-vertically polarized wave arriving from the backplane-parallel direction, and it is possible to receive the backplane-parallel polarized wave arriving from the backplane-vertical direction.

As described above, the vehicle exterior communication device 12 β operates in the zero-order resonance mode, and can transmit and receive the backplane vertically polarized wave in the entire backplane parallel direction. At the same time, the vehicle exterior communication device 12 β operates in the backplane excitation mode, and can transmit and receive backplane-parallel polarized waves in the backplane vertical direction. The vehicle-exterior communication device 12 β can transmit and receive radio waves having different polarization planes in the directions orthogonal to each other. Hereinafter, the antenna having the above-described structure is also referred to as a chassis extension type zero-order resonant antenna.

(mounting position, mounting posture and action of the vehicle-exterior communication device 12. beta.)

The outdoor left communication device 12L is an in-vehicle communication device 12 for setting the periphery of a door for a front seat (hereinafter, a front left door) provided on the left side of the vehicle Hv to a strong electric field region. Here, since the driver's seat is disposed on the left side of the vehicle Hv, the front left door corresponds to a door for the driver's seat.

As shown in fig. 17, the outdoor left-side communication device 12L is mounted on the surface of the vehicle interior side of the B-pillar 42B provided on the vehicle left side in a posture in which the bottom plate 51 faces the surface of the B-pillar 42B and the X-axis direction is along the longitudinal direction of the B-pillar 42B. The outdoor left communication device 12L may be attached to a portion overlapping the B pillar 42B in the door module 45 in the above-described posture. The manner of mounting the bottom plate 51 in a posture in which it faces the outer surface portion (for example, the outdoor side surface of the B pillar 42B) may include a state in which the bottom plate 51 is substantially parallel to the vehicle side surface portion (so-called substantially parallel state). The above mounting posture also includes a structure in which the bottom plate 51 is mounted along the vehicle outer surface portion.

In accordance with the above mounting posture, the floor parallel direction of the vehicle exterior communication device 12 β is a direction along the vehicle side surface portion (in other words, parallel). The floor vertical direction of the vehicle exterior communication device 12 β faces a direction perpendicular to the side surface portion of the vehicle. That is, as shown in fig. 18, the outdoor left-side communication device 12L is mounted in a posture in which the center of the directivity provided by the zeroth-order resonance mode is parallel to the side surface portion (specifically, the door panel) and the center of the directivity provided by the floor excitation mode is perpendicular to the side surface portion. As shown in fig. 18, the outdoor left-side communicator 12L has the electric field vibration direction of the linearly polarized wave radiated in the zeroth-order resonance mode perpendicular to the vehicle side surface portion, and the electric field vibration direction of the linearly polarized wave radiated in the outdoor direction in the floor excitation mode parallel to the vehicle side surface portion.

The vertical direction is not limited to a strict vertical direction, and may be inclined by about 30 °. That is, here, vertical also includes substantially vertical. The parallel and opposite expressions also include a state of being inclined by about 30 °. Hereinafter, a direction perpendicular to the vehicle side surface portion and away from the vehicle side surface portion will also be referred to as an outdoor direction. From another viewpoint, the outdoor direction corresponds to a direction parallel to the vehicle width direction and away from the vehicle side surface portion.

As shown in fig. 19, the directivity can be formed in both the direction parallel to the side surface of the vehicle and the outdoor direction according to the above mounting position and mounting posture. Here, the gain in the vehicle width direction is based on the asymmetry portion width W. Therefore, by adjusting the asymmetric portion width W, the substantial communication range of the vehicle exterior communication device 12 β can be limited to the inside of the vehicle side surface portion 2 m. As a result, a flat, substantially elliptical communication area with the vehicle width direction as the short side direction can be formed on the side of the vehicle Hv (near the B pillar). According to the above mounting method, the metal B-pillar 42B functions as a ground plate/reflector of the antenna 121 operating in the floor excitation mode, and therefore the amount of radio waves radiated in the floor excitation mode entering the vehicle interior can be further reduced.

From the above-described mounting position and mounting posture, as shown in fig. 18, the outdoor left-side communicator 12L propagates linearly polarized waves radiated in the zero-order resonance mode along the metal plate providing the side surface portion of the vehicle. This is because an electric wave whose electric field vibration direction is perpendicular to the metal plate has a property of propagating along the metal plate. Therefore, the electric wave radiated in the zero-order resonance mode propagates in the outdoor operation region while maintaining a relatively strong level from the upper end to the lower end as a whole. The radio wave radiated in the zero-order resonance mode also enters the vehicle interior to some extent via the edge portion of the side window.

As a result, according to the zero-order resonance mode, as shown in fig. 20, substantially the entire area of the outdoor operation area Rx can be set to the strong electric field area. However, since the electric field perpendicular to the B-pillar 42B is also likely to flow into the vehicle interior, the electric field strength in the vehicle interior is relatively high. The electric field intensity and the reception intensity of the transmission signal are strictly different physical quantities, but they have a proportional relationship due to the reversibility of transmission and reception, and can be used as an alternative characteristic. The electric field strength shown in fig. 20 indicates the maximum value of the electric field strengths of three channels of 2402MHz, 2442MHz, and 2480 MHz. Fig. 20 shows a result of simulation of electric field distribution in a case where the dipole antenna is strictly attached in a posture perpendicular to the B-pillar 42B (that is, a posture substantially along the vehicle width direction). However, it was confirmed through simulation that the propagation manner of the radio wave radiated by the vehicle outdoor communication device 12 β installed in the above-described position and orientation in the zero-order resonance mode is substantially the same as the case where the dipole antenna is installed in the orientation perpendicular to the B-pillar 42B. Therefore, fig. 20 can be generally regarded as a graph showing radiation characteristics when the left and right outdoor communication devices 12 β operate in the zero-order resonance mode.

The linearly polarized wave radiated in the outdoor direction by the outdoor left-side communicator 12L in the chassis excitation mode is easily intensified in the outdoor direction by reflection on a metal part (for example, a door panel) of a vehicle body. This is because an electric wave whose electric field vibration direction is parallel to the metal plate has a property of being easily rebounded by the metal plate. Therefore, the electric wave radiated in the floor excitation mode is less likely to enter the vehicle interior. As a result, as shown in fig. 21, the electric field strength in the vehicle interior can be suppressed to a relatively low level. Fig. 21 shows a result of simulation of an electric field distribution in a case where the dipole antenna is attached in a posture along the longitudinal direction of the B pillar 42B (i.e., a posture substantially along the vehicle height direction). However, it was confirmed through simulation that the propagation manner of the radio wave radiated by the floor excitation pattern by the vehicle exterior communication device 12 β mounted in the above-described position and orientation is substantially the same as that in the case where the dipole antenna is mounted in the orientation along the B-pillar 42B. This is because the operation principle of the backplane excitation mode is the same as that of a dipole antenna, a monopole antenna, or the like. Therefore, fig. 21 can be generally regarded as a graph showing radiation characteristics when the left and right outdoor communicators 12 β are operated in the floor excitation mode. Further, the dipole antenna has a ring-shaped radiation directivity (from another viewpoint, 8-character characteristic) which is rotationally symmetric with respect to the axis of the radiation element. Therefore, when the dipole antenna is mounted in a posture along the vehicle height direction, the electric field strength in the lower half of the outdoor working area Rx becomes low. The lower half of the outdoor work area Rx corresponds to an area where the user's body-feet are located.

The outdoor right communication device 12M is an in-vehicle communication device 12 for setting the periphery of a door for a front seat (hereinafter, a front right door) provided on the right side of the vehicle Hv to a strong electric field region. Here, since the driver's seat is disposed on the right side of the vehicle Hv, the front right door corresponds to a door for a passenger seat.

The outdoor right-side communication device 12M is disposed on the right-side surface portion of the vehicle Hv at a position opposite to the outdoor left-side communication device 12L. The outdoor right-side communicator 12M corresponds to the in-vehicle communicator 12 paired with the outdoor left-side communicator 12L. The outdoor right-side communication device 12M is mounted on the outer surface of the B-pillar 42B provided on the vehicle right side in a posture in which the bottom plate 51 faces the surface of the B-pillar 42B and the X-axis direction is along the longitudinal direction of the B-pillar 42B.

The outdoor rear communication device 12N is a vehicle-mounted communication device 12 for forming a strong electric field region near the trunk door. The outdoor rear communication device 12N is disposed in the vehicle width direction center portion of the vehicle rear end portion. As the installation position of the outdoor rear communication device 12N, for example, a door handle for a trunk, the vicinity of a license plate, the inside/lower end portion of a rear bumper, the upper end portion of a rear window, and the like can be used. For example, the outdoor rear communication device 12N is housed in an outside door handle for a trunk in a posture in which the X axis is along the vehicle width direction and the Z axis is toward the vehicle rear.

According to this mounting posture, directivity can be formed in both the direction along the vehicle rear surface portion and the direction perpendicular to the vehicle rear surface portion. As a result, a substantially oblong communication area is formed with the outdoor rear communication device 12N as the center and the vehicle width direction as the longitudinal direction. The direction along the vehicle rear surface portion includes a vehicle width direction and a height direction. The direction perpendicular to the vehicle rear surface portion corresponds to the vehicle rear. Since the gain toward the vehicle rear is based on the asymmetric portion width W, the substantial communication range of the outdoor rear communication device 12N toward the vehicle rear can be limited to within 2m from the vehicle rear end portion by adjusting the asymmetric portion width W.

Hereinafter, the in-vehicle communication device 12 disposed on the left side surface portion or the right side surface portion, such as the outdoor left communication device 12L and the outdoor right communication device 12M, among the in-vehicle outdoor communication devices 12 β, will also be referred to as a side communication device. The number of the vehicle-external communication devices 12 β included in the in-vehicle system 1 can be changed as appropriate. The number of the outside-vehicle communication devices 12 β may be two, four, or the like, or may be five or more.

Both the in-vehicle communication device 12 α and the out-vehicle communication device 12 β are configured to report the reception intensity of the signal from the mobile terminal 2 to the smart ECU 11. Therefore, hereinafter, the various in-vehicle communication devices 12 α and the out-vehicle communication device 12 β are also referred to as intensity monitoring devices. Each intensity monitoring unit provides the reception intensity of the signal transmitted from the mobile terminal 2 to the smart ECU11 together with the channel number of the received signal and the terminal ID indicating the transmission source of the received signal.

(function of Intelligent ECU 11)

The smart ECU11 provides functions corresponding to the various functional blocks shown in fig. 22 by executing the position determination program described above. That is, the smart ECU11 includes, as functional blocks, a vehicle information acquisition unit F1, a communication processing unit F2, an authentication processing unit F3, a position determination unit F4, and a vehicle control unit F5.

The vehicle information acquisition unit F1 acquires various information (hereinafter, vehicle information) indicating the state of the vehicle Hv from a sensor, an ECU (for example, the vehicle body ECU16), a switch, and the like mounted on the vehicle Hv. The vehicle information includes, for example, the open/close state of the doors, the locked/unlocked state of each door, the presence or absence of the depression of the door button 13, the presence or absence of the depression of the start button 14, and the like. The vehicle information acquisition unit F1 specifies the current state of the vehicle Hv based on the various information described above. For example, when the engine is off and all the doors are locked, the vehicle information acquisition unit F1 determines that the vehicle Hv is stopped. Of course, the condition for determining that the vehicle Hv is stopped may be appropriately designed, and various determination conditions and the like may be applied.

Acquiring the information indicating the locked/unlocked state of each door corresponds to determining the locked/unlocked state of each door and detecting the locking/unlocking operation of the door by the user. Acquiring the electric signals from the door button 13 and the start button 14 corresponds to detecting user operations for these buttons. The vehicle information acquired by the vehicle information acquisition portion F1 also includes a user operation for the vehicle Hv. The type of information included in the vehicle information is not limited to the above. The vehicle information includes a shift position detected by a shift position sensor, not shown, a detection result of a brake sensor that detects whether or not a brake pedal is depressed, an operation state of a parking brake, and the like.

The communication processing unit F2 is configured to perform transmission and reception of data with the portable terminal 2 in cooperation with the in-vehicle communication device 12 (in this case, the in-vehicle communication device 12 α) as a data communication device. For example, the communication processing unit F2 generates data to be sent to the mobile terminal 2 and outputs the data to the in-vehicle communication device 12 α. Thereby, a signal corresponding to desired data is transmitted as a radio wave. The communication processing unit F2 receives the data from the portable terminal 2 received by the in-vehicle communication device 12 α. In the present embodiment, for example, the wireless communication between the smart ECU11 and the mobile terminal 2 is configured to be encrypted. In the present embodiment, the smart ECU11 and the mobile terminal 2 are configured to encrypt data communication for authentication and the like in order to improve security, but the present invention is not limited to this. In another embodiment, the smart ECU11 and the mobile terminal 2 may be configured to perform data communication without encryption.

The communication processing unit F2 recognizes that the user is present in the vicinity of the vehicle Hv based on the connection established by the mobile terminal 2 in communication with the in-vehicle communication device 12 α. The communication processing unit F2 acquires the terminal ID of the mobile terminal 2 to which communication is connected from the in-vehicle communication device 12 α. Even if the vehicle Hv is a vehicle shared by a plurality of users, the smart ECU11 can identify the user present in the vicinity of the vehicle Hv based on the terminal ID of the portable terminal 2 communicatively connected to the in-vehicle communication device 12 α.

The smart ECU11 as the communication processing unit F2 acquires the channel information from the in-vehicle communication device 12 α. Thus, the smart ECU11 specifies the channel used for the communication between the in-vehicle communication device 12 α and the mobile terminal 2. The communication processing unit F2 distributes the channel information and the terminal ID acquired from the in-vehicle communication device 12 α to each intensity monitoring device as reference information. Each intensity observation device can recognize, based on the channel information indicated by the reference information, which of the plurality of channels provided in the Bluetooth standard is to be received, and can receive the signal from the mobile terminal 2. The intensity observation device can determine which device the reception intensity of the signal from should be reported to the smart ECU11, even when signals from a plurality of devices are received, based on the terminal IDs indicated by the reference information.

The authentication processing unit F3 performs processing for confirming (in other words, authenticating) that the communication destination is the portable terminal 2 of the user in cooperation with the in-vehicle communication device 12 α. The communication for authentication is encrypted and implemented via the in-vehicle communication device 12 α. That is, the authentication process is implemented by cryptographic communication. The authentication process itself may be implemented in a variety of ways, using a challenge-response approach. Here, detailed description thereof is omitted. Data (for example, a cryptographic key) and the like necessary for the authentication process are stored in the portable terminal 2 and the smart ECU11, respectively. The authentication processing unit F3 may perform the authentication processing at a timing when the in-vehicle communication device 12 α establishes a connection with the mobile terminal 2. The authentication processing unit F3 may be configured to perform the authentication processing at a predetermined cycle while the in-vehicle communication device 12 α is in communication connection with the mobile terminal 2. When the start button 14 is pressed by the user, or the like, password communication for authentication processing may be performed using a predetermined user operation on the vehicle Hv as a trigger.

In the Bluetooth standard, establishment of a communication connection between the in-vehicle communication device 12 α and the mobile terminal 2 indicates that the communication partner of the in-vehicle communication device 12 α is the mobile terminal 2 registered in advance. Therefore, the smart ECU11 may be configured to determine that the authentication of the mobile terminal 2 has succeeded based on the communication establishment connection between the in-vehicle communication device 12 α and the mobile terminal 2.

The position determination unit F4 is configured to execute processing for estimating the position of the mobile terminal 2 based on the communication status between each in-vehicle communication device 12 and the mobile terminal 2. As an example, the position determination unit F4 of the present embodiment determines which of the vehicle interior, the outdoor work area Rx, and the area outside the vehicle interior the mobile terminal 2 is present in, based on the reception status and the reception intensity of the signal from the mobile terminal 2 supplied from each of the plurality of vehicle-mounted communication devices 12. The outside area herein means an area outside the outdoor working area Rx in the vehicle exterior. The region outside the region, particularly, the region at a predetermined prohibition distance or more from the outside door handle is referred to as a prohibition region. The prohibited distance is set to 2m from the viewpoint of theft prevention described later. Since the mobile terminal 2 is basically carried by the user, determining the position of the mobile terminal 2 corresponds to determining the position of the user. The forbidden distance may also be 1.6m, 3m, etc. The prohibition distance defining the size of the prohibition area may be changed as appropriate depending on the region where the vehicle is used.

The position determination unit F4 sequentially acquires the reception intensity of the signal from the mobile terminal 2 from the plurality of in-vehicle communication devices 12 as intensity observation devices, and stores the acquired reception intensity in the RAM113 by distinguishing it for each acquisition source as a preparatory process for determining the position of the mobile terminal 2. The position determination unit F4 determines whether or not the mobile terminal 2 is present in the vehicle interior based on the reception intensity of each intensity monitor stored in the RAM113 and various determination thresholds registered in the flash memory 112. The position determination unit F4 details a method of determining the position of the mobile terminal 2 based on the reception intensity of each intensity observation device. The determination result of the position determination unit F4 is referred to by the vehicle control unit F5.

The vehicle controller F5 is configured to execute vehicle control corresponding to the position of the portable terminal 2 (in other words, the user) and the state of the vehicle Hv in cooperation with the vehicle body ECU16 and the like when the authentication of the portable terminal 2 by the authentication processor F3 is successful. The state of the vehicle Hv is determined by the vehicle information acquisition unit F1. The position of the mobile terminal 2 is determined by the position determination unit F4.

For example, in a situation where the vehicle Hv is parked, when the portable terminal 2 is present outside the vehicle and the door button 13 is pressed by the user, the vehicle control unit F5 operates in cooperation with the vehicle body ECU16 to unlock the lock mechanism of the door. For example, when the position determination unit F4 determines that the mobile terminal 2 is present in the vehicle interior and detects that the start button 14 is pressed by the user, the engine is started in cooperation with the engine ECU 15. In this way, the vehicle control unit F5 is basically configured to execute vehicle control corresponding to the position of the user and the state of the vehicle Hv using the user operation on the vehicle Hv as a trigger. However, the vehicle control that can be performed by the vehicle control unit F5 may be automatically executed according to the position of the user without requiring a user operation on the vehicle Hv.

(connection-related processing)

Next, a connection-related process performed by the in-vehicle system 1 will be described with reference to a flowchart shown in fig. 23. The connection-related process is a process related to establishment of a communication connection between the in-vehicle system 1 and the portable terminal 2. The connection-related processing shown in fig. 23 may be started, for example, when the in-vehicle communication device 12 α as a data communication device receives an advertisement packet from the mobile terminal 2.

In step S101, a communication connection (in other words, a connection) between the in-vehicle communication device 12 α and the mobile terminal 2 is established, and the process proceeds to step S102. When the in-vehicle communication device 12 α establishes a communication connection with the portable terminal 2, the terminal ID of the portable terminal 2 that is in communication connection with the in-vehicle communication device 12 α is supplied to the smart ECU 11. When the intensity monitoring unit is in the idle mode at the time of establishing a connection between the in-vehicle communication unit 12 α and the mobile terminal 2, the smart ECU11 outputs a predetermined control signal to the intensity monitoring unit, and shifts to the standby state. The sleep mode is, for example, a state in which the signal reception function is stopped. The rest mode also includes a state in which the power supply is turned off.

In step S102, the in-vehicle communication device 12 α periodically performs password communication based on an instruction from the smart ECU 11. In this case, the content of the exchanged data may be any content as long as the mobile terminal 2 is requested to return a response signal. Or may be data for authenticating the portable terminal 2, such as a challenge code. By periodically performing wireless communication with the mobile terminal 2, the smart ECU11 can confirm that the mobile terminal 2 is present in the vehicle interior or in the vicinity of the vehicle.

In step S103, the in-vehicle communication device 12 α and the smart ECU11 cooperate with each other to start sharing reference information. Specifically, the in-vehicle communication device 12 α sequentially provides the terminal ID of the mobile terminal 2 and the channel information to be connected for communication to the smart ECU 11. The smart ECU11 distributes the channel information and the terminal ID supplied from the in-vehicle communication device 12 α to each intensity monitoring device in order as reference information.

In step S104, each intensity monitor starts to monitor the reception intensity of the signal from the mobile terminal 2 using the reference information supplied from the smart ECU 11. That is, the intensity monitor sets, as a reception target, a channel of a number indicated by channel information among a plurality of channels provided in the Bluetooth standard. The intensity monitoring unit sequentially changes the channel to be received based on the channel information supplied from the smart ECU 11.

Even when the mobile terminal 2 and the in-vehicle communication device 12 α perform wireless communication of the frequency hopping method, the reception intensity of the signal from the mobile terminal 2 is acquired and sequentially reported to the smart ECU 11. That is, in a state where the concealment (in other words, the security) of the communication between the in-vehicle system 1 and the portable terminal 2 is ensured, the various in-vehicle communication devices 12 included in the in-vehicle system 1 can detect the reception intensity of the signal from the portable terminal 2.

In step S105, the intensity monitor determines whether or not a signal including the terminal ID indicated by the reference information is received. When the signal including the terminal ID indicated by the reference information is received, the process proceeds to step S106. In step S106, the reception intensity of the reception signal is reported to the smart ECU 11. That is, in steps S105 to S106, each intensity monitor associates the reception intensity of the signal including the terminal ID indicated by the reference information with the channel number indicating the frequency at which the signal is received, and reports the signal to the smart ECU 11. In step S105, if the signal from the mobile terminal 2 is not received for a certain period of time, step S108 may be executed.

In step S107, the smart ECU11 distinguishes the reception intensity supplied from each intensity monitor for each intensity monitor as a supply source and stores the reception intensity in the RAM 113. The reception intensity supplied from the intensity monitor is distinguished for each channel number (in other words, each frequency) used for reception and stored. In particular, the smart ECU11 of the present embodiment roughly divides the reception intensity of each frequency supplied from each intensity monitor into the reception intensity of the first frequency band and the reception intensity of the second frequency band, and stores them.

The first frequency band is a frequency in a region where the vehicle outdoor communication device 12 β mainly operates in the zero-order resonance mode and within a predetermined range before and after the first frequency. The second frequency band is a frequency in a range around the second frequency in a region where the vehicle exterior communication device 12 β mainly operates in the floor resonance mode. In the system use frequency band, the first frequency band and the second frequency band are set so as not to overlap with each other. For example, when the vehicle exterior antenna 121 β has the radiation characteristic shown in fig. 16, 2400MHz to 2440MHz can be used as the first frequency band. Here, as an example, from 2402MHz to 2438MHz are set as the first frequency band. When the vehicle exterior antenna 121 β has the radiation characteristic shown in fig. 16, 2460MHz to 2500MHz can be used as the second frequency band. Here, as an example, from 2460MHz to 2480MHz are set as the second frequency band. In addition, a range in which a gain difference from the first frequency in the simulation is within ± 3dB may be defined as the first frequency band. Similarly, a range in which the gain difference from the second frequency in the simulation is within ± 3dB may be defined as the second frequency band. The ranges of the first frequency band and the second frequency band may be appropriately changed according to the operating characteristics of the antenna 121.

In step S108, the smart ECU11 and the in-vehicle communication device 12 α cooperate to determine whether or not the communication connection with the mobile terminal 2 is completed. The case where the communication connection with the mobile terminal 2 is completed is, for example, a case where the in-vehicle communication device 12 α cannot receive a signal from the mobile terminal 2. When the communication connection with the mobile terminal 2 is completed, the determination is affirmative in step S108 and step S109 is executed. On the other hand, if the communication connection with the mobile terminal 2 is still maintained, the process returns to step S105.

In step S109, the smart ECU11 outputs a predetermined control signal to the intensity monitor, and ends the process of monitoring the reception intensity of the signal from the mobile terminal 2. For example, the smart ECU11, for example, shifts the intensity monitor to the rest mode. When the processing in step S109 is completed, the present flow ends.

(position determination processing)

Next, the position determination process performed by the smart ECU11 will be described with reference to the flowchart shown in fig. 24. The position determination process is a process for determining the position of the mobile terminal 2. This position determination process is performed, for example, at a predetermined position determination cycle in a state where the communication connection between the in-vehicle communication device 12 α and the mobile terminal 2 is established. The position determination period is, for example, 200 milliseconds. Of course, the position determination period may be 100 milliseconds or 300 milliseconds.

In step S201, the authentication processing unit F3 cooperates with the in-vehicle communication device 12 α to execute the process of authenticating the portable terminal 2, and the process proceeds to step S202. Further, step S201 can be omitted. The timing of performing authentication of the mobile terminal 2 can be changed as appropriate. In step S202, the position determination unit F4 calculates a representative value of the reception intensity of the signal in the first frequency band and a representative value of the reception intensity of the signal in the second frequency band for each intensity monitor based on the reception intensity of each intensity monitor stored in the RAM 113. That is, a representative value of the reception intensity in each intensity monitor is calculated for each frequency band.

The representative value of the reception intensity of the signal of the first frequency band in a certain intensity monitor is a value that representatively indicates the reception intensity of the signal of the first frequency band within the latest predetermined time in the intensity monitor. Hereinafter, the representative value of the reception intensity of the signal of the first frequency band in each intensity monitor is referred to as an individual first intensity. In addition, the first frequency band corresponds to a frequency band mainly operating in the zero-order resonance mode (in other words, the zero-order resonance mode is dominant) of the vehicle exterior communication device 12 β. Therefore, the individual first intensity corresponds to the reception intensity in the zero-order resonance mode for the vehicle exterior communication device 12 β.

Here, as an example, the individual first intensity is an average value of the reception intensities of the signals of the latest N first frequency bands. Such individual first intensities correspond to a moving average of the received intensities of the signals of the first frequency band. N may be a natural number of 2 or more, and N is 5 in the present embodiment. In this case, the position determination unit F4 calculates a moving average value using the reception intensities of the signals of the first frequency band transmitted from the mobile terminal 2 acquired (in other words, sampled) at the last five times. Of course, N may be 10, 20, etc. In another embodiment, N may be 1. The configuration in which N is 1 corresponds to a configuration in which the latest reception intensity is directly adopted as a representative value.

The representative value of the reception intensity of the signal of the second frequency band in a certain intensity monitor is a value that representatively indicates the reception intensity of the signal of the second frequency band within the latest predetermined time in the intensity monitor. Hereinafter, the representative value of the reception intensity of the signal in the second frequency band is referred to as an individual second intensity. In addition, the second frequency band corresponds to a frequency band in which the vehicle outdoor communication device 12 β mainly operates in the floor excitation mode (in other words, the floor excitation mode is dominant). Therefore, the individual second intensity corresponds to the reception intensity in the floor excitation mode for the vehicle exterior communication device 12 β. The individual second intensities may also be calculated in the same way as the individual first intensities. That is, the individual second intensity for a certain intensity monitor corresponds to the average value of the reception intensities of the signals of the latest N second frequency bands in the intensity monitor.

Hereinafter, the reception intensity of the signal of the first frequency band transmitted from the mobile terminal 2 is also referred to as a first frequency reception intensity. Similarly, the reception intensity of the signal of the second frequency band transmitted from the mobile terminal 2 is also referred to as a second frequency reception intensity.

In step S202, the position determination unit F4 calculates an average value of the latest five first frequency reception intensities supplied from the in-vehicle communication device 12 α as a whole as the individual first intensity in the in-vehicle communication device 12 α. An average value of the latest five second-frequency reception intensities supplied from the in-vehicle communication device 12 α as a whole is calculated as the individual second intensities in the in-vehicle communication device 12 α. In addition, when a plurality of in-vehicle communication devices 12 α are provided, the individual first intensity is calculated for each of the plurality of in-vehicle communication devices 12 α using the latest five first frequency reception intensities supplied from the in-vehicle communication device 12 α. The same applies to the individual second intensities. In step S202, the position determination unit F4 calculates the individual first and second intensities for each of the outside-vehicle communication devices 12 β using the latest five first and second frequency reception intensities provided from the outside-vehicle communication device 12 β, as in the case of the inside-vehicle communication device 12 α.

The individual first intensities of the intensity monitoring devices having the number of the first reception intensities stored in the RAM113 smaller than N may be calculated as the reception intensity of the data-missing part instead of the lower limit value of the reception intensity that can be detected by the in-vehicle communication device 12. The lower limit of the reception intensity that can be detected by the in-vehicle communication device 12 may be determined by the configuration of the in-vehicle communication device 12, and may be, for example, -60 dBm. The same applies for the individual second intensities.

According to the above-described aspect, even when only a part of the plurality of intensity monitoring devices provided in the in-vehicle system 1 can receive the signal from the portable terminal 2 due to the position of the portable terminal 2, for example, the subsequent processing can be performed. For example, even when the outdoor right-side communication device 12M cannot receive the signal from the portable terminal 2 because the portable terminal 2 is present on the right side outside the vehicle Hv, it is possible to calculate the individual first and second intensities for each intensity monitor.

In the present embodiment, the average value of the received intensities of the latest N first frequencies is used as the individual first intensity, but the present invention is not limited thereto. The individual first intensity may be a median or a maximum of the received intensities of the latest N first frequencies. The individual first intensity may be an average value of the reception intensities excluding the maximum value and the minimum value from the latest N reception intensities. The individual first intensity may be a value excluding a fluctuation component of the instantaneous reception intensity. The same applies for the individual second intensities. If the processing in step S202 is completed, the process proceeds to step S203.

In step S203, the position determination unit F4 determines the indoor-unit representative first intensity Pa1 based on the individual first intensities for the one or more in-vehicle communication devices 12 α. Here, as an example, since there is only one in-vehicle communication device 12 α, the individual first intensity for the one in-vehicle communication device 12 α is directly adopted as the indoor unit representative first intensity Pa 1. In step S203, the position determination unit F4 determines the indoor-unit representative second intensity Pa2 based on the individual second intensity for the one or more indoor-unit representative first intensities Pa1, similarly to the indoor-unit representative first intensity Pa 1. In another aspect, when a plurality of in-vehicle communication devices 12 α are provided, the maximum value of the individual first intensity of each in-vehicle communication device 12 α may be used as the indoor-device representative first intensity Pa 1. The indoor unit representative first intensity Pa1 in the case where a plurality of in-vehicle communication devices 12 α are provided may be an average value or a median value of individual first intensities in the respective in-vehicle communication devices 12 α. The same applies to the indoor unit representative second intensity Pa 2. When the indoor unit representative first intensity Pa1 and the indoor unit representative second intensity Pa2 are not distinguished from each other, these are described as indoor unit representative intensities.

In step S204, the position determination unit F4 determines the outdoor-unit representative first intensity Pb1 based on the individual first intensity for each of the outdoor communicators 12 β. The position determination unit F4 of the present embodiment adopts the maximum value of the individual first intensities for the respective outdoor communicators 12 β as the outdoor-unit representative first intensity Pb 1. The maximum value of the individual second intensities for each of the outdoor communicators 12 β is taken as the outdoor-unit representative second intensity Pb 2. If the processing in step S204 is completed, the process proceeds to step S205. The outdoor-unit representative first intensity Pb1 may be an average value or a median value of the individual first intensities of the respective outdoor communicators 12 β. The same applies to the outdoor unit representative second intensity Pb 2. When the outdoor unit representative first intensity Pb1 and the outdoor unit representative second intensity Pb2 are not distinguished from each other, they are described as the outdoor unit representative intensities.

In step S205, the position determination unit F4 determines whether or not the outdoor unit representative first intensity Pb1 is equal to or higher than the operation threshold Prx. As described above, the operation threshold value Prx is a threshold value for determining that the mobile terminal 2 is present in the outdoor operation area Rx. The operation threshold value Prx may be designed based on the minimum value of the outdoor-unit representative first intensity Pb1 that can be observed when the mobile terminal 2 is present in the outdoor work area Rx. The minimum value of the outdoor-unit representative first intensity Pb1 that can be observed when the mobile terminal 2 is present in the outdoor work area Rx can be determined based on, for example, the result of a test in which the outdoor-unit representative first intensity Pb1 is measured when the mobile terminal 2 is disposed at each location in the outdoor work area Rx.

It is sometimes preferable that the operation threshold value Prx is set to a value that gives a predetermined margin to the maximum value of the representative outdoor-unit first intensity Pb1 that can be observed when the mobile terminal 2 is present in the prohibited area. With such a configuration that the operation threshold value Prx is set according to the technical idea, when the outdoor-unit representative first intensity Pb1 is equal to or higher than the operation threshold value Prx, it indicates that the mobile terminal 2 is present in the outdoor work area Rx or the vehicle interior. In other words, it indicates that at least the mobile terminal 2 is not present in the prohibited area.

In the determination processing in step S205, if the outdoor unit representative first intensity Pb1 is equal to or higher than the operation threshold value Prx, the determination step S205 is affirmative and the process proceeds to step S206. On the other hand, if the outdoor unit representative first intensity Pb1 is smaller than the operation threshold value Prx, step S205 is negatively determined and step S208 is executed.

In step S206, it is determined whether or not the second intensity difference Δ P2, which is a value obtained by subtracting the outdoor-unit representative second intensity Pb2 from the indoor-unit representative second intensity Pa2, is equal to or greater than a predetermined threshold value (hereinafter, intensity difference threshold value Pg). If the mobile terminal 2 is present in the vehicle interior, the indoor unit indicates that the second intensity Pa2 is at a high level, and the outdoor unit indicates that the second intensity Pb2 is at a low level. Therefore, the second intensity difference Δ P2 has a relatively large value. If the mobile terminal 2 is present below the outdoor work area Rx, both the indoor-unit representative second intensity Pa2 and the outdoor-unit representative second intensity Pb2 are at low levels, and the second intensity difference Δ P2 is a relatively small value. Further, when the mobile terminal 2 is present above the outdoor work area Rx, the outdoor representative second intensity Pb2 is higher than the indoor representative second intensity Pa2, and the second intensity difference Δ P2 is expected to be a negative value. Therefore, whether the mobile terminal 2 is present in the outdoor work area Rx or the vehicle interior can be discriminated on the basis of whether or not the second intensity difference Δ P2 is equal to or greater than the predetermined intensity difference threshold Pg. The second intensity difference Δ P2 is a threshold value for distinguishing whether the mobile terminal 2 is present in the vehicle interior or the outdoor work area Rx, and may be set as appropriate based on the results of the simulation/test. The intensity difference threshold Pg may also be 0. In addition, the mode of determining that the mobile terminal 2 is present in the vehicle interior when the second intensity difference Δ P2 is equal to or greater than the predetermined intensity difference threshold Pg corresponds to an example of the mode of determining that the mobile terminal 2 is present in the vehicle interior based on the indoor unit representing the second intensity being equal to or greater than the outdoor unit representing the second intensity.

If the second intensity difference Δ P2 is equal to or greater than the intensity difference threshold Pg, the determination is affirmative at step S206 and S209 is executed. On the other hand, in the case where the second intensity difference Δ P2 is smaller than the intensity difference threshold value Pg, step S206 is negatively determined and S207 is executed. In step S207, the position determination unit F4 determines that the mobile terminal 2 is present in the outdoor work area Rx, and ends the present flow.

In step S208, the position determination unit F4 determines whether or not at least one of the indoor-unit representative first intensity Pa1 and the indoor-unit representative second intensity Pa2 is equal to or greater than the vehicle-interior equivalent value Pin. As described above, the vehicle interior equivalent value Pin is a threshold value for determining that the mobile terminal 2 is present in the vehicle interior. The vehicle interior equivalent value Pin is appropriately designed by experiments or the like. The indoor equivalent value Pin is designed based on the minimum value of the representative intensity of the indoor unit that can be observed when only the mobile terminal 2 is present in the empty vehicle interior, for example. The indoor equivalent value Pin can be determined based on the result of a test for measuring the indoor unit representative strength at each observation point in the vehicle interior set to the empty state, for example. Here, the empty state refers to a state in which there is no luggage or passenger brought in by the user. That is, the state refers to a state where there is no object other than a structure previously provided in the vehicle interior. The indoor equivalent value Pin may be designed based on the minimum value of the representative strength of the indoor unit that can be observed when a person having an average physical size sits on the driver seat. With the configuration in which the indoor equivalent value Pin is set by the technical idea described above, the indoor unit representative strength being equal to or higher than the indoor equivalent value Pin indicates that the mobile terminal 2 is present in the vehicle interior.

In the determination processing in step S208, if at least one of the indoor unit representative first intensity Pa1 and the indoor unit representative second intensity Pa2 is equal to or greater than the vehicle interior equivalent value Pin, the determination step S208 is affirmative and the process proceeds to step S209. On the other hand, if both the indoor unit representative first intensity Pa1 and the indoor unit representative second intensity Pa2 are smaller than the indoor equivalent value Pin, the determination step S208 is negated and the step S210 is executed. In step S209, the position determination unit F4 determines that the mobile terminal 2 is present in the vehicle interior, and ends the present flow. In step S210, the position determination unit F4 determines that the mobile terminal 2 is present outside the area, and ends the present flow.

The determination results in steps S207, S209, and S210 are stored in the RAM113 as the position information of the mobile terminal 2, and are referred to by the vehicle control unit F5 and the like.

(essential element of electronic Key System for vehicle)

Here, as a premise for explaining the effects of the embodiment, the requirements required for the electronic key system for a vehicle will be explained. In the electronic key system for a vehicle, it is required to prohibit automatic unlocking of a door by wireless communication when a distance of 2m or more from an outer surface portion (for example, an outside door handle) of the vehicle is obtained as shown in fig. 25 from the viewpoint of theft prevention. This requirement is based on The provisions of The Motor Instrument review Research Centre, a group established by The Association of British Instructions. Therefore, the in-vehicle system 1 may be preferably configured to be able to accurately determine whether or not the mobile terminal 2 is present within the distance Hv2 m. The forbidden area is set according to the requirement.

The range within 2m from the outer surface portion of the vehicle described above is an index. From the viewpoint of improving safety, the outdoor work area Rx set by the vehicle manufacturer is often limited to a narrower range. For example, the outdoor work area Rx is often set to be within 0.7m from the vehicle hv. That is, as the electronic key system for a vehicle, it is required to accurately determine whether or not the mobile terminal 2 is present in the outdoor work area Rx on the premise that at least whether or not the mobile terminal 2 is present in the distance to the vehicle Hv2m can be determined with high accuracy. In addition, the accuracy of determining whether or not the portable terminal 2 is present in the vehicle interior is also an important requirement as an electronic key system for a vehicle.

In the electronic key system for a vehicle, it is sometimes preferable that the vehicle-exterior communication device 12 β is configured to cause an intentional difference in the reception intensity of the signal from the portable terminal 2 when the portable terminal 2 is present in the outdoor work area Rx and when the portable terminal 2 is present in the prohibited area. In the electronic key system for a vehicle, it is preferable that the external communication device 12 β is configured such that the reception intensity of the signal from the portable terminal 2 is significantly different depending on whether or not the portable terminal 2 is present in the vehicle interior. The reference surface for the outdoor working area and the prohibited area is the vehicle side surface. The reference surface (in other words, the plane regarded as the side surface portion) of the outdoor working area or the prohibited area based on the evaluation of the position determination accuracy may be a plane passing through the outside door handle and perpendicular to the vehicle width direction, for example. The area between the outdoor working area Rx and the forbidden area corresponds to a buffer area (in other words, a gray zone).

According to the structure and the mounting posture of the vehicle outdoor communication device 12 β disclosed in the present embodiment, the main beam does not face the outdoor direction when operating in the zero-order resonance mode. In the zeroth-order resonance mode, a linearly polarized wave whose electric field vibration direction is perpendicular to the side surface of the vehicle is radiated in both directions on the side surface of the vehicle. According to such radiation characteristics, as shown in fig. 20, the strong electric field region can be formed substantially in the entire three-dimensional space within 0.7m from the B pillar 42B, and the forbidden region can be suppressed from being formed in the strong electric field region. As a result, an intentional difference occurs in the reception intensity of the signal from the mobile terminal 2 in the vehicle-outside communication device 12 β between the case where the mobile terminal 2 is present in the outdoor work area Rx and the case where the mobile terminal 2 is present in the prohibited area. A strong electric field region (not shown) may be formed so as to extend along the vehicle longitudinal direction from the vicinity of the door for the front seat to the vicinity of the door for the rear seat. Therefore, the smart ECU11 can accurately determine the position of the mobile terminal 2 using the reception intensity of the signal from the mobile terminal 2 in the vehicle exterior communication device 12 β. In addition, since the mobile terminal 2 is less likely to be present in the vicinity of the road surface within 0.1m from the road surface or in the region having a height of 2m or more from the road surface, it can be excluded from the outdoor work area Rx.

The vehicle outdoor communication device 12 β of the present embodiment radiates linearly polarized waves having electric field vibration directions parallel to the side surface portion of the vehicle in a direction perpendicular to the side surface portion (i.e., the outdoor direction) when operating in the floor excitation mode. With such a configuration, the interior of the vehicle becomes a weak electric field region in accordance with the relationship between the directivity and the polarized wave in the floor excitation mode. Therefore, it is possible to accurately determine whether or not the mobile terminal 2 is present in the vehicle interior based on the reception intensity and the vehicle interior representative intensity in the vehicle exterior communication device 12 β operating in the floor excitation mode.

According to the structure of the present embodiment, the height (in other words, the thickness) of the antenna 121 can be reduced as compared with a polar antenna such as a dipole antenna or a monopole antenna. Specifically, while the monopole antenna needs a height of about λ/4, the antenna 121 of the present embodiment can be realized with a height (in other words, thickness) of about λ/100 to λ/40. Accordingly, the vehicle outdoor communication device 12 β can be made thin, and therefore has an advantage of being easily mounted on the side surface portion of the vehicle. The antenna 121 provided in the vehicle outdoor communication device 12 β according to the present embodiment is formed in a plate shape having a thickness of about several millimeters. Therefore, the possibility of the antenna 121 protruding from the side surface portion can be reduced.

While the present disclosure has been described above with reference to an example of the embodiment of the vehicle communication device, the present disclosure is not limited to the above embodiment, and various modifications described below are also included in the technical scope of the present disclosure. In addition, various modifications can be made to the embodiments without departing from the scope of the present invention. For example, the following modifications can be combined and implemented as appropriate within a range in which no technical contradiction occurs. The members having the same functions as those described in the above embodiment are given the same reference numerals, and the description thereof is omitted. When only a part of the structure is referred to, the structure of the embodiment described above can be applied to the other part.

(modification 1)

According to the above-described vehicle exterior communication device 12 β, when the mobile terminal 2 is present under the outdoor operation area or in the vehicle interior, an intentional difference occurs in the reception intensity of the signal from the mobile terminal 2 between when the mobile terminal is operated in the zero-order resonance mode and when the mobile terminal is operated in the floor excitation mode. When the mobile terminal 2 is present under the outdoor work area or in the vehicle interior, the reception intensity in the chassis excitation mode is significantly (for example, 5dB or more) lower than the reception intensity in the zero-order resonance mode. Therefore, by comparing the reception intensity in the zero-order resonance mode with the reception intensity in the bottom plate excitation mode, the presence in the upper half of the outdoor operating region Rx can be detected. Further, it can be recognized that the vehicle is not present in the vehicle interior. For example, when both the reception intensity in the zeroth-order resonance mode and the reception intensity in the floor excitation mode are equal to or greater than the threshold value, it is determined that the mobile terminal 2 is present above the outdoor operation area (i.e., is not present in the vehicle interior). In addition, when the reception intensity in the zeroth-order resonance mode is equal to or higher than a predetermined threshold value and the reception intensity in the floor excitation mode is equal to or lower than a predetermined threshold value, it may be determined that the mobile terminal 2 is present below the outdoor operating area or in the vehicle interior. As the reception intensity in the zero-order resonance mode, the individual first intensity described above and the outdoor unit representative first intensity can be used. As the reception intensity in the base plate excitation mode, the individual second intensity described above and the outdoor unit representative second intensity can be used.

(modification 2)

Modification 2 is a modification of the position determination algorithm. In the above-described embodiment, the position determination unit F4 has been disclosed as a system for determining that the mobile terminal 2 is present in the vehicle interior when the indoor unit representative intensity is equal to or greater than the vehicle interior equivalent value Pin, but the algorithm for determining whether the mobile terminal 2 is present in the vehicle interior is not limited to this. As an algorithm for determining whether or not the mobile terminal 2 is present in the vehicle interior, various algorithms can be employed.

For example, the position determination unit F4 may be configured to determine that the mobile terminal 2 is present in the vehicle interior based on the indoor unit representative intensity being equal to or higher than the vehicle interior equivalent value Pin and the outdoor unit representative second intensity Pb2 being smaller than the predetermined vehicle exterior equivalent value Pout. The outside vehicle equivalent value Pout introduced here is a threshold value for determining that the mobile terminal 2 is present outside the vehicle, and is a parameter different from the operation threshold value Prx. The outdoor equivalent value Pout may be set to a value obtained by giving a predetermined margin (for example, -3dBm) to the maximum value of the representative outdoor-unit second intensity Pb2 that can be observed when the mobile terminal 2 is present in the vehicle interior. The maximum value of the representative second intensity Pb2 of the outdoor unit that can be observed in the case where the portable terminal 2 is present in the vehicle interior can be determined based on simulation/experiment. Since the outdoor unit representative second intensity Pb2 is set to be equal to or higher than the maximum value of the outdoor unit representative second intensity Pout that can be observed when the mobile terminal 2 is present in the vehicle interior, the outdoor unit representative second intensity Pb2 being equal to or higher than the outdoor unit representative value Pout indicates that the mobile terminal 2 is present outside the vehicle interior.

The position determination unit F4 may be configured to determine that the mobile terminal 2 is present outside the vehicle when the indoor-unit representative intensity is equal to or greater than the indoor-unit equivalent value Pin and the outdoor-unit representative first intensity Pb1 is equal to or greater than the outdoor-unit equivalent value Pout. The outdoor equivalent value Pout may be set to the minimum value of the representative outdoor-unit second intensity Pb2 observed when the mobile terminal 2 is present in a leakage area formed outside the vehicle by the in-vehicle communication device 12 α. The leakage region is a region in the outside-vehicle interior region where the second intensity Pa2 is equal to or higher than the vehicle interior equivalent value Pin. The region that is likely to become a leakage region is mainly near the window portion 43. Here, the vicinity of the window portion 43 is a range within several cm to several tens cm from the window frame.

The position determination unit F4 may be configured to determine whether or not the mobile terminal 2 is present in the vehicle interior using the indoor unit representative strength, the high level threshold, and the low level threshold. The high level threshold is a threshold for determining that the mobile terminal 2 is present in the vehicle interior. The high level threshold is set to a relatively higher value than the low level threshold. For example, the high level threshold may be designed based on the representative strength of the indoor unit when the mobile terminal 2 is present in the vehicle interior (particularly around the driver's seat) as determined by an experiment or the like. The high level threshold may be set to a value sufficiently larger than the representative indoor unit intensity observed when the mobile terminal 2 is present in the prohibited area, based on the above-described test results. For example, the high level threshold may be set to the lowest value of the representative intensity of the indoor unit observed when the mobile terminal 2 is present in the vehicle interior. The low level threshold is a threshold for determining that the mobile terminal 2 is present outside the vehicle. The low level threshold may be set to a value lower than the high level threshold by 10dBm or more. In the above configuration, the position determination unit F4 determines that the mobile terminal 2 is present in the vehicle interior until the indoor unit representative intensity becomes lower than the low level threshold value when the indoor unit representative intensity temporarily becomes equal to or higher than the high level threshold value. When the indoor unit representative intensity is temporarily lower than the low level threshold, it may be determined that the mobile terminal 2 is present outside the vehicle room until the indoor unit representative intensity becomes equal to or higher than the high level threshold. Whether or not the mobile terminal 2 is present in the outdoor work area Rx can be determined by applying various determination algorithms, as in the case of determining whether or not the mobile terminal 2 is present in the vehicle interior.

The position determination of the mobile terminal 2 may be performed in several stages. For example, it is determined whether the mobile terminal 2 is present in the vehicle interior. Further, it may be configured to determine whether or not the mobile terminal 2 is present in the outdoor operation area Rx only when it is determined that the mobile terminal 2 is present outside the vehicle. That is, after the mobile terminal 2 is determined not to be present in the vehicle interior by a predetermined determination algorithm, it is determined whether or not the mobile terminal is present in the outdoor working area by another determination algorithm. With this configuration, since the radio wave of the external communication device 12 β easily enters the vehicle interior, it is possible to reduce the possibility that the mobile terminal 2 is erroneously determined to be present in the vehicle interior even though it is present in the outdoor work area Rx.

(modification 3)

Modification 3 is a modification of the structure of the vehicle-outside communication device. As shown in fig. 26, the vehicle exterior communication device 12 β may be provided with a mother chassis 58, which is a metal plate larger than the chassis 51, on the inner bottom surface of the resin-made housing 6. As shown in fig. 26 (B), the mother chassis 58 may be disposed on the outer bottom surface of the housing 6 of the vehicle exterior communication device 12 β. The housing 6 and the female base plate 58 may also be integrally formed. The bottom of the housing 6 may also be realized in metal. In this case, the metal case bottom 61 corresponds to the mother substrate 58. Further, the vehicle body metal part 4 can be cited as the mother floor 58. If the sealing material 7 remains solid at the assumed use temperature, either the case top 63 or the case bottom 61 can be omitted. That is, the housing 6 may be formed in a flat box shape having an opening on the top surface or the bottom surface. The opening surface of the housing 6 may be in contact with a member to be mounted, such as the B pillar 42B or the inner door panel.

As described above, the in-vehicle communication device 12 integrally includes electronic components such as the antenna 121 and the transmission/reception circuit 122 (so-called circuit integrated antenna), but is not limited thereto. The transmission/reception circuit 122 and the communication microcomputer 123 may be housed in a case different from the antenna 121. The in-vehicle communication device 12 α and the out-vehicle communication device 12 β may have the same configuration, or may have different configurations. The vehicle exterior communication device 12 β may have a configuration different from that of the side communication device such as the outdoor left communication device 12L with respect to the outdoor rear communication device 12N.

The housing top 63 may be omitted as shown in fig. 27. The housing 6 may also omit the housing bottom 61. In the case where either one of the housing top 63 and the housing bottom 61 is omitted from the housing 6, it may be preferable that the sealing material 7 is formed using a resin that is maintained in a solid state within a range of an ambient temperature (hereinafter, a use temperature range) assumed to use the vehicle exterior communication device 12 β. The temperature range of use can be, for example, -30 ℃ to 100 ℃.

(modification 4)

Modification 4 is a modification of the mounting position of the vehicle exterior communication device. The mounting position and mounting posture of the vehicle outdoor communication device 12 β as the side communication device are not limited to the above-described examples. The outdoor communicator 12 β can be attached to any position of the vehicle outer surface portion such as the a-pillar 42A, C pillar, the upper end portion of the door panel, and the inside/vicinity of the outside door handle 44. For example, the vehicle exterior communication device 12 β may be housed inside the outside door handle 44 in a posture in which the X-axis direction is along the longitudinal direction of the handle and the Y-axis direction is along the vehicle height direction. The vehicle exterior communication device 12 β as a side communication device may be attached to a portion (hereinafter, window frame portion) functioning as a window frame of a side window in the door module 45 in a posture in which the bottom plate 51 is along the side surface of the vehicle. However, it may be preferable that the vehicle-exterior communication device 12 β is mounted in a posture in which a flat metal vehicle body portion (hereinafter, the vehicle body metal portion 4) provided in the vehicle and the floor panel 51 face each other. According to the mode in which the vehicle exterior communication device 12 β is attached to the outer side surface of the vehicle body metal part 4, the vehicle body metal part 4 functions as the mother floor 58 of the floor panel 51, and the operation of the vehicle exterior communication device 12 β is stabilized. For example, when the outdoor left communication device 12L is mounted in the door module 45 in which the inner door panel and the outer door panel are combined, it may be preferable that the outer door panel is made of resin and the inner door panel is made of metal. This is because the metal inner door panel can function as the mother chassis 58 of the vehicle exterior communication device 12 β. In the case where the inner door panel is made of resin, the outdoor left-side communication device 12L may be mounted in a portion overlapping with a metal frame such as the B pillar 42B in the door module 45. The same applies to the outdoor right-side communication device 12M. The installation position of the outdoor rear communication device 12N can be changed as appropriate. It is also preferable that the outdoor rear communication device 12N is in contact with the flat vehicle body metal part 4.

(modification 5)

Modification 5 is a modification of the antenna structure. The configuration of the antenna 121 of the vehicle exterior communication device 12 β (that is, the vehicle exterior antenna 121 β) is not limited to the above configuration. As shown in fig. 28, the short-circuit portion 54 provided in the vehicle exterior antenna 121 β may be disposed at a position shifted by a predetermined amount (hereinafter, short-circuit portion shift amount Δ Sb) in the Y-axis direction from the center of the opposite conductor plate 53. With this configuration, the symmetry of the current distribution in the opposite conductive plate 53 is broken, and a linearly polarized wave parallel to the Y-axis direction is radiated from the opposite conductive plate 53. Specifically, the following is described.

In a configuration in which the short-circuit portion 54 is disposed at the center of the opposite conductive plate 53, the current flowing through the opposite conductive plate 53 is symmetrical about the short-circuit portion 54 as shown in fig. 29. Therefore, in the opposite conductive plate 53, a radio wave generated by a current flowing in a certain direction as viewed from a connection point (hereinafter, short-circuited portion) between the short-circuit portion 54 and the opposite conductive plate 53 is cancelled by a radio wave generated by a current flowing in the opposite direction.

In contrast, in the configuration in which the short-circuit portion 54 is disposed at a position shifted by a predetermined amount in the Y-axis direction from the center of the opposite conductive plate 53, as shown in fig. 30 (a), the symmetry of the current distribution flowing through the opposite conductive plate 53 is broken. Therefore, as shown in fig. 30 (B), the radio wave radiated by the current component in the Y-axis direction remains without being canceled. That is, in the configuration in which the short-circuit portion 54 is disposed at a position shifted by a predetermined amount in the Y-axis direction from the center of the opposite conductor plate 53, a linearly polarized wave whose electric field vibration direction is parallel to the Y-axis (hereinafter, a Y-axis parallel polarized wave) is radiated upward from the opposite conductor plate 53. Further, since the current component in the X-axis direction maintains symmetry, linearly polarized waves of the electric field vibrating in the X-axis direction cancel each other. That is, a linearly polarized wave in which the electric field vibrates in the X-axis direction is not radiated from the opposite conductor plate 53.

The chassis vertically polarized wave is radiated in the chassis parallel direction by parallel resonance of the capacitance formed between the opposing conductor plate 53 and the chassis 51 and the inductance provided by the short-circuit portion 54. That is, according to the above configuration, a vertically polarized wave in the direction parallel to the substrate, an X-axis parallel polarized wave in the direction perpendicular to the substrate, and a Y-axis parallel polarized wave in the direction perpendicular to the substrate can be simultaneously radiated. Further, radiation of the X-axis parallel polarized wave in the direction perpendicular to the substrate is supplied from the asymmetric portion 511 of the substrate 51. Radiation of the Y-axis parallel polarized wave in the direction perpendicular to the chassis is provided by the offset arrangement of the short-circuit portion 54 in the Y-axis direction.

When the vehicle exterior antenna 121 β operates in the zeroth-order resonance mode, the Y-axis parallel polarized wave provided by the offset arrangement of the short circuit portion 54 is radiated in the floor-perpendicular direction (in the outdoor direction with respect to the vehicle Hv). That is, only the region which cannot be covered by the backplane vertically polarized wave radiated from the edge portion of the opposing conductor plate 53 is covered by the Y-axis parallel polarized wave. As a result, as shown in fig. 31, the entire outdoor working area Rx can be further set to be a strong electric field area without omission. In fig. 31, the contour lines indicated by broken lines indicate points equal to the minimum value of the electric field intensity in the outdoor operating region Rx. The above-mentioned operation threshold Prx is set to the electric field intensity of the contour line. With such a setting, it is possible to reduce the possibility that the mobile terminal 2 is erroneously determined to be present in the outdoor work area Rx even though the mobile terminal 2 is present in the prohibited area.

The direction in which the short-circuit portion 54 is offset with respect to the center of the opposing conductive plate 53 (hereinafter, short-circuit portion offset) may be a direction orthogonal to the conductive plate offset direction. Two linearly polarized waves whose electric field vibration directions are orthogonal to each other can be radiated as the linearly polarized wave radiated in the direction perpendicular to the substrate.

The short-circuit portion 54 may be formed in the central region of the opposite conductive plate 53. In order to maintain the omni-directivity (in other words, non-directivity) in the direction parallel to the chassis base, the short-circuit offset Δ Sb may be set to 0.04 λ or less. The short-circuit portion offset amount Δ Sb may be set to a value of 0.02 λ (═ 2.5mm) or less, such as 0.004 λ (═ 0.5mm), 0.008 λ (═ 1.0mm), and 0.012 λ (═ 1.5 mm). By changing the short-circuit offset Δ Sb, the radiation gain of the Y-axis parallel polarized wave in the direction perpendicular to the base plate can be adjusted. Even if the short-circuit offset amount Δ Sb is changed, the operating frequency does not change. When the position of power feeding point 531 is fixed, the Voltage Standing Wave Ratio (VSWR) may vary depending on short-circuit offset amount Δ Sb. However, since the feeding point 531 can be set at an arbitrary position, the VSWR in the first frequency band can be suppressed to the application level (for example, 3 or less) by setting the feeding point 531 at a position corresponding to the short-circuit portion offset amount Δ Sb. That is, by adjusting the position of the feeding point 531 in accordance with the position of the short-circuit portion 54, the return loss can be suppressed to a desired allowable level.

(modification 6)

Modification 6 is a modification of the antenna structure. The outdoor antenna 121 β may have a structure disclosed in japanese patent application laid-open No. 2016 and 15688. That is, the antenna 121 may be configured such that the length of the opposing conductive plate 53 in the X axis direction is set to 0.5 λ as shown in fig. 32₂And the feeding point 531 is disposed on a symmetry axis parallel to the X axis to operate as a patch antenna at the second frequency. Such a zero-order resonant antenna is described as a half-wavelength type zero-order resonant antenna in the present specification. In the half-wavelength type zero-order resonant antenna, the feeding point 531 can also function as a feeding point of the zero-order resonant mode.

In the opposing conductive plate 53 of the present modification, cutouts may be formed as the separation elements in a pair of diagonal corners. With this configuration, the circularly polarized wave can be radiated, and the influence of the posture of the mobile terminal 2 can be alleviated. In the above example, the X axis corresponds to the first axis of symmetry. In addition, in the opposite conductor plate 53, the electrical length is set to 0.5 λ₂The direction of (d) may also be the Y-axis direction. That is, the first axis of symmetry may also be the Y-axis.

The antenna 121 includes a mode (that is, a zero-order resonance mode) operating as a zero-order resonance antenna and a mode (hereinafter, a patch antenna mode) operating as a patch antenna. The patch antenna forms a main beam in a vertical direction (that is, a Z-axis direction) of the chassis. The electric field vibration direction is parallel to the base plate 51 (here the X axis). Therefore, the patch antenna pattern corresponds to the second pattern. The reception signal of the zeroth-order resonance mode (in other words, the signal of the first frequency band) and the reception signal of the patch antenna mode (in other words, the signal of the second frequency band) input from the feeding point 531 may be separated using a filter or the like.

(modification 7)

In the bottom-plate extension type zeroth-order resonant antenna, the symmetry maintaining unit 512 and the asymmetry unit 511 may be physically divided as shown in fig. 33, and the electrical connection state between the two units may be switched by using a switch 513. The interval between the symmetry maintaining unit 512 and the asymmetry unit 511 may be set to a value that does not electromagnetically couple at the first frequency based on simulation. The switch 513 is disposed at an edge portion of the bottom plate 51. The symmetry maintaining section 512 corresponds to a plate-shaped conductive member that is rectangular and is disposed concentrically with the opposing conductive plate 53. The asymmetry portion 511 corresponds to a plate-like conductor member disposed on the side of the symmetry maintaining portion 512. When the switch 513 is set to be off, the asymmetric portion 511 is electrically disconnected, and therefore the vehicle exterior antenna 121 β operates only in the zero-order resonance mode. When the switch 513 is set to on, the vehicle exterior antenna 121 β can operate in two modes, that is, the zero-order resonance mode and the floor excitation mode.

By adjusting the asymmetry portion width W and the distance between the back metal (here, the B pillar 42B) and the bottom plate 51, the gain ratio between the zero-order resonance mode and the bottom plate excitation mode when the switch 513 is set to on can be changed. In other words, by adjusting the above parameters, the switch 513 can be set to be on, and can be configured to operate substantially only in the backplane excitation mode. Here, as an example, when the switch 513 is set to be on, the antenna 121 is configured such that the gain in the zeroth-order resonance mode is sufficiently smaller than the gain in the bottom plate excitation mode, and operates substantially only in the bottom plate excitation mode. For example, it may be preferable to set the asymmetrical portion width W to an integral multiple of λ/4, such as λ/4 or λ/2. With such a setting, the gain as the chassis excitation mode can be increased. According to the above configuration, the switch 513 is turned on or off, whereby the operation in the operation mode of the vehicle exterior communication device 12 β, that is, the zero-order resonance mode and the floor excitation mode can be controlled.

As shown in fig. 34, the smart ECU11 of the present modification includes an operation mode indicating unit F6 as a configuration for intentionally switching the operation mode of the vehicle outdoor communication device 12 β. Each of the outdoor communicators 12 β has an operation mode switching unit 125. Note that, in fig. 34, the configuration described in the above embodiment is not illustrated.

The operation mode instructing unit F6 is configured to collectively control the operation mode of each of the outdoor communication devices 12 β (substantially, the operation mode of the outdoor antenna 121 β). For example, when determining whether or not the mobile terminal 2 is present in the vehicle interior, the operation mode instructing unit F6 instructs each of the vehicle exterior communication devices 12 β to operate in the floor excitation mode. When determining whether or not the mobile terminal 2 is present in the outdoor operation area Rx, the operation mode instructing unit F6 instructs each of the vehicle-outdoor communication devices 12 β to operate in the zero-order resonance mode.

The operation mode switching unit 125 is configured to switch the operation mode of the vehicle exterior antenna 121 β based on an instruction from the smart ECU 11. For example, when the smart ECU11 instructs the operation mode switching unit 125 to operate in the floor excitation mode, the switch 513 is turned on. When the smart ECU11 instructs the operation mode switching unit 125 to operate in the zero-order resonance mode, the switch 513 is turned off.

The vehicle exterior communication device 12 β can be operated in the operation mode corresponding to the determination target of the position determination unit F4. The operation mode of the switching outdoor communication device 12 β substantially corresponds to the operation mode of the switching outdoor antenna 121 β. The operation mode of the switching vehicle exterior antenna 121 β corresponds to switching the directivity and the polarization plane of the vehicle exterior antenna 121 β. In other words, switching the operation mode of the vehicle exterior antenna 121 β corresponds to switching the polarization and the reception direction of the external communication device 12 β to be received.

The technical idea disclosed in the present modification can also be applied to the case where the vehicle exterior antenna 121 β is configured as the half-wavelength type zero-order resonant antenna disclosed in modification 6. For example, as shown in fig. 35, a feeding point 531a for zero-order resonance and a feeding point 531b for operating as a patch antenna may be provided on the counter conductor plate 53 of the half-wavelength type zero-order resonance antenna. By using the two feeding points 531a, 531b separately, the operation modes of the antenna 121 can be used separately. Which power feeding point 531 is used is collectively controlled by the operation mode instructing unit F6 through the operation mode switching unit 125. The feeding point 531a corresponds to a first feeding point, and the feeding point 531b corresponds to a second feeding point.

In the half-wavelength type zero-order resonant antenna, as shown in fig. 36, the antenna 121 and the transmission/reception circuit 122 may be connected via a matching circuit 59 configured to be capable of adjusting internal inductance or capacitance. In this configuration, the operation mode can be switched by adjusting the internal inductance or the electrostatic capacitance of the matching circuit 59. In the example shown in fig. 36, a structure in which the resonance frequency of the antenna 121 is changed by adjusting the electrostatic capacitance of the variable capacitor 591 is shown. As the variable capacitor 591, for example, an element (so-called varactor) whose capacitance changes by changing a voltage level applied to a predetermined input terminal can be used. Of course, the specific configuration of the matching circuit 59 that can change the internal inductance or the capacitance can be changed as appropriate, and is not limited to the configuration shown in fig. 36. For example, in a configuration in which the matching circuit 59 includes a variable coil, the resonance frequency of the antenna 121 may be changed by adjusting the inductance of the variable coil. The inductance and capacitance of the matching circuit 59 can be collectively controlled by the operation mode indicating section F6 described above. The variable capacitor 591 and the variable coil correspond to the impedance variable element.

(modification 8)

The modification 8 is a modification of the index of the distance between the mobile terminal 2 and the in-vehicle communication device 12. In the above-described embodiment, the method of determining the position of the mobile terminal 2 using the reception intensity of the signal from the mobile terminal 2 as the index of the distance from each in-vehicle communication device 12 to the mobile terminal 2 is disclosed, but the present invention is not limited thereto. As an index of the distance from each in-vehicle communication device 12 to the mobile terminal 2, the one-way/reciprocating propagation time of the wireless signal from the in-vehicle communication device 12 to the mobile terminal 2 may be used. That is, the position determination unit F4 may be configured to determine the position of the mobile terminal 2 using the one-way/reciprocating propagation time of the wireless signal from the in-vehicle communication device 12 to the mobile terminal 2. The propagation time of the radio signal can be measured by receiving a signal from the mobile terminal 2. That is, the configuration for determining the position of the mobile terminal 2 using the one-way/reciprocating propagation time of the wireless signal from the in-vehicle communication device 12 to the mobile terminal 2 also corresponds to the configuration for determining the position of the mobile terminal 2 based on the reception state of the signal from the mobile terminal 2.

(modification 9)

Modification 9 is a modification of the communication method with the mobile terminal 2. In the above-described embodiment, the mobile terminal 2 and the in-vehicle communication device 12 perform wireless communication in both directions according to the Bluetooth standard, but the communication method between the mobile terminal 2 and the in-vehicle communication device 12 is not limited to this. The portable terminal 2 and the in-vehicle system 1 may be configured to perform wireless communication using a pulse signal used for Ultra-wideband (UWB) communication. In other words, the in-vehicle communication device 12 may be a communication module that performs UWB communication. The pulse signal used in UWB communication is a signal having a pulse width of an extremely short time (for example, 2ns) and a bandwidth of 500MHz or more (that is, a super bandwidth). Examples of frequency bands that can be used for UWB communication (hereinafter, UWB frequency bands) include 3.1GHz to 16GHz, 3.4GHz to 4.8GHz, 7.25GHz to 16GHz, and 22GHz to 29 GHz. The standard for the portable terminal 2 and the in-vehicle system 1 to perform wireless communication and the frequency of a radio wave used for wireless communication (hereinafter, a system-used radio wave) can be appropriately selected.

(modification 10)

Modification 10 is a modification of the material of the vehicle body. In the above-described embodiment, the embodiment in which the position determination system according to the present disclosure is applied to the vehicle Hv having the metal vehicle body is disclosed, but the vehicle preferable as the application of the position determination system is not limited to the vehicle having the metal vehicle body. For example, various body panels constituting the body of the vehicle Hv may be formed using a carbon-based resin filled with carbon in an amount sufficient to attenuate the propagation of radio waves by 5dB or more. A vehicle provided with such a vehicle body is also preferably an application target of the position determination system. Of course, the vehicle body of the vehicle Hv may be formed using a general-purpose resin that does not contain carbon. The vehicle exterior communication device 12 β is preferably attached to a position where it has a structure for blocking electric waves on the back surface side and does not block electric waves on the side and upper side.

The control unit (e.g., vehicle control device) and the method thereof described in the present disclosure may also be realized by a special purpose computer constituting a processor programmed to execute one or more functions embodied by a computer program. The apparatus and methods described in this disclosure may also be implemented by dedicated hardware logic circuits. The apparatus and the method described in the present disclosure may be implemented by one or more special purpose computers that are configured by a combination of a processor that executes a computer program and one or more hardware logic circuits. The computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

The control unit here is, for example, the smart ECU 11. The mechanisms and/or functions provided by the smart ECU11 can be provided by software recorded in a physical memory device and a computer executing the software, software only, hardware only, or a combination thereof. Part or all of the functions provided by the smart ECU11 may be implemented as hardware. The embodiment in which a certain function is implemented as hardware includes an embodiment in which the function is implemented using one or more ICs or the like. In the above-described embodiment, the smart ECU11 is implemented using a CPU, but the configuration of the smart ECU11 is not limited thereto. The smart ECU11 may be implemented using an MPU (Micro Processor Unit: microprocessor), a GPU (Graphics Processing Unit: Graphics Processor), or a Data Flow Processor (DFP: Data Flow Processor) instead of the CPU 111. The smart ECU11 may be implemented by combining various processors such as the CPU111, MPU, GPU, and DFP. In addition, a part of the functions to be provided by the smart ECU11 may be implemented using an FPGA (Field-Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like.