阅读说明：本技术 距离测定系统 (Distance measuring system ) 是由 内木一辉 岩下明晓 森惠 古贺健一 大屋佳之 古田昌辉 小杉正则 于 2019-02-28 设计创作，主要内容包括：距离测定系统(2)具备：多个通信部(16),通讯部根据通信器(20)的位置而形成不同的电波传播路径,以即使一个电波传播路径被遮断也能够通过其他的电波传播路径与通信器进行通信的方式设置于通信对象(1)；和测距部(4),其利用在通信部及通信器之间通过电波传播路径中的任一个收发测距信号的测距通信,测定通信器及通信对象之间的距离。(A distance measurement system (2) is provided with: a plurality of communication units (16) which form different radio propagation paths depending on the position of the communicator (20) and are provided in the communication destination (1) so as to be able to communicate with the communicator via another radio propagation path even if one radio propagation path is blocked; and a distance measurement unit (4) that measures the distance between the communicator and the communication target by using distance measurement communication in which a distance measurement signal is transmitted and received through any one of the radio propagation paths between the communicator and the communicator.)

1. A distance measurement system for measuring a distance between a communicator and a communication destination of the communicator, the distance measurement system comprising:

a plurality of communication units that form different radio propagation paths depending on the position of the communicator and are provided to the communication destination so that even if one radio propagation path is blocked, communication with the communicator can be performed through another radio propagation path; and

and a distance measuring unit that measures a distance between the communicator and the communication target by using distance measurement communication in which a distance measurement signal is transmitted and received between the communicator and the communicator through any one of the radio wave propagation paths.

2. The distance measuring system according to claim 1,

the distance measurement system is provided with:

a communication control unit that selectively operates the plurality of communication units; and

and a communication stop unit configured to stop subsequent transmission or reception of the ranging signal and not perform subsequent ranging communication when the ranging communication is established on any of the radio wave propagation paths.

3. The distance measuring system according to claim 2,

the distance measurement system includes a position confirmation unit that confirms a position of the communicator with respect to the communication destination,

the communication control unit sets an operation order of the plurality of communication units based on a result of the confirmation by the position confirmation unit.

4. The distance measuring system according to claim 3,

the communication control unit may limit only a communication unit associated with an area in which the communicator is determined to be present among the plurality of communication units, and may operate the communication unit.

5. The distance measuring system according to claim 3,

the distance measurement system includes a plurality of operation units provided to the communication partner for operating the communication partner,

when one of the plurality of operation units is operated, the communication control unit may limit only the communication unit arranged at a position corresponding to the operated operation unit among the plurality of communication units and operate the communication unit.

6. The distance measuring system according to claim 3,

the communication control unit preferentially operates one of the plurality of communication units associated with the area determined to have the communicator, and operates the remaining communication units of the plurality of communication units in a predetermined order.

Technical Field

The present invention relates to a distance measuring system for measuring a distance between a communicator and a communication target.

Background

Conventionally, for example, in a vehicle, the following electronic key systems are known: the vehicle is controlled by wireless communication between an electronic key carried by a user and a vehicle-mounted device mounted on the vehicle. As an electronic key system, the following smart check system is known: the electronic key automatically responds and performs ID verification by wireless communication.

However, in such an electronic key, there is an illegal act of using a repeater as an act of attempting to establish the ID verification at a place not in accordance with the intention of the user carrying the authorized electronic key. The unauthorized act of using the relay is, for example, an act of making the ID verification unauthorized by relaying the communication between the in-vehicle device and the electronic key through the plurality of relays when the electronic key is located at a place away from the vehicle. Therefore, there is a possibility that the ID verification is established in a place which is not detected by the user carrying the authorized electronic key.

In response to such illegal actions using a repeater, patent document 1 discloses a technique of: the distance between the vehicle and the electronic key is measured to detect an illegal action. In this case, a distance measurement signal in a UWB Band (UWB) is transmitted to and received from the in-vehicle device and the electronic key, and the distance between the vehicle and the electronic key is measured by analyzing the distance measurement signal. Therefore, when the repeater is used, the arrival time of the ranging signal becomes long, and the measured distance becomes larger than the threshold value. Therefore, an illegal action can be detected.

Disclosure of Invention

Problems to be solved by the invention

However, when an obstacle (for example, the body of the user) exists in the propagation path of the ranging signal between the in-vehicle device and the electronic key, the ranging signal may not reach the electronic key from the in-vehicle device, and the ranging may not be performed. In particular, when UWB radio waves are used as the distance measurement signals, the UWB radio waves are easily affected by the human body because of their high frequency and short wavelength, and it is difficult to establish distance measurement communication based on the mutual positional relationship. Thus, in the ranging communication, there is a problem in ensuring the communication establishment.

The invention aims to provide a distance measuring system which improves communication establishment of distance measuring communication.

Means for solving the problems

A distance measurement system according to one aspect measures a distance between a communicator and a communication destination of the communicator, the distance measurement system including: a plurality of communication units that form different radio propagation paths depending on the position of the communicator and are provided to the communication destination so that even if one radio propagation path is blocked, communication with the communicator can be performed through another radio propagation path; and a distance measuring unit that measures a distance between the communicator and the communication target by using distance measuring communication in which a distance measuring signal is transmitted and received through any one of the radio wave propagation paths between the communicator and the communicator.

According to this configuration, since the plurality of radio wave propagation paths for the ranging signal are provided by the communicator and the communication partner, even if one radio wave propagation path is blocked by an obstacle, the ranging communication can be established by using another radio wave propagation path. Thus, the communication establishment of the ranging communication can be improved.

Preferably, the distance measuring system includes: a communication control unit that selectively operates the plurality of communication units; and a communication stop unit configured to stop subsequent transmission or reception of the ranging signal and not perform subsequent ranging communication when the ranging communication is established on any of the radio wave propagation paths.

According to this configuration, the subsequent ranging communication is not performed at the time point when the ranging communication is established between any one of the communication units and the communicator. Therefore, current consumption can be suppressed.

Preferably, the distance measurement system further includes a position confirmation unit that confirms a position of the communicator with respect to the communication destination, and the communication control unit sets an operation procedure of the plurality of communication units based on a result of confirmation by the position confirmation unit.

According to this configuration, since the communication unit located near the communicator among the plurality of communication units can be operated, the ranging communication can be easily established. Therefore, the ranging communication can be established quickly, contributing to suppression of power consumption. In addition, the response speed of the ranging communication can be improved.

In the distance measurement system, it is preferable that the communication control unit operates only the communication unit associated with the area in which the communicator is determined to be present, among the plurality of communication units.

According to this configuration, only the communication unit required for the distance measurement is operated, which further contributes to the suppression of the current consumption.

Preferably, the distance measurement system may further include a plurality of operation units provided to the communication partner for operating the communication partner. In this case, it is preferable that the communication control unit, when one of the plurality of operation units is operated, operates only the communication unit disposed at a position corresponding to the operated operation unit among the plurality of communication units.

According to this configuration, only the necessary communication unit is activated using the operation of the operation unit as a trigger during the distance measurement, which further contributes to the suppression of the current consumption.

In the distance measurement system, the communication control unit may preferentially operate one of the plurality of communication units associated with the area determined to have the communicator, and operate the remaining communication units of the plurality of communication units in a predetermined order.

Effects of the invention

In the distance measuring system of the present invention, it is easy to establish the distance measuring communication.

Drawings

Fig. 1 is a block diagram showing a configuration of a distance measuring system according to an embodiment.

Fig. 2 is a diagram of an area of LF radio waves formed around the vehicle according to the embodiment.

Fig. 3 is a UWB radio wave propagation path diagram formed in the vehicle periphery of the embodiment.

Fig. 4 is a time-series diagram of ranging communication in the embodiment.

Fig. 5 is a time-series diagram of ranging communication in the embodiment.

Fig. 6 is a time-series diagram of ranging communication in another embodiment.

Fig. 7 is a block diagram showing a configuration of a distance measuring system according to another embodiment.

Fig. 8 is a diagram showing a case where the outside door handle is operated in another embodiment.

Fig. 9 is a diagram showing a case where an engine switch is operated in another embodiment.

Detailed Description

An embodiment of the distance measuring system will be described below with reference to fig. 1 to 5.

As shown in fig. 1, the vehicle 1 includes a distance measurement system 2 (in this example, an electronic key system 3), and the distance measurement system 2 authenticates the correctness of the electronic key 20 by wireless communication. The electronic key system 3 includes an in-vehicle device 10 mounted on the vehicle 1 and an electronic key 20 carried by a user. The electronic key 20 corresponds to a communicator, and the vehicle 1 corresponds to a communication destination of the communicator.

The vehicle 1 includes: a vehicle body ECU31 electrically connected to the door lock device 32 to control locking/unlocking of the door lock; and an engine ECU33 that performs a starting operation of the engine 34. The vehicle body ECU31 and the engine ECU33 are electrically connected to the vehicle-mounted device 10. In the electronic key system 3, a series of ID checks are performed by automatically communicating the in-vehicle device 10 and the electronic key 20 with each other, and lock/unlock of the door lock and start of the engine are permitted or executed on the condition that the ID check is established in the vicinity of the vehicle 1.

The in-vehicle device 10 includes a verification ECU11, and a verification ECU11 controls the operation of the in-vehicle device 10. The in-vehicle device 10 includes: an LF transmitter 14 that transmits radio waves in an LF band (LF: Low Frequency) by short-distance communication; a UHF receiver 15 that receives an electric wave in a UHF band (UHF); and a UWB transceiver 16 that transmits and receives radio waves in a UWB band. The LF transmitter 14, the UHF receiver 15, and the UWB transceiver 16 are electrically connected to the verification ECU 11. The verification ECU11 controls transmission and reception of electric waves. The UWB transceiver 16 corresponds to a communication unit.

The electronic key 20 includes an electronic key control unit 21, and the electronic key control unit 21 controls the operation of the electronic key 20. The electronic key 20 further includes: an LF receiver 24 that receives LF radio waves; a UHF transmitter 25 that transmits UHF radio waves; and a UWB transceiver 26 that transmits and receives UWB radio waves. The LF receiver 24, the UHF transmitter 25, and the UWB transceiver 26 are electrically connected to the electronic key control section 21. The electronic key control unit 21 controls transmission and reception of radio waves.

When the LF transmitter 14 of the in-vehicle device 10 transmits the wake-up signal by LF, the electronic key 20 switches to activation upon receiving the wake-up signal, and transmits the confirmation signal from the UHF transmitter 25. The verification ECU11 starts ID verification (smart verification) when receiving a confirmation signal as a response to the transmitted wake-up signal. At this time, the verification ECU11 acquires the electronic key ID registered in the electronic key 20, performs electronic key ID verification, and executes authentication processing such as challenge response authentication using a key. When the verification ECU11 confirms that the verification and authentication are established, the ID verification is established.

The electronic key system 3 includes a distance measuring unit 4, and the distance measuring unit 4 measures the distance between the in-vehicle device 10 and the electronic key 20 by distance measurement communication based on UWB radio waves. The distance measuring unit 4 of this example includes: a distance measuring unit 12 provided on the vehicle-mounted device 10 side; and a distance measuring unit 22 provided on the electronic key 20 side. The distance measuring unit 4 transmits and receives a distance measuring signal between the in-vehicle device 10 and the electronic key 20 by UWB radio waves, for example, and measures a distance between the two based on a propagation time of the transmission and reception at that time. The distance measuring unit 4 determines that the distance measurement authentication is established when the distance between the two is equal to or less than the threshold value.

As shown in fig. 2, the LF transmitter 14 is provided at a plurality of locations of the vehicle 1. In this example, the LF transmitters 14 are provided at four locations of the vehicle 1, and a plurality of communication areas 40 are formed around the vehicle 1. The 1 st LF transmitter 14a forms a 1 st communication area 40a around the door of the driver seat by being disposed, for example, at the door handle outside the vehicle of the door of the driver seat. The 2 nd LF transmitter 14b is disposed, for example, at a door handle outside the vehicle of the passenger seat door, thereby forming a 2 nd communication area 40b in the vicinity of the passenger seat door. The 3 rd LF transmitter 14c is disposed in, for example, a rear door, and thereby forms a 3 rd communication area 40c in the periphery of the rear door. The 4 th LF transmitter 14d is disposed in the vehicle, thereby forming a communication area (not shown) in the vehicle.

When the electronic key 20 enters any one of the communication areas 40(40a to 40c), the electronic key 20 receives the LF radio wave via the LF receiver 24. The electronic key 20 transmits a response signal (UHF radio wave) to the LF radio wave via the UHF transmitter 25. When the verification ECU11 receives the response signal via the UHF receiver 15, it detects that the electronic key 20 has entered any one of the communication areas 40a to 40 c. In this way, the verification ECU11 has a function of specifying the presence area of the electronic key 20.

As shown in fig. 3, the UWB transceiver 16 is provided at a plurality of locations in the vehicle 1. In this example, the UWB transceivers 16 are provided at five locations of the vehicle 1. The 1 st UWB transceiver 16a is arranged at a corner of the vehicle 1 on the front side of the driver's seat, and thereby transmits UWB radio waves to the front side and the driver's seat side of the vehicle 1. The 2 nd UWB transceiver 16b is disposed at a corner of the front side of the passenger seat of the vehicle 1, and thereby transmits UWB radio waves to the front side of the vehicle 1 and the passenger seat side. The 3 rd UWB transceiver 16c is disposed at a corner behind the driver's seat of the vehicle 1, and thereby transmits UWB radio waves to the rear of the vehicle 1 and the driver's seat. The 4 th UWB transceiver 16d is disposed at a corner of the vehicle 1 on the rear side of the passenger seat, and thereby transmits UWB radio waves to the rear side of the vehicle 1 and the passenger seat side. The 5 th UWB transceiver 16e is disposed in the vehicle, and thereby transmits UWB radio waves to the vehicle.

The UWB transceiver 16 has an electronic key 20 outside the vehicle and a plurality of radio wave propagation paths L. For example, when the electronic key 20 is present at a predetermined point P1 on the driver's seat side outside the vehicle, a radio wave propagation path L1 is formed between the electronic key 20 and the 1 st UWB transceiver 16a, and a radio wave propagation path L3 is formed between the electronic key 20 and the 3 rd UWB transceiver 16 c.

When the electronic key 20 is present at the predetermined point P2 on the passenger seat side, a radio wave propagation path L2 is formed between the electronic key 20 and the 2 nd UWB transceiver 16b, and a radio wave propagation path L4 is formed between the electronic key 20 and the 4 th UWB transceiver 16 d.

Returning to fig. 1, the distance measuring system 2 (the verification ECU11) includes a position confirmation unit 5, and the position confirmation unit 5 confirms which of the communication areas 40(40a to 40c) formed by short-range communication using LF radio waves the electronic key 20 exists in. The position confirmation unit 5 recognizes, as the presence area of the electronic key 20, the communication area 40 in which communication with the electronic key 20 is established among the plurality of communication areas 40.

The distance measuring system 2 (verification ECU11) includes a communication control unit 6, and the communication control unit 6 controls the transmission of radio waves by the UWB transceiver 16 (operation for transmitting UWB radio waves). The communication control unit 6 of this example sets the operation procedure of the UWB transceiver 16 based on the confirmation result of the position confirmation unit 5 every time the plurality of UWB transceivers 16(16a to 16e) are selectively operated. In this way, in the present example, the communication control unit 6 sets the operation procedure of the UWB transceiver 16 according to which of the communication areas 40a to 40c the electronic key 20 enters.

The distance measuring system 2 (electronic key control unit 21) includes a communication stop unit 7, and the communication stop unit 7 stops the subsequent ranging communication at the time point when the ranging communication is established. When ranging communication is established on any of the radio wave propagation paths L, the communication stop unit 7 of the present example stops transmission or reception of the ranging signal and does not perform the subsequent ranging communication. In this example, the communication stop unit 7 stops reception of the ranging signal in the electronic key 20 at the time point when ranging communication is established with any one of the UWB transceivers 16.

Next, a procedure of the ranging communication in the electronic key system 3 will be described with reference to fig. 4. The following is assumed here: a user carrying a regular electronic key 20 enters the 1 st communication area 40a and attempts to unlock the door of the driver's seat. In this case, the position confirmation unit 5 detects that the electronic key 20 has entered the 1 st communication area 40a by communication of the LF radio wave and the UHF radio wave between the in-vehicle device 10 and the electronic key 20. In addition, when the smart check of the LF-UHF communication of the in-vehicle device 10 and the electronic key 20 is established, the range communication is shifted to.

As shown in fig. 4, in the ranging communication, the ranging unit 22 of the electronic key 20 transmits a ranging start signal Sds (UWB band) via the UWB transceiver 26. When receiving the ranging start signal Sds via the UWB transceiver 16, the ranging unit 12 of the in-vehicle device 10 transmits a ranging response signal Sdr (UWB band). The ranging start signal Sds and the ranging response signal Sdr correspond to ranging signals, respectively.

The communication control unit 6 sets the operation sequence of the radio wave transmission of the UWB transceivers 16a to 16e to the sequence based on the confirmation result of the position confirmation unit 5. In this example, since the electronic key 20 is present in the 1 st communication area 40a, the 1 st UWB transceiver 16a and the 3 rd UWB transceiver 16c close to the 1 st communication area 40a are preferentially operated. Therefore, the order of transmitting the ranging response signal Sdr is set to the order of the 1 st UWB transceiver 16a, the 3 rd UWB transceiver 16c, the 2 nd UWB transceiver 16b, the 4 th UWB transceiver 16d, and the 5 th UWB transceiver 16 e.

Here, since the electronic key 20 exists in the 1 st communication area 40a, the ranging response signal Sdr transmitted from the 1 st UWB transceiver 16a reaches the electronic key 20 without being affected by occlusion or the like. When receiving the ranging response signal Sdr from the 1 st UWB transceiver 16a via the UWB transceiver 26, the ranging unit 22 of the electronic key 20 analyzes the ranging response signal Sdr to calculate the distance between the vehicle 1 and the electronic key 20. In this case, the distance between the two is sufficiently short, and the ranging authentication is established.

When the ranging communication is established (in this example, the ranging authentication is established), the communication stop unit 7 of the electronic key 20 stops the UWB transceiver 26 from receiving the radio wave thereafter. Therefore, even if the UWB transceiver 16 of the in-vehicle device 10 transmits the ranging response signal Sdr later, the electronic key 20 does not receive the ranging response signal Sdr. That is, the ranging response signal Sdr is transmitted from the vehicle 1 by the 3 rd UWB transceiver 16c, the 2 nd UWB transceiver 16b, the 4 th UWB transceiver 16d, and the 5 th UWB transceiver 16e in order, but the electronic key 20 does not receive them.

The distance measuring unit 22 of the electronic key 20 transmits a response signal Sac (UHF band) indicating that the distance measuring communication is established. When the response signal Sac is received via the UHF receiver 15, the distance measurement unit 12 of the in-vehicle device 10 recognizes that the distance measurement authentication is established, and makes the ID verification (smart verification) established. When the ID check (smart check) is established, unlocking of the door lock is permitted or performed.

In this example, although the case where the electronic key 20 receives the radio wave of the 1 st UWB transceiver 16a is described, for example, when there is an obstruction (a human body or the like) between the 1 st UWB transceiver 16a and the electronic key 20 and the distance measurement communication is not established, the electronic key 20 continues the reception of the UWB radio wave. In this case, since the electronic key 20 is located on the driver seat side (the 1 st communication area 40a), there is a high possibility that the 3 rd UWB transceiver 16c establishes the ranging communication. Therefore, even if the radio wave of the 1 st UWB transceiver 16a cannot be received, the ranging authentication can be established by receiving the radio wave of the 3 rd UWB transceiver 16 c.

The following is assumed here: when the relay or the like has made an act of establishing communication with the electronic key 20 away from the vehicle 1, the distance between the vehicle 1 and the electronic key 20 exceeds the threshold value in the distance measurement authentication. Therefore, when the distance measurement response signal Sdr from the 1 st UWB transceiver 16a is analyzed, the distance measurement unit 22 of the electronic key 20 determines that the distance between the vehicle 1 and the electronic key 20 exceeds the threshold value, and in this case, the distance measurement communication is continued without being stopped. When it is determined that the distance between the vehicle 1 and the electronic key 20 exceeds the threshold value, the distance measuring unit 22 of the electronic key 20 transmits the response signal Sac indicating that the distance measurement authentication is not established, regardless of which distance measurement response signal Sdr in the UWB transceivers 16a to 16 e. In this case, the ID check becomes false.

Next, the ranging communication in the case where the electronic key 20 enters the 2 nd communication area 40b in the electronic key system 3 will be described with reference to fig. 5. The same portions as those in the case where the electronic key 20 enters the 1 st communication area 40a described above will not be described.

As shown in fig. 5, the communication control unit 6 of the in-vehicle device 10 operates the UWB transceivers 16a to 16e in the order of the 2 nd UWB transceiver 16b, the 4 th UWB transceiver 16d, the 1 st UWB transceiver 16a, the 3 rd UWB transceiver 16c, and the 5 th UWB transceiver 16 e. That is, the communication control unit 6 preferentially operates the UWB transceiver 16 located close to the 2 nd communication area 40 b. When the distance measuring unit 22 of the electronic key 20 determines that the distance measuring communication is established, the communication stop unit 7 stops the UWB transceiver 26 from receiving the radio wave thereafter.

In this example, since a plurality of radio wave propagation paths for the ranging signal are provided between the in-vehicle device 10 and the electronic key 20, the possibility of establishing ranging communication can be improved.

The communication stop unit 7 of the electronic key 20 stops the UWB transceiver 26 from receiving the radio wave thereafter when the ranging communication is established between any one of the UWB transceivers 16 and the electronic key 20. Therefore, the electronic key 20 does not need to communicate with all the UWB transceivers 16, and an increase in power consumption can be suppressed.

Further, the communication control unit 6 of the in-vehicle device 10 is configured to: the operation sequence of the UWB transceiver 16 is determined based on the presence region (communication region 40) of the electronic key 20 detected by the verification ECU 11. This enables the UWB transceiver 16, which facilitates establishment of ranging communication, to operate preferentially, thereby enabling the ranging communication to be completed quickly. This contributes to suppression of power consumption and speed increase of ranging communication.

The present embodiment can be modified as follows. This embodiment and the following modifications can be combined and implemented within a range not technically contradictory.

In the present embodiment, the communication control unit 6 may be configured to operate only the UWB transceiver 16 associated with the communication area 40 in which the electronic key 20 is present. The processing procedure in this case will be described with reference to fig. 6. Here, the description will be made assuming that the electronic key 20 enters the 1 st communication area 40 a.

As shown in fig. 6, since the communication control unit 6 of the in-vehicle device 10 determines that the electronic key 20 is present in the 1 st communication zone 40a, the 1 st UWB transceiver 16a and the 3 rd UWB transceiver 16c that are close to the 1 st communication zone 40a are to be operated, and the remaining UWB transceivers do not operate. In addition, the operation order of the UWB transceiver 16 to be operated is not limited. In this example, the UWB transceiver 16 is operated in the order of the 1 st UWB transceiver 16a and the 3 rd UWB transceiver 16c, and the 2 nd UWB transceiver 16b, the 4 th UWB transceiver 16d, and the 5 th UWB transceiver 16e are not operated. Even in this case, since the 1 st UWB transceiver 16a or the 3 rd UWB transceiver 16c has a high possibility of establishing the ranging communication, the ranging communication can be easily established. In addition, in the in-vehicle device 10, since the UWB transceiver 16 to be operated is limited, it contributes to suppression of power consumption.

In the present embodiment, the process of operating which transceiver of the plurality of UWB transceivers 16 is to be operated is not limited to the process of operating the transceiver corresponding to the communication area 40 into which the electronic key 20 enters. For example, the following method may be adopted: the UWB transceiver 16 at a position corresponding to the operated operation unit 50 is operated by using an operation of the operation unit 50 provided in the vehicle 1 as a trigger. The procedure of the ranging communication in this case will be described with reference to fig. 7 to 9.

As shown in fig. 7, the operation unit 50 includes a door outside handle 51 provided on a door of the vehicle 1 and an engine switch 53 provided in the vehicle. The door outside handle 51 includes a touch sensor 52, and the touch sensor 52 is operated when the door is opened and closed and detects contact with the door outside handle 51. The engine switch 53 is, for example, a push-type switch, and is operated when the state of the engine 34 is switched. The position confirmation unit 5 of the present example determines the position of the electronic key 20 based on the operation of the operation unit 50 provided in the vehicle 1.

As shown in fig. 8, for example, when the outside door handle 51 provided on the driver's seat door of the vehicle 1 is operated, the touch sensor 52 detects contact with the outside door handle 51 and outputs a detection signal. The position confirmation unit 5 recognizes the position of the electronic key 20 based on the detection signal of the touch sensor 52. That is, the position confirmation unit 5 determines that the electronic key 20 is located near the driver's seat door. In this case, the communication control unit 6 operates the 1 st UWB transceiver 16a and the 3 rd UWB transceiver 16c located near the driver's seat door, and the remaining transceivers do not operate.

In the example of fig. 9, a 6 th UWB transceiver 16f is further provided in the vehicle interior in addition to the 5 th UWB transceiver 16 e. As shown in fig. 9, when the engine switch 53 is operated, the position confirmation unit 5 determines that the electronic key 20 is located in the vehicle. In this case, the communication control unit 6 sets the 5 th UWB transceiver 16e and the 6 th UWB transceiver 16f installed in the vehicle as the objects of operation, and the UWB transceiver 16 installed outside the vehicle does not operate.

In the above configuration, when the user carrying the electronic key 20 operates the operation unit 50, the UWB transceiver 16 suitable for the position of the electronic key 20 can be selectively operated, and thus the distance measurement communication can be easily established. In this way, when the operation procedure of the UWB transceiver 16 (communication unit) is set based on the confirmation result of the position confirmation unit 5, the configuration for confirming the position of the electronic key 20 (communicator) with respect to the vehicle 1 (communication target) is not particularly limited as long as it is a configuration in which at least the region where the electronic key 20 exists can be confirmed.

In the present embodiment, the communication stop unit 7 may be provided in the in-vehicle device 10. For example, the following may be used: when the ranging response signal Sdr is transmitted from the vehicle-mounted device 10 via the UWB transceiver 16 and then the response signal Sac is returned from the electronic key 20, the transmission of the ranging response signal Sdr is stopped. In this case, it contributes to suppression of power consumption. As described above, the communication stop unit 7 may have a function of stopping transmission or reception of the ranging signal during ranging communication.

In the present embodiment, when the ranging authentication is established, it is determined that the ranging communication is established, but the present invention is not limited thereto. For example, when the electronic key 20 receives the ranging signal, it may be determined that ranging communication is established. In addition, parameters such as the reception intensity of the received ranging signal may be used as the criterion.

In the present embodiment, the number and position of the UWB transceivers 16 of the in-vehicle device 10 are not limited as long as a plurality of propagation paths different from the electronic key 20 outside the vehicle can be formed. As a position for mounting the UWB transceiver 16, for example, a stand column of the vehicle 1, a rear view mirror, and the like are given as candidates to be a place where the UWB transceiver is expected to be viewed without being blocked by each member of the vehicle 1.

In the present embodiment, the method of ranging communication is not limited. The distance measurement can be performed using parameters such as the reception intensity, arrival time, and phase of the ranging signal. The ranging start signal Sds and the ranging response signal Sdr may be transmitted from either the in-vehicle device 10 or the electronic key 20, or three messages or four messages may be exchanged.

In the distance measuring system 2 of the present example, the function of confirming the area position of the electronic key 20 in the communication area 40 and selectively operating the UWB transceiver 16 associated with the area position may be omitted from the constituent elements.

In the present embodiment, the frequency band of the wireless communication between the in-vehicle device 10 and the electronic key 20 for ID verification is not particularly limited. The communication method may be changed to various methods.

In the present embodiment, the method of distance measurement (ranging) is not limited to the use of UWB radio waves. For example, a distance measurement method such as ToF (Time of Flight: RSSI) and RSSI (Received Signal Strength Indication) can be applied to communication standards such as Bluetooth (registered trademark) and Wi-Fi (registered trademark).

In the present embodiment, the electronic key 20 may be a high-function mobile phone such as a smartphone.

In the present embodiment, the electronic key system 3 is not limited to a system in which the electronic key 20 transmits the electronic key ID at UHF to verify the electronic key ID when the electronic key 20 receives the LF radio wave periodically transmitted from the vehicle 1. In short, any system may be used as long as it can confirm the correctness of the electronic key 20 by wireless.

In the present embodiment, the distance measuring system is not limited to be applied to a vehicle. For example, the present invention may be used for locking/unlocking a door of a house.