阅读说明：本技术 测距系统、测距装置以及测距方法 (Distance measuring system, distance measuring device and distance measuring method ) 是由 真狩弘夫 西川正树 仁藤与晴 大高章二 吉田弘 于 2019-08-26 设计创作，主要内容包括：一种测距系统、测距装置以及测距方法,实施方式的测距系统为,在第一装置以及第二装置间基于收发来计算上述装置间的距离,具备：通信部,以第一频带以及/或者不同于上述第一频带的第二频带进行通信；判定部,判定上述第一装置相对于上述第二装置是否位于预定的范围内；以及控制部,根据上述判定部的判定结果进行控制,以使得当表示上述第一装置并不位于上述预定的范围内的情况下,使用上述第一频带进行测距运算,当表示上述第一装置位于上述预定的范围内的情况下,使用上述第二频带进行测距运算。(A ranging system according to an embodiment calculates a distance between a first device and a second device based on transmission and reception between the devices, and includes: a communication unit that performs communication in a first frequency band and/or a second frequency band different from the first frequency band; a determination unit configured to determine whether the first device is located within a predetermined range with respect to the second device; and a control unit that performs control so that, in accordance with a determination result of the determination unit, a distance measurement operation is performed using the first frequency band when the first device is not within the predetermined range, and the distance measurement operation is performed using the second frequency band when the first device is within the predetermined range.)

1. A ranging system for calculating a distance between first and second devices based on transmission and reception between the devices, comprising:

a communication unit that performs communication in a first frequency band and/or a second frequency band different from the first frequency band;

a determination unit configured to determine whether the first device is located within a predetermined range with respect to the second device; and

and a control unit that performs control so that, in accordance with a determination result of the determination unit, a distance measurement operation is performed using the first frequency band when the first device is not within the predetermined range, and the distance measurement operation is performed using the second frequency band when the first device is within the predetermined range.

2. The ranging system according to claim 1,

the second frequency band corresponds to a weak radio wave prescribed by the radio wave law of various countries.

3. The ranging system according to claim 1,

the control unit performs control so that, when the determination result indicating that the first device is located within the predetermined range is obtained, a distance measurement calculation using the second frequency band is performed when a distance measurement using the first frequency band is not possible.

4. The ranging system according to claim 1,

the control unit performs control so that the distance measurement calculation is performed while changing the second frequency band.

5. The ranging system according to claim 1,

the first device is provided with a first communication unit,

the second device includes a second communication unit capable of performing communication only within the predetermined range and a third communication unit capable of performing communication outside the predetermined range,

the determination unit determines that the first device is out of the predetermined range when the first communication unit and the third communication unit communicate with each other, and determines that the first device is within the predetermined range when the first communication unit and the second communication unit communicate with each other.

6. The ranging system according to claim 1,

the first device is configured as a smart key,

the second device is configured as an in-vehicle device,

the predetermined range is an interior of a vehicle to which the in-vehicle device is attached.

7. The ranging system of claim 6,

the control unit performs control so that the distance measurement calculation is performed when the authentication is successful through the authentication process between the smart key and the in-vehicle device.

8. The ranging system of claim 6,

the smart key is provided with a first communication unit,

the in-vehicle device includes a second communication unit capable of performing only indoor communication of the vehicle and a third communication unit capable of performing outdoor communication of the vehicle,

the determination unit determines that the smart key is located outside the vehicle when the first communication unit communicates with the third communication unit, determines that the smart key is located inside the vehicle when the first communication unit communicates with the second communication unit,

the control unit performs control such that, based on the determination result of the determination unit, a distance measurement operation is performed using a normal distance measurement radio wave when the smart key is located outside the vehicle, and a distance measurement operation is performed using a weak radio wave when the smart key is located inside the vehicle.

9. A ranging method for calculating a distance between a first device and a second device based on transmission and reception between the devices,

performing communication in a first frequency band and/or a second frequency band different from the first frequency band;

determining whether the first device is within a predetermined range relative to the second device;

and performing control such that, when the first device is not within the predetermined range, the distance measurement is performed using a first frequency band, and when the first device is within the predetermined range, the distance measurement is performed using a second frequency band.

10. The ranging method according to claim 9,

and performing control so that, when it is indicated that the first device is located within the predetermined range, the distance measurement calculation using the second frequency band is performed when the distance measurement using the first frequency band is not possible.

11. A distance measuring device for calculating a distance to a first device based on transmission and reception with the first device, comprising:

a communication unit that performs communication in a first frequency band and/or a second frequency band different from the first frequency band;

a determination unit configured to determine whether or not the first device is located within a predetermined range; and

and a control unit that performs control so that, in accordance with a determination result of the determination unit, a distance measurement operation is performed using a first frequency band when the first device is not within the predetermined range, and a distance measurement operation is performed using a second frequency band when the first device is within the predetermined range.

Technical Field

Embodiments of the present invention relate to a distance measurement system, a distance measurement device, and a distance measurement method.

Background

In recent years, keyless entry systems have been employed in many vehicles. This technique locks/unlocks a door by wireless communication between a key of an automobile and the automobile. In recent years, smart entry systems have been used which can lock/unlock doors and start an engine without touching a key.

However, many incidents occur in which an attacker steals the vehicle by breaking into wireless communication between the key and the car. As a countermeasure against an attack (relay attack), a countermeasure is studied in which control of a vehicle by communication is prohibited when it is determined that the distance between a key and the vehicle is equal to or greater than a predetermined value.

As a system for performing such distance measurement, there is a communication type distance measurement system that obtains a distance between devices by wireless communication using a phase detection method.

However, the smart entry system has a problem that the influence of multiple channels in the vehicle cabin is extremely large, and the distance measurement cannot be performed by the communication type distance measurement, and the engine start may be difficult.

Disclosure of Invention

Drawings

Fig. 1 is a block diagram showing an in-vehicle device and a key device to which a distance measuring system according to a first embodiment of the present invention is applied.

Fig. 2 is a diagram for explaining the architecture of the smart entry system.

Fig. 3 is an explanatory diagram showing a mounting state of the LF unit 20 in the vehicle 1.

Fig. 4 is an explanatory diagram showing a radio wave arrival range of a transmission radio wave of the LF unit 20.

Fig. 5 is a diagram showing an example of an external appearance of the smart key 2 corresponding to the vehicle 1.

Fig. 6 is a diagram for explaining an architecture of the smart entry system using the ranging result.

Fig. 7 is a diagram for explaining a weak radio wave.

Fig. 8 is a block diagram showing an example of a specific configuration of the RF unit 30.

Fig. 9 is a flowchart for explaining the operation of the in-vehicle device 10.

Fig. 10 is a flowchart for explaining the operation of the key device 40.

Fig. 11 is a diagram for explaining the architecture of the smart entry system in the present embodiment.

Fig. 12 is a flowchart showing an operation of the in-vehicle device employed in the second embodiment of the present invention.

Fig. 13 is a flowchart showing an operation of the key device employed in the second embodiment of the present invention.

Embodiments provide a ranging system, a ranging apparatus, and a ranging method that reduce the influence of multiple channels by using a weak radio wave having a wide frequency band, thereby enabling reliable ranging.