WO2019138819A1

WO2019138819A1 - Communication system

Info

Publication number: WO2019138819A1
Application number: PCT/JP2018/046798
Authority: WO
Inventors: 佳之大屋; 一輝内木
Original assignee: 株式会社東海理化電機製作所
Priority date: 2018-01-09
Filing date: 2018-12-19
Publication date: 2019-07-18
Also published as: JP2019121949A; DE112018006800T5; JP6971156B2

Abstract

This communication system comprises an on-vehicle device that can be installed in a vehicle, and an electronic key that can be carried by a user. The on-vehicle device forms a communication area surrounding the vehicle for detecting the presence of the electronic key, and authenticates the electronic key by the transmission and reception of a wireless signal between the on-vehicle device and the electronic key when the electronic key is present in the communication area. The on-vehicle device measures the distance (Ld) between the on-vehicle device and the electronic key or a parameter pertaining to the distance in each of a plurality of situations (A, B, C) with differing communication situations. The on-vehicle device determines whether there are illegitimate communications between the on-vehicle device and the electronic key on the basis of the measured distance or the measured parameter under the plurality of situations.

Description

Communications system

The present invention relates to communication systems.

Conventionally, a communication system as described in Patent Literature 1 is known.
In the above communication system, transmission and reception of a wireless signal including an ID code is performed between the on-vehicle device of the vehicle and the electronic key, and when it is determined that the normal communication is established between the on-vehicle device and the electronic key, the door Lock and unlock and start the engine.

By the way, with the development of communication technology in recent years, there is assumed a method of illegally establishing communication between an electronic key present at a position far from a vehicle and a vehicle-mounted device. As a countermeasure, for example, the distance between the in-vehicle device and the electronic key is measured, and it is determined whether communication is established between the in-vehicle device and the electronic key illegally depending on whether the measured distance exceeds a threshold. There is a way. Also, by correlating the received signal strength of the wireless signal transmitted and received between the in-vehicle device and the electronic key with the distance between the in-vehicle device and the electronic key, communication between the in-vehicle device and the electronic key is illegally established. It is also known how to determine if it is present.

JP 2012-36582 A

However, in the above communication system, depending on the environment in which the in-vehicle device and the electronic key are placed, the wireless signal is reflected by an obstacle such as a vehicle or a building, and the reflected wireless signal is It may be received. In this case, the measured distance between the in-vehicle device and the electronic key becomes longer than the actual distance between the in-vehicle device and the electronic key, or the received signal strength between the in-vehicle device and the electronic key becomes weaker than usual. As a result, there is a possibility that the communication may be erroneously determined as being established between the in-vehicle device and the electronic key.

Further, it may be considered that it is a temporary situation that it is determined that the communication is illegal between the in-vehicle device and the electronic key. Therefore, although it is preferable to determine whether communication is established between the in-vehicle device and the electronic key improperly several times, the positional relationship between the in-vehicle device and the electronic key or the propagation of the wireless signal If there is no change in the condition such as the condition, the same determination result may be repeated.

An object of the present invention is to provide a communication system that improves the accuracy of determination of the correctness of communication between the on-vehicle device and the electronic key.

The communication system according to one aspect includes an on-vehicle device mountable in a vehicle and an electronic key portable by a user, and the on-vehicle device forms a communication area around the vehicle for detecting the presence of the electronic key. The on-vehicle apparatus authenticates the electronic key by transmitting and receiving a wireless signal between the on-vehicle apparatus and the electronic key in a state where the electronic key is present in the communication area. The in-vehicle device measures a distance related to the in-vehicle device and the electronic key or a parameter related to the distance under each of a plurality of different communication conditions, and the in-vehicle device is configured to It is determined whether communication is established between the in-vehicle device and the electronic key illegally based on the distance or the parameter measured by each.

According to this configuration, it is possible to suppress that the same measurement result is repeatedly repeated as compared with the case where the measurement of the distance or the parameter is performed in the state where there is no change in the communication condition between the onboard device and the electronic key. Therefore, even if it is determined that the communication between the in-vehicle device and the electronic key is temporarily established illegally due to the reflection of the wireless signal, the in-vehicle device again has an incorrect communication between the in-vehicle device and the electronic key. There is an opportunity to determine that it has not been established. Therefore, it is possible to improve the determination accuracy as to whether or not the communication between the in-vehicle device and the electronic key is normal.

In the communication system having the above configuration, it is preferable that the plurality of situations are situations where propagation states of wireless signals between the in-vehicle device and the electronic key are different.
In the communication system having the above configuration, preferably, the plurality of situations are situations in which the position of the electronic key with respect to the in-vehicle device changes.

In the communication system having the above configuration, the number of the plurality of situations is set to an odd number, and the on-vehicle device measures the distance in each of the plurality of situations and whether the distance is less than or equal to a threshold The communication between the on-vehicle device and the electronic key is correct when the judgment result indicating that the distance is equal to or more than the threshold is a majority among the plurality of judgment results obtained in the plurality of situations. It is preferable to determine that the communication between the on-vehicle device and the electronic key is not correct when it is determined that the distance is less than the threshold value and the determination result indicating that the distance is equal to or less than the threshold is less than a majority.

According to this configuration, the reliability of the determination as to whether or not the communication between the on-vehicle device and the electronic key is improperly established by determining whether the distance measured a plurality of times is equal to or less than the threshold value by majority decision. Can be improved.

In the communication system having the above configuration, the vehicle includes a first sensor that detects an operation of a door, and a second sensor that detects a user's seating on a seat, and the plurality of statuses are the electronic keys The in-vehicle device including a first situation entering a communication area, a second situation in which the electronic key is approaching the vehicle, and a third situation in which the electronic key is present inside the vehicle A position of the electronic key by the onboard unit transmitting a first wireless signal to detect the presence of the electronic key and receiving a second wireless signal from the electronic key as a response to the first wireless signal Detects the first situation, and the operation of the door is detected through the first sensor to detect that the position of the electronic key is the second situation, the second sensor Through It is preferred that the over THE detects that the position of the electronic key by being detected that seated on the seat is the third situation.

In the communication system having the above configuration, the in-vehicle apparatus may detect a plurality of situations in which the communication conditions are different based on the received signal strength measured by the in-vehicle apparatus.
In the communication system having the above configuration, the vehicle may include a plurality of antennas used for transmitting a wireless signal for measuring the distance or the parameter related to the distance. In this case, the in-vehicle apparatus may switch between a plurality of situations in which the communication status is different by switching the plurality of antennas.

According to the communication system of the present invention, it is possible to improve the determination accuracy of the communication between the in-vehicle device and the electronic key.

FIG. 1 is a block diagram showing the configuration of a communication system. BRIEF DESCRIPTION OF THE DRAWINGS The schematic which showed the mounting condition to the vehicle of a vehicle-mounted machine and various sensors, and the communication condition around a vehicle. BRIEF DESCRIPTION OF THE DRAWINGS The schematic which showed the condition of the radio | wireless communication in the communication system of one Embodiment. The flowchart which showed the process procedure of the distance determination in the communication system of one embodiment. The schematic which showed the position of the electronic key in each condition which implements distance determination of one Embodiment. The flowchart which showed the process procedure of the distance determination in the communication system of one embodiment. The flowchart which showed the process procedure of the distance determination in the communication system of other embodiment.

Hereinafter, one embodiment of the communication system will be described.
As shown in FIG. 1, the communication system 3 includes an on-vehicle device 10 mounted on the vehicle 1 and an electronic key 2 carried by a user.

First, the configuration of the vehicle 1 will be described.
As shown in FIG. 2, the vehicle 1 includes an in-vehicle device 10, a body ECU 30 that controls driving of on-vehicle electrical components such as the door lock device 40, and an engine ECU 50 that operates the engine 60 by operating the engine switch 70. A plurality of doors 80, a plurality of seats 90, a door handle sensor 85 as a first sensor, and a seating sensor 91 as a second sensor. Note that FIG. 2 shows only the driver's seat as one of the seats 90. Further, in the example shown in FIG. 2, the vehicle 1 includes three doors provided at positions corresponding to a driver's seat, a passenger seat, and a trunk as the plurality of doors 80. Further, an electrostatic sensor is adopted for the door handle sensor 85.

In the example shown in FIG. 2, the door lock device 40 is incorporated in the door 80 on the driver's seat side and the door 80 on the passenger's seat side. The door handle sensor 85 is incorporated in the door handle 81 of the driver's side door 80, the door handle 82 of the passenger's side door 80, and the door handle 83 of the trunk side door 80, respectively. The door handle sensor 85 detects that the user's hand contacts the door handle 83. The seating sensor 91 is built in at least the seat 90 on the driver's seat side. The seating sensor 91 is a load sensor that detects the load when the user is seated on the seat 90.

Next, the configuration of the in-vehicle apparatus 10 will be described.
As shown in FIG. 1, the on-vehicle device 10 includes a matching ECU 11, an LF transmitter 12, a UHF transmitter / receiver 13, and a UWB transmitter / receiver 14. The LF transmitter 12 transmits an LF band radio signal to the inside and the outside of the vehicle through the transmission antenna 12a. The UHF transmission and reception unit 13 transmits and receives radio signals in the UHF band to the inside and the outside of the vehicle through the transmission and reception antenna 13a. The UWB transceiver unit 14 transmits and receives radio signals in the UWB band to the inside and the outside of the vehicle through the transmitting and receiving antenna 14 a. The LF transmission unit 12, the UHF transmission / reception unit 13, and the UWB transmission / reception unit 14 are electrically connected to the verification ECU 11. Further, a body ECU 30 and an engine ECU 50 are electrically connected to the verification ECU 11 through a communication line L mounted on the vehicle. For example, a CAN (Controller Area Network) is used as the communication line L. Further, a door handle sensor 85 and a seating sensor 91 are electrically connected to the verification ECU 11. The verification ECU 11 includes a memory 11 a, a calculation unit 11 b, and a communication correctness determination unit 11 c. The calculation unit 11 b measures the distance Ld (see FIG. 2) between the on-vehicle device 10 and the electronic key 2. The communication correctness determination unit 11 c determines whether the normal communication is illegally established between the in-vehicle device 10 and the electronic key 2. The memory 11a stores an ID code, a distance measurement code, and an encryption key. The ID code includes a vehicle ID code and an electronic key ID code.

As shown in FIG. 2, the transmitting antenna 12 a is provided in the inside and the inside of the door handles 81, 82, 83 of the vehicle 1. When the vehicle 1 is in the parked state (the door 80 is in the locked state, the engine 60 is in the stopped state), the on-vehicle device 10 intermittently sets the radio signal of the LF band through the transmitting antenna 12a of each door handle 81 to 83. Send by Thus, a communication area R capable of communicating with the electronic key 2 is formed around the door 80 outside the vehicle. When the door 80 is unlocked and the user's boarding is detected, the in-vehicle device 10 transmits a radio signal of the LF band to the entire area of the vehicle interior through the transmission antenna 12 a in the vehicle.

Next, the configuration of the electronic key 2 will be described.
As shown in FIG. 1, the electronic key 2 includes a key control unit 20 for controlling the operation of the electronic key 2, a memory 21, an LF reception unit 22 for receiving a radio signal of the LF band, and a radio signal of the UHF band. It has a UHF transmitting / receiving unit 23 for transmitting / receiving, and a UWB transmitting / receiving unit 24 for transmitting / receiving a radio signal in the UWB band. The LF control unit 22, the UHF transmission / reception unit 23, and the UWB transmission / reception unit 24 are electrically connected to the key control unit 20. The memory 21 stores an ID code similar to that of the in-vehicle device 10, a distance measurement code, and an encryption key.

Next, wireless communication performed between the on-vehicle apparatus 10 and the electronic key 2 configured as described above will be described. The vehicle 1 is in a parked state.
As shown in FIG. 3, the on-vehicle device 10 transmits a wake signal Swk, which is a radio signal of the LF band, from the transmitting antenna 12 a provided on the

door handle

81, 82, 83 at a preset intermittent cycle. Thus, a communication area R (see FIG. 2) is formed around the vehicle 1. The wake signal Swk is for detecting the presence of the electronic key 2 in the communication area R.

When the user enters the communication area R (see FIG. 2) and the electronic key 2 receives the wake signal Swk, the electronic key 2 switches from the standby state to the activated state and transmits an acknowledgment signal Sac that is a wireless signal in the UHF band. .

When receiving the acknowledgment signal Sac in response to the wake signal Swk, the in-vehicle device 10 transmits a vehicle ID signal Svi, which is a wireless signal in the UHF band.
When the electronic key 2 receives the vehicle ID signal Svi, the electronic key 2 collates the vehicle ID code included in the vehicle ID signal Svi with the vehicle ID code stored in the memory 21, and when the collation is established, the ack signal Sac Send.

When receiving the acknowledgment signal Sac for the vehicle ID signal Svi, the in-vehicle device 10 transmits a challenge signal Scc including a challenge code. Further, the on-vehicle device 10 calculates a response code to be transmitted from the electronic key 2 by encrypting the challenge code using the encryption key stored in the memory 11 a.

When receiving the challenge signal Scc, the electronic key 2 computes a response code by encrypting the challenge code included in the challenge signal Scc with the encryption key (see FIG. 1) stored in the memory 21. The electronic key 2 transmits a response signal Sre including the electronic key ID code stored in the memory 21 and the response code calculated by itself.

When receiving the response signal Sre, the in-vehicle device 10 collates the electronic key ID code stored in the memory 11a with the electronic key ID code included in the response signal Sre. Further, the on-vehicle apparatus 10 collates the response code calculated by itself with the response code included in the response signal Sre.

When the ID code collation and the response code collation outside the vehicle compartment are established, the in-vehicle apparatus 10 sets in advance the wake signal Swk, which is a radio signal of the LF band, from the transmitting antenna 12a provided in the vehicle compartment to the entire area inside the vehicle compartment. Transmit at intermittent intervals. Between the in-vehicle device 10 and the electronic key 2, the same process as the ID code verification and the response code verification performed outside the vehicle is performed in the vehicle interior.

In addition to the ID code verification and the response code verification, the in-vehicle device 10 performs distance determination. The in-vehicle device 10 determines the distance between the in-vehicle device 10 and the electronic key 2. In the distance determination, the distance between the in-vehicle device 10 and the electronic key 2 is calculated through exchange of wireless signals between the in-vehicle device 10 and the electronic key 2, and the validity of the calculated distance is confirmed. The process of

As shown in FIG. 4, the vehicle-mounted device 10 first transmits a distance measurement request signal Sdc, which is a radio signal in the UWB band, when performing distance determination (step S101). When the electronic key 2 receives the distance measurement request signal Sdc (step S102), the electronic key 2 transmits a distance measurement response signal Sdr, which is a wireless signal in the UWB band (step S103). When the in-vehicle device 10 receives the distance measurement response signal Sdr from the electronic key 2 (step S104), the in-vehicle device 10 sends back the distance measurement request signal Sdc to the round-trip time until the distance measurement response signal Sdr is received. Based on the calculated distance Ld from the on-board unit 10 to the electronic key 2 (step S105). The in-vehicle device 10 performs distance determination to compare the distance Ld calculated in step S105 with the threshold Lth (step S106). When the distance Ld is equal to or less than the threshold Lth, the on-vehicle device 10 determines that the electronic key 2 is located in the communication area R. The on-vehicle device 10 determines that the electronic key 2 is outside the communication area R when the distance Ld exceeds the threshold Lth. In this case, for example, it may be considered that the communication is illegal using a relay. The threshold Lth is a value for determining whether or not the electronic key 2 is inside the communication area R of the vehicle 1, and the threshold Lth is required for the electronic key 2 according to the product specification of the communication system 3 or the like. It is set based on the working distance to the vehicle 1.

However, as shown in FIG. 2, depending on the positional relationship between the in-vehicle device 10 and the electronic key 2, wireless signals transmitted and received between the in-vehicle device 10 and the electronic key 2 (ranging request signal Sdc and ranging response signal The reflected radio signal may be received by the on-vehicle device 10 or the electronic key 2 by reflecting Sdr) on the obstacle Ob such as a surrounding wall (or another vehicle around the building) or a building. That is, it is conceivable that the distance Ld calculated by the in-vehicle device 10 becomes longer than the actual distance between the in-vehicle device 10 and the electronic key 2, and the distance Ld becomes larger than the threshold Lth. In such a case, even though the electronic key 2 exists in the communication area R, it is determined that the electronic key 2 exists outside the communication area R because the distance Ld is not correctly calculated. There is a possibility that it may be determined that the communication is illegal.

Since it may be a temporary situation that the distance Ld exceeds the threshold Lth, the distance determination between the on-vehicle device 10 and the electronic key 2 is preferably performed multiple times. However, if there is no change in the propagation state of the wireless signal between the in-vehicle device 10 and the electronic key 2, even if the distance determination is performed multiple times, the same result can only be repeatedly obtained.

Therefore, in order to improve the distance determination accuracy, the on-vehicle device 10 calculates the distance Ld under each situation in consideration of a plurality of situations where the communication situations are different. For example, as such a situation, a situation in which the propagation state of the wireless signal between the on-vehicle device 10 and the electronic key 2 is different can be considered. In this example, as shown in FIG. 5, the on-vehicle device 10 detects a first situation A, a second situation B, and a third situation C, which differ in the position of the electronic key 2 with respect to the on-vehicle device 10. Under the circumstances, the distance Ld between the in-vehicle device 10 and the electronic key 2 is calculated. When there are two or more situations where the distance Ld is less than or equal to the threshold Lth, the on-vehicle device 10 has the electronic key 2 in the communication area R and the communication between the on-vehicle device 10 and the electronic key 2 is correct. It is determined that the

The first situation A is a situation in which the user carrying the electronic key 2 has entered the communication area R. When receiving the acknowledgment signal Sac from the electronic key 2 in response to the wake signal Swk, the on-vehicle device 10 determines that the communication situation (the position of the electronic key 2 in this example) is the first situation A.

The second situation B is a situation in which the user carrying the electronic key 2 is in proximity to the vehicle 1. In the on-vehicle apparatus 10, assuming that the first situation A, when the user operates the

door handle

81, 82, or 83 through the door handle sensor 85, the communication situation (the position of the electronic key 2 in this example) Is determined to be the second situation B).

The third situation C is a situation in which the user carrying the electronic key 2 gets into the vehicle 1. When it is detected through the seating sensor 91 that the user is seated on the seat 90, the in-vehicle device 10 determines that the communication status (the position of the electronic key 2 in this example) is the third status C.

The first situation A, the second situation B, and the third situation C are situations that occur in a series of actions until the user approaches the vehicle 1 and gets into the vehicle 1, and the first situation A, the second situation The position of the electronic key 2 with respect to the in-vehicle device 10 changes between the situation B and the third situation C. Therefore, in each of the first to third situations A, B and C, the propagation state of the radio signal transmitted and received between the in-vehicle device 10 and the electronic key 2 is also different. That is, among the first to third situations A, B and C, the influence on the distance measurement by the reflection of the wireless signal by the obstacle Ob also changes.

The processing procedure of the distance determination between the on-vehicle device 10 and the electronic key 2 will be described according to the flowchart of FIG.
As shown in FIG. 6, the verification ECU 11 of the in-vehicle apparatus 10 determines whether the communication status (the position of the electronic key 2 in this example) is the first status A (step S201). When determining that the communication state is the first state A (YES in step S201), collation ECU 11 measures distance Ld between on-vehicle device 10 and electronic key 2, and distance Ld is equal to or less than threshold Lth. The first distance determination as to whether or not it is executed (step S202). Specifically, the verification ECU 11 executes steps S101 to S106 in the flowchart of FIG. 4 described above. The verification ECU 11 temporarily stores the determination result as to whether the distance Ld is equal to or less than the threshold Lth. In addition, when collation ECU 11 determines that the communication state is first state A (YES in step S201), authentication of electronic key 2 through wireless communication shown in the flowchart of FIG. It is determined whether to do. Then, when the authentication of the electronic key 2 is established in the first situation A, the collation ECU 11 permits the unlocking operation of the door 80. When the matching ECU 11 determines that the communication status is not the first status A (NO in step S201), the processing ends.

Next, the collation ECU 11 determines whether the communication state (the position of the electronic key 2 in this example) is the second state B (step S203). When determining that the communication state is the second state B (YES in step S203), verification ECU 11 measures distance Ld between on-vehicle device 10 and electronic key 2, and executes the second distance determination. (Step S204). The verification ECU 11 temporarily stores the determination result as to whether the distance Ld is equal to or less than the threshold Lth. Further, when it is determined that the communication status is the second status B (YES in step S201), the verification ECU 11 unlocks the door 80. When the matching ECU 11 determines that the communication status is not the second status B (NO in step S203), the processing ends.

Next, the collation ECU 11 determines whether the communication state (the position of the electronic key 2 in this example) is the third state C (step S205). When determining that the communication state is the third state C (YES in step S205), collation ECU 11 measures distance Ld between on-vehicle device 10 and electronic key 2, and executes the third distance determination. (Step S206). The verification ECU 11 temporarily stores the determination result as to whether the distance Ld is equal to or less than the threshold Lth. When the matching ECU 11 determines that the communication status is not the third status C (NO in step S205), the processing ends.

Next, the verification ECU 11 determines whether or not normal communication is established between the in-vehicle device 10 and the electronic key 2 based on the temporarily stored result of the distance determination (step S207). In this example, the matching ECU 11 determines whether or not the determination result that the distance Ld is equal to or less than the threshold Lth is two or more based on the result of the distance determination performed in each of the situations A, B, and C. If the determination result that the distance Ld is equal to or less than the threshold Lth is two or more, the verification ECU 11 determines that the communication between the on-vehicle device 10 and the electronic key 2 is a legitimate communication (step S207). YES). Then, verification ECU 11 determines whether or not the authentication of electronic key 2 through the wireless signal shown in the flowchart of FIG. 3 is established in the vehicle interior, and when the authentication of electronic key 2 is established, engine 60 The start of the control is permitted (step S208). For example, the verification ECU 11 transmits to the engine ECU 50 that the start of the engine 60 is permitted (see FIG. 1). Further, when there are not two or more determination results indicating that the distance Ld is equal to or less than the threshold Lth (NO in step S207), the verification ECU 11 disallows the start of the engine 60. For example, the verification ECU 11 transmits to the engine ECU 50 that the start of the engine 60 is not permitted.

The operation and effects of the present embodiment will be described.
(1) The first situation where the in-vehicle apparatus 10 has different communication conditions between the in-vehicle apparatus 10 and the electronic key 2 (in this example, the position of the electronic key 2 relative to the in-vehicle apparatus 10 that changes the propagation state of the wireless signal). In consideration of A, the second situation B, and the third situation C, the measurement of the distance Ld is performed under each of the situations A to C. Since the propagation state of the wireless signal between the in-vehicle device 10 and the electronic key 2 is different in each of the situations A to C, the measurement of the distance Ld is performed without any change in the communication condition between the in-vehicle device 10 and the electronic key 2 It is suppressed that the exact same measurement result is repeated compared with the case of implementation. Therefore, even if the in-vehicle device 10 determines that the communication between the in-vehicle device 10 and the electronic key 2 is temporarily established illegally due to the reflection of the wireless signal, the in-vehicle device 10 is again An opportunity can be obtained to determine that the communication between 10 and the electronic key 2 has not been established illegally. Therefore, it is possible to improve the determination accuracy as to whether or not the communication between the in-vehicle device 10 and the electronic key 2 is normal.

(2) The in-vehicle apparatus 10 determines whether or not normal communication is being performed by majority based on the whole determination result of whether the distance Ld is equal to or less than the threshold Lth. Thereby, the reliability of the determination as to whether or not the communication between the on-vehicle device 10 and the electronic key 2 is established illegally can be improved.

The above embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with one another as long as there is no technical contradiction.
In the above embodiment, the trigger for recognizing the third situation C is that the user is seated on the seat 90. For example, the stepping operation of the brake pedal provided on the vehicle 1 is used as a trigger Also good. That is, the operation detected before the user tries to start the engine 60 by the operation of the engine switch 70 may be set as a trigger for recognizing the third situation C.

-In the said embodiment, although the trigger for recognizing 2nd condition B was that a user's hand

contacts door handle

81, 82, 83, opening and closing of door 80 is detected, for example through a courtesy switch. It may be triggered.

In the above embodiment, although the distance Ld is measured in the first situation A, the second situation B, and the third situation C, for example, the first situation A, the second situation B, and the second situation B, The distance Ld may be measured in four or more different situations, including the third situation C. That is, by measuring the distance Ld more times under different communication conditions between the on-vehicle device 10 and the electronic key 2 (for example, different radio signal propagation conditions), the distance between the on-vehicle device 10 and the electronic key 2 is increased. It is possible to further improve the determination accuracy of the communication.

In the above embodiment, the measurement of the distance Ld and the distance determination are performed in any two situations of three or more different situations including the first situation A, the second situation B, and the third situation C. The engine 60 may be allowed to start. At this time, since the start of the engine 60 can not be determined by majority decision, the start of the engine 60 may be permitted as long as the determination result that the distance Ld is equal to or less than the threshold Lth is obtained even in only one of two situations. For example, assuming that the first situation A and the third situation C are selected as the two situations, if it is determined that the distance Ld is less than or equal to the threshold Lth in the third situation C alone, the engine 60 is started. May be permitted.

Describing this process in detail, in the above embodiment, the in-vehicle device 10 permits the unlocking of the door 80 when the first situation A is detected, but a third party uses the relay or the like to execute the in-vehicle device When attempting to establish the communication between 10 and the electronic key 2 illegally, the electronic key 2 does not exist in the communication area R formed by the on-vehicle device 10 (that is, the first situation A is not detected) ), And the distance Ld between the electronic key 2 and the on-vehicle device 10 is kept constant in the state of exceeding the threshold Lth. Therefore, even if it is determined whether communication between the on-vehicle device 10 and the electronic key 2 is improperly made multiple times, communication is always established between the on-vehicle device 10 and the electronic key 2 incorrectly. It is determined that the Therefore, it is assumed that the factor for determining that the distance Ld is not less than or equal to the threshold Lth in the first situation A is that the radio signal is reflected by the obstacle Ob. Therefore, the fact that the distance Ld exceeds the threshold Lth in the first situation A is considered to be a temporary effect caused by the reflection of the radio signal on the obstacle Ob. Therefore, if it is determined that the distance Ld is equal to or less than the threshold Lth under the third situation C, the start of the engine 60 may be permitted.

Also, although it is set to permit starting of the engine 60 when it is determined that communication is correct between the in-vehicle device 10 and the electronic key 2, in order to allow locking and unlocking of the door 80. It may be determined whether the communication is normal or not.

For example, a control flow as shown in FIG. 7 may be employed. Steps S201 to S204 of FIG. 7 are the same as steps S201 to S204 shown in the flowchart of FIG.

After performing the distance determination in the situations A and B, the in-vehicle device 10 determines whether the communication between the in-vehicle device 10 and the electronic key 2 is correct (step S301). In this case, it is determined whether or not one of the results of the distance determination performed in each of the situations A and B indicates that the distance Ld is less than or equal to the threshold Lth. When it is determined that there is at least one determination result that the distance Ld is equal to or less than the threshold Lth (YES in step S301), the in-vehicle device 10 permits unlocking of the door 80 (step S302). When it is determined that the determination result that the distance Ld is equal to or less than the threshold Lth is not present (NO in step S301), the in-vehicle device 10 prohibits the unlocking of the door 80. Step S302 may be changed to "permit start of engine 60", and step S302 may be changed to "disallow start of engine 60".

That is, in selecting at least two of the three or more situations including the first situation A, the second situation B, and the third situation C, the communication between the on-vehicle device 10 and the electronic key 2 is correct If the permitted event is the start of the engine 60, at least two situations are selected before the engine switch 70 is operated. In addition, when the event permitted by the correct communication between the in-vehicle device 10 and the electronic key 2 is the locking and unlocking of the door 80, at least two situations are selected before the door 80 is opened. Do.

In the above embodiment, the control of whether to permit the operation of the engine 60 and the control of whether to permit the unlocking of the door 80 may be used in combination.
· As a means for changing the propagation state of the wireless signal between the in-vehicle device 10 and the electronic key 2, the position of the user carrying the electronic key 2 is the first situation A, the second situation B, and the third situation It is not limited to changing like C.

For example, two or more transmission / reception antennas 14a of the UWB transmission / reception unit 14 are provided, and the propagation state of the wireless signal between the on-vehicle device 10 and the electronic key 2 is changed by switching and using the plurality of transmission / reception antennas 14a. It is also good. At this time, the transmission / reception antenna 14a is switched using a trigger that the distance Ld is not smaller than the threshold Lth in any of the first situation A and the second situation B. In this way, even if the position of the user (electronic key 2) does not change until the third situation C, the propagation state of the wireless signal between the on-vehicle device 10 and the electronic key 2 can be changed. . Alternatively, as a further specific example for realizing different communication situations, the frequency band of the radio signal used to measure the distance Ld may be changed, triggered by the fact that the distance Ld is not less than the threshold Lth.

In the above embodiment, although the distance Ld is used to determine whether the communication between the in-vehicle device 10 and the electronic key 2 is correct, for example, in the wireless signal between the in-vehicle device 10 and the electronic key 2 Received signal strength may be used. Thus, different communication conditions may be detected depending on the received signal strength. The received signal strength is an example of a parameter related to the distance Ld.

It is conceivable that as the distance Ld between the in-vehicle device 10 and the electronic key 2 becomes longer, the received signal strengths of the wireless signals received mutually decrease. That is, it is considered that the distance Ld and the received signal strength are in inverse proportion. Therefore, the path taken by the wireless signal (the distance measurement request signal Sdc and the distance measurement response signal Sdr) is long until the on-vehicle device 10 and the electronic key 2 mutually transmit and receive, thereby causing a failure in the wireless signal. It is considered that the possibility of reflection on the object Ob increases, and the received signal strength also decreases. Therefore, measurement is performed by setting the received signal strengths of the distance measurement request signal Sdc and the distance measurement response signal Sdr when the distance Ld is the threshold Lth as the reference intensity (threshold), and receiving the in-vehicle device 10 and the electronic key 2 respectively. When the received signal strengths of the distance request signal Sdc and the distance measurement response signal Sdr exceed the threshold value, it may be determined that the electronic key 2 is present at a distance at which normal communication is established with the on-vehicle device 10.

In the above embodiment, the radio signal used may be changed to a signal of any frequency band.
In the above embodiment, the door handle sensor 85 and the door lock device 40 may be provided in all the doors 80. Further, the seating sensor 91 may be provided not only at the driver's seat but also at the passenger seat or the rear seat.

Claims

The vehicle-mounted device includes an on-vehicle device mountable in a vehicle and an electronic key portable by a user, wherein the on-vehicle device forms a communication area around the vehicle for detecting the presence of the electronic key. A communication system in which the in-vehicle device authenticates the electronic key by transmitting and receiving a radio signal between the in-vehicle device and the electronic key in a state where the in-vehicle device exists in a communication area,
The in-vehicle device measures a distance related to the in-vehicle device and the electronic key or a parameter related to the distance under each situation in a plurality of different communication situations.
The in-vehicle apparatus determines whether communication is established between the in-vehicle apparatus and the electronic key improperly based on the distance or the parameter measured in each of the plurality of situations.
The communication system according to claim 1, wherein the plurality of situations are situations where propagation states of the wireless signal between the in-vehicle apparatus and the electronic key are different.
The communication system according to claim 2, wherein the plurality of situations are situations in which the position of the electronic key with respect to the in-vehicle device changes.
The number of said plurality of situations is set to an odd number,
The in-vehicle device measures the distance in each of the plurality of situations and determines whether the distance is equal to or less than a threshold, and the distance among the plurality of determination results obtained in the plurality of situations is determined. When the determination result indicating that the value is greater than or equal to the threshold value is a majority, it is determined that the communication between the on-vehicle device and the electronic key is correct, and the determination result indicating that the distance is less than or equal to the threshold value is The communication system according to any one of claims 1 to 3, wherein it is determined that the communication between the in-vehicle device and the electronic key is not correct when the number is less than a majority.
The vehicle includes a first sensor that detects an operation of a door, and a second sensor that detects a user's seating on a seat.
The plurality of situations include a first situation in which the electronic key has entered the communication area, a second situation in which the electronic key is approaching the vehicle, and the electronic key inside the vehicle. Including the third situation,
The in-vehicle device is
The in-vehicle device transmits a first wireless signal to detect the presence of the electronic key, and the position of the electronic key is determined by receiving a second wireless signal from the electronic key as a response to the first wireless signal. Detect that it is the first situation,
The operation of the door is detected through the first sensor to detect that the position of the electronic key is in the second state,
The communication according to any one of claims 1 to 4, wherein it is detected that the position of the electronic key is the third situation by detecting that the user is seated on the seat through the second sensor. system.
The in-vehicle device detects a plurality of situations in which the communication conditions are different based on the received signal strength measured by the in-vehicle device.
The communication system according to any one of claims 1 to 5.
The vehicle includes a plurality of antennas used to transmit a wireless signal to measure the distance or the parameter related to the distance;
The in-vehicle device switches a plurality of situations in which the communication status is different by switching the plurality of antennas.
The communication system according to any one of claims 1 to 6.