JP2019121949A - Communication system - Google Patents

Abstract

To provide a communication system which in which determination accuracy of validity of a communication between an on-vehicle machine and an electronic key is improved.SOLUTION: An on-vehicle machine executes first measurement of a distance Ld between the on-vehicle machine and an electron key and executes a distance determination whether the distance Ld is equal to a threshold value or less when determining that the electron key is in a first situation A. When it is determined that the electron key is in a second situation B, the on-vehicle machine executes second measurement of a distance Ld between the on-vehicle machine and the electron key, and executes the distance determination whether the distance Ld is equal to the threshold value or less. When it is determined that the electron key is in a third situation C, the on-vehicle machine executes a third measurement of distance Ld between the on-vehicle machine and the electron key, and executes the distance determination whether the distance Ld is equal to the threshold value or less. The on-vehicle machine determines whether a communication between the on-vehicle machine and the electron key is a qualified communication or not on the basis of a result of the distance determination.SELECTED DRAWING: Figure 6

Description

  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.

  A communication system that can achieve the above object includes an on-vehicle device mounted on a vehicle and an electronic key carried by a user, and the on-vehicle device communicates 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 forming an area and transmitting and receiving a wireless signal between the in-vehicle device and the electronic key in a state where the electronic key is present in the communication area And The in-vehicle device measures the distance between the in-vehicle device and the electronic key or a parameter related to the distance for each of a plurality of situations, and the in-vehicle device measures the distances or the parameters measured in the plurality of situations. It is determined whether communication is established between the in-vehicle device and the electronic key based on the above.

  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 situation between the in-vehicle device and the electronic key. Therefore, the on-vehicle device re-determines that the communication between the on-vehicle device and the electronic key is temporarily established illegally due to the reflection of the wireless signal, and the inter-vehicle device and the electronic key are again determined as a determination result. An opportunity can be obtained to determine that communication has not been established fraudulently. Therefore, the communication accuracy between the in-vehicle device and the electronic key can be improved.

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, when the plurality of situations are set to an odd number, and the in-vehicle device determines that the distance measured for each of the plurality of situations is less than or equal to a threshold, Between the in-vehicle device and the electronic key when it is determined that the communication between the in-vehicle device and the electronic key is correct and the determination result indicating that the distance is less than or equal to the threshold is less than a majority It is preferable to determine that the communication of the is not correct.

  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 The electronic key is in the first state by the onboard unit receiving the wireless signal as a response from the electronic key to the wireless signal transmitted to detect the presence of the electronic key. The operation of the door is detected through the first sensor, and that the electronic key is in the second situation is detected when the user is seated on the seat through the second sensor. It is preferable to detect said electronic key is in the third status by.

  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. In the present embodiment, the seat 90 is a driver's seat. The plurality of doors 80 are doors provided at positions corresponding to the driver's seat, the passenger's seat, and the trunk. Further, an electrostatic sensor is adopted for the door handle sensor 85.

  The door lock device 40 is built in the door 80. The door handle sensor 85 is incorporated in the door handle 81 of the door 80 on the driver's side, the door handle 82 of the door 80 on the passenger's side, and the door handle 83 on the trunk side. The door handle sensor 85 detects that the user's hand contacts the door handle 83. The seating sensor 91 is built in the seat 90. 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 is in a parked state (the door 80 is in a locked state and the engine 60 is in a stopped state), the on-vehicle device 10 transmits a radio signal of the LF band at a preset intermittent cycle through the transmission antenna 12a. Thus, a communication area R 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 calculated by itself 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 an electronic key ID code stored in the memory 21 and a response code to be 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 the 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 the reflection of the signal Sdr) on the obstacle Ob such as the vehicle 1 or the building Build. 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. That is, although the electronic key 2 is present in the communication area R, it is determined that the electronic key 2 is present outside the communication area R because the distance Ld is not correctly calculated. There is a possibility that it may be determined as communication.

  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, as shown in FIG. 5, the on-vehicle device 10 has a first situation A, a second situation B, and a third situation A as positions of the electronic key 2 with respect to the on-vehicle device 10 where the propagation state of the wireless signal is considered different. In the three situations of situation C, 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. The in-vehicle device 10 determines that the first situation A is in effect when the acknowledgment signal Sac from the electronic key 2 in response to the wake signal Swk is received.

  The second situation B is a situation in which the user carrying the electronic key 2 is in proximity to the vehicle 1. The on-vehicle device 10 determines that it is in the second situation B when the operation of the door handles 81, 82, 83 of the user is detected through the door handle sensor 85 on the premise that it is the first situation A.

  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 that the user is seated on the seat 90 through the seating sensor 91, the in-vehicle device 10 determines that it is the third situation C.

  The first situation A, the second situation B, and the third situation C are situations in a series of flows until the user approaches the vehicle 1 and gets on the vehicle 1, and the first situation A, the second situation In the situation B and the third situation C, the position of the electronic key 2 with respect to the in-vehicle device 10 changes. For this reason, in the situations A, B and C, the propagation states of radio signals transmitted and received between the on-vehicle device 10 and the electronic key 2 are also different. The influence on the distance measurement by the reflection of the radio signal on 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 position of the electronic key 2 is in the first situation A (step S201). When it is determined that the electronic key 2 is in the first situation A (YES in step S201), the verification ECU 11 performs the first measurement of the distance Ld between the in-vehicle device 10 and the electronic key 2; It is determined whether the distance Ld is equal to or less than the threshold Lth (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. Further, when it is determined that electronic key 2 is in the first state A (YES in step S201), verification ECU 11 of electronic key 2 through the wireless communication shown in the flowchart of FIG. When the authentication is established, the door 80 is permitted to unlock. When it is determined that the electronic key 2 is not in the first situation A (NO in step S201), the verification ECU 11 ends the process.

  Next, the collation ECU 11 determines whether the position of the electronic key 2 is in the second situation B (step S203). When it is determined that the electronic key 2 is in the second situation B (YES in step S203), the verification ECU 11 performs measurement and distance determination of the second distance Ld between the in-vehicle device 10 and the electronic key 2 It executes (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. When it is determined that the electronic key 2 is in the second situation B (YES in step S201), the verification ECU 11 unlocks the door 80. When it is determined that the electronic key 2 is not in the second situation B (NO in step S203), the verification ECU 11 ends the process.

  Next, the collation ECU 11 determines whether the position of the electronic key 2 is in the third situation C (step 205). When it is determined that the electronic key 2 is in the third situation C (YES in step S205), the verification ECU 11 performs third distance Ld measurement and distance determination between the on-vehicle device 10 and the electronic key 2 Execute (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. Further, when it is determined that the electronic key 2 is not the third situation C (NO in step S205), the verification ECU 11 ends the process.

  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). Specifically, the verification ECU 11 determines whether or not the determination result indicating 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 normal communication (step S207) YES), when the authentication of the electronic key 2 through the wireless signal shown in the flowchart of FIG. 3 is established in the vehicle interior, the engine 60 is permitted to be started (step S208). Specifically, the verification ECU 11 notifies the engine ECU 50 that the start of the engine 60 has been 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. Specifically, verification ECU 11 transmits to engine ECU 50 that the start of engine 60 is not permitted.

The operation and effects of the present embodiment will be described.
(1) The measurement of the distance Ld is performed in the first situation A, the second situation B, and the third situation C in which the propagation states of wireless signals between the on-vehicle apparatus 10 and the electronic key 2 are different. Since the propagation state of the wireless signal between the in-vehicle device 10 and the electronic key 2 is different, compared to the case where the measurement of the distance Ld is performed in a state where there is no change in the condition between the in-vehicle device 10 and the electronic key 2 It is suppressed that the exact same measurement result is repeated. 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, the communication accuracy between the in-vehicle device 10 and the electronic key 2 can improve the accuracy of the determination.

  (2) Confidence in determination as to whether communication between the on-vehicle device 10 and the electronic key 2 is improperly established by determining whether or not the distance Ld measured a plurality of times is equal to or less than the threshold Lth by majority decision It is possible to improve the quality.

The present embodiment can be modified as follows. 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 present embodiment, the trigger for recognizing the third situation C is that the user is seated on the seat 90. However, for example, even if the trigger operation of the brake provided on the vehicle 1 is triggered good. That is, the configuration operated before the user tries to activate the engine 60 by operating the engine switch 70 may be set as a trigger for recognizing the third situation C.

  The trigger for recognizing the second situation B is that the user's hand contacts the door handle 81, 82, 83. For example, the opening / closing of the door 80 is detected through the courtesy switch May be used as a trigger.

  In the present embodiment, the distance Ld is measured in the first situation A, the second situation B, and the third situation C, but, for example, the first situation A, the second situation B, and the second situation B, The distance Ld may be measured also in other situations other than the third situation C. That is, by measuring the distance Ld multiple times in a situation where the propagation state of the wireless signal between the in-vehicle device 10 and the electronic key 2 is different, the accuracy of determination of the correctness of communication between the in-vehicle device 10 and the electronic key 2 is improved. .

  In addition, measurement of the distance Ld and distance determination are performed in any one of the first situation A, the second situation B, the third situation C, and the other situations, and the engine 60 is started. May be permitted. 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.

  In the present embodiment, the on-vehicle device 10 is set to permit the unlocking of the door 80 when the first situation A is detected. When attempting to establish communication between the keys 2 illegally, the electronic key 2 does not exist in the communication area R formed by the on-vehicle device 10, and between the electronic key 2 and the on-vehicle device 10 The distance Ld is maintained constant above the threshold Lth. Therefore, it is always determined whether communication has been established between the on-vehicle device 10 and the electronic key 2 more than once. It is determined that communication has been established between the on-vehicle device 10 and the electronic key 2 improperly. That is, a factor in which the distance Ld is not equal to or less than the threshold Lth is that the radio signal is reflected to the obstacle Ob. Therefore, the fact that the distance Ld is less than or equal to the threshold Lth in the first situation A is a temporary effect that the radio signal is reflected to the obstacle Ob, so the distance at the third situation C opportunity again. If it is determined that Ld is equal to or less than the threshold Lth, the start of the engine 60 may be permitted.

  -Also, when it is determined that the communication between the on-vehicle device 10 and the electronic key 2 is correct, the start of the engine 60 is set to be permitted, but the lock and unlock of the door 80 is permitted. You may

For example, a control flow as shown in FIG. 7 may be used. Steps S201 to S204 are the same as in the present embodiment 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). Specifically, it is determined whether the distance Ld is less than or equal to the threshold Lth as a result of the distance determination performed in each of the situations A and B. 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 first situation A, the second situation B, the third situation C, and the other situations, the communication between the on-vehicle device 10 and the electronic key 2 is correct. When a certain permitted event is the start of the engine 60, at least two situations are selected before the operation of the engine switch 70. In addition, when the event permitted by the correct communication between the on-vehicle device 10 and the electronic key 2 is the locking and unlocking of the door 80, at least two situations before the opening of the door 80 are Select

The control of whether to permit the operation of the engine 60 in the present embodiment 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. Is considered. 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 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. Furthermore, as a further specific example, 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 or equal to the threshold Lth.

  In the present embodiment, 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. 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, since the distance Ld and the received signal strength are considered to be in inverse proportion to each other, the distance measurement request signal Sdc and the distance measurement response signal Sdr are reflected by the obstacle Ob, whereby the on-vehicle device 10 and the electronic key 2 mutually It is also conceivable that the received signal strength is also reduced by increasing the route taken until transmission and reception. Therefore, the distance measurement request signal Sdc received by the on-vehicle device 10 and the electronic key 2 is set based on the received signal intensities of the distance measurement request signal Sdc and the distance measurement response signal Sdr when the distance Ld is the threshold Lth. When the received signal strength of the distance measurement response signal Sdr exceeds the threshold, the electronic key 2 may be determined to be at a distance at which normal communication is established with the on-vehicle device 10.

In the present embodiment, the radio signal used may be changed to a signal of any frequency band.
In the present 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.

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... electronic key, 3 ... communication system, 10 .. in-vehicle machine, 60 ... engine, 80 ... door, 85 ... door handle sensor, 90 ... seat, 91 ... seating sensor, Ld ... distance, Lth ... threshold value, A: First situation, B: Second situation, C: Third situation, Swk: Wake signal, Sac: Ac signal, Svi: Vehicle ID signal, Scc: Challenge signal, Sre: Response signal, Sdc: Measurement Distance request signal, Sdr ... distance measurement response signal, R ... communication area.

Claims (5)

The vehicle-mounted device includes a vehicle-mounted device mounted on a vehicle and an electronic key carried by a user, wherein the vehicle-mounted device forms a communication area around the vehicle for detecting the presence of the electronic key, and 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 between the in-vehicle device and the electronic key or a parameter related to the distance for each of a plurality of 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 the plurality of situations. The communication system according to claim 1, wherein the plurality of situations are situations where propagation states of wireless signals between the in-vehicle device 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 plurality of situations are set to an odd number,
The in-vehicle device determines that the communication between the in-vehicle device and the electronic key is correct when the determination result indicating that the distance measured for each of the plurality of situations is equal to or less than a threshold is a majority. The communication between the on-vehicle device and the electronic key is determined not to be correct when the determination result indicating that the distance is less than or equal to the threshold is less than a majority. The communication system described in the section. 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 enters the communication area, a second situation in which the electronic key approaches the vehicle, and the electronic key inside the vehicle Including the third situation,
The on-vehicle device receives the wireless signal as a response from the electronic key to the wireless signal transmitted to detect the presence of the electronic key, and the on-vehicle device receives the wireless signal and the electronic key is in the first state. It is detected that the user is seated on the seat through the second sensor through the second sensor that the operation of the door is detected through the first sensor. The communication system according to any one of claims 1 to 4, wherein it is detected that the electronic key is in the third state.