JP2010090581A - Vehicle-side device and electronic key system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic key system which enables the inexpensive unlocking of a door without deteriorating convenience to a user. <P>SOLUTION: This vehicle-side device 11 of the electronic key system 100 authenticates a portable machine 16 on the basis of authentication information wirelessly received from the portable machine 16 outside a vehicle, and makes the door lock openable. The vehicle-side device 11 includes: a noise electric wave detecting means 71 for detecting noise electric waves generating noises in the reception of the electric waves transmitted by the portable machine 16; a registration means 72 for registering positional information on a location of the detection of the noise electric waves into a server 14 or a user's own vehicle; a noise position information acquiring means 23 for acquiring a noise generating location DB 15 in which the positional information on the location of the detection of the noise electric waves is registered, from the server 14 or another vehicles; a determination means 73 for determining whether or not the present location of the vehicle is a noise generating location, on the basis of the noise generating location DB 15, in the authentication of the portable machine 16; and an output increase requiring means 74 for requiring the portable machine 16 to increase the transmission output of the authentication information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic key system that can authenticate a portable device outside a vehicle and unlock a door lock, and a vehicle side device thereof. About.

  An electronic key system has been put into practical use in which a door of a vehicle is unlocked when a keyless entry key (hereinafter referred to as an electronic key) within a predetermined distance from the vehicle responds. In the electronic key system, a request signal is constantly transmitted from the vehicle, and when the electronic key receives the request signal, a response signal is transmitted to the communication device of the vehicle. Therefore, the electronic key system does not function unless either the request signal or the response signal is received due to noise or the like. However, since the electronic key is small and the output of the electronic key is often set low from the viewpoint of the capacity of the built-in battery and security, the door may not be unlocked in a noisy environment.

  In this regard, a technique for making the output of the request signal variable has been proposed (see, for example, Patent Document 1). Patent Document 1 discloses an electronic key system that increases the output of a request signal according to the number of times a user presses the button of the electronic key.

  Even if the request signal is disturbed by noise, the request signal can be received if the reception sensitivity of the vehicle communication device is good (see, for example, Patent Document 2). Therefore, Patent Document 2 discloses an electronic key system that separates an antenna from a receiving circuit when the noise signal strength obtained for each of a plurality of antennas having different directivities is greater than or equal to a threshold value. By separating an antenna that easily receives noise, the reception level of noise is reduced as a whole, so that reception sensitivity can be increased.

In addition, an electronic key system has been proposed in which a frequency different from the noise frequency is selectively used to communicate between a communication device and an electronic key (see, for example, Patent Document 3). Patent Document 3 discloses an electronic key system in which a preferable frequency is registered in advance in map data, the map data is referred to based on a position when the vehicle is parked, and a communication device of the vehicle transmits a request signal at a preferable frequency at that position. Is disclosed.
Japanese Patent Laid-Open No. 11-59331 JP 2008-5120 A Japanese Patent Laid-Open No. 10-292700

  However, as in the electronic key system described in Patent Document 1, if the user has to press the button of the electronic key when communication is difficult, it is necessary to take out and hold the electronic key. There is a problem of lowering. Further, the electronic key system described in Patent Document 2 cannot avoid an increase in cost, for example, by providing a plurality of directional antennas or by selecting and disconnecting the antennas. Further, in the electronic key system described in Patent Document 3, since it is necessary to mount an antenna corresponding to a plurality of frequencies on the electronic key, there is a problem that the electronic key becomes large and the cost increases.

  In view of the above problems, an object of the present invention is to provide an electronic key system and a vehicle-side device capable of unlocking a door at low cost without impairing user convenience.

  In view of the above problems, the present invention relates to a vehicle-side device of an electronic key system that can authenticate the portable device based on authentication information received wirelessly from a portable device outside the vehicle and unlock the door lock. Noise radio wave detection means for detecting noise radio waves that interfere with reception of radio waves to be transmitted, registration means for registering location information of locations where noise radio waves are detected in a server or own vehicle, and location information of locations where noise radio waves are detected Noise location information acquisition means for acquiring a registered noise occurrence location database from a server or other vehicle, and when authenticating a portable device, the current location of the vehicle is determined from the location where the noise radio wave is detected based on the noise occurrence location database. The determination means for determining whether or not the distance is within a predetermined distance, and if the current location is within a predetermined distance from the location registered in the noise occurrence location database, And having a output up request means for requesting to up the transmission output testimony information.

  By increasing the transmission output of the portable device, the communication error can be reduced and the authentication information can be received even in a place where noise occurs.

  It is possible to provide an electronic key system and a vehicle-side device capable of unlocking a door at low cost without impairing user convenience.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of an overall configuration diagram of an electronic key system 100 according to the present embodiment. The vehicle-side device 11 of each vehicle monitors radio waves that are noise for the electronic key system 100, and transmits noise generation location information indicating the location to the server 14 when large noise is detected. Since the noise occurrence location information is transmitted from each vehicle to the server 14, the server 14 has a noise occurrence location database (hereinafter referred to as DB) in which the latest noise occurrence location is registered. The vehicle-side device 11 of each vehicle stores a copy of all or part of the noise generation location DB 15 and determines whether the location where the vehicle is parked and unlocked and the door lock is unlocked is close to the noise generation location. It can be done.

  And if the vehicle side apparatus 11 of this embodiment determines that the place where the vehicle is parked is close to the noise occurrence place, the vehicle side apparatus 11 transmits an output up signal requesting to increase the output of the portable device 16 to the portable device 16, or Alternatively, at least one of increasing the reception sensitivity of the vehicle side device 11 is performed. Thereby, the vehicle side apparatus 11 and the portable device 16 can communicate satisfactorily even in a noise generation place and can unlock or lock the door of the vehicle.

  The noise is noise that causes radio wave interference in the electronic key system 100, and is radio waves having a frequency similar to the frequency of radio waves communicated between the vehicle-side device 11 and the portable device 16 and having high radio wave intensity. . In the electronic key system 100, a request signal and a response signal are transmitted and received at a specific frequency. However, depending on the vehicle model, the frequency may be different, so the presence or absence of noise is determined for the frequency employed in the electronic key system 100. The Therefore, in the noise generation location DB 15, a location where noise exists for each frequency employed in the electronic key system 100 is registered.

[Configuration of Electronic Key System 100]
FIG. 2 shows an example of a schematic configuration diagram of the vehicle-side device 11 and the portable device 16 constituting the electronic key system 100.

<Vehicle side device 11>
The vehicle side device 11 includes a portable device communication device 21 that communicates with the portable device 16, a verification ECU (electronic control unit) 22 that authenticates a key code received from the portable device 16, a communication device 23 that communicates with the server 14, and A navigation ECU 24 that controls the navigation system is connected via a vehicle-mounted LAN such as a CAN (Controller Area Network) or a LIN (Local Interconnect Network).

  The verification ECU 22 in the door-locked state requests the portable device communication device 21 to transmit a request signal at a predetermined time interval. This request signal forms a detection area in a range of about 50 to 1 m outside the vehicle centering on the portable device communication device 21, and when the portable device 16 enters the detection area, the request signal between the portable device 16 and the portable device communication device 21. Communication becomes possible, and the portable device communication device 21 receives the key code.

  The key code of the portable device 16 received by the portable device communication device 21 is sent to the verification ECU 22. When the received key code matches the key code of the portable device 16 registered in advance, the verification ECU 22 determines that the authentication of the portable device 16 has been established and requests the body ECU to unlock the door. Thereby, when the user carrying the portable device 16 touches the door knob, the door is unlocked.

  The communication device 23 is a mobile phone, a PHS (Personal Handyphone System), a wireless LAN unit or the like according to IEEE802.11b / g and IEEE 802.16a standards, and is connected to a mobile phone or a PHS base station 12 or a wireless LAN access point. Then, it connects to the network 13 via a business server such as a mobile phone. The communication device 23 stores data to be transmitted / received to / from the server 14 in a frame according to a protocol such as FTP (File Transport Protocol), and generally travels along a route to the server 14 determined by IP which is a protocol followed by a router. It communicates with the server 14 in accordance with TCP, which is a protocol that defines a procedure such as retransmission.

  The navigation ECU 24 determines the position of the host vehicle based on the distances to a plurality of GPS satellites supplemented by the GPS receiver 25. This position determines the position of one point on the three-dimensional latitude / longitude / altitude GPS coordinate system, and accumulates the distance detected by the wheel speed sensor in the direction detected by the gyro sensor from this position. Is detected. A map DB 26 and a vehicle noise DB 27 are connected to the navigation ECU 24. The map DB 26 stores links and nodes in association with the position information, and other position information such as gas stations and public facilities. The vehicle noise DB 27 is a copy of the noise occurrence location information DB stored in the server 14 or a partial copy including noise occurrence location information around the current position of the vehicle. The vehicle noise DB 27 is downloaded from the server 14 at regular intervals or upon request from the vehicle. The noise occurrence location may be registered directly in the map DB 26.

  The verification ECU 22 and the navigation ECU 24 have a computer including a CPU, RAM, ROM, NVRAM, ASIC (Application Specific Integrated Circuit), and an input / output interface as a substance. In the present embodiment, the verification ECU 22 determines whether the location where the parking is close is near the location where the noise is generated, when the noise is generated, the registration request unit 72 that requests the server 14 to register the location. A place determination unit 73; an output up request unit 74 that requests the portable device 16 to increase output when close to a place where noise occurs; and a reception sensitivity increase unit 75 that increases reception sensitivity when close to a place where noise occurs. Have. Each of these functions is realized by the CPU executing a program or by ASIC hardware.

<Portable machine communication device 21>
The portable device communication device 21 will be described. FIG. 3 shows an example of a schematic configuration diagram of the portable device communication device 21 and the portable device 16. The portable device communication device 21 is controlled by the control unit. The control unit 39 outputs a command code included in the request signal for each cycle time, and generates an intermediate wave by modulating the command code using a modulation method such as BPSK or QPSK. The intermediate wave is mixed with the high frequency generated by the transmission circuit 45 by the mixer 43, amplified by the amplification circuit 44, and then transmitted from the antenna. The command codes of this embodiment are a command requesting a key code from the portable device 16 (in the case of a request signal) and a command requesting output up (in the case of an output up signal).

  On the other hand, the received signal from the portable device 16 received by the antenna is filtered with a high frequency, amplified by the amplifier circuit 31, and output to the mixer 33. The mixer 33 mixes the reception signal and the oscillation signal generated by the transmission circuit 32 to generate a lower frequency intermediate wave. The filter 34 passes only a desired frequency band from the intermediate wave, amplifies it by the amplifier circuit 35, demodulates it by the demodulation circuit 36, and takes out the key code.

  In the present embodiment, the switch 30 is provided after the antenna, and the switch 30 is switched to the filter 37 side when communicating with the portable device 16 near the place where noise is generated. The filter 37 has a pass band narrower than that of the carrier wave of the portable device 16. In general, since the carrier frequency band and the noise frequency spread rarely coincide with each other, the S / N ratio is improved by passing the filter 37 having a narrow pass band. Since the reception signal that has passed through the filter 37 is amplified by the amplifier circuit 38, the same effect as that obtained by increasing the reception sensitivity can be obtained. Further, if the received signal is amplified with a high frequency, the received signal may oscillate between the antenna and the amplifier circuit 31, so that the gain of the amplifier circuit 31 has a margin. On the other hand, the amplification circuit 38 after the filter 37 has a gain that is amplified to the maximum within a range in which the reception signal does not oscillate, and can further increase the reception sensitivity in a place where noise is likely to be mixed.

  The received signal that has passed through the filter 34 is guided to an RSSI (Receive Signal Strength Indication) circuit 41 that detects the received signal strength. A known configuration can be used for the RSSI circuit 41. For example, the RSSI circuit 41 includes a multistage configuration in which a received signal is input to an amplifier circuit and a rectified signal corresponding to the level of the received signal is output. This operation is repeated by the number of amplifier circuits, and the rectified signals output from the amplifier circuits are added to output a received signal intensity proportional to the magnitude. Since the received intensity signal is A / D converted and input to the control unit 39, the control unit 39 can detect the intensity of noise at that location. Instead of the RSSI circuit 41, an AGC (Automatic Gain Control) circuit may be used. Since the AGC circuit is a circuit that adjusts the gain of the amplifier circuit so that a constant output level can be obtained even if the strength of the received signal varies, the strength before amplification of the received signal can be obtained from the adjusted gain.

  The control unit 39 has a computer including a CPU or the like as the verification ECU 22 and the navigation ECU 24. The vehicle-side device 11 may be controlled by any of the control unit 39, the verification ECU 22, and the navigation ECU 24. For example, since the portable device communication device 21 directly monitors whether noise is occurring, It is preferable that the noise generation determination unit 71 that determines whether or not the error occurs is included in the control unit of the portable device communication device 21. On the other hand, the verification ECU 22 is CAN-connected to the navigation ECU 24 that manages the position information, and is also directly connected to the portable device communication device 21. Therefore, it is preferable that the verification ECU 22 executes registration of the noise occurrence location. As a result, the verification ECU 22 has a registration request unit 72, a location determination unit 73, an output increase request unit 74, and a reception sensitivity increase unit 75. The location of each functional block is not limited.

<Portable machine 16>
When the portable device 16 receives the request signal, the portable device 16 transmits a response signal to the vehicle-side device 11. Therefore, the portable device 16 also includes a reception system including the amplification circuit 54, the mixer 53, the filter 52, the amplification circuit 51, and the demodulation circuit 50, and a transmission system including the modulation circuit 59, the mixer 57, and the amplification circuit 56. The request radio wave transmitted by the vehicle-side device 11 is received by the antenna, filtered as it is at a high frequency, amplified by the amplifier circuit 54, and then output to the mixer 53. The mixer 53 mixes the received signal and the transmission signal generated by the transmission circuit 55 to generate a lower frequency intermediate wave. The filter 52 passes only a desired frequency band from the intermediate wave, amplifies it by the amplifier circuit 51, demodulates it by the demodulation circuit 50, and extracts a command code.

  The microcomputer 61 controls the entire portable device 16 in an integrated manner, and stores a key code unique to the portable device 16 in a storage element such as a ROM. The microcomputer 61 interprets the command code and controls the portable device 16. For example, if the command code requires transmission of a key code, the modulation circuit 59 modulates the key code with a modulation method such as BPSK or QPSK to generate an intermediate wave. The intermediate wave is mixed with the oscillation signal generated by the transmission circuit 55 by the mixer, amplified by the amplification circuit 56, and then transmitted from the antenna.

  When the command code is a request for increasing the output of the portable device 16, the microcomputer 61 controls the booster 58 to boost the battery voltage and supplies the boosted voltage to the amplifier circuit 56. Thereby, the output of the radio wave transmitted from the antenna is increased and the electric field strength is increased.

  The portable device 16 is provided with a plurality of buttons, and the microcomputer 61 transmits a control code corresponding to the button operated by the user to the vehicle side device 11. Thereby, for example, the lock can be unlocked from the outside of the vehicle, the door glass can be opened and closed, and the indoor lamp and the outdoor lamp can be turned on. In the vicinity of the noise generation place, it is preferable to increase the output even when this control code is transmitted.

[When registering noise occurrence location]
First, registration of noise occurrence locations will be described. The vehicle side device 11 detects the received signal strength by the RSSI circuit 41. By the way, even when the vehicle is traveling, the vehicle-side device 11 can constantly detect the received signal strength by the RSSI circuit 41 and detect whether the noise is large or not. Therefore, it is difficult to detect stable noise. Therefore, in the present embodiment, the received signal strength is detected while the vehicle is parked or parked. Whether the vehicle is stopped or parked can be detected, for example, from the detected value of the vehicle speed sensor or the shift position being parked.

  Further, the received signal strength may be detected while the portable device communication device 21 outputs the request signal. Because the place where the portable device communication device 21 outputs the request signal is a place where the vehicle is door-locked and parked, radio interference between the portable device 16 and the vehicle-side device 11 is likely to be a problem in such a place. is there.

  FIG. 4 is an example of a flowchart showing a procedure for registering a noise occurrence location. In the registration procedure of FIG. 4, the location of noise generation is detected while parking and transmitting a request signal every cycle time.

  First, the noise occurrence determination unit 71 determines whether or not the received signal strength detected by the RSSI circuit 41 is greater than or equal to a threshold value (S10). FIG. 5A is an example of a diagram for schematically explaining the relationship between the frequency and the received signal strength. As shown in the figure, if the communication frequency between the portable device 16 and the portable device communication device 21 is close to the noise frequency and the noise signal strength is greater than or similar to the strength of the response signal transmitted by the portable device 16, the key code Demodulation becomes difficult. Therefore, the noise occurrence determination unit 71 sets a value that is approximately the same as or slightly smaller than the received signal strength of the portable device 16 as a threshold value.

  However, the RSSI circuit 41 cannot distinguish between the received signal strength of the response signal and the received signal strength of noise. Therefore, the noise occurrence determination unit 71 determines whether or not a request signal has been transmitted (S20). Since the response signal is returned from the portable device 16 immediately after the request signal, it may be determined as noise if the request signal is not transmitted.

  Next, the noise occurrence determination unit 71 determines whether or not the received signal strength of noise is continuous (S30). The term “continuous” means that a state where the threshold value is exceeded continues without interruption so that it is difficult to receive a response signal. More specifically, for example, the number of times per unit time that the received signal strength of noise exceeds the threshold value is predetermined. It means that the value is greater than or equal to the value. If it is not continuous (No in S30), it may be regarded as transient, and the process is terminated as it is.

  When it is continuous (Yes in S30), the noise occurrence determination unit 71 determines that the place where the vehicle is parked or stopped is a noise occurrence location (S40). The noise generation determination unit 71 sends noise detection information indicating that noise is generated to the verification ECU 22.

  The registration request unit 72 of the verification ECU 22 determines whether or not the parking / parking location is already registered in the vehicle noise DB 27 (S50). For this reason, the registration request unit 72 requests the navigation ECU 24 to determine whether or not the position information of the current position is registered in the vehicle noise DB 27. If the position information is not registered, the registration request unit 72 obtains the position information of the current position. Request to register in DB27 (S60).

  Since the current position and the noise occurrence location registered in the vehicle noise DB 27 rarely coincide completely, whether or not the current position is registered in the vehicle noise DB 27 is within a predetermined distance (determination distance described later) If it is equal to L), it is determined that the position information of the current position is registered in the vehicle noise DB 27. In other words, if there is a noise occurrence place registered within a predetermined distance from the current position, it is determined that the position information of the current position is registered in the vehicle noise DB 27.

  Moreover, when registering the position information of the current position in the vehicle noise DB 27, it is preferable to register the frequency of the carrier wave of the portable device 16 together. Thereby, the frequency of noise can be recorded.

  Next, since the noise occurrence location is shared with other vehicles, the registration request unit 72 transmits the noise occurrence location information to the server 14 through the communication device 23 (S70). The server 14 determines whether or not the noise generation location is registered in the noise generation location DB 15 in the same manner as in step S60. If not, the server 14 generates the noise generation location and preferably the frequency of the carrier wave of the portable device 16 as the noise generation location. Register in the location DB 15.

  FIG. 6 is a diagram illustrating an example of the noise generation location DB 15 of the present embodiment. The location information of the place of occurrence and the frequency of the carrier wave of the portable device 16 are registered. Further, the last detection date is the latest date when it is detected that the noise is generated, and if the latest date is not updated for a long period of time, the noise can be deleted and the location can be deleted.

  As described above, since the noise occurrence location detected by each vehicle is registered in the server 14, each vehicle can share the noise occurrence location by distributing the noise occurrence location DB to each vehicle. . In the present embodiment, the server 14 distributes vehicle noise, but the noise occurrence location DB 15 may be shared by inter-vehicle communication. For example, when two vehicles communicate with each other when the vehicles communicate with each other, the vehicle noise DB 27 is exchanged with each other, and each vehicle registers a noise occurrence location that is not registered in the vehicle noise DB 27 of the own vehicle. It is possible to share the vehicle noise DB 27 while updating the vehicle noise DB 27 without using it.

[When unlocking the door lock]
Next, the reception procedure of the response signal at the noise occurrence location will be described based on the flowchart of FIG.

  When all the occupants get off and the occupants lock the door, the place determination unit 73 of the verification ECU 22 determines whether or not the place where the vehicle is parked is a place where noise is generated (S110). For this reason, the place determination unit 73 requests the navigation ECU 24 to determine whether or not the position information of the current position is registered in the vehicle noise DB 27. This determination is made based on whether or not the current position is within the determination distance L from the noise occurrence location registered in the vehicle noise DB 27. This is because if it is within the determination distance L from the noise generation location, it is considered that the noise is large even if it is not exactly the same location.

  If not registered in the vehicle noise DB 27 (No in S110), the process ends without increasing the output of the portable device 16 or increasing the reception sensitivity of the portable device communication device 21.

  When the current position is within a predetermined distance L from the noise occurrence location registered in the vehicle noise DB 27 (Yes in S110), the output up request unit 74 requests the portable device communication device 21 to transmit an output up signal, The reception sensitivity increasing unit 75 requests the portable device communication apparatus 21 to increase the reception sensitivity (S120).

  The control unit 39 of the portable device communication apparatus 21 transmits an output up signal including command data for requesting output up to the portable device 16. FIG. 5B schematically shows an example of the relationship between the carrier signal and the received signal strength of noise when the output of the portable device 16 is increased, and FIG. 5C shows the reception of the portable device communication device 21. An example of a diagram schematically showing the relationship between the carrier wave and the received signal strength of noise when the sensitivity is increased is shown. As shown in FIG. 5B, when the output of the portable device is increased, the received signal strength of the response signal is larger than the noise, the S / N ratio is improved, and the response signal can be easily received. . In addition, as shown in FIG. 5C, by further narrowing the carrier frequency with a filter, the ratio of noise to the received signal intensity is reduced, the S / N ratio is improved, and the response signal can be easily received. it can.

  As described above, in the electronic key system 100 according to the present embodiment, the portable device 16 increases the output and transmits a response signal in a place where noise occurs, so that the vehicle-side device 11 can reliably receive the key code. It becomes like this. Further, since the reception sensitivity is increased, it becomes easier to receive a response signal that was apt to be buried in noise. Since each vehicle shares the noise generation location DB 15, the door lock can be unlocked by reducing the radio wave interference even at the first parking location.

It is an example of the whole block diagram of an electronic key system. It is an example of the schematic block diagram of the vehicle side apparatus 11 and the portable device 16 which comprise an electronic key system. It is an example of a schematic block diagram of a portable device communication apparatus and a portable device. It is an example of the flowchart figure which shows the registration procedure of a noise generation place. It is an example of the figure which illustrates typically the relationship between a frequency and received signal strength. It is a figure which shows an example of noise generation location DB15. It is an example of the flowchart figure which shows the reception procedure of the response signal in a noise generation place.

Explanation of symbols

11 Vehicle side device 14 Server 15 Noise occurrence location DB
16 Mobile device 21 Mobile device communication device 22 Verification ECU
23 communication device 24 navigation ECU
25 GPS receiver 27 Vehicle noise DB

Claims (3)

In the vehicle side device of the electronic key system that authenticates the portable device based on the authentication information received wirelessly from the portable device outside the vehicle and enables the door lock to be unlocked,
Noise radio wave detection means for detecting noise radio waves that interfere with reception of radio waves transmitted by portable devices;
Registration means for registering the location information of the place where the noise radio wave is detected in the server or the own vehicle;
Noise location information acquisition means for acquiring a noise occurrence location database in which location information of a location where noise radio waves are detected is registered from a server or another vehicle;
When authenticating the portable device, based on the noise occurrence location database, a determination means for determining whether the current location of the vehicle is within a predetermined distance from the location where the noise radio wave is detected;
If the current location is within a predetermined distance from the location registered in the noise occurrence location database, output up request means for requesting the portable device to increase the transmission output of the authentication information;
The vehicle side device characterized by having. Receiving sensitivity increasing means for increasing the receiving sensitivity of the radio wave carrying the authentication information when the current location of the vehicle is within a predetermined distance from the location registered in the noise occurrence location database;
The vehicle-side device according to claim 1, comprising: In the electronic key system that enables the door lock to be unlocked by authenticating the portable device based on the authentication information received from the portable device outside the vehicle,
The vehicle side device
Noise radio wave detection means for detecting noise radio waves that interfere with reception of radio waves transmitted by portable devices;
Registration means for registering the location information of the place where the noise radio wave is detected in the server or the own vehicle;
Noise location information acquisition means for acquiring a noise occurrence location database in which location information of a location where noise radio waves are detected is registered from a server or another vehicle;
When authenticating the portable device, based on the noise occurrence location database, a determination means for determining whether the current location of the vehicle is within a predetermined distance from the location where the noise radio wave is detected;
When the current location is within a predetermined distance from the location registered in the noise occurrence location database, output up request means for requesting the portable device to increase the transmission output of the authentication information,
The portable device is
When an increase in transmission output is requested, the transmission output of the carrier wave of the authentication information is increased.
An electronic key system characterized by that.

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