Unauthorized use prevention device

Abstract

To prevent theft by an interference wave with a simpler configuration.SOLUTION: An encrypted signal used for authentication is transmitted / received multiple times between a vehicle side device 60 and an electronic key 22. For authentication, an LF wave is transmitted from the vehicle side device 60, and a UHF wave is transmitted from the electronic key 22 side. An unauthorized use prevention device 10 has an antenna 320 for the LF wave. In an authentication work between the vehicle side device 60 and the electronic key 22, when the antenna 320 detects that the LF wave has been transmitted from the vehicle side device 60, the unauthorized use prevention device 10 immediately outputs an interference wave LFjam of an LF band to interfere with authentication processing. By receiving the LF wave from the vehicle side device 60 by the antenna 320 and outputting the interference wave LFjam of a frequency band identical with the LF wave from the antenna 320 that has received the wave, the unauthorized use can be prevented with a single antenna without modifying the electronic key 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an unauthorized use prevention device, and more particularly to a technology for preventing theft by outputting jamming waves in, for example, car sharing services or rental car services that use electronic keys. [Background technology]

[0002] Electronic keys that allow you to lock / unlock vehicle doors and start the engine without inserting a key are now widely used. On the other hand, car sharing, where vehicles are shared among registered members, is also becoming popular. In this car sharing system, since not all users can own an electronic key, the electronic key is left in the vehicle and the user locks and unlocks the vehicle by operating a user terminal. For example, based on an operation instruction from a user terminal that has been authenticated, an actuator that physically presses the lock / unlock button on an electronic key inside the vehicle is driven to lock / unlock the vehicle. A similar method may also be adopted in a service in which a vehicle is used jointly by multiple users, such as a rental car service in which any applicant uses the vehicle.

[0003] In vehicles that use such electronic keys, various technologies have been proposed to prevent unauthorized unlocking of the vehicle doors to steal items from the interior, or unauthorized starting of the engine to steal the vehicle. For example, by removing the battery that powers the electronic key and wiring the activation control unit that drives the actuator to supply power to the electronic key, power can be supplied only to operations by authenticated users (Patent Document 1). In addition, when locking / unlocking or starting the engine by operating the electronic key, an authentication process is performed between the vehicle-mounted device (vehicle side) and the electronic key. This takes advantage of this fact, and a technology has been proposed in which, when a signal from the vehicle-mounted device is detected by the receiving antenna, an interference wave is emitted from the transmitting antenna toward the electronic key (Patent Document 2, Patent Document 3).

[0004] However, the technology described in Patent Document 1 requires modification of the electronic key, which poses the problem of increased wiring work and modification costs. Furthermore, the techniques described in Patent Documents 2 and 3 each have the problem that they require multiple antennas for receiving the signal emitted from the vehicle-mounted device toward the electronic key and for outputting interference waves. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7012178 [Patent Document 2] Patent Publication No. 2021-167151 [Patent Document 3] Patent Publication No. 2021-10054 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to realize theft prevention using jamming waves with a simpler configuration. [Means for solving the problem]

[0007] The present invention provides an unauthorized use prevention device that is installed in a vehicle together with an electronic key that performs authentication processing with a vehicle-side device, comprising: an antenna that receives, as a target wave, a first signal wave transmitted from the vehicle-side device or a second signal wave transmitted from the electronic key in the authentication process; a target wave detection means for detecting reception of the target wave by the antenna; a jamming wave output means for outputting a jamming wave Fjam having the same frequency band as the received target wave from the antenna when the target wave detection means detects reception of the target wave; The present invention provides an unauthorized use prevention device characterized by comprising: [Effects of the Invention]

[0008] According to the present invention, when reception of a target wave is detected, a jamming wave Fjam in the same frequency band as the target wave received from the antenna is output, so that theft prevention can be achieved with a simpler configuration. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram showing the functional configuration of an entire electronic key control system including an unauthorized use prevention device in a first embodiment. [Figure 2] 10 is a timing chart showing the process up to outputting the jamming wave LFjam by the jamming control unit of the fraud prevention device. [Figure 3] FIG. 10 is an explanatory diagram showing the flow of interference control processing. [Figure 4] FIG. 10 is an explanatory diagram showing the functional configuration of the entire electronic key control system including the unauthorized use prevention device in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A preferred embodiment of the fraud prevention device 10 of the present invention will be described in detail below with reference to FIGS. (1) Overview of the embodiment In a vehicle equipped with an electronic key 22, when starting the engine and locking / unlocking the doors, encrypted authentication signals are sent and received multiple times between the vehicle-side device 60 and the electronic key 22. The authentication process is performed using various known methods, such as sending and receiving an encryption code between the vehicle 1 and the electronic key 22, and if the two codes match, the electronic key 22 is authenticated as being genuine. For this authentication, the vehicle-side device 60 transmits a signal in the LF (Low Frequency) band (hereinafter referred to as LF wave), and the electronic key 22 transmits a signal in the UHF (Ultra High Frequency) band (hereinafter referred to as UHF wave). In this embodiment, the LF wave functions as a first signal wave, and the UHF wave functions as a second signal wave.

[0011] The fraud prevention device 10 of the first embodiment includes an antenna 320 for LF waves. When the antenna 320 detects that an LF wave has been transmitted from the vehicle-side device 60 during authentication between the vehicle-side device 60 and the electronic key 22, the fraud prevention device 10 immediately outputs jamming waves LFjam in the LF band to disrupt the authentication process. That is, the electronic key 22 is unable to decode the signal from the vehicle-side device 60 that has been encrypted by the jamming waves LFjam, disrupting the authentication process. As a result, fraudulent locking / unlocking and engine starting are prevented. In this way, the fraud prevention device 10 receives LF waves from the vehicle-side device 60 as target waves using the antenna 320, and then oscillates and outputs jamming waves LFjam in the same frequency band as the LF waves from the received antenna 320, thereby preventing fraudulent use using a single antenna without modifying the electronic key 22.

[0012] The fraud prevention device 10 receives a valid / invalid signal from the external device 50, and during the invalid period from when the invalid signal is received until when the valid signal is received, it is considered to be fraudulent use, so it detects the LF wave and outputs an interference wave LFjam. On the other hand, the fraudulent use prevention device 10 does not detect LF waves or output jamming waves LFjam during the valid period from when it receives a valid signal to when it receives an invalid signal from the external device 50, since it considers that the device is being used by a legitimate user. The valid period and invalid period are determined based on the valid / invalid signal output from the external device 50. That is, the period from when the valid signal is output until when the invalid signal is output is determined to be the valid period, and the period from when the invalid signal is output until when the valid signal is output is determined to be the invalid period. The external device 50 outputs a valid signal at the date and time when use of the vehicle 1 begins (or the date and time that is the preparation time Z1 before the start time), and outputs an invalid signal at the date and time when use ends (or the date and time that is the grace time Z2 after the end time).

[0013] If an LF wave is detected during the invalid period, power consumption will increase if the output of the jamming wave LFjam continues until the invalid period ends. Therefore, the fraudulent use prevention device 10 does not output the jamming wave LFjam until the invalid period ends, but outputs the jamming wave LFjam for a fixed period (= jamming duration T), and then detects the LF wave again after stopping the output of the jamming wave LFjam. The frequency of the LF wave and the jamming duration T, which are determined for each vehicle model, are stored in the memory unit 40 as parameters.

[0014] In addition, the fraud prevention device 10 stores parameters for changing the frequency of the jamming wave LFjam in the memory unit 40, and by using parameters corresponding to the vehicle model of the vehicle 1, it is possible to output a jamming wave LFjam with a frequency that matches the wavelength of the LF wave transmitted by the vehicle-side device 60. The parameters (frequency of jamming wave LFjam and jamming duration T) according to the vehicle model of vehicle 1 to be stored in memory unit 40 are set in advance when setting up fraud prevention device 10 in vehicle 1, but can also be obtained from external device 50.

[0015] On the other hand, the fraud prevention device 10 of the second embodiment uses two dedicated antennas: a receiving antenna 320a that receives LF waves and a transmitting antenna 320b that transmits jamming waves LFjam, and the jamming control unit 32 is composed of an LF wave receiving IC that is an IC dedicated to LF wave detection, and a dedicated IC of a microcomputer that oscillates jamming waves LFjam only during the jamming duration T. By using a dedicated IC for the interference control unit 32 in this way, it is possible to achieve high functionality, low power consumption, and low costs. Furthermore, by using antennas dedicated to transmission and reception, a switch for switching between transmission and reception and its control are no longer necessary, which simplifies the components and control.

[0016] (2) Details of the embodiment FIG. 1 shows the functional configuration of the entire electronic key control system including an unauthorized use prevention device 10 to which the first embodiment is applied. In this embodiment, an electronic key control system for a vehicle 1 that is a car sharing target and is used jointly by a plurality of registered users will be described. The electronic key control system includes the unauthorized use prevention device 10 of this embodiment, a vehicle-side device 60, an external device 50, a mobile terminal 70, and a reservation server 80. 1, of the components of the electronic key control system, the fraud prevention device 10, the vehicle-side device 60, and the external device 50 are arranged inside the vehicle 1. That is, the fraud prevention device 10, the vehicle-side device 60, and the external device 50 are arranged inside each vehicle 1 that is the subject of car sharing. The fraud prevention device 10 and the external device 50 are arranged inside or below the dashboard, under the passenger seat, etc., and the vehicle-side device 60 is arranged in a predetermined position as equipment provided in the vehicle 1. On the other hand, the mobile terminal 70 is used inside or outside the vehicle 1, and the reservation server 80 is located outside the vehicle 1.

[0017] The fraud prevention device 10 includes a key control unit 20 and a usage control unit 30, and enables the vehicle-side device 60 to lock and unlock the door and start the engine, while outputting jamming waves LFjam to disrupt engine start-up, etc., in order to prevent fraudulent use. The key control unit 20 has an actuator 21 that physically presses the lock button and unlock button (not shown) of the electronic key 22, a fixing unit (not shown) that fixes the buttons of the electronic key 22 facing toward the actuator 21, and a container (not shown) that houses these fixing units and the actuator 21 inside. The usage control unit 30 and key control unit 20 of the unauthorized use prevention device 10 may be housed in the same container, and the control system may be formed on the same substrate.

[0018] The electronic key 22 includes an unlock button for unlocking the doors of the vehicle 1 and a lock button for locking the doors (not shown). When the lock button or unlock button on the electronic key 22 is pressed, or when the EG (engine) button 62 on the vehicle-side device 60 is pressed, authentication processing of the electronic key 22 is performed between the electronic key 22 and the vehicle-side device 60. The electronic key 22 is equipped with a receiving antenna for receiving LF band signals (LF waves) transmitted from the vehicle-side device 60 during the authentication process, and a transmitting antenna for transmitting UHF band signals (UHF waves) to the vehicle-side device 60 (not shown). The electronic key 22 of this embodiment transmits UHF waves of, for example, 315 MHz from the transmitting antenna.

[0019] The actuator 21 has a pressing mechanism that presses the unlock button and lock button at positions corresponding to the unlock button and lock button of the electronic key 22. The pressing mechanism is realized by a motor, a solenoid, or the like (not shown). The actuator 21 presses the unlock button or the lock button of the electronic key 22 in response to a button pressing instruction issued from the usage control unit 30.

[0020] The usage control unit 30 includes a switching control unit 31, an interference control unit 32, and a storage unit 40. The usage control unit 30 is equipped with a computer system including a CPU, ROM, RAM, etc. (not shown), and functions as an opening / closing control unit 31 that controls the locking / unlocking of the doors by executing the opening / closing control PG stored in the memory unit 40, and functions as an interference control unit 32 that performs interference control against unauthorized use of the vehicle 1 by executing the interference control PG.

[0021] The opening / closing control unit 31 receives a locking / unlocking instruction from the external device 50, and supplies an instruction to the actuator 21 of the key control unit 20 to press the lock button or the unlock button according to the instruction.

[0022] The jamming control unit 32 includes a status flag (not shown), an antenna 320, an amplifier circuit 321, a detection circuit 322, a one-shot circuit 323, and an oscillation circuit 324 to prevent unauthorized use of the vehicle 1 by outputting jamming waves LFjam. The status flag is a flag that stores the status signal "1" for validity or "0" for invalidity output from the external device 50, and each time a valid / invalid signal is received from the external device 50, the status flag is updated to "1" or "0". The antenna 320 is an antenna for transmitting and receiving LF waves, and is an antenna for receiving and transmitting LF waves of a plurality of predetermined frequencies, such as 125 kHz and 134 kHz. The function of preventing unauthorized use of the vehicle 1 by the unauthorized use prevention device 10 of this embodiment is realized by one antenna 320.

[0023] The amplifier circuit 321 is an amplifier such as a low-noise amplifier that amplifies the LF wave received by the antenna 320 from the vehicle-side device 60 .

[0024] The detection circuit 322 is a circuit that detects the LF wave amplified by the amplifier circuit 321, and functions as a target wave detection means. The detection circuit 322 determines the edge of the LF wave so that it can immediately detect the emission of the LF wave and output the jamming wave LFjam. The detection circuit 322 detects the LF wave from the vehicle-side device 60 when the edge of the LF wave exceeds the minimum detectable voltage MinVpp.

[0025] The one-shot circuit 323 is a circuit for outputting an interference wave LFjam for a predetermined time T only when the detection circuit 322 detects an LF wave, in order to reduce power consumption. After the detection circuit 322 detects the LF wave, the one-shot circuit 323 supplies a Hi signal to the oscillation circuit 324 for the duration T of the interference. The one-shot circuit 323 of this embodiment is configured by a timer that measures the disturbance duration T. For setting the disturbance duration T, the time stored as PM (parameter) in the storage unit 40 is used. The one-shot circuit 323 may be configured as an IC circuit that receives an edge of the LF wave detected by the detection circuit 322 as an input signal and outputs a Hi pulse signal for the interference duration T. In this case, the interference duration T is a fixed value determined by the time constant of a capacitor, resistor, etc., and is therefore not stored in the memory unit 40.

[0026] Here, the interference duration T during which the interference wave LFjam is output will be described. As described above, in the authentication process performed between the vehicle-side device 60 and the electronic key 22, encrypted signals (LF waves and UHF waves) for authentication are transmitted and received multiple times. If this authentication process is not successful, the vehicle-side device 60 performs re-authentication by transmitting the LF wave again. This re-authentication process is repeated multiple times, so the LF wave is also transmitted multiple times. Therefore, in the interference control unit 32 of this embodiment, the interference duration time T is set to a time longer than the time until the retransmission of the LF wave is completed in the re-authentication process. For example, if the first LF wave is transmitted for 110 ms, and then the LF wave is retransmitted 125 ms later, for a total of three LF waves, the time from the first transmission of the LF wave to the end of the LF wave retransmission is (110 ms x 3 times) + (125 ms x 2 times) = 580 ms. In the above example, the interference control unit 32 outputs the interference wave LFjam for the interference duration T=600 ms, which is longer than 580 ms.

[0027] The oscillation circuit 324 is a circuit that oscillates the jamming wave LFjam and outputs it from the antenna 320 only during the jamming duration T during which the one-shot circuit 323 outputs the Hi pulse signal. In addition, the jamming wave circuit 32 is equipped with an antenna switching switch (not shown) to enable the antenna 320 to be used for both transmission and reception, and while a Hi pulse signal is being output from the one-shot circuit 323, the antenna 320 is switched to transmission mode, thereby outputting the jamming wave LFjam from the oscillator circuit 324.

[0028] The oscillator circuit 324 is capable of oscillating jamming waves LFjam at a plurality of different frequencies (two in this embodiment). That is, there are a plurality of frequencies of LF waves output from the vehicle-side device 60, and the frequency of the LF waves actually output is determined depending on the vehicle model, for example, to LF waves of 125 kHz or 134 kHz. The oscillation circuit 324 oscillates an interference wave LFjam having a frequency (for example, 125 kHz) corresponding to the type of vehicle 1 for only the interference duration T based on the PM (parameters) stored in the storage unit 40.

[0029] In addition, when the one-shot circuit 323 is configured as an IC circuit, the oscillator circuit 324 outputs an interference wave LFjam of a frequency specified by the type of vehicle 1 for the time when a Hi pulse signal is output from the one-shot circuit 323 (interference duration T).

[0030] The memory unit 40 stores PGs (programs) such as a switching control program that causes the usage control unit 30 to function as a switching control unit 31 when executed by a CPU not shown, and an interference control program that causes the usage control unit 30 to function as an interference control unit 32. Furthermore, the storage unit 40 stores PM (parameters) for outputting the jamming wave LFjam from the antenna 320.

[0031] The frequency of the LF waves output from the vehicle-side device 60 to the jamming control unit 32 is determined for each vehicle model. Therefore, the storage unit 40 stores a plurality of parameters for each vehicle model, such as the frequency of the LF waves (jamming waves LFjam) and the duration (jamming duration T) for continuously outputting the jamming waves LFjam, as parameters for outputting jamming waves LFjam of this LF wave frequency from the antenna 320 of the jamming control unit 32. The jamming duration T may be longer than the time required for the authentication process between the vehicle-side device 60 and the electronic key 22, and varies depending on the vehicle model. In this embodiment, the jamming duration T is set to 3 seconds, but it can also be set shorter or longer depending on the vehicle model. The storage unit 40 also stores the model of the vehicle 1 in which the fraud prevention device 10 is installed. The vehicle model stored in the memory unit 40 is stored by an installer, such as a company that owns the vehicle 1 for car sharing or a company that installs the fraudulent use prevention device 10, when the fraudulent use prevention device 10 is installed in the vehicle 1, or after the vehicle 1 to be installed has been decided. The information on the vehicle model may be acquired from the external device 50 and stored in the storage unit 40. Alternatively, the vehicle model may be received from the external device 50 together with an invalid signal without being stored in the storage unit 40.

[0032] Here, the output of the jamming wave LFjam by the jamming control section 32 will be described. FIG. 2 is a timing chart showing the process up to the output of the jamming wave LFjam by the jamming control section 32. In FIG. 2 is an invalid period (period with no reservations) from when an invalid signal is supplied from the external device 50 to the interference control unit 32 until when an valid signal is supplied. In other words, during the period shown in FIG. 2, there is no reservation for use of the vehicle 1 by a legitimate user, and the status flag that stores the status signal (valid / invalid) from the external device 50 is set to invalid "0".

[0033] As shown in FIG. 2(a), it is assumed that an LF wave is transmitted from the vehicle device 60 to the electronic key 22 at time t1. The LF wave output from the vehicle-side device 60 is received by the electronic key 22 and the interference control unit 32, as shown in FIGS. As shown in FIG. 2(c), the interference control unit 32 performs edge determination using the detection circuit 322, and the LF wave from the vehicle-side device 60 is detected when the minimum voltage MinVpp is exceeded. When an edge of the LF wave is detected, the interference control unit 32 causes the oscillation circuit 324 to output an interference wave LFjam from the antenna 320 from time t2 to t3 (interference duration T), as shown in FIG. 2(d).

[0034] As shown in FIG. 2(d), there is a delay of time (t2-t1=Δt) from the time t1 when the LF wave is output from the vehicle-side device 60 until the oscillation circuit 324 outputs the jamming wave LFjam. However, since the detection circuit 322 detects the LF wave by edge detection, the delay time Δt until the jamming wave LFjam is output can be kept very short. The delay time Δt is, for example, about 1 to 2 bits of the encrypted signal in the LF wave. Therefore, even if the electronic key 22 can analyze the first two bits of the LF wave, the third bit and beyond are interfered with by the LF jamming wave LFjam, and the electronic key 22 is unable to analyze the entire bit, resulting in failure of communication with the vehicle-side device 60. As a result, even if the output of the LF wave is due to pressing the EG button 62, the vehicle-side device 60 cannot confirm a response from the electronic key 22 to the output LF wave, and therefore will not start the engine using the engine control mechanism 63. In particular, in the authentication process, if the first few bits are a synchronization preamble consisting of a repeated signal of "1010," the delay time Δt before the jamming wave LFjam is output is a synchronization signal that does not contribute to authentication, so the delay time Δt does not pose a problem.

[0035] Returning to FIG. 1, the vehicle-side device 60 is a device provided in the vehicle 1 in response to the various functions of the electronic key 22, and includes a communication unit 61, an EG (engine) button 62, an engine control mechanism 63, and other devices. When starting the engine of the vehicle 1 or locking / unlocking the doors, an authentication process is performed between the vehicle-side device 60 and the electronic key 22 by sending and receiving encrypted signals multiple times. This authentication process is performed when the EG button 62 is pressed while the brake (not shown) is being depressed to start the engine. In this authentication process, the vehicle device 60 transmits an LF wave signal, and the electronic key 22 transmits a UHF wave signal.

[0036] The communication unit 61 includes a transmitting antenna for transmitting LF waves to the electronic key 22 and a receiving antenna for receiving UHF waves transmitted from the electronic key 22 (not shown). The EG button 62 is a button for starting and stopping the engine of the vehicle 1 when the electronic key 22 is inside the vehicle 1.

[0037] The engine control mechanism 63 is an operating mechanism that starts and stops the engine of the vehicle 1, and includes an actuator such as a motor or a solenoid. The vehicle-side device 60 also includes a door control mechanism (not shown) as another device. The door control mechanism is an operating mechanism that locks and unlocks the doors of the vehicle 1, and includes a locking / unlocking actuator such as a motor or a solenoid.

[0038] The external device 50 includes a processing function unit 51, which is connected to the mobile terminal 70 via short-range wireless communication and is connected to the reservation server 80 via a network such as the Internet. Various functions of the external device 50 are realized by processing by the processing function unit 51. When the reservation for use of the vehicle 1 is completed in the reservation server 80, the external device 50 receives reservation information about the reservation date and time, etc., transmitted from the reservation server 80, and stores the information in a storage device (not shown). When the external device 50 receives a key operation on the electronic key 22 and the authentication information required for authentication from the mobile terminal 70, it compares the information with the stored reservation information to determine whether the reservation for use of the vehicle 1 has been completed, whether the operation is within the reserved time, whether the user is authenticated, etc., and accepts the key operation if all conditions are met.

[0039] Based on the reservation information stored in the memory unit, the external device 50 outputs a valid signal at the start date and time of use of the vehicle 1 (or the date and time that is a preparation time Z1 before the start time, hereinafter referred to as the start date and time of use), and outputs an invalid signal at the end date and time of use (or the date and time that is a grace time Z2 after the end time, hereinafter referred to as the end date and time of use), thereby supplying a valid / invalid signal to the interference control unit 32 of the fraudulent use prevention device 10. When the enable / disable signal is supplied from the external device 50 to the interference control unit 32, in this embodiment it is supplied wirelessly, but it can also be supplied via a wired connection connecting the external device 50 and the interference control unit 32.

[0040] In addition, instead of outputting the valid / invalid signal at the start and end of the valid period, the external device 50 may be configured to continuously output the valid signal during the reservation period based on the reservation information, and to continuously output the invalid signal outside the reservation period.

[0041] All of the functions and processes of the external device 50 described above may be provided in the usage control unit 30 of the unauthorized use prevention device 10. In this case, the external device 50 is not installed inside the vehicle 1, and the usage control unit 30 is connected to the mobile terminal 70 via short-range wireless communication, and is also connected to the reservation server 80 via a network such as the Internet.

[0042] The mobile terminal 70 is a portable terminal owned by a user who uses the vehicle 1 that is the subject of car sharing. In this embodiment, a smartphone is used as the mobile terminal 70, but other devices such as a mobile phone, a personal computer, a tablet computer, or a wearable computer can also be used. The mobile terminal 70 communicates with the external device 50 in the vehicle 1 by short-range wireless communication, and is also connectable to the reservation server 80 via various networks such as the Internet. The user of the mobile terminal 70 registers an account for car sharing in advance with the reservation server 80, and, if necessary, makes a reservation for use of the vehicle 1 from a reservation screen provided by the reservation server 80. After issuing an instruction to the external device 50 to lock or unlock the door, the mobile terminal 70 is notified by the external device 50 of the result of the determination as to whether the operation based on the instruction was successful or not, and the mobile terminal 70 displays the result on the screen. This allows the user of the mobile terminal 70 to know the door status.

[0043] The reservation server 80 stores information on all vehicles 1 that are eligible for car sharing, information on registered users, reservation information for each vehicle 1 by registered users, and the like. The reservation server 80 of this embodiment is configured to provide reservation information for each vehicle 1 in response to a request from the external device 50. In addition, after the reservation operation from the mobile terminal 70 is completed, the reservation server 80 may send new reservation information to the external device 50 installed in the target vehicle 1 or to the external devices 50 of all vehicles 1. Each external device 50 supplies valid / invalid to the interference control section 32 based on the transmitted reservation information.

[0044] Furthermore, the reservation server 80 provides the mobile terminal with various screens necessary for reservation processing, allowing the user to input necessary information (user ID, date and time of use, location, etc.) from the mobile terminal .

[0045] Next, the interference control process performed by the interference control unit 32 will be described. FIG. 3 is an explanatory diagram showing the flow of the interference control process. The interference control process by the interference control unit 32 is performed by a CPU (not shown) included in the usage control unit 30 executing an interference control program stored in the storage unit 40. The interference control unit 32 determines whether or not the current period is a valid period in which the interference wave LFjam is not output, that is, whether or not the status flag is valid "1" (step 11). If it is a valid period (a reservation period in which the status flag is valid "1" and vehicle 1 is reserved) (step 11; Y), the interference control unit 32 determines whether detection is in progress by the detection circuit 322 (step 12), and if detection is not in progress (step 12; N), returns to step 11 and monitors the signal supplied from the vehicle-side device 60. On the other hand, if detection is in progress (step 12; Y), the interference control unit 32 ends detection by the detection circuit 322 (step 13) and returns to step 11.

[0046] On the other hand, if the current period is not a valid period, i.e., if the status flag is invalid and the period is invalid (step 11; N), the interference control unit 32 performs edge detection in the detection circuit 322 of the signal received by the antenna 320 and amplified by the amplifier circuit 321 (step 14), and determines whether the signal is an LF wave of a predetermined frequency output from the vehicle-side device 60 of the vehicle 1 (step 15). If the LF wave is not detected (step 15; N), that is, if the LF wave is not of the specified frequency output from the vehicle-side device 60, or if the LF wave itself is not being output, the interference control unit 32 returns to step 14 and continues detection.

[0047] As described above, in this embodiment, detection is not performed during the valid period (step 11; Y), and detection is performed only during the invalid period, so that power consumption by the detection circuit 322 can be reduced. If the interference control unit 32 is configured using an analog circuit and a dedicated IC for a microcomputer, power consumption is low, so it is possible to perform constant detection regardless of the valid period or invalid period.

[0048] On the other hand, if the detection circuit 322 detects an LF wave (step 15; Y), the interference control unit 32 immediately causes the oscillation circuit 324 to oscillate an interference wave LFjam (step 16). As a result, the interference wave LFjam is output from the antenna 320 toward the electronic key 22. When the jamming wave LFjam is first output (time t2 in FIG. 2), the jamming control section 32 sets the timer of the one-shot circuit 323.

[0049] Then, the interference control unit 32 monitors the timer of the one-shot circuit 323 that has been set, and determines whether or not the time T (interference duration time T) has elapsed (step 17). If the time T of the timer has not elapsed (step 17; N), the interference control unit 32 returns to step 16, and continues outputting the interference wave LFjam from the oscillation circuit 324. On the other hand, if the time T of the timer has elapsed (step 17; Y), the interference control section 32 stops the output of the interference wave LFjam by the oscillation circuit 324 (step 18).

[0050] The interference control unit 32 determines whether or not the process has ended (step 19), and if not (step 19; N), returns to step 11, and if it has ended (step 19; Y), ends the process. Since the interference control process by the interference control unit 32 is basically a process that is always performed, the process is ended (step 19; Y) when, for example, the unauthorized use prevention device 10 is removed.

[0051] As described above, due to the interference control processing of the interference control unit 32, when an LF wave is output from the vehicle-side device 60 during a period when an invalid signal is supplied from the external device 50, i.e., a period when no reservation has been made for use of the vehicle 1, an interference wave LFjam is output from the oscillator circuit 324 before the authentication processing between the vehicle-side device 60 and the electronic key 22 is completed. This prevents the doors from being locked or unlocked illicitly, and the engine from being started illicitly. In addition, the interference control unit 32 receives LF waves of a predetermined frequency determined for each model of vehicle 1 using antenna 320, and uses this received antenna 320 to output interference waves LFjam of the same frequency, so that a single antenna can prevent unauthorized locking and unlocking of doors and unauthorized starting of the engine.

[0052] In addition, the interference control unit 32 does not continuously output the interference wave LFjam during the invalid period (unreserved period) when there is no reservation for use of the vehicle 1, but rather outputs the interference wave LFjam only for the interference duration T after detecting the LF wave and first outputting the interference wave LFjam, thereby reducing power consumption. Furthermore, since the detection circuit 322 quickly detects the LF wave by edge detection, the delay time Δt from when the vehicle-side device 60 outputs the LF wave at time t1 to when it outputs the jamming wave LFjam at time t2 can be shortened (see Figure 2), thereby effectively jamming the authentication process performed by the vehicle-side device 60 and the electronic key 22.

[0053] The above has described a case where the CPU of the interference control unit 32 outputs the interference wave LFjam while controlling the hardware such as the amplifier circuit 321, the detection circuit 322, and the oscillation circuit 324 in accordance with the interference control program, but the entire interference control unit 32 may be configured with an electronic circuit or a dedicated IC circuit, etc. This can further shorten the delay time Δt (see FIG. 2(d)) until the interference wave LFjam is output.

[0054] Next, an overview of the operation when a valid user issues a lock / unlock command or presses the engine button 62 during the valid period (reservation period) for which the vehicle 1 has been reserved will be described. (a) First, the locking / unlocking operation will be explained. When the user performs a locking / unlocking operation from the mobile terminal 70, a key operation instruction and authentication information are transmitted from the mobile terminal 70, and are received by the external device 50. Based on the authentication information, the external device 50 determines that the reservation for use of the vehicle 1 has been completed, that the operation was performed within the reserved time, and that the user is authenticated by comparing it with the reservation information for the vehicle 1 registered in the reservation server 80, and if all conditions are met, it issues a locking / unlocking instruction corresponding to the key operation received from the mobile terminal 70 to the opening / closing control unit 31. When the opening / closing control unit 31 receives a locking / unlocking instruction from the external device 50, it outputs to the key control unit 20 an instruction to press the corresponding locking button / unlocking button.

[0055] When receiving the button pressing instruction, the key control unit 20 drives the actuator 21 to press the lock button / lock button of the electronic key 22. As a result, the electronic key 22 transmits a locking signal / unlocking signal to the vehicle-side device 60, and an encrypted signal is transmitted and received between the electronic key 22 and the vehicle-side device 60 for authentication. Once the authentication is complete, a door control mechanism (not shown) of the vehicle-side device 60 locks / unlocks the doors.

[0056] (b) Next, the engine starting operation will be described. When a legitimate user operates the mobile terminal 70 within the validity period (reservation period) to unlock the doors of the vehicle 1 and get in, and then presses the EG button 62 while stepping on the brake pedal, the vehicle-side device 60 outputs an LF wave for authentication to the electronic key 22. In response to the transmission of the LF waves, the electronic key 22 outputs UHF waves for authentication, which are received by the vehicle-side device 60, whereby authentication processing of the electronic key 22 is performed. It should be noted that this authentication process is performed during the valid period for which the reservation for use has been made, and therefore the jamming wave LFjam is not output from the jamming control section 32. When the vehicle-side device 60 completes authentication of the electronic key 22, the engine control mechanism 63 starts the engine.

[0057] Next, a second embodiment of the unauthorized use prevention device 10 will be described. In the first embodiment described above, the jamming control unit 32 of the unauthorized use prevention device 10 is configured with an analog circuit, and one antenna is used by switching between transmission and reception. In contrast, the interference control unit 32 of the fraud prevention device 10 in the second embodiment uses two antennas, a receiving antenna 320a and a transmitting antenna 320b, and is composed of an LF wave receiving IC 32a made up of a dedicated IC for detecting LF waves, and a microcomputer-dedicated IC 32b.

[0058] FIG. 4 is an explanatory diagram showing the functional configuration of the entire electronic key control system including the unauthorized use prevention device 10 in the second embodiment. In addition, since the fraud prevention device 10 in the second embodiment has the same configuration and operation as the first embodiment except for the interference control unit 32, the explanation will focus on the interference control unit 32 part, and explanations of other parts will be omitted as appropriate. As shown in FIG. 4, the interference control unit 32 of the second embodiment includes an LF wave receiving IC 32a and a microcomputer dedicated IC 32b.

[0059] The LF wave receiving IC 32a is an IC dedicated to LF wave detection, which realizes the function of detecting LF waves by the amplifier circuit 321 and the detection circuit 322 in the first embodiment. A receiving antenna 320a, which is a reception-only antenna for receiving LF waves output from the vehicle-side device 60, is connected to the LF wave receiving IC 32a. The LF wave receiving IC 32a converts the LF waves received by the receiving antenna 320a into low frequency signals that are easy to process using envelope detection, and then performs edge detection to detect the reception of the LF waves. However, the LF wave receiving IC 32a can also perform direct detection instead of envelope detection. In the interference control unit 32 of the second embodiment, the LF wave reception IC 32a constantly detects the LF wave, but it is also possible to perform detection only during the invalid period, as in the first embodiment.

[0060] The microcomputer dedicated IC 32b is a microcomputer dedicated IC that realizes the functions of the one-shot circuit 323 and the oscillation circuit 324 in the first embodiment. A dedicated transmitting antenna 320b for transmitting jamming waves LFjam toward the electronic key 22 is connected to the microcomputer dedicated IC 32b. When the microcomputer-dedicated IC 32b is notified of the detection of LF waves by the LF wave receiving IC 32a, it oscillates an interference wave LFjam and outputs it from the transmitting antenna 320b, provided that it is an invalid period (a period other than the reservation period in which the status flag is invalid "0" and vehicle 1 is reserved), as in the first embodiment. The jamming wave LFjam oscillates for the same predetermined time T (jam duration T) as in the one-shot circuit 323 in the first embodiment, and is output from the transmitting antenna 320b.

[0061] According to the interference control unit 32 configured in this manner, when an LF wave is output from the communication unit 61 of the vehicle-side device 60 toward the electronic key 22, the LF wave is detected by the receiving antenna 320a and the LF wave receiving IC 32a and notified to the microcomputer-dedicated IC 32b. When the microcomputer dedicated IC 32b is notified of the detection of the LF wave, it immediately outputs the jamming wave LFjam from the transmitting antenna 320b to the electronic key 22 if it is in an invalid period. As a result, similar to the first embodiment, it is possible to prevent the doors from being locked or unlocked illegally and the engine from being started illegally.

[0062] As described above, according to the second embodiment, the interference control unit 32 is configured by the LF wave receiving IC 32a and the microcomputer dedicated IC 32b, thereby achieving high functionality, low power consumption, and low costs. Furthermore, by using the transmitting antenna 320b dedicated to transmission and the receiving antenna 320a dedicated to reception, a switch for switching between transmission and reception and its control are no longer necessary, which simplifies the components and control.

[0063] As described above, in the first embodiment, the detection function for detecting LF waves in the interference control unit 32 and the oscillation function for outputting the interference wave LFjam are described as being configured using discrete elements (analog elements), while in the second embodiment, the case where both functions are configured using dedicated ICs (LF wave receiving IC 32a, microcontroller-dedicated IC 32b) is described. On the other hand, as a first modification of the interference control unit 32, it is also possible to configure the detection function with analog elements (amplification circuit 321, detection circuit 322) and the oscillation function with a microcomputer-dedicated IC 32b. Conversely, as a second modification of the interference control unit 32, it is also possible to configure the detection function with the LF wave receiving IC 32a and the oscillation function with analog elements (one-shot circuit 323, oscillation circuit 324).

[0064] In addition, in the first embodiment described above, a case where one antenna 320 is used by switching between transmitting and receiving is described, while in the second embodiment, a case where two dedicated antennas (receiving antenna 320a, transmitting antenna 320b, the same applies below) are used is described. On the other hand, two dedicated antennas may be used in the first embodiment, and one antenna 320 may be used in the second embodiment by switching between transmission and reception. In the first and second variants of the interference control unit 32, it is possible to switch between transmitting and receiving using one antenna 320, as in the first embodiment, and it is also possible to use two dedicated antennas, as in the second embodiment.

[0065] The unauthorized use prevention device 10 of each of the above-described embodiments and modifications has been described as including the key control unit 20, but the unauthorized use prevention device 10 may also be configured by the usage control unit 30. In this case, the key control unit 20 is placed inside the vehicle 1 as an external device of the fraud prevention device 10, but the configurations, connections between components, signal transmission and reception, etc. are the same as those in the first and second embodiments described above.

[0066] In addition, in each of the embodiments and variants described above, when the interference control unit 32 detects LF waves transmitted by the vehicle-side device 60 toward the electronic key 22 during an invalid period (unreserved period), an interference wave LFjam generated by the LF waves is immediately output from the antenna 320. In response to this, the interference control unit 32 may detect UHF waves emitted from the electronic key 22 during door unlocking / locking operations, or UHF waves responding to LF waves emitted from the vehicle-side device 60 during engine start operations, and output an interference wave UHFjam using UHF waves. In this case, the UHF waves output by the electronic key 22 function as the target waves, and an antenna for transmitting and receiving UHF waves is used as the antenna 320. This allows the same antenna 320 to receive UHF waves from the electronic key 22 and output jamming waves UHFjam. In addition, it is possible to prevent unauthorized unlocking by emitting jamming waves UHFjam using UHF waves.

[0067] Furthermore, while each of the embodiments and variants described above has been explained using the example of car sharing, the present invention can also be applied to other services in which an unspecified number of users use the same vehicle by keeping an electronic key inside the vehicle at all times, such as rental car services in which multiple users share a vehicle.

[0068] Furthermore, in each of the embodiments and variants described above, the invalid / valid signal indicating whether it is an invalid period (unreserved period) or a valid period (reserved period) is obtained from the external device 50, but it may also be received from the reservation server 80.

[0069] In the above-described embodiments and modifications, the external device 50 outputs a valid signal at the date and time when use starts, and an invalid signal at the date and time when use ends. In contrast, the external device 50 may be configured to continuously output a valid signal (a signal indicating an available state) during the valid period from the usage start date and time to the usage end date and time, and to continuously output an invalid signal (a signal indicating an unavailable state) during the invalid period from the usage end date and time to the usage start date and time. In this case, the external device 50 determines the usage start date and time and the usage end date and time based on the reservation information transmitted from the reservation server 80, as in the respective embodiments and modifications. On the other hand, the interference control unit 32 does not need to store or update the status flag of valid "1" or invalid "0", and the determination of whether or not it is a valid period (step 11) is made by determining whether or not the output from the external device 50 is a valid signal. This determination of the valid / invalid signal functions as a determination of whether or not it is an unreserved period.

[0070] In addition, in each of the embodiments and variants described above, the external device 50 outputs a valid / invalid signal to the interference control unit 32 based on the reservation information received from the reservation server 80, and the interference control unit 32 determines whether or not it is an effective period in which the interference wave LFjam is not output based on the valid / invalid signal (step 11). In contrast to this, the interference control unit 32 (or the usage control unit 30) may receive reservation information for the vehicle 1 from the external device 50 or the reservation server 80, store it in the memory unit 40, and determine whether the period is valid or invalid based on the stored reservation information.

[0071] In each of the embodiments and modifications described above, the jamming wave LFjam is intermittently output when an LF wave is detected during the invalid period from the usage start date and time to the usage end date and time. On the other hand, even if the validity period is still in effect, the jamming wave LFjam may be output during periods when the user locks the doors of vehicle 1 and is away from vehicle 1 for reasons such as shopping or staying overnight (hereinafter referred to as the absence period). That is, the interference control unit 32 regards the absence period as an invalid period even if it is within the valid period, and outputs an interference wave LFjam when an LF wave is detected. The interference control unit 32 determines whether or not it is an absence period based on the absence signal and return signal transmitted from the external device 50.

[0072] In the first embodiment described above, the case where the interference control unit 32 determines that it is an invalid period (step 11; N), the detection circuit 322 detects the LF wave (step 14). In contrast to this, the detection circuit 322 may be configured to constantly detect LF waves, and when an LF wave is detected, determine whether it is a valid period or not, and if it is an invalid period, output the jamming wave LFjam, or if it is a valid period, not output the jamming wave LFjam.

[0073] In the oscillator circuit 324 of the first embodiment, the microcomputer-dedicated IC 32b of the second embodiment, and the modified examples thereof, the cases where a jamming wave LFjam having the same frequency as the frequency of the LF wave output from the vehicle-side device 60 have been described. That is, in both embodiments, the cases where a jamming wave LFjam of 125 kHz is output when a 125 kHz LF wave is output from the vehicle-side device 60, and a jamming wave LFjam of 134 kHz is output when a 134 kHz LF wave is output have been described. In response to this, the inventors have confirmed through experiments that when the frequency of the LF wave output from the vehicle-side device 60 is F, even an interference wave LFjam having a frequency of F±10 kHz can sufficiently interfere. Therefore, when the frequency of the LF wave output from the vehicle-side device 60 is F, the interference control unit 32 may output an interference wave LFjam having a frequency of F±10 kHz, preferably a frequency of F±5 kHz. For example, when LF waves of either 125 kHz or 135 kHz are output from the vehicle-side device 60 depending on the type of vehicle 1, it becomes possible to deal with only one type of interference wave, LFjam, of 130 kHz, as an interference wave common to LF waves of both frequencies.

[0074] Furthermore, in each of the embodiments and modifications described above, the detection of LF waves is performed by edge detection, but LF waves may also be detected by other methods, such as detecting the voltage level of LF waves. For example, when the frequency range of the LF wave is 100 kHz to 150 kHz, the LF wave is detected when the reception level (voltage level) of the frequency reaches 100 μVpp.

[0075] From the above-described embodiments and modifications, the unauthorized use prevention device can be configured as follows. (Configuration 1) An unauthorized use prevention device disposed in a vehicle together with an electronic key that performs authentication processing with a vehicle-side device, an antenna that receives, as a target wave, a first signal wave transmitted from the vehicle-side device or a second signal wave transmitted from the electronic key in the authentication process; a target wave detection means for detecting reception of the target wave by the antenna; a jamming wave output means for outputting a jamming wave LFjam having the same frequency band as the received target wave from the antenna when the target wave detection means detects reception of the target wave; An unauthorized use prevention device comprising: (Configuration 2) A determination means for determining whether or not a vehicle is available for use is provided, The jamming wave output means outputs the jamming wave Fjam when the determination means determines that the vehicle is not available for use. 2. The fraud prevention device according to configuration 1. (Configuration 3) The jamming wave output means outputs the jamming wave Fjam for a time T that is longer than the time it takes for the authentication process between the vehicle device and the electronic key to be completed. 3. The fraud prevention device according to configuration 1 or 2. (Configuration 4) an adjusting means for adjusting a time T for outputting the jamming wave Fjam; 4. The fraud prevention device according to configuration 3, comprising: (Configuration 5) The jamming wave output means outputs the jamming wave Fjam for a time T that is longer than a time until the repeated retransmission of the target wave is completed when the authentication process between the vehicle-side device and the electronic key cannot be completed. 5. The fraud prevention device according to configuration 3 or 4. (Configuration 6) The determination means determines whether the vehicle is available for use based on a signal indicating the vehicle usage period, the unreserved period, the start and end of the usage period, or the availability status, transmitted from an external device. 6. The fraud prevention device according to any one of configurations 2 to 5, wherein: (Configuration 7) The target wave detection means detects reception of a LF wave in a long wave band when the target wave is the first signal wave, and detects reception of a UHF wave in an ultra high frequency band when the target wave is the second signal wave. 7. The fraud prevention device according to any one of configurations 1 to 6, wherein: (Configuration 8) The target wave detection means detects the LF wave as the target wave, and the jamming wave output means outputs a jamming wave LFjam of the LF wave. 8. The fraud prevention device according to configuration 7. (Configuration 9) The target wave detection means detects reception of the target wave by the antenna by edge detection or voltage level detection. 9. The fraud prevention device according to any one of configurations 1 to 8, wherein: (Configuration 10) An electronic key placement means for placing the electronic key in the vehicle; a button operating means for operating the door lock button and the door unlock button of the electronic key; a push instruction means for instructing the button operation means to push a lock button or an unlock button; 10. The fraud prevention device according to any one of configurations 1 to 9, comprising: (Configuration 11) The target wave detection means detects reception of the target wave by the antenna by direct detection or envelope detection. 11. The fraud prevention device according to claim 1, wherein: (Configuration 12) The jamming wave output means outputs the jamming wave LFjam from the antenna or from a transmission antenna different from the antenna. 12. The fraud prevention device according to claim 1, wherein: [Explanation of symbols]

[0076] 1 vehicle 10 Unauthorized use prevention device 20 Key control section 21 Actuator 22 Electronic Key 30 Usage control section 31 Opening and closing control section 32 Interference control unit 32a LF wave receiving IC 32b Microcontroller Dedicated IC 320 Antenna 320a receiving antenna 320b transmitting antenna 321 Amplifier Circuit 321 Radiation section 322 Detector circuit 323 One-Shot Circuit 324 Oscillator Circuit 40 Storage section 50 External device 60 Vehicle side device 61 Communications Department 62 EG button 63 Engine, door control mechanism 70 Mobile Devices 80 Reservation Server

Claims

1. An unauthorized use prevention device disposed in a vehicle together with an electronic key that performs authentication processing with a vehicle-side device, an antenna that receives, as a target wave, a first signal wave transmitted from the vehicle-side device or a second signal wave transmitted from the electronic key during the authentication process; a target wave detection means for detecting reception of the target wave by the antenna; a jamming wave output means for outputting a jamming wave LFjam having the same frequency band as the received target wave from the antenna when the target wave detection means detects reception of the target wave; An unauthorized use prevention device comprising:

2. a determination means for determining whether or not a vehicle is available for use; the jamming wave output means outputs the jamming wave Fjam when the determination means determines that the vehicle is not available for use.

2. The fraud prevention device according to claim 1.

3. the interference wave output means outputs the interference wave Fjam for a time T that is longer than the time required for the authentication process between the vehicle-side device and the electronic key to be completed; 3. The fraud prevention device according to claim 2.

4. an adjusting means for adjusting the time T for outputting the interference wave Fjam; 4. The fraud prevention device according to claim 3, further comprising:

5. the jamming wave output means outputs the jamming wave Fjam for a time T that is longer than a time until the retransmission of the target wave, which is repeated when the authentication process between the vehicle-side device and the electronic key cannot be completed, is completed.

4. The fraud prevention device according to claim 3.

6. The determination means determines whether the vehicle is available for use based on a signal indicating the vehicle usage period, the unreserved period, the start and end of the usage period, or the availability status, transmitted from an external device.

3. The fraud prevention device according to claim 2.

7. the target wave detection means detects reception of a LF wave in a long wave band when the target wave is the first signal wave, and detects reception of a UHF wave in an ultra high frequency band when the target wave is the second signal wave.

2. The fraud prevention device according to claim 1.

8. The target wave detection means detects the LF wave as the target wave, and the jamming wave output means outputs a jamming wave LFjam of the LF wave.

8. The fraud prevention device according to claim 7.

9. the target wave detection means detects reception of the target wave by the antenna by edge detection or voltage level detection; 2. The fraud prevention device according to claim 1.

10. an electronic key placement means for placing the electronic key in the vehicle; a button operating means for operating the door lock button and the door unlock button of the electronic key; a push instruction means for instructing the button operation means to push a lock button or an unlock button; 10. The fraud prevention device according to claim 1, further comprising:

11. the target wave detection means detects reception of the target wave by the antenna by direct detection or envelope detection; 10. The fraud prevention device according to claim 1, wherein the fraud prevention device comprises: a first access point;

12. The jamming wave output means outputs the jamming wave LFjam from the antenna or from a transmission antenna separate from the antenna.

10. The fraud prevention device according to claim 1, wherein the fraud prevention device comprises: a first access point;

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