JP2012054662A - Control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system capable of effectively preventing generation of a vehicle theft by a relay attack while making a remote keyless entry system operate normally by controlling a discriminating signal (RF signal) transmitted from a key so as not to reach the vehicle in a smart entry system and controlling a command signal for locking and unlocking a door so as to reach the vehicle in a remote keyless entry system.SOLUTION: A user's portable key 3 has two antennas of an antenna 31b and an antenna 31c for transmitting an RF signal. A gain of the antenna 31b is larger than that of the antenna 31c. Since a switching section 31a switches to the antenna 31b and transmits a signal for unlocking a door when depressing an unlock switch 36, the door can be unlocked remotely. Since the switching section 31a switches to the antenna 31c and transmits an ID 34 when receiving a polling signal, a relay attack cannot be successful because the RF signal does not reach the vehicle when its owner is distant from the vehicle during the relay attack.

Description

  The present invention relates to a control system.

  Smart key systems for vehicles (smart entry systems, smart start systems) are in widespread use. In the current smart entry system, for example, when a user performs an operation such as a door handle contact or an engine start switch depression, a polling signal is transmitted, and when the ID returned from the smart key and the master ID are collated. Door unlocking and engine starting are executed.

  For example, in Patent Document 1 below, in the smart key system, a means for determining whether or not the occupant intends to continue driving is equipped, and the portable device is separated from the vehicle, and driving continues for those who do not have the portable device. A system is disclosed that permits the restart of the internal combustion engine when there is an intention to prevent theft of the vehicle more reliably.

JP 2007-153190 A

  A theft technique called relay attack is known for smart key systems. It is shown in FIG. In this method, theft persons A and B are located between the vehicle and the owner in a situation where the owner is away from the vehicle. Assume that the owner carries a smart key. Thieves A and B possess radio wave repeaters.

  In this state, first, the thieves A and B relay the polling signal transmitted from the vehicle and transmit it to the owner's place. Normally, the reach range of the polling signal is limited to the periphery of the vehicle, but the polling signal can be sent to the owner by relaying the thieves A and B. When the smart key carried by the owner of the vehicle receives the polling signal, it returns an ID code unique to the smart key stored therein as an RF signal.

  The returned RF signal reaches the vehicle. The vehicle executes a matching process with the master ID on the received RF signal. Since the RF signal is a signal transmitted from the smart key of the owner, the verification is naturally successful. As a result, the vehicle is allowed to unlock the door. In this way, the theft can enter the vehicle.

  Further, when the same procedure is repeated after the thief A has boarded the vehicle, the vehicle interior verification is successful and the vehicle is permitted to start the engine. In this way, the thief can drive the vehicle. The above is the outline of the relay attack.

  Naturally, effective countermeasures against such relay attacks are necessary. Relay attack is usually done when the vehicle owner is far away from the vehicle. Therefore, it is considered that an effective measure for preventing damage caused by relay attack is to prevent the RF signal transmitted from the smart key far away from the vehicle from reaching the vehicle.

  In this case, a smart entry system and a remote keyless entry system (RKE) coexist. Today, a smart entry system and an RKE often coexist as a vehicle door unlocking system. RKE is equipped with an unlock button for unlocking the door of the vehicle, a lock button for locking the key carried by the user, and the fact that the user has pressed them is wirelessly communicated to the vehicle, This is a system in which a door of a vehicle is unlocked or locked.

  Therefore, in the system where the smart entry system and the RKE coexist, the RF signal does not reach the vehicle in the smart entry system as described above, and the lock / unlock radio signal (RF signal) in the RKE reaches the vehicle. Such ingenuity is necessary.

  In view of the above problems, the problem to be solved by the present invention is to prevent the identification signal (RF signal) transmitted from the key in the smart entry system from reaching the vehicle, and to unlock and lock in the remote keyless entry system. It is an object of the present invention to provide a control system capable of effectively preventing vehicle theft by a relay attack while controlling the command signal to reach the vehicle so that the remote keyless entry system functions normally.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, a control system according to the present invention includes a first communication unit that is portable by a user and has a wireless communication function, and a command input from a user that commands unlocking of a vehicle door. A portable device including an input means for receiving the first communication unit, a second communication unit provided in the vehicle and having a wireless communication function with the first communication unit, and from the second communication unit to the first communication unit A command signal for requesting a reply of the identification signal is transmitted, the signal received by the second communication unit is collated with the identification signal unique to the portable device, and if the collation is successful, the vehicle door is unlocked. And an unlock command signal indicating that the input means has received the command input is transmitted from the first communication unit, and when the unlock command signal is received by the second communication unit, the vehicle door is unlocked. A second unlocking means, wherein the first communication unit is a front Wherein the gain of the transmission antennas in the time of transmission of the transmission time and the unlock command signal identification signal including a control means for controlling differently.

  Thus, in the control system according to the present invention, the first unlocking means according to the so-called smart entry system and the second unlocking means according to the so-called remote keyless entry system are provided. Control is performed so that the gain of the transmission antenna is different between the time of transmission and the time of transmission of the unlock command signal in the remote keyless entry system. Therefore, in the smart entry system, the damage due to the relay attack is suppressed, and in the remote keyless entry system, it is possible to adjust the gain to unlock the door from a location far from the vehicle. Therefore, it is possible to build a control system that combines the relay attack countermeasures in the smart entry system and the convenience of the remote keyless entry system.

  Further, the control means may perform control so that the gain of the transmission antenna is smaller when the identification signal is transmitted than when the unlock command signal is transmitted.

  As a result, the transmission antenna gain is controlled to be smaller when the identification signal is transmitted than when the unlock command signal is transmitted. Therefore, in the smart entry system, the gain of the transmission antenna is reduced to move away from the vehicle. Vehicle theft by relay attack is suppressed by preventing the identification signal from the key from reaching the vehicle. In the remote keyless entry system, the gain of the transmission antenna is increased so that the door can be unlocked from a location far from the vehicle. Therefore, it is possible to build a control system that combines the relay attack countermeasures in the smart entry system and the convenience of the remote keyless entry system.

  The first communication unit includes: a first antenna unit for transmitting the identification signal; and a second antenna unit having a gain larger than that of the first antenna unit for transmitting the unlock command signal. Switching means for switching the antenna for signal transmission to the first antenna unit when transmitting the identification signal and switching to the second antenna unit when transmitting the unlocking command signal. May be provided.

  Accordingly, the first antenna unit for transmitting the identification signal and the second antenna unit for transmitting the unlock command signal are equipped, and the second antenna unit has a larger gain than the first antenna unit, In the case of transmission of the identification signal, it switches to the first antenna unit, and in the case of transmission of the unlocking command signal, it switches to the second antenna unit, so it is equipped with a configuration having two antennas and a switching unit, and smart entry In the system, a transmission antenna with a small gain is used to prevent an identification signal from a key far away from the vehicle from reaching the vehicle to suppress damage caused by relay attack. In a remote keyless entry system, a transmission antenna with a large gain is used. Used to unlock the door from a location far from the vehicle. Therefore, it is possible to build a control system that combines the relay attack countermeasures in the smart entry system and the convenience of the remote keyless entry system.

  In addition, the gain of the transmission antenna at the time of transmission of the identification signal controlled by the control means is such that the identification signal transmitted from the portable device possessed by the user who is in contact with the door handle of the vehicle is the first signal. The gain may be receivable by the two communication units.

  As a result, the gain of the transmitting antenna at the time of transmitting the identification signal is such that the second communication unit can receive the identification signal transmitted from the portable device possessed by the user who is in contact with the door handle of the vehicle. Therefore, by specifically controlling the gain value at the time of the smart entry system in this way, the door opening by the vehicle owner in the smart entry system can be appropriately executed, and the vehicle theft by the relay attack can be suppressed. It can be a small gain value. Therefore, the gain value in the smart entry system is controlled independently of controlling the gain value for the relay attack countermeasure in the remote keyless entry system, and the convenience by the relay attack countermeasure in the smart entry system and the remote keyless entry system A coexisting control system can be constructed.

  The gain of the antenna at the time of transmission of the unlocking command signal controlled by the control means is transmitted from the portable device possessed by the user located farther from the vehicle than the position contacting the door handle of the vehicle. The unlock command signal may be a gain that can be received by the second communication unit.

  As a result, the gain of the antenna at the time of transmission of the unlocking command signal is the same as that of the unlocking command signal transmitted from the portable device held by the user located farther from the vehicle than the position contacting the door handle of the vehicle. 2 Since the gain is receivable by the communication unit, in the remote keyless entry system, the gain value is specifically controlled in this way, and the user can unlock the vehicle door even from a location away from the vehicle. Can do. Therefore, the gain value for remote keyless entry system is controlled independently of controlling the gain value for relay attack countermeasures in the smart entry system. A coexisting control system can be constructed.

The block diagram in one Example of the control system of this invention. The flowchart which shows the process sequence in the case of a smart entry system. The flowchart which shows the process sequence in the case of a smart start system. The flowchart which shows the process sequence in the case of a remote keyless entry system. The figure which shows the example of a design of an antenna. The figure which shows the outline | summary of a relay attack.

  Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a schematic diagram of a device configuration of a vehicle control system 1 (system, control device) according to the present invention. A system 1 shown in FIG. 1 includes a collation control unit (ECU: Electronic Control Unit) 4 provided in a vehicle 2 and a key 3 (smart key, electronic key, portable device) that can be carried by a user. The vehicle 2 is not limited as long as it is an automobile, and may be, for example, a gasoline engine car, a diesel engine car, an electric car, or a hybrid car.

  The ECU 4 includes a vehicle interior LF transmitter 40, a vehicle interior LF transmitter 41, and an RF receiver 42. The vehicle exterior LF transmission unit 40 is installed, for example, at a door handle portion of the vehicle 2 and transmits a polling signal to the vehicle interior of the vehicle 2 using electromagnetic waves in the LF (long wave) band.

  The vehicle interior LF transmission unit 41 is installed in the vehicle interior and transmits a polling signal to the vehicle interior of the vehicle 2 by electromagnetic waves in the LF (long wave) band. The RF receiver 42 is installed in, for example, a vehicle interior and receives RF signals transmitted from outside the vehicle interior.

  The ECU 4 has a normal computer structure, and includes a CPU that controls various operations and information processing, a RAM that is a temporary storage unit as a work area of the CPU, and a nonvolatile memory 43 that stores various information. It is assumed that a master ID 44 described later is stored in the memory 43.

  The door 5 of the vehicle 2 is equipped with a lock mechanism 50, a touch sensor 51, a lock button 52, and a key cylinder 53. The door is locked or unlocked by the lock mechanism 50. The touch sensor 51 is a sensor that is mounted on the door handle of the vehicle 2 and detects that the user has gripped the door handle.

  The lock button 52 is a door locking button in the smart key system, and is provided near the door handle, and is a button that locks the door when pressed by the user when the vehicle exterior verification is successful. The key cylinder 53 is a hole for inserting a mechanical key portion 37 provided near the door handle.

  The door 5 refers to a plurality of doors (driver's seat side door, passenger seat side door, rear seat right side, left side door, etc.) equipped on the vehicle 2, and each of the doors has a lock mechanism 50, a touch sensor 51, and a lock. It is only necessary that the button 52 and the key cylinder 53 are equipped.

  The vehicle 2 also includes a key cylinder 60 and an engine start switch 61 in the vicinity of the driver's seat in the passenger compartment. The key cylinder 60 is a hole for inserting the mechanical key portion 37, and a cranking switch (SW) that is a switch for starting the engine of the vehicle 2 according to the rotation angle of the inserted mechanical key, and the engine of the vehicle 2. An on / off control of an ignition switch for continuing operation and an accessory switch for causing various electric devices to function without starting the engine of the vehicle 2 is controlled.

  The engine start switch 61 is a switch for starting the engine in the smart start system, and is a switch for starting the engine when the user presses the button while the vehicle interior verification is successful. Each of the above units is connected by in-vehicle communication (CAN communication) and can exchange information.

  Key 3 is an electronic key related to the smart key system, which can be carried by the user, and includes LF receiver 30, RF transmitter 31, controller 32, memory 33, lock switch 35 (lock button), and unlock switch 36 (unlock). Lock button) and a mechanical key part 37. The memory 33 stores an identification signal 34 (ID code, ID) unique to the key 3.

  The LF receiving unit 30 receives the above-described polling signal. The RF transmitter 31 receives the polling signal and transmits the ID code 34 unique to the key 3 as an RF signal. Furthermore, the RF transmission unit 31 includes two antennas, an antenna 31b, an antenna 32c, and a switching unit 31a as main parts of the present invention.

  The antenna 31b is an antenna for transmitting an RF signal (lock signal, unlock signal) in RKE. The antenna 31c is an antenna for transmitting an RF signal (identification signal) in the smart entry system. The switching unit 31a switches the RF signal transmitting antenna to the antenna 31b in the case of RKE, and to the antenna 31c in the case of the smart entry system.

  A design example of the antenna 31b, the antenna 32c, and the switching unit 31a is shown in FIG. In the example of FIG. 5, in the key 3, the antenna 31b and the antenna 32c are arranged on the same electronic circuit board together with the control unit 32 and the like. The high gain antenna 31b is formed in a U shape at the periphery of the substrate, and the low gain antenna 31c is formed in the vicinity thereof. The switching unit 31a is formed adjacent to both antennas 31b and 31c. If it carries out like FIG. 5, the installation of two antennas will not become the obstacle of the space saving of the key 3. FIG.

  The lock switch 35 and the unlock switch 36 are switches for unlocking and locking the door in the wireless keyless entry system. When the user presses the lock switch 35 within the communication range outside the vehicle, the door 5 of the vehicle 2 is locked, and when the unlock switch 36 is pressed, the unlocking permitted state is entered.

  The mechanical key unit 37 is a mechanical key unit, and is inserted into the key cylinder 53 of the door 5 or the key cylinder 60 in the passenger compartment, and door unlocking, locking, engine starting, and the like are executed. The control unit 32 has the same structure as a normal computer, and includes a CPU for various information processing, a RAM of a temporary storage unit as a work area of the CPU, and the like. The RF transmission unit 31, the control unit 32, the memory 33, the lock switch 35, and the unlock switch 36 are controlled by the control unit 32.

  As described above, this system includes three methods as a method for unlocking a door of a vehicle. The first method is a so-called smart entry system. In this method, when the touch sensor 51 detects an operation for unlocking the door that is gripped by the user, the LF wave commanding a reply of the identification signal (ID34) from the outside LF transmitter 40 to the key 3 is used. A polling signal is transmitted.

  For example, it is assumed that a predetermined number of polling signals are transmitted per contact detection of the door handle. When the key 3 receives the polling signal, it returns an RF wave signal including ID 34 from the RF transmitter 31. The ECU 4 collates the signal received by the RF receiving unit 42 with the master ID 44. If the collation is successful, the ECU 4 unlocks the door 5 of the vehicle or sets the unlocking permitted state.

  The second method is a so-called keyless entry system. In this method, when a user outside the vehicle presses the unlock switch 36 of the key 3, the unlock command signal is transmitted from the RF transmission unit 31 in a form including the ID 34. The ECU 4 receives this signal at the RF receiver 42 and, if the collation with the master ID 44 is successful, sets the vehicle door 5 to the unlocked (permitted) state. If the user grasps the door handle in this state, the door is unlocked (opened).

  The third method is door unlocking by the mechanical key portion 37. In this method, the door 5 is unlocked by inserting the mechanical key portion 37 into the key cylinder 53 and turning it.

  Based on the above configuration, the system 1 executes processing for preventing door unlocking due to a relay attack in the smart entry system in the vehicle 2. The processing procedure is shown in FIG. The processing procedure of FIG. 2 (and FIGS. 3 and 4 to be described later) may be programmed in advance and stored in, for example, the memory 43, and called by the ECU 4 and automatically executed. The process on the right side in FIG. 2 is a process using the regular key 3 of the owner of the vehicle 2.

  In the process of FIG. 2, first, in S10, the ECU 4 determines whether or not the touch sensor 51 has detected contact with the door handle by the user. When the touch sensor 51 detects contact (S10: YES), the process proceeds to S20, and when contact is not detected (S10: NO), S10 is repeated to enter a waiting state. After proceeding to S20, the ECU 4 transmits an LF signal (polling signal) from the vehicle exterior LF transmitter 40.

  The key 3 receives the LF signal transmitted in S20 by the LF receiver 30 in S100. Then, the key 3 analyzes that the received signal is a polling signal related to the smart entry system by the control unit 32, and in step S110, the RF signal transmission antenna is changed to the identification signal transmission antenna 31c (smart antenna). Switch. In S120, the ECU 4 transmits an RF signal (identification signal) including the ID 34 unique to the key 3 from the antenna 31c.

  Subsequently, in S30, the ECU 4 determines whether or not an RF signal has been received. When the RF signal is received (S30: YES), the process proceeds to S40, and when the RF signal is not received (S30: NO), the process proceeds to S50.

  After proceeding to S40, the ECU 4 performs collation between the RF signal confirmed to be received in S30 and the master ID 44, and determines whether the collation is successful. When the collation is successful (S40: YES), the process proceeds to S80, and when the collation is unsuccessful (S40: NO), the process proceeds to S50. In S80, the ECU 4 instructs the lock mechanism 50 to unlock the door.

  After proceeding to S50, the ECU 4 determines whether or not the elapsed time has exceeded a predetermined time. Here, the elapsed time is the elapsed time since the transmission of the LF signal in S20. If the elapsed time exceeds the predetermined time (S50: YES), the process of FIG. 2 is terminated. If the predetermined time has not been exceeded (S50: NO), the process returns to S30 and waits for reception of the RF signal.

  As described above, in the process of FIG. 2, when the key 3 carried by the owner of the vehicle receives the polling signal (LF signal), it is switched to the smart antenna 31c and transmitted in S110. The smart antenna 31c is an antenna having a small gain. Therefore, if the authorized owner of the vehicle is trying to unlock the door (that is, if the contact to the door by S10 is a contact by the authorized owner of the vehicle 2), the key 3 is close to the vehicle 2. Therefore, the RF signal (identification signal) reaches the vehicle 2 even if the gain of the smart antenna 31c is small. And collation is successful (S40: YES) and a door is unlocked (S80).

  On the other hand, if a relay attack is being performed (that is, if the door contact by S10 is a contact by a thief), the key 3 is usually far away from the vehicle 2, so the gain of the smart antenna 31c is The RF signal (identification signal) does not reach the vehicle 2 due to being small. Therefore, no RF signal is received even after a predetermined time has elapsed (S50: YES), so the door is not unlocked. Therefore, the unlocking of the vehicle door by the relay attack is suppressed. The above is the processing of FIG.

  Next, FIG. 3 will be described. 2 shows the procedure for relay attack countermeasures in smart entry (opening the door using a smart key), while FIG. 2 shows the processing for relay attack countermeasures in smart start (engine start using a smart key). It is a procedure. Among the processes in FIG. 3, the same reference numerals as those in FIG. 2 perform the same processes as in FIG. Hereinafter, parts different from FIG. 2 will be described.

  In the process of FIG. 3, S10 of FIG. 2 is replaced with S15. In S <b> 15, the ECU 4 determines whether or not the user has turned on the engine start switch 61. When the on operation for the engine start switch 61 is performed (S15: YES), the process proceeds to S20. When the on operation for the engine start switch 61 is not performed (S15: NO), S10 is repeated to wait for the on operation. In FIG. 3, S80 in FIG. 2 is replaced with S85. In S85, the ECU 4 starts the engine.

  In the process of FIG. 3, the same principle as in FIG. 2 works, and the engine start due to the relay attack is suppressed. That is, if the authorized owner of the vehicle is about to start the engine (that is, if the on operation of the engine start switch in S15 is an operation by the authorized owner of the vehicle 2), the key 3 is the vehicle 2's vehicle. Since it is indoors, the RF signal (identification signal) reaches the RF receiver 42 even if the gain of the smart antenna 31c is small. And collation is successful (S40: YES) and an engine is started (S85).

  On the other hand, if the relay attack is being performed (that is, if the engine start switch is turned on by S15 by a thief), the key 3 is far away from the vehicle 2, so the gain of the smart antenna 31c is increased. Is small, the RF signal (identification signal) does not reach the RF receiver 42. Therefore, even if the predetermined time has elapsed, no RF signal is received (S50: YES), so the engine does not start. Therefore, engine start due to relay attack is suppressed. The above is the processing of FIG.

  Next, FIG. 4 will be described. 2 and 3 are processes related to the smart key system, whereas FIG. 4 is a process related to the remote keyless entry system (RKE). In RKE, when the user presses the lock switch 35 and the unlock switch 36, the door is locked and unlocked.

  Specifically, in the process of FIG. 4, first, in S <b> 200, it is determined whether or not the control unit 32 has detected that the user has pressed the unlock button 36 provided on the key 3. If it is detected that the unlock button 36 is pressed (S200: YES), the process proceeds to S210, and if the pressing of the unlock button 36 is not detected (S200: NO), S200 is repeated to enter a waiting state.

  After proceeding to S210, the control unit 32 switches the RF signal transmitting antenna to the RKE antenna 31b. In S220, the control unit 32 transmits an RF signal (unlock signal) including information that the unlock button is pressed from the RKE antenna 31b. It is assumed that the information of ID34 is included in the unlock signal.

  In S430, the ECU 4 determines whether or not the RF receiver 42 has received an unlock signal. If an unlock signal has been received (S230: YES), the process proceeds to S240. If an unlock signal has not been received (S230: NO), S230 is repeated to wait for the unlock signal.

  After proceeding to S240, the ECU 4 collates the ID 34 and the master ID 44 included in the received unlock signal. If the verification is successful (S240: YES), the process proceeds to S250. If the verification is unsuccessful (S240: NO), the process returns to S230 and waits for an unlock signal. After proceeding to S250, since the ECU 4 has received the unlock signal from the regular key 3, the door 5 of the vehicle 2 is unlocked.

  As described above, in the process of FIG. 4, when the pressing of the unlock button by the user is detected, the RF signal transmitting antenna is switched to the RKE antenna 31 b. The RKE antenna 31b is a high gain antenna. Therefore, even when the user is away from the vehicle, the unlock signal reaches the vehicle 2 and can unlock the door. Even when the user presses the lock button, the mode is switched to the RKE antenna 31b as described above.

  2, 3, and 4, in the present invention, when the identification signal (ID 34) is transmitted in the smart entry system, the antenna 31 c with a small gain is used to suppress vehicle theft by the relay attack, and in the remote keyless entry system (RKE) In the case of transmitting an unlock signal, the door 31 can be unlocked from a distance by using the antenna 31b having a large gain. Therefore, in the present invention, the convenience of RKE is not reduced by the relay attack countermeasure.

  The gain of the antenna 31c may be set so that the identification signal transmitted from the key 3 possessed by the user who is in contact with the door handle of the vehicle can be received by the RF receiver 42. The gain of the antenna 31b is such that the unlock signal transmitted from the key 3 held by the user located at a position (predetermined distance) away from the vehicle from the position in contact with the door handle of the vehicle is received by the RF receiver 42. What is necessary is just to set it as possible gain.

1 Control system 2 Vehicle 3 Key (portable machine)
4 ECU

Claims (5)

A portable device including a first communication unit that is portable by a user and having a wireless communication function; and an input unit that receives a command input from a user that commands unlocking of a vehicle door;
A second communication unit provided in a vehicle and having a wireless communication function with the first communication unit;
A command signal for requesting a reply of an identification signal is transmitted from the second communication unit to the first communication unit, the signal received by the second communication unit is collated with the identification signal unique to the portable device, and the collation is A first unlocking means for unlocking the vehicle door if successful;
When the unlocking command signal indicating that the input means has received the command input is transmitted from the first communication unit and the unlocking command signal is received by the second communication unit, the second opening for unlocking the vehicle door is performed. A locking means,
The control system according to claim 1, wherein the first communication unit includes control means for controlling the gain of the transmission antenna to be different between when the identification signal is transmitted and when the unlocking command signal is transmitted.   2. The control system according to claim 1, wherein the control unit controls the gain of the transmission antenna to be smaller when the identification signal is transmitted than when the unlock command signal is transmitted. The first communication unit is
A first antenna unit for transmitting the identification signal;
A second antenna unit having a gain larger than that of the first antenna unit for transmitting the unlock command signal;
The control means includes switching means for switching an antenna for signal transmission to the first antenna unit in the case of transmission of the identification signal and to switch to the second antenna unit in the case of transmission of the unlock command signal. The control system according to claim 1.   The gain of the transmission antenna at the time of transmission of the identification signal controlled by the control means is such that the identification signal transmitted from the portable device possessed by the user at a position in contact with the door handle of the vehicle is the second. The control system according to claim 1, wherein the control system has a gain that can be received by the communication unit.   The transmission antenna gain at the time of transmission of the unlocking command signal controlled by the control means is transmitted from the portable device possessed by the user located farther from the vehicle than the position contacting the door handle of the vehicle. The control system according to any one of claims 1 to 4, wherein the unlocking command signal thus obtained is a gain that can be received by the second communication unit.