JP2012051421A - Control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system capable of effectively preventing any theft of a vehicle by the relay attack while a remote keyless entry system is normally functioned by preventing reach of the identification signal (RF signal) transmitted from a key to the vehicle in a smart entry system, and performing the control so that the unlocking/locking command signal in the remote keyless entry system reaches the vehicle.SOLUTION: A key 3 carried by a user regulates the attenuation factor in an RF transmission unit 31. When an unlock switch 36 is depressed, the attenuation factor is set to be low, and the door unlocking signal is transmitted from the RF transmission unit 31, and a door can be unlocked remotely. When the polling signal is received, the attenuation factor is set to be high, and the ID 34 is transmitted from the RF transmission unit 31. Thus, if an owner is apart from the vehicle in a case of the relay attack, the RF signal does not reach the vehicle, and the relay attack is not successful.

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 vehicle theft 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 Characterized by comprising damping means for attenuating the signal to be transmitted in the time of transmission of the transmission time and the unlock command signal identification signal at different attenuation factor.

  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 attenuation rate of the signal transmitted to the transmission antenna differs between when transmitting and when transmitting the unlock command signal in the remote keyless entry system. Therefore, in the smart entry system, damage due to the relay attack is suppressed, and in the remote keyless entry system, it is possible to adjust the attenuation rate so that the door is unlocked from a place 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 attenuation means may increase the attenuation rate when the identification signal is transmitted than when the unlock command signal is transmitted.

  As a result, when the identification signal is transmitted, the attenuation rate is controlled to be larger than when the unlocking command signal is transmitted. Therefore, in the smart entry system, the attenuation rate is increased and the identification signal from a key far from the vehicle is Prevents damage from relay attacks. In the remote keyless entry system, the attenuation rate is reduced 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.

  Further, the transmission path of the identification signal and the unlock command signal is branched into a first path having a high attenuation rate and a second path having a low attenuation rate, and the attenuation means is configured to transmit the identification signal in the case of transmitting the identification signal. In the case of transmission of the unlock command signal, the first route may be provided with switching means for switching to the second route.

  As a result, the transmission path of the identification signal and the unlocking command signal is branched into two. In the case of transmission of the identification signal, the path of the high attenuation rate is used. In the case of transmission of the unlocking command signal, the path of the low attenuation rate is selected. Since switching is performed, a configuration having two paths with different attenuation factors and a switching unit is installed, and in a smart entry system, an identification signal from a key far from the vehicle does not reach the vehicle using a high attenuation factor path. In this way, the damage by the relay attack is suppressed, and in the remote keyless entry system, the door can be unlocked from a place far from the vehicle by using a low attenuation rate route. 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 attenuation rate of the signal at the time of transmission of the identification signal adjusted by the attenuation means is determined by the identification signal transmitted from the portable device held by the user at the position in contact with the door handle of the vehicle. It is good also as an attenuation factor receivable by 2 communication parts.

  As a result, the attenuation rate at the time of transmission of the identification signal is an attenuation rate at which the identification signal transmitted from the portable device held by the user in contact with the door handle of the vehicle can be received by the second communication unit. In this way, the attenuation rate at the time of the smart entry system is specifically controlled, and the door opening by the vehicle owner in the smart entry system can be appropriately executed, and the high attenuation rate that can suppress the vehicle theft by the relay attack It can be. Therefore, controlling the attenuation rate for the smart entry system independently of controlling the attenuation rate for relay attack countermeasures in the remote keyless entry system, the convenience of the relay attack countermeasures and the remote keyless entry system in the smart entry system is controlled. A coexisting control system can be constructed.

  The attenuation rate of the signal at the time of transmission of the unlocking command signal adjusted by the attenuation means is from the portable device possessed by the user located farther from the vehicle than the position contacting the door handle of the vehicle. The transmitted unlocking command signal may be an attenuation rate that can be received by the second communication unit.

  As a result, when the unlocking command signal is transmitted, the attenuation rate is the second when the unlocking command signal transmitted from the portable device possessed by the user located farther from the vehicle than the position contacting the door handle of the vehicle is second. Since the attenuation rate can be received by the communication unit, the remote keyless entry system can specifically control the attenuation rate in this way, and the user can unlock the vehicle door even from a location away from the vehicle. Can do. Therefore, by controlling the attenuation rate in the remote keyless entry system independently of controlling the attenuation rate for relay attack countermeasures in the smart entry system, the convenience of the relay attack countermeasure and remote keyless entry system in the smart entry system is controlled. 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 the transmission path | route of a transmission signal. 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. Further, the RF transmission unit 31 includes an attenuator 31c as a main part of the present invention.

  A specific configuration example of the RF transmission unit 31 is shown in FIG. In the example of FIG. 5A, an attenuator 31c having a variable attenuation rate is used. 5A includes a transmission IC 31a, an antenna 31b, an attenuator 31c, and a microcomputer 31d. The transmission IC 31a is an IC that processes information content of a signal (RF signal) transmitted from the antenna 31b.

  The microcomputer 31d acquires information about whether the RF signal transmitted from the antenna 31b is an identification signal including ID 34 or a signal indicating that the user has pressed the unlock switch from the control unit 32 of the key 3, The attenuation rate in the attenuator 31c is controlled according to the information.

  As will be described later, when the RF signal transmitted from the antenna 31b is an identification signal including ID 34, the attenuation rate in the attenuator 31c is set to a predetermined high attenuation rate, and the RF signal transmitted from the antenna 31b is unlocked by the user. In the case of a signal indicating that is pressed, the attenuation factor in the attenuator 31c is a predetermined low attenuation factor. As shown in FIG. 5A, specifically, the attenuator 31c may be configured by a variable resistor.

  In the example of FIG. 5B, the RF transmission unit 31 includes a transmission IC 31a, an antenna 31b, an attenuator 31c, and a microcomputer 31d. The RF signal transmission path is branched into a path 31g and a path 31f, and an attenuator 31c is arranged only on the path 31f side. The attenuator 31c may be a fixed electric resistance, for example.

  The microcomputer 31d acquires information about whether the RF signal transmitted from the antenna 31b is an identification signal including ID 34 or a signal indicating that the user has pressed the unlock switch from the control unit 32 of the key 3, The switch 31e is switched according to the information.

  As will be described later, when the RF signal transmitted from the antenna 31b is an identification signal including ID 34, the switch 31e is switched to the path 31f side, and the RF signal transmitted from the antenna 31b indicates that the user has pressed the unlock switch. In the case of the signal shown, the switch 31e is switched to the path 31g side.

  Returning to FIG. 1, 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 user presses the unlock switch 36, the unlocked (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 FIG. 2, the RF transmitter 31 is the case of FIG.

  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 switches the transmission path of the RF signal to the path 31f side in S110. 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 route 31f and transmitted in S110. An attenuator 31c (resistor) is disposed in the path 31f. 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 attenuation rate of the route 31f is high. 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 normal key 3 is far away from the vehicle 2, so the attenuation factor of the path 31f is high. As a result, the RF signal (identification signal) does not reach the vehicle 2. 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 attenuation rate of the path 31f is high. 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 is operated by a thief), the key 3 is far away from the vehicle 2 and the attenuation rate of the path 31f is Due to the high frequency, 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 key 3 switches the transmission path of the RF transmission signal to the path 31g side. In step S <b> 220, the control unit 32 transmits an RF signal (unlock signal) including information that the unlock button is pressed from the RF transmission unit 31. 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 transmission path of the RF signal transmission is switched to the path 31g. In the path 31g, the attenuator 31c is not disposed and the attenuation rate is low. Therefore, even when the user is away from the vehicle, the unlock signal reaches the vehicle 2 and can unlock the door.

  2, 3 and 4, according to the present invention, in the case of transmission of the identification signal (ID34) in the smart entry system, the route 31f having a high attenuation rate is switched to suppress vehicle theft by the relay attack, and the remote keyless entry system (RKE). In the case of transmission of the unlock signal at, the door is unlocked even from a distance by switching to the path 31g having a low attenuation factor. Therefore, in the present invention, the convenience of RKE is not reduced by the relay attack countermeasure.

  2, 3, and 4 show the case of FIG. 5 (b), clearly in the case of FIG. 5 (a), and in S <b> 110, the attenuation rate of the variable attenuator 31 c is adjusted to a predetermined high attenuation rate. In S210, the attenuation factor of the variable attenuator 31c may be adjusted to a predetermined low attenuation factor.

  The high attenuation rate in the above description is set so that the identification signal transmitted from the key 3 held by the user in contact with the door handle of the vehicle can be received by the RF receiver 42. do it. The low attenuation rate means that the RF receiving unit 42 receives an unlock signal transmitted from the key 3 held by the user located at a position (predetermined distance) from the vehicle than the position at which the door handle of the vehicle is contacted. What is necessary is just to set so that it is a possible attenuation factor.

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 attenuation means for attenuating signals to be transmitted at different attenuation rates when the identification signal is transmitted and when the unlock command signal is transmitted.   The control system according to claim 1, wherein the attenuation unit increases the attenuation rate when the identification signal is transmitted compared to when the unlock command signal is transmitted. The transmission path of the identification signal and the unlock command signal is branched into a first path having a high attenuation rate and a second path having a low attenuation rate,
2. The control system according to claim 1, wherein the attenuation unit includes a switching unit that switches to the first path when the identification signal is transmitted and switches to the second path when the unlock command signal is transmitted.   The attenuation rate of the signal at the time of transmission of the identification signal adjusted by the attenuation means is determined based on the second identification signal transmitted from the portable device held by the user who is in contact with the door handle of the vehicle. The control system according to any one of claims 1 to 3, which is an attenuation rate receivable by the communication unit.   The attenuation rate of the signal at the time of transmission of the unlocking command signal adjusted by the attenuation 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 an attenuation rate receivable by the second communication unit.