JP2016037729A - Control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system capable of more accurately identifying a relay attack without increasing processing load of a portable device and an on-board apparatus.SOLUTION: A control system includes a plurality of control units installed around a parking position of a vehicle. The control unit includes: a request signal reception section for receiving a request signal transmitted by radio waves from an on-board apparatus mounted on the vehicle; a response signal reception section for receiving a response signal transmitted by radio waves to the on-board apparatus, in response to the request signal; a determination section for determining whether or not the response signal received by the response signal reception section is a proper signal, on the basis of a reception state of the response signal by other control units and installation locations of the control unit and the other control units; and an output section for outputting the determination result of the determination section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control system.

  A smart key system, which is one of control systems that realize various functions in a vehicle by wireless communication between a portable device possessed by a user and an in-vehicle device mounted on the vehicle, does not use a mechanical key. Even if it authenticates by radio | wireless communication between a portable machine and a vehicle-mounted apparatus, based on the authentication result, operation | movement which a user desires, such as door unlocking and engine starting, can be performed.

  In the smart key system, for example, a request signal is periodically transmitted from the vehicle using an LF (long wave) band radio wave, and when the portable device receives the request signal, for example, a response signal is transmitted using an RF (high frequency) band radio wave. In response, the position of the portable device in the vicinity of the vehicle is estimated. Since the propagation distance of the LF band radio wave can be controlled, the output is set so that the request signal reaches only near the vehicle in consideration of security.

  In the situation where the user (portable device) is away from the vehicle, two thieves with radio wave repeaters are located between the vehicle and the portable device, and communication between the in-vehicle device and the portable device (request) A theft technique called a relay attack is known in which a verification process is performed by relaying a signal or a response signal, and the vehicle invades and travels.

  In order to prevent this relay attack, the request signal received by the portable device (RSSI) is compared with the response signal received by the in-vehicle device. A smart keyless entry system has been devised that determines whether a person who has received a signal is a legitimate user who has sent a response signal to the vehicle (see Patent Document 1).

JP 2010-121297 A

  In Patent Document 1, a high resolution is required for RSSI detection means. Based on the RSSI correlation between the request signal and the response signal, it can also be determined whether or not it is a relay attack. In this case, a certain countermeasure effect can be expected even when the resolution of RSSI is low, but it is necessary to prepare the correlation as map data in advance. In order to increase the accuracy of the relay attack, it is necessary to prepare a correlation according to the propagation state of each radio wave, which increases the processing load of the portable device and the in-vehicle device.

  Against the background of the above problems, an object of the present invention is to provide a control system that can determine a relay attack more accurately without increasing the processing load of a portable device and an in-vehicle device.

  A control system for solving the above problem includes a plurality of control units installed around a parking position of a vehicle, and the control unit receives a request signal transmitted wirelessly by an in-vehicle device mounted on the vehicle. Signal reception unit, response signal reception unit that receives response signal wirelessly transmitted to in-vehicle device in response to request signal, and radio wave reception information including reception status of response signal of other control unit Radio wave reception information acquisition unit, storage unit for storing the installation location of the control unit, installation location information acquisition unit for acquiring installation location information including the installation location of other control units, and reception of response signals from other control units The response signal received by the response signal receiver is based on the status and the installation location of the control unit and other control units. It comprises a determination section for determining whether or not Tadashina ones, and an output unit for outputting a determination result of the determination unit.

  In the present invention, a plurality of control units for monitoring communication between an in-vehicle device and its communication target are provided, and a control unit (infrastructure equipment such as a parking lot system) that should not be received in consideration of the propagation distance of radio waves When the communication is received, it is determined that a relay attack has occurred (that is, it is determined that the response signal received by the response signal receiving unit is not appropriate). Therefore, the relay attack can be determined without increasing the load on the vehicle side such as the in-vehicle device.

The figure which shows the structure of a control system. The figure which shows the positional relationship of a control unit and a vehicle. The figure which shows the structure of a control unit. The figure which shows the structure of a smart key system. The flowchart which shows a relay attack determination process. The schematic diagram which shows the example of the determination method of positional relationship. The schematic diagram which shows another example of the determination method of positional relationship.

  As shown in FIG. 1, the control system 1 includes, for example, a plurality of control units attached to car stops (S1a to Sna, S11a to S1na) installed in the parking spaces (P1 to Pn, P11 to P1n) of the parking lot. (U1-Un, U11-U1n), the control unit attached to the street lamps L1, L2 installed between the parking section P including the parking spaces P1-Pn and the parking section P1 including the parking spaces P11-P1n UL1 and UL2. In addition to the above, the control unit may be attached to a structure such as a building near the parking space.

  Since the configuration of the parking space and the control unit is the same, the following description will be given by taking the parking space P1 as an example. For example, when there are two block-shaped car stops (S1a, S1b), the control unit U1 is attached to either one (S1a).

  Further, in the parking space P2 or P11 adjacent to the parking space P1, it is desirable that the control unit is not attached to the vehicle stop (S2b, S11b) facing the vehicle stop S1a to which the control unit U1 is attached. Accordingly, it is possible to prevent the LF radio wave of the vehicle parked in the adjacent parking space from being received and misidentifying that the vehicle is parked in the own parking space.

  The control unit is attached to the vehicle stop so as to be able to receive radio waves in the LF band and the RF band, such as at least an antenna (described later) is exposed (may be either pasted or embedded). Moreover, about the vehicle stop which attaches a reflecting plate, you may integrate a control unit and a reflecting plate. The power source may be a battery (a combination of one or more of a primary battery, a secondary battery, and a solar battery), or a commercial power source.

  As shown in FIG. 2, the control unit UL1 in the streetlight L1 is attached to a position where radio waves in the LF band and the RF band can be received. For example, it is desirable that the antenna position be installed so as not to exceed the vehicle height of the vehicle C1. As a result, unnecessary radio waves from a distance are not received, so that the accuracy of relay attack determination is improved.

  As shown in FIG. 3, the control unit U1 includes a control unit 11 (determination unit and detection unit of the present invention) and a non-volatile memory 12 connected to the control unit 11 for storing various types of information (of the present invention). Storage unit), LF receiver 13 (request signal receiver of the present invention), RF receiver 14 (response signal receiver of the present invention), RF transmitter 15 (output unit of the present invention), communication I / F 16 (book) Including a radio wave reception information acquisition unit and an installation location information acquisition unit).

  The control unit 11 is configured as a computer including a well-known CPU and peripheral circuits (not shown), and the CPU executes a control program stored in the memory 12 to realize various functions of the control system 1.

  The memory 12 stores at least installation location information of the control unit U1 (which may be an absolute position such as latitude / longitude, a relative position with other control units, or a distance between other control units). You may memorize | store the installation location information of another control unit. In addition, radio wave reception information (which may include the installation location information of the unit) reflecting the reception status of the request signal and the response signal transmitted from another control unit is temporarily stored.

  The LF reception unit 13 receives a request signal transmitted from an LF band radio wave (radio wave of the first frequency band of the present invention) from the vehicle. The RF receiving unit 14 receives a response signal transmitted by an RF band radio wave (radio wave of the second frequency band of the present invention) from the vehicle. The RF transmitter 15 transmits a radio signal to the vehicle using radio waves in the RF band (details will be described later). The transmission power of the RF transmitter 15 may be such that only the vehicle (C1) parked in the parking space P1 can receive it.

  The communication I / F 16 is an interface circuit for connecting to the network 19 (which may be wired or wireless). Thereby, each control unit is connected so that communication is possible. When a request signal or a response signal is received, the radio wave reception information reflecting the received contents is broadcasted to other control units via the communication I / F 16. The radio wave reception information includes, for example, the position of the transmission source control unit, signal contents (polling signal, response signal), radio wave reception intensity, and installation location information of the control unit U1.

  An outline of a smart key system of a vehicle (C1 is exemplified) will be described with reference to FIG. Details of the smart key system are described in, for example, Japanese Patent Application Laid-Open No. 2012-054662.

  The smart key system 2 includes a verification ECU 4 (a verification unit and a control unit of the present invention) provided in the vehicle C1, and a portable device 3 possessed by the user. The vehicle 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 verification ECU 4 is configured as a computer including a well-known CPU and peripheral circuits (not shown), and further includes a nonvolatile memory 43 for storing various types of information. The memory 43 stores a master ID 44 described later.

  The reference ECU 4 is connected to the outside LF transmission unit 40, the vehicle interior LF transmission unit 41, the RF reception unit 42, the door unit 5, and the engine start switch 61. The in-vehicle device of the present invention includes at least a verification ECU 4, a vehicle exterior LF transmitter 40, a vehicle interior LF transmitter 41, and an RF receiver 42.

  The vehicle exterior LF transmitter 40 is attached to, for example, a door handle (not shown) of the vehicle C1, and the vehicle interior LF transmitter 41 is attached to the vehicle interior. These LF transmitters transmit a polling signal to the outside of the vehicle interior or the interior of the vehicle interior using LF band radio waves. For example, the polling signal reaches only within a limited transmission area (for example, a range of 1 to 1.5 m from the antenna) in the vicinity outside the door, in the vicinity of the trunk, in the passenger compartment, and in the trunk.

  The RF receiving unit 42 is attached, for example, in the vehicle interior, and receives a response signal transmitted from the outside of the vehicle or from the vehicle interior using radio waves in the RF band. By using radio waves in the RF band, even if the output level of the portable device 3 is relatively weak, a communication distance (for example, 30 to 100 m) is appropriately obtained, and a response signal can be received more reliably.

  The door unit 5 includes a lock mechanism 50, a touch sensor 51, and a lock button 52. The door is locked or unlocked by the lock mechanism 50. The touch sensor 51 is mounted on the door handle and detects that the user has gripped the door handle. The lock button 52 is provided in the vicinity of the door handle, and the door is locked when pressed by the user when the vehicle exterior verification is successful.

  The door unit 5 is a collective term for each door unit of the vehicle C1 (driver's side door, passenger side door, rear seat right door, rear seat left door, etc.).

  The engine start switch 61 is a switch for starting the engine in the smart key system 2, and the engine is started when the user presses it while the vehicle interior verification is successful. Each of the above units is connected by in-vehicle communication (for example, CAN communication) and can exchange information.

  The portable device 3 includes an LF receiver 30, an RF transmitter 31, a controller 32, a memory 33, a lock switch 35, and an unlock switch 36. The control unit 32 is configured as a well-known computer and performs operation control of the entire portable device 3. The memory 33 stores an ID 34 that identifies the portable device 3.

  The LF receiver 30 receives a polling signal from the vehicle C1. When receiving the polling signal, the RF transmitter 31 transmits a response signal including the ID 34.

  The lock switch 35 and the unlock switch 36 are switches for unlocking and locking the door in the remote keyless entry (RKE) system. When the user presses the lock switch 35 within the communication range outside the vehicle, the lock mechanism 50 of the vehicle C1 is locked, and when the unlock switch 36 is pressed, the lock mechanism 50 is unlocked.

  With the configuration as described above, in the smart key system 2, when the touch sensor 51 detects an operation for unlocking the door by the user to grip the door handle, a polling signal is sent from the outside LF transmitter 40 to the portable device 3. Send a predetermined number of times. When the portable device 3 receives the polling signal, the portable device 3 returns a response signal from the RF transmission unit 31. The collation ECU 4 collates the ID 34 and the master ID 44 included in the received response signal. If the collation is successful, the collating ECU 4 unlocks the lock mechanism 50 or sets the unlocking permitted state.

  The configuration of FIG. 4 indicates that “the in-vehicle device transmits a request signal by radio waves in the first frequency band to the portable device possessed by the user, and when the portable device receives the request signal, the response signal is the first frequency band. The response signal includes an ID for identifying the portable device, and the in-vehicle device collates the ID included in the received response signal with the master ID stored in advance. And a control unit that controls the operation of a predetermined function of the vehicle based on the collation result of the collation unit or the determination result output from the output unit. With this configuration, it is possible to more accurately determine the relay attack in the smart key system.

The verification ECU 4 may be able to exchange information with the following devices by in-vehicle communication.
Anti-theft system: A well-known device that issues an alarm upon detection of unauthorized intrusion or theft of a vehicle.
A device (also referred to as DCM) for communicating with an external communication network such as a public communication line.

  The relay attack determination process of FIG. 5 will be described. This process is repeatedly executed at a predetermined timing by the control unit (U1 or the like). First, it is determined whether or not the LF receiver 13 has received an LF radio wave. When a request signal is received (S11: Yes), radio wave reception information is acquired from another control unit (S12). This may be read out temporarily stored in the memory 12 or newly acquired via the communication I / F 16. At this time, the reception intensity (RSSI) of the request signal is measured.

  Next, it is determined whether or not a relay attack determination condition (determination condition of the present invention) is satisfied. The determination method uses at least one of the following. This configuration is “the determination unit determines whether or not the response signal is appropriate when a predetermined determination condition is satisfied”. With this configuration, it is possible to determine whether or not a relay attack has occurred only when necessary, and the processing load on the control unit can be reduced.

The relay attack determination condition is satisfied when the reception intensity of the request signal exceeds a predetermined threshold value.
The above-described configuration is “the control unit includes a detection unit that detects the received signal strength of the request signal, and the determination unit assumes that the determination condition is satisfied when the received signal strength exceeds a predetermined threshold”. is there. With this configuration, a weak request signal can be excluded from the determination target, and it is possible to avoid determining a relay attack for a plurality of vehicles with one control unit.

-When the reception intensity of the request signal received by the control unit of the other parking space included in the received radio wave reception information is compared and the reception intensity is lower than the reception intensity of the other control unit, the relay attack determination condition is not satisfied.
For example, U1, U12, Um, U1m, and UL1 can be cited as control units that can receive a request signal in addition to U2 when the vehicle is parked in the parking space P2 in FIG. The reception intensity of these control units is considered to be smaller than U2. Therefore, it can be estimated that the vehicle is parked in the parking space P2, and the relay attack determination condition is established at U2.

  In the above configuration, “the radio wave reception information includes the received signal strength of the request signal of the other control unit, and the determination unit determines the determination condition based on the comparison of the received signal strength of the request signal between the control unit and the other control unit. It is determined whether or not is established ”. With this configuration, for example, only the control unit closer to the vehicle among the plurality of control units determines the relay attack, so that it is possible to avoid making a determination by using the plurality of control units that have received the request signal and giving different results.

The establishment of the relay attack determination condition may be determined using a combination of the reception strength and the installation location information of the control unit described later.
For example, when a vehicle parks in the parking space P2 in FIG.
-The reception intensity of U2 is considered to be the same as or slightly higher than U1 and UL1.
-The reception intensity of U1 and UL1 is considered to be larger than U12.
The reception intensity of U1m is considered to be larger than U11 and smaller than U12.
As a result, it is estimated that the vehicle is parked in the parking space P2 mainly based on the magnitude relationship between the received strengths of U1 and Um, the magnitude relationship between the received strengths of U11 and U1m, and the installation location information of each control unit. Yes, the relay attack determination condition is satisfied at U2.

  The above-mentioned configuration is “the radio wave reception information includes the received signal strength of the request signal of the other control unit, the determination unit compares the received signal strength of the request signal of the control unit and the other control unit, and each control unit. It is determined whether or not the determination condition is satisfied based on the installation location. Even with this configuration, for example, since only the control unit closer to the vehicle among the plurality of control units determines the relay attack, it is possible to avoid making a determination by using the plurality of control units that have received the request signal and giving different results. .

  When the relay attack determination condition is not satisfied (S13: No), this process ends. On the other hand, when the relay attack determination condition is satisfied (S13: Yes), a response signal reception waiting state is set.

  When the response signal is received (S14: Yes), the radio wave reception information is acquired from the other control unit as described above (S15). When none of the radio wave reception information includes information related to the response signal corresponding to the received polling signal (S16: No), this process ends. In this case, since only the control unit U1 is in a state of receiving a response signal, it is considered that no relay attack has occurred.

  On the other hand, when any of the radio wave reception information includes information related to the response signal corresponding to the received polling signal (S16: Yes), the positional relationship with the control unit that is the transmission source of the radio wave reception information is determined. (S17). A method for determining the positional relationship will be described later.

Note that the installation location information used for determining the positional relationship uses at least one of the following.
When the installation location information of another control unit is stored in the memory 12, the installation location information of the control unit that is the transmission source of the received radio wave reception information is read.
When the reception location information of the control unit is included in the radio wave reception information received from another control unit, the installation location information is read from the radio wave reception information.

  When there is no contradiction in the positional relationship (S18: No), this process ends. On the other hand, when there is a contradiction in the positional relationship (S18: Yes), it is determined that the received response signal is not appropriate and a relay attack has occurred, and the relay attack is performed by the verification ECU 4 via the RF transmission unit 15. Information is transmitted (S19).

The verification ECU 4 that has received the relay attack information performs the following operation, for example.
-Unlocking is not permitted with the lock mechanism 50 in the locked state.
-The state of the lock mechanism 50 is not changed.
-Send information to the security ECU that controls the anti-theft system that an intrusion or theft has been detected. Subsequent operations are based on the specifications of the anti-theft system.
・ Sends a signal to DCM for emergency call outside the vehicle. The subsequent operation is based on the DCM specification.
-Send a control signal to the device that performs the corresponding control so that the light blinks and the horn sounds.

  The determination of the positional relationship of the control units in FIG. 5 will be described with reference to FIG. The situation where the vehicle C1 is parked in the parking space P1 is illustrated. The transmission range 70 of the LF radio wave from the vehicle C1 can be expressed in a substantially circular shape with a radius r centered on the vehicle C1. In addition, r is the maximum value (maximum reachable distance of the request signal of the present invention) at which the portable device 3 (not shown) possessed by the owner P can receive the request signal from the vehicle C1, for example, r = 1.0 to 1.5 m.

  The owner P is positioned such that the vehicle C1 is within the response signal transmission range 90 of the portable device 3. The transmission range 90 of the response signal can be represented in a substantially circular shape having a radius R with the owner P as the center. In addition, R is the maximum value (maximum reachable distance of the response signal of the present invention) at which the vehicle C1 can receive the response signal from the portable device 3, and is, for example, R = 30 to 100 m. Since the response signal is not transmitted when the owner P is not within the request signal transmission range 70 at the normal time, the response signal from the portable device 3 at the normal time is substantially circular with a radius (r + R) centered on the vehicle. (Hereinafter referred to as “maximum transmission range 99”).

  Of the thieves A and B who attempt to steal the vehicle C1, the thief A is located in the request signal transmission range 70, and the transmission range 80 of a relay device (not shown) possessed by the thief A is included. (For example, using radio waves in the RF band) can be represented in a substantially circular shape centered on the thief A (the radius is substantially the same as R). The thief B is located at a location where the owner P is located within the transmission range of the request signal of the relay device (not shown) owned by the thief B and within the transmission range 80 described above.

  When the vehicle C1 transmits a request signal (Q1), the control unit U1 receives the signal and determines that the relay attack determination condition is satisfied. Further, the radio wave is transmitted to the repeater possessed by the thief B using the RF band radio wave via the repeater possessed by the thief A (Q2). The repeater possessed by the thief B transmits a request signal using LF band radio waves (Q3).

  When the portable device 3 possessed by the owner P receives the request signal from the relay device possessed by the thief B, the portable device 3 determines that it is a legitimate signal and transmits a response signal (Q4). The vehicle C1 receives the radio wave. In the conventional technique, since the collation is normally performed, the thief A can unlock the vehicle C1.

  The response signal from the portable device 3 can also be received by the control units U101 to U104 installed in the transmission range 90. Since the control units U103 and U104 are installed within the maximum transmission range 99, they receive the radio waves regardless of whether they are normal or abnormal.

However, the installation positions of the control units U101 and U102 are outside the maximum transmission range 99. For example, when the distance from the vehicle C1 (that is, the control unit U1) to the control unit U101 is a, the control unit U1 can determine the presence or absence of a relay attack from the positional relationship of the control units as follows.
When r + R> a, for example, since the control unit is located within the maximum transmission range 99, it is determined that there is no contradiction in the positional relationship and no relay attack has occurred. That is, even if the control units U103 and U104 receive the response signal, it is not determined as a relay attack.
When r + R ≦ a, for example, since the control unit is located outside the maximum transmission range 99, it is determined that the positional relationship is inconsistent and a relay attack has occurred (U101, U102).

  The above-mentioned configuration is that the determination unit determines whether the response signal is appropriate based on the maximum arrival distance of the request signal, the maximum arrival distance of the response signal, and the distance between the control unit and another control unit that has received the response signal. "Determine whether or not". More specifically, “the determination unit determines that when the sum of the maximum arrival distance of the request signal and the maximum arrival distance of the response signal exceeds the distance between the control unit and another control unit that has received the response signal, the response signal Is determined to be appropriate ”. Since the maximum reachable distance of each signal and the distance between the control units are known, this configuration can determine the relay attack without performing complicated calculations.

  With reference to FIG. 7, another example of determination of the positional relationship of the control units in FIG. 5 will be described. In addition, about the structure similar to FIG. 6, the code | symbol same as FIG. 6 is provided, and detailed description here is omitted.

  Unlike FIG. 6, the owner P is positioned such that the vehicle C <b> 1 is outside the transmission range 90 of the response signal from the portable device 3. The thief A is located within the transmission range 70 of the request signal from the vehicle C1, as in FIG. The thief B has the owner P within the transmission range of a relay device (not shown) possessed by the thief B, and the RF radio wave transmission range 80 of the relay device (not shown) possessed by the thief A. Or in a substantially circular region with a radius R centered on the vehicle C1 (that is, the vehicle C1 is positioned within the reach of the response signal from the stolen vehicle B).

  When the vehicle C1 transmits a request signal (Q1), the control unit U1 receives the signal and determines that the relay attack determination condition is satisfied. Further, the radio wave is transmitted to the repeater possessed by the thief B via the repeater possessed by the thief A (Q2). The repeater possessed by the thief B transmits a request signal (Q3).

  When the portable device 3 possessed by the owner P receives the request signal from the relay device possessed by the thief B, the portable device 3 determines that it is a legitimate signal and transmits a response signal (Q4a). This response signal does not reach the vehicle C1. Then, the relay device possessed by the thief B relays the response signal from the portable device 3 to the vehicle C1 using radio waves in the RF band (Q5). In the conventional technique, since the collation is normally performed, the thief A can unlock the vehicle C1.

  Also in the situation of FIG. 7, as in FIG. 6, the control unit U1 can determine the presence or absence of a relay attack from the positional relationship (r + R> a) with each control unit.

  Although the embodiments of the present invention have been described above, these are merely examples, and the present invention is not limited to these embodiments, and the knowledge of those skilled in the art can be used without departing from the spirit of the claims. Various modifications based on this are possible.

1 Control System 2 Smart Key System 3 Mobile Device 4 Verification ECU (Verification Unit, Control Unit)
11 Control unit (determination unit, detection unit)
12 Memory (storage unit)
13 LF receiver (request signal receiver)
14 RF receiver (response signal receiver)
15 RF transmitter (output unit)
16 Communication I / F (Radio wave reception information acquisition unit, installation location information acquisition unit)
44 Master ID
34 ID
C1-C4 vehicles P1-Pn, P11-P1n Parking spaces U1-Un, U11-U1n, UL1, UL2 Control unit

Claims (7)

Including a plurality of control units installed around the parking position of the vehicle,
The control unit is
A request signal receiving unit that receives a request signal wirelessly transmitted by an in-vehicle device mounted on the vehicle;
In response to the request signal, a response signal receiving unit that receives a response signal wirelessly transmitted to the in-vehicle device;
A radio wave reception information acquisition unit for acquiring radio wave reception information including a reception state of the response signal of another control unit;
A storage unit for storing an installation location of the control unit;
An installation location information acquisition unit for acquiring installation location information including an installation location of the other control unit;
Based on the reception state of the response signal of the other control unit and the installation location of the control unit and the other control unit, it is determined whether or not the response signal received by the response signal receiving unit is appropriate. A determination unit;
An output unit for outputting a determination result of the determination unit;
A control system comprising:   The control system according to claim 1, wherein the determination unit determines whether or not the response signal is appropriate when a predetermined determination condition is satisfied. The control unit is
A detection unit for detecting the received signal strength of the request signal;
The control system according to claim 2, wherein the determination unit determines that the determination condition is satisfied when the received signal strength exceeds a predetermined threshold. The radio wave reception information includes the received signal strength of the request signal of the other control unit,
The determination unit according to claim 2 or 3, wherein the determination unit determines whether the determination condition is satisfied based on a comparison of received signal strengths of the request signal between the control unit and the other control unit. Control system.   The determination unit determines that the response signal is appropriate based on a maximum reach distance of the request signal, a maximum reach distance of the response signal, and a distance between the control unit and another control unit that has received the response signal. The control system according to any one of claims 1 to 4, wherein it is determined whether or not it is an object.   When the sum of the maximum arrival distance of the request signal and the maximum arrival distance of the response signal exceeds the distance between the control unit and another control unit that has received the response signal, the determination unit The control system according to claim 5, wherein the signal is determined to be appropriate. The in-vehicle device transmits the request signal to the portable device owned by the user by radio waves in the first frequency band,
When the portable device receives the request signal, it transmits the response signal to the in-vehicle device using radio waves in a second frequency band different from the first frequency band,
The response signal includes an ID for identifying the portable device,
The in-vehicle device is
A collation unit that collates an ID included in the received response signal with a master ID stored in advance;
A control unit that performs operation control of a predetermined function of the vehicle based on a collation result of the collation unit or a determination result output from the output unit;
The control system according to any one of claims 1 to 6, further comprising:

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