JP2016183489A - Keyless entry apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a keyless entry apparatus capable of accurately operating without being erroneously determined to be an unauthorized relay machine, even when strength of a signal transmitted from a portable machine is weakened by an obstacle.SOLUTION: A keyless entry apparatus performs mutual communication between a vehicle side device and a portable machine. The portable machine includes a portable machine control unit that detects reception intensities of request signals transmitted from a plurality of transmission antennas of the vehicle side device, respectively, and makes a portable machine transmission unit transmit answer signals including first intensity information based on the reception intensity of each of the plurality of transmission antennas. The vehicle side device includes a vehicle side control unit that determines whether or not to perform predetermined control on the basis of information on the position or direction of the portable machine with respect to a vehicle obtained from the first intensity information included in a received answer signal and second intensity information based on the reception intensity of the answer signal at a vehicle side reception unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a keyless entry device that performs predetermined control such as unlocking a door of a vehicle by performing mutual communication between a vehicle-side device and a portable device.

  The control system described in Patent Literature 1 includes an RSSI value (radio wave intensity, electromagnetic wave intensity, electric field strength) of an LF signal transmitted from a vehicle-side device and received by a portable device, and an RF signal transmitted from the portable device and received by the vehicle-side device. The RSSI values of the signals are compared with each other, and when the ratio of these RSSI values is within a predetermined range, it is determined that there is no relay attack. In this control system, when the distance obtained from the RSSI value of the RF signal is considerably larger than the distance obtained from the RSSI value of the LF signal and the ratio of both RSSI values is out of the predetermined range, there is a relay attack. Is determined.

  Here, the relay attack is performed by an unauthorized first repeater disposed in the vicinity of the vehicle and an unauthorized second repeater disposed at a position separated from the vehicle and performing wireless communication with the first repeater. That is, a request signal composed of an LF signal transmitted from the vehicle side device in the vicinity of the vehicle is relayed by the first repeater and the second repeater, and the signal is transmitted from the second repeater. When a person with a portable device approaches the second repeater, the portable device receives a signal from the second repeater. Here, in response to reception of signals relayed by two relays, the portable device transmits an answer signal composed of an RF signal, and when the vehicle side device receives the signal, the user is away from the vehicle. Thus, the vehicle is unlocked at a place not intended by the user.

JP 2012-060482 A

  However, in communication between the portable device and the vehicle-side device, the RF signal from the portable device may be attenuated and attenuated by an obstacle made of a vehicle structure such as a vehicle pillar or a metal object. If there is a portable device in the direction of the obstacle as seen from the vehicle side, the state is the same as when the radio wave interference occurs. For this reason, even though there is actually a portable device near the vehicle side device, the RSSI value of the RF signal transmitted from the portable device becomes small and it is determined that the portable device is far from the actual device. There is. In this case, the vehicle-side device calculates the distance between the portable device and the vehicle-side device calculated from the LF signal received by the portable device and the RSSI value of the RF signal received by the vehicle-side device. Since it becomes impossible to match between the distances between the side devices, an incorrect repeater may erroneously determine that the RF signal is transmitted from a distance from the vehicle.

  Therefore, the present invention is accurate without being erroneously identified as an unauthorized repeater even if the strength of the signal transmitted from the portable device may be weakened by an obstacle composed of a vehicle structure. It is an object of the present invention to provide a keyless entry device that can operate.

  In order to solve the above-described problems, a keyless entry device according to the present invention includes a vehicle-side transmission unit that is provided in a vehicle and transmits a request signal from a plurality of transmission antennas, and a vehicle-side reception unit that receives an answer signal. Side device, a portable device receiver that receives a request signal, and a portable device that includes a portable device transmitter that transmits an answer signal in response to the request signal. A portable device control unit that detects the reception strength of the request signal transmitted from each of the transmission antennas and causes the portable device transmission unit to transmit an answer signal including first intensity information based on the reception strength for each of the plurality of transmission antennas And the vehicle side device has information about the position or direction of the portable device relative to the vehicle obtained from the first intensity information included in the received answer signal, and It is characterized by having a second intensity information based on the reception intensity of the vehicle side receiver of the service signal, the vehicle control unit to determine whether to perform predetermined control based on.

  As a result, information related to the position and direction of the portable device relative to the vehicle can be obtained from the first intensity information based on the received intensity of the request signal transmitted from a plurality of transmission antennas in the portable device. It is possible to know whether or not the portable device is in a direction in which the answer signal from the portable device is easily attenuated by a vehicle structure or the like. Accordingly, by changing the determination condition of the second intensity information based on the reception intensity of the answer signal, it can be determined in consideration of the influence of the attenuation by the vehicle structure, so the answer signal is a normal signal. Therefore, it is possible to prevent the signal from being misidentified as having been transmitted by using an illegal repeater.

  In the keyless entry device of the present invention, the vehicle-side control unit determines whether or not to perform predetermined control based on information about the position or direction of the portable device with respect to the vehicle obtained from the first intensity information. It is preferable to change the determination condition of the second intensity information.

  This makes it possible to recognize the position of the portable device in the direction where the strength of the signal transmitted from the portable device becomes small due to an obstacle, as well as the other direction, and the portable device is actually close enough. However, there is no possibility of being misidentified as being far away or being misidentified as an unauthorized repeater.

  In the keyless entry device of the present invention, the vehicle-side control unit provides information on the position or direction of the portable device relative to the vehicle for all or some of the plurality of transmission antennas derived from the first intensity information. It is preferable to change the determination condition of the second intensity information based at least on the ratio of the received intensity or the ratio of the values correlated with the received intensity.

  When the ratio of the reception strength for each of the transmission antennas is used, it is possible to make a simple configuration with a small number of transmission antennas. Based on the principle of surveying, the direction of the portable device relative to the transmitting antenna can be obtained more easily.

  In the keyless entry device of the present invention, the vehicle-side control unit makes a determination by comparing the second intensity information with a predetermined threshold as a determination condition for the second intensity information, and the threshold is obtained from the first intensity information. It is preferably changed based on information about the position or direction of the portable device relative to the vehicle.

  As a result, since the portable device determines whether or not to perform the predetermined control based on whether or not the answer signal is in a direction in which the answer signal is easily attenuated, the signal transmitted from the unauthorized repeater Therefore, it is possible to accurately detect the predetermined control.

  In the keyless entry device of the present invention, the vehicle-side device has a receiving antenna for receiving an answer signal, and the vehicle control unit is based on information about the position or direction of the portable device with respect to the vehicle obtained from the first intensity information, When it is determined that there is a vehicle structure in which the strength of the answer signal is attenuated between the portable device and the receiving antenna, it is preferable to reduce the threshold value.

  As a result, it becomes possible to recognize the position of the portable device in the direction in which the strength of the signal transmitted from the portable device is reduced by an obstacle, so the portable device is actually close enough but far away. And no misclassification as an unauthorized repeater.

  In the keyless entry device of the present invention, the vehicle-side control unit may unlock the vehicle door as a predetermined control when the second intensity information is larger than a threshold as the determination condition of the second intensity information. preferable.

  As a result, even if there is a case where the strength of the signal transmitted from the portable device is weakened by an obstacle made of a vehicle structure, the vehicle can be operated accurately without being erroneously identified as an unauthorized repeater. be able to.

  According to the present invention, even if the reception intensity of a signal transmitted from a portable device is reduced due to an obstacle made of a vehicle structure, a legitimate signal is erroneously discriminated as a signal from an unauthorized repeater. Therefore, it is possible to provide a keyless entry device that can operate accurately.

It is a block diagram which shows the structure of the keyless entry apparatus which concerns on embodiment of this invention. It is a top view which shows the structure of the keyless entry apparatus which concerns on embodiment of this invention.

  Hereinafter, a keyless entry device according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the keyless entry device according to the present embodiment, and FIG. 2 is a plan view showing the configuration of the keyless entry device according to the present embodiment.

  As shown in FIG. 2, the keyless entry device according to the present embodiment is provided with a vehicle-side device 2 on the vehicle 1 side, and performs wireless communication with a portable device 3 that can be carried by a user, thereby doors. Unlock 1a and other predetermined control of the vehicle 1 is performed.

  As shown in FIG. 1, the vehicle-side device 2 includes an electronic control unit 2 a arranged in the vehicle 1, a plurality of transmission antennas ANT1 to ANT3, and a reception antenna 14. The electronic control unit 2 a includes a vehicle side receiving unit 10 (receiving unit), a vehicle side transmitting unit 11 (transmitting unit), a vehicle side control unit 12 (control unit), and a memory 13.

  The portable device 3 includes a portable device receiving unit 20 (receiving unit), a portable device transmitting unit 21 (transmitting unit), a portable device control unit 22 (control unit), and a portable device receiving antenna 23 (receiving antenna). And a memory 24 and a portable device transmission antenna 25 (transmission antenna).

  The plurality of transmission antennas ANT1 to ANT3 of the vehicle-side device 2 are connected to the vehicle-side transmission unit 11 and sequentially transmit signals at the first frequency. As shown in FIG. 2, the plurality of transmission antennas ANT <b> 1 to ANT <b> 3 are provided at various locations on the vehicle 1, for example, at a plurality of doors or in the vicinity thereof. Here, the first frequency is preferably a low frequency (LF) in the long wave region, for example, 30 to 300 kHz, and a very long wave region (VLF) can also be used.

  The vehicle-side transmission unit 11 transmits request signals and other signals to the portable device 3 from the plurality of transmission antennas ANT1, ANT2, and ANT3. The request signal normally includes a wake-up signal, a synchronization signal, a command signal, an intensity measurement signal, and the like, and ID information unique to the vehicle 1 set in the vehicle-side device 2 is added. This ID information is stored in advance in the memory 13, and in addition, IDs of a plurality of portable devices capable of operating one vehicle are stored in the memory 13 in advance.

  The vehicle-side control unit 12 is (1) control of transmission of a request signal by the vehicle-side transmission unit 11, (2) control of operations of the vehicle-side reception unit 10 and the vehicle-side transmission unit 11, and (3) transmission from the portable device 3. Detection of received strength (second strength information) of the received answer signal, (4) authentication processing based on ID information included in the answer signal transmitted from the portable device 3, and (5) a plurality of included in the answer signal Whether the door 1a is unlocked or other predetermined control of the vehicle 1 is performed based on the information (first intensity information) based on the reception intensity for each of the transmission antennas ANT1, ANT2, and ANT3 and the second intensity information. Determine whether or not.

  A receiving antenna 14 for receiving a signal transmitted from the portable device 3 is connected to the vehicle-side receiving unit 10. The vehicle-side receiving unit 10 receives an answer signal and other signals transmitted from the portable device 3.

  The portable device receiving unit 20 receives a request signal and other signals transmitted from the vehicle side device 2. A signal transmitted from the vehicle-side device 2 is received by the receiving antenna 23 connected to the portable device receiver 20. The receiving antenna 23 is, for example, a triaxial antenna having directivity characteristics in three directions orthogonal to each other.

  The portable device transmission unit 21 transmits an answer signal and other signals corresponding to the request signal to the vehicle side device 2. ID information set in the portable device 3 is added to the answer signal. This ID information is stored in advance in the memory 24. In addition to this, an answer signal, a vehicle-side ID, and the like are stored in advance. The answer signal and other signals are transmitted from the transmission antenna 25 connected to the portable device transmission unit 21. The transmission antenna 25 transmits a signal to the vehicle side device 2 at the second frequency. Here, the second frequency is a higher frequency RF than the first frequency.

  The answer signal includes information based on the reception strength at the portable device 3 of the strength measurement signal included in the request signal transmitted from each of the plurality of transmission antennas ANT1, ANT2, and ANT3. The answer signal also includes information for transmitting the request signal to the vehicle side device 2, ID information, and the like.

  The portable device control unit 22 (1) detects the reception intensity for each of the plurality of transmission antennas ANT1, ANT2, and ANT3 with respect to the request signal transmitted from the vehicle side device 2, and (2) the plurality of transmission antennas ANT1, ANT2 , Calculating information based on the reception strength for each ANT3, for example, the distance from each of the transmission antennas ANT1, ANT2, and ANT3, (3) the portable device transmitter 21 receives the first strength information ((1) reception) Control of transmitting an answer signal including the strength or information based on the reception strength of (2), and (4) controlling the operations of the portable device receiver 20 and the portable device transmitter 21.

  Here, the reception intensity of the request signal transmitted from the plurality of transmission antennas ANT1, ANT2, and ANT3 in the portable device 3 for each antenna corresponds to the distance between the portable device 3 and each transmission antenna of the vehicle 1. That is, when there is no obstacle, the reception intensity attenuates as the distance from the transmission antenna increases. Therefore, when the reception intensity is low, the portable device 3 is located far from the vehicle 1 (transmission antenna), and the reception intensity is high. There is a portable device 3 near the vehicle 1. Therefore, the distance from each antenna of the vehicle 1 to the portable device 3 based on the reception intensity for each of the plurality of transmission antennas ANT1, ANT2, and ANT3 and the arrangement position of the plurality of antennas ANT1, ANT2, and ANT3 in the vehicle 1 Since the position and direction of the portable device 3 with respect to each antenna of the vehicle 1 can be calculated using the principle of trilateral surveying, the portable device 3 can be calculated in any region (for example, regions A1, D1, D2 described later). ) Is identified.

  As a specific method for specifying the position and direction of the portable device 3 with respect to the vehicle 1, for example, since the arrangement position of each transmission antenna in the vehicle 1 is known, the portable device 3 of the signal transmitted from each transmission antenna is used. The distance and the direction of the portable device 3 with respect to each transmission antenna of the vehicle 1 can be obtained using the principle of trilateral surveying. Here, since the positional relationship between the transmission antennas ANT1, ANT2, and ANT3 and the vehicle 1 or the reception antenna 14 is known, a certain position or direction of the portable device 3 with respect to the vehicle 1 or the reception antenna 14 is obtained. At this time, if the reception strengths from at least two transmission antennas are known, the position and direction of the portable device 3 can be obtained. Therefore, when there are three or more transmission antennas, the position and direction of the portable device 3 may be calculated by selecting the information of the reception strengths from the two transmission antennas having high reception strengths, or the reception of more than a predetermined amount The position or direction of the portable device 3 may be calculated and averaged for each combination of reception strengths from two transmission antennas from information on reception strengths of three or more transmission antennas having strength.

  Here, if the ratio of the reception intensity in the portable device 3 from the plurality of transmission antennas ANT1, ANT2, and ANT3 or a value correlated with the reception intensity, for example, the distance from the transmission antenna to the portable device 3 is taken, Based on the above-mentioned principle of triangulation, the direction of the portable device 3 relative to the transmission antenna can be obtained more easily.

  The position or direction of the portable device 3 with respect to each of the transmission antennas ANT1, ANT2, and ANT3 can be obtained without using a method based on the above-mentioned triangulation principle. For example, when the transmission antenna is disposed in the vicinity of a radio wave obstruction caused by a vehicle structure such as a pillar, if only the reception intensity of the radio wave from the transmission antenna in the vicinity of the portable device 3 is viewed, It can be determined whether 3 is near an obstacle. Since the position of the obstacle such as the pillar in the vehicle 1 is known from the beginning, the position and direction of the portable device 3 relative to the vehicle 1 or the receiving antenna 14 can be obtained from the information. In addition to this example, there are methods for calculating the position and direction of the portable device 3 with respect to the vehicle 1, but the arrangement of the transmission antennas ANT1, ANT2, and ANT3 of the vehicle 1 and the structure of the vehicle 1 such as pillars that may interfere with radio waves Depending on the arrangement, a suitable method is selected.

  The position or direction of the portable device 3 relative to the receiving antenna 14 is specified from the position or direction where the portable device 3 exists with respect to the vehicle 1 obtained as described above.

  Whether the door 1a is unlocked or other predetermined control of the vehicle 1 is determined by comparing the second intensity information with a predetermined threshold value stored in the memory 13 in advance. As the second intensity information, the reception intensity of the answer signal detected by the vehicle-side device 2 correlates with the distance between the portable device 3 and the vehicle 1 (the reception antenna 14 of the vehicle-side device 2). That is, since the signal radio wave attenuates with distance, the reception intensity is high when the distance is short, and the reception intensity is low when the distance is long. When the second intensity information is larger than the threshold value, the vehicle-side control unit 12 determines that the owner of the portable device 3 is sufficiently close to the vehicle 1, and performs door 1 a of the vehicle 1 as predetermined control. To unlock. In addition, when a relay attack that is a fraudulent act as described above is performed, the fraudulent second repeater is arranged at a position far away from the vehicle 1, and thus the first frequency from the second repeater The portable device 3 that receives the (LF) signal and transmits the answer signal is also far from the vehicle 1. Accordingly, if the door 1a of the vehicle 1 is unlocked only when the second reception intensity information is compared with the threshold and it is determined that the owner of the portable device 3 is sufficiently close to the vehicle 1, an illegal operation caused by a relay attack is performed. Unlocking by action can be prevented. In addition to the unlocking of the door 1a, the predetermined control includes permission to start the engine and permission to operate the vehicle.

  The threshold value mentioned above is set according to the position or direction of the portable device 3 with respect to the vehicle 1 (receiving antenna 14) obtained from the first intensity information for each of the plurality of transmission antennas ANT1, ANT2, and ANT3. That is, the determination condition of the second intensity information for determining whether or not to perform the predetermined control is changed based on the information about the position or direction of the portable device 3 with respect to the vehicle 1 obtained from the first intensity information. Is done. For example, when the portable device 3 is in a direction in which there is no obstacle such as a vehicle structure that attenuates pillars and other radio waves when viewed from the receiving antenna 14, the threshold value is set to the first value, while the pillars and other radio waves are The threshold value is set to a second value that is smaller than the first value for a direction in which an obstacle such as a vehicle structure to be attenuated exists. The second value is set based on the material, shape, physical properties, etc. of the obstacle.

  As a result, it is possible to recognize the position of the portable device 3 in the direction in which the strength of the signal transmitted from the portable device 3 decreases due to an obstacle, as in the other directions. Although it is close enough, it is not mistakenly identified as being far away or misidentified as an unauthorized repeater.

  Here, in the example shown in FIG. 2, a region A1 in which a signal having the same intensity reaches the vehicle-side device 2 (receiving antenna 14) from the portable device 3 is schematically shown, and in an oblique rear where the pillars P1 and P2 exist. Regions D1 and D2 in which radio waves are difficult to reach are formed. In such a radio wave state, even when the portable device 3 is in the region D2 and the reception intensity is low, the portable device 3 is correctly recognized as being in the vicinity of the vehicle without erroneously determining that the portable device 3 is far away. be able to.

  In addition, arrangement | positioning of area | region A1 and the area | region where a radio wave cannot reach | attain can be arbitrarily set according to the structure and material of a vehicle body. A region where radio waves are difficult to reach can be defined as a region where the signal reception sensitivity is a predetermined value or less, for example, 50% or less, with respect to the signal reception sensitivity in a normal region.

  Next, predetermined control such as mutual communication between the vehicle-side device 2 and the portable device 3 and unlocking of a vehicle door will be described.

  Request signals are transmitted at predetermined timings from the transmission antennas ANT1, ANT2, and ANT3. The request signal is transmitted from the vehicle-side transmitter 11 according to the control of the vehicle-side controller 12.

  In the portable device 3, when the request signal is received, the portable device control unit 22 detects the reception strength of the strength measurement signal included in the request signal. The reception intensity is detected for each of the signals from the transmission antennas ANT1, ANT2, and ANT3. Further, the portable device control unit 22 calculates, for example, distances from the transmission antennas ANT1, ANT2, and ANT3 based on the reception intensity. Here, the reception intensity and the distance are correlated such that the reception intensity is small when the distance from the transmission antenna is long and increases when the distance from the transmission antenna is near. The portable device control unit 22 transmits, for example, information on the reception strength from each antenna or information based on the reception strength, distance information from each antenna, and an answer signal including ID information set in the portable device 3 to the portable device 3. The data is transmitted from the unit 21.

  In the vehicle side device 2, the answer signal transmitted by the portable device 3 is received, and the vehicle side control unit 12 detects the reception strength of the answer signal. Subsequently, the vehicle side control unit 12 executes a predetermined authentication process. As authentication processing, (1) collation of the ID of the vehicle side device 2 and the ID of the received portable device 3, (2) information based on the reception intensity of the request signal included in the answer signal (first intensity information), Based on the reception strength (second strength information) of the answer signal, it is determined whether or not the portable device 3 has approached the vehicle 1 within a predetermined range. As a result of the authentication process, when authentication is performed, it is determined whether or not to unlock the door 1a of the vehicle 1 as predetermined control. Here, the determination method in (2) is as described above.

  In the above description, information (first intensity information) based on the reception intensity is transmitted from the portable device 3, and the vehicle-side controller 12 receives the vehicle 1 (reception antenna 14) based on the first intensity information. Although the position and direction of the portable device 3 with respect to the vehicle are specified, the portable device control unit 22 calculates the position and direction with respect to the vehicle 1 (transmission antenna 14) and transmits the information including the answer signal. May be.

  In the above description, whether or not the portable device 3 is in the vicinity of the vehicle 1 is determined based on the strength of the answer signal (second strength information) and the threshold value. Since information on the position and distance of the portable device 3 can also be obtained, it may be used in combination.

  With the configuration as described above, the following effects can be obtained according to the embodiment and the modification.

(1) The portable device 3 detects the reception strengths of the request signals from the plurality of transmission antennas ANT1, ANT2, and ANT3 of the vehicle-side device 2, respectively, and is based on the reception strength for each of the plurality of transmission antennas ANT1, ANT2, and ANT3. The vehicle side apparatus 2 transmits an answer signal including the intensity information of 1 and information on the position or direction of the portable device 3 with respect to the vehicle 1 (receiving antenna 14) obtained from the first intensity information, and the answer signal Whether or not to perform the predetermined control is determined based on the second intensity information calculated from the received intensity in the vehicle side device 2. Thereby, since the direction and position where the portable device 3 exists with respect to the vehicle 1 can be specified from the first intensity information, it is possible to determine whether or not the answer signal from the portable device 3 is easily attenuated. It is possible to prevent the answer signal from being erroneously determined as a signal transmitted by an unauthorized repeater.

(2) The vehicle-side control unit 12 determines whether or not to perform the predetermined control by comparing the second intensity information calculated from the reception intensity of the answer signal in the vehicle-side device 2 with a predetermined threshold, The threshold is set by the reception intensity ratio. Accordingly, since the portable device 3 determines whether or not to perform the predetermined control based on whether or not the answer signal is in a direction in which the answer signal is likely to be attenuated, the answer signal is transmitted from an unauthorized repeater. It is no longer erroneously detected that the signal is a signal, and it is possible to accurately determine the predetermined control.

  Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment, and can be improved or changed within the scope of the purpose of the improvement or the idea of the present invention.

  As described above, the keyless entry device according to the present invention is accurate without being misidentified as an unauthorized repeater even if the strength of the signal transmitted from the portable device may be weakened by an obstacle. It is useful in that it can work.

DESCRIPTION OF SYMBOLS 1 Vehicle 1a Door 2 Vehicle side apparatus 3 Portable machine 10 Vehicle side receiving part (receiving part)
11 Vehicle side transmitter (transmitter)
12 Vehicle-side control unit (control unit)
13 Memory 14 Receiving Antenna 20 Mobile Device Receiver (Receiver)
21 Mobile device transmitter (transmitter)
22 Mobile device control unit (control unit)
23 receiving antenna 24 memory 25 transmitting antenna ANT1, ANT2, ANT3 transmitting antenna

Claims (6)

A vehicle-side device provided with a vehicle-side transmission unit that is provided in the vehicle and transmits a request signal from a plurality of transmission antennas;
A portable device having a portable device receiver that receives the request signal, and a portable device transmitter that transmits the answer signal in response to the request signal;
With
The portable device detects the reception intensity of request signals transmitted from the plurality of transmission antennas of the vehicle-side device, and includes an answer signal including first intensity information based on the reception intensity for each of the plurality of transmission antennas. A portable device control unit that transmits the portable device from the portable device transmission unit,
The vehicle-side device receives information on the position or direction of the portable device relative to the vehicle obtained from the first intensity information included in the received answer signal, and receives the answer signal at the vehicle-side receiving unit. A keyless entry device comprising a vehicle-side control unit that determines whether or not to perform predetermined control based on second strength information based on strength.   The vehicle-side control unit determines whether or not to perform the predetermined control based on information about the position or direction of the portable device with respect to the vehicle obtained from the first intensity information. The keyless entry device according to claim 1, wherein a condition for discriminating the strength information is changed.   The vehicle-side control unit, as information about the position or direction of the portable device with respect to the vehicle, receives the reception intensity of all or a part of the plurality of transmission antennas derived from the first intensity information. 3. The keyless entry device according to claim 1, wherein the determination condition of the second intensity information is changed based on at least a ratio or a ratio of values correlated with reception intensity. 4.   The vehicle-side control unit makes a determination by comparing the second intensity information with a predetermined threshold as a determination condition for the second intensity information, and the threshold is carried by the vehicle obtained from the first intensity information. The keyless entry device according to any one of claims 1 to 3, wherein the keyless entry device is changed based on information on a position or direction of the machine.   The vehicle-side device has a reception antenna for receiving the answer signal, and the vehicle control unit is obtained from the information about the position or direction of the portable device with respect to the vehicle, which is obtained from the first intensity information. 5. The keyless entry device according to claim 4, wherein when it is determined that there is a vehicle structure that attenuates the strength of the answer signal between the receiving antennas, the threshold value is decreased.   The vehicle-side control unit unlocks the vehicle door as the predetermined control when the second intensity information is larger than the threshold as the determination condition of the second intensity information. The keyless entry device according to claim 4 or 5.

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