JP2010060457A - Position determination apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position determination apparatus capable of facilitating exactly determining at which of vehicle inside or outside a portable apparatus is positioned. <P>SOLUTION: The inside of a region connecting an electric wave transmission section including a window glass of a vehicle with a communication antenna 32 is defined as a first region A1. As an extension of the first region A1, the inside of a region developed to the vehicle outside from the electric wave transmission section is defined as a second region A2. Of all regions in the vehicle, the inside of region except the first region A1 is defined as a third region A3. A communication circuit of a security apparatus determines at which of vehicle inside or outside an electronic key is positioned, based on a distance from the communication antenna 32 to the electronic key along a direction from the second region A2 toward the communication antenna 32. The communication circuit, when it is estimated that a direction from the third region A3 toward the communication antenna 32 is an incoming direction of a signal, determines that the electronic key is positioned in the vehicle without performing distance estimation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a position determination device that determines the position of a portable device possessed by a vehicle user, and more particularly to a position determination device that determines whether the portable device is located inside or outside the vehicle.

  Patent Document 1 discloses a technique related to an electronic key system capable of bidirectional communication between a portable device possessed by a user and a security device on the vehicle side. In this electronic key system, a request signal is transmitted from the vehicle side, and when it is received by the portable device, a response signal (ID code signal) to the request signal is transmitted from the portable device, and a reference ID When an ID code that matches the code is included, the door lock and the engine start prohibition are released.

  In this type of electronic key system, in-vehicle communication control in which a request signal is transmitted from a security device on the vehicle side to a predetermined area outside the vehicle, and in the vehicle in which the request signal is transmitted from the security device to a predetermined area in the vehicle. Communication control is performed. When the ID code signal is received along with the former vehicle exterior communication control, it is determined on the security device side that the portable device is located outside the vehicle, and in this case, by the vehicle user who owns the portable device. The door is unlocked to allow boarding.

  On the other hand, when the ID code signal is received with the latter in-vehicle communication control, it is determined on the security device side that the portable device is located in the vehicle, and in this case, by the vehicle user who owns the portable device. In order to allow driving, the engine start prohibition is released.

Therefore, in a vehicle to which such an electronic key system is applied, the security device plays a role as a position determination device that determines whether the portable device is located inside or outside the vehicle, so that it corresponds to the position of the portable device. Appropriate vehicle control is performed.
JP 2002-029385 A (paragraph numbers 0002 to 0008)

  By the way, when the request signal reaches not only a predetermined area outside the vehicle but also an in-vehicle area in the case of outside-vehicle communication control, an ID code signal is transmitted from the portable apparatus when the portable device is located in the in-vehicle area. In this case, although the portable device is located inside the vehicle, it is erroneously determined that it is located outside the vehicle.

  On the other hand, when the request signal reaches not only a predetermined area inside the vehicle but also the outside area in the in-vehicle communication control, if the portable device is located in the outside area, an ID code signal is transmitted from the portable device. In this case, although the portable device is located outside the vehicle, it is erroneously determined that it is located inside the vehicle.

  If the position of the portable device is erroneously determined as described above, it becomes impossible to perform appropriate vehicle control according to the position of the portable device. Therefore, in order to prevent this, only a predetermined area outside the vehicle is controlled. While the request signal is transmitted to the vehicle, it is necessary to consider that the request signal is transmitted only to a predetermined area in the vehicle when performing in-vehicle communication control.

  For example, by increasing the number of transmission antennas for request signals, the transmission power of request signals from individual transmission antennas can be reduced, thereby reducing the variation in transmission power of request signals from individual transmission antennas. Furthermore, it is necessary to finely set the transmission output of the request signal for each transmission antenna. Then, depending on the vehicle type, many transmission antennas are required, and there arises a problem that the work necessary for setting the transmission area of the request signal is complicated regardless of the vehicle type.

  The present invention has been made paying attention to such problems, and the purpose of the present invention is to make it easy to accurately determine whether the portable device is located inside or outside the vehicle. An object of the present invention is to provide a position determination apparatus capable of

  In order to achieve the above object, the invention according to claim 1 is provided in a vehicle in a position determination device that determines whether a portable device possessed by a vehicle user is located inside or outside the vehicle, A receiving antenna serving as a medium for receiving a signal transmitted from a portable device, direction estimation means for estimating an arrival direction of the signal by analyzing a reception mode of the signal by the receiving antenna, and the direction Position determining means for determining whether the portable device is located inside or outside the vehicle based on the direction of arrival of the signal estimated by the estimating means, and a radio wave transmitting portion including a window glass of the vehicle; The area connecting the receiving antenna is defined as a first area, and as an extension of the first area, the area expanded from the radio wave transmission portion to the outside of the vehicle is defined as a second area. Of all the areas in the vehicle, the area excluding the first area is defined as a third area, and the position determining means is configured such that the direction from the second area toward the receiving antenna is the arrival direction of the signal. As determined by the direction estimating means, the portable device is determined to be located outside the vehicle, and the position determining means determines that the direction from the third region toward the receiving antenna is the arrival direction of the signal. As a gist, it is determined that the portable device is located in the vehicle when estimated by the direction estimating means.

  According to the same configuration, a signal transmitted from a portable device located in the second area, which is an area outside the vehicle, reaches a receiving antenna provided in the vehicle via a radio wave transmission unit including a window glass, and When received by the receiving antenna, it is determined that the portable device is located outside the vehicle. On the other hand, when a signal transmitted from a portable device located in the third area, which is an area inside the vehicle, reaches a receiving antenna provided in the vehicle and is received by the receiving antenna, the portable device is moved into the vehicle. It is determined that it is located.

  For this reason, even if it does not necessarily consider that a request signal is transmitted only to a predetermined area outside the vehicle or a predetermined area inside the vehicle from the vehicle to which the position determination device is applied, the portable device responds to the request signal. By estimating the direction of arrival of the transmitted signal, it can be accurately determined whether the portable device is located inside or outside the vehicle. That is, the work necessary for setting the transmission area of the request signal is sufficient. Therefore, it can be easily performed when accurately determining whether the portable device is located inside or outside the vehicle.

  Note that the present invention is not limited to a communication system in which bidirectional communication is performed between a portable device and a vehicle, but is also applicable to a communication system in which unidirectional communication is performed with the portable device as a transmission side. In the latter case, when the signal transmitted from the portable device reaches the receiving antenna and is received by the receiving antenna, the arrival direction of the signal is estimated, so that the portable device can be located either inside or outside the vehicle. It is determined whether it is doing.

  For example, an unlocking switch operated to unlock the door by remote operation, a locking switch operated to lock the door by remote operation, and an engine operated to start the engine by remote operation A start switch is provided on the portable device. And when the unlocking switch or locking switch is operated outside the vehicle, the door is unlocked and unlocked, the engine is started only when the engine start switch is operated inside the vehicle, and the engine start switch is operated outside the vehicle It is possible to prohibit the starting of the engine. This prevents the engine from starting even though the portable device is located outside the vehicle. That is, appropriate vehicle control according to the position of the portable device can be performed.

  In addition, when the portable device is located in the vehicle, once the door is locked, if the door cannot be opened from the outside of the vehicle, a third party is contrary to the will of the user existing in the vehicle. In other words, it is possible to prevent the door from being opened without permission and to improve security. And this can also be counted as one of the appropriate vehicle controls according to the position of the portable device.

  According to a second aspect of the present invention, in the position determination device according to the first aspect, three axes extending orthogonally with respect to a common origin are defined as an X axis, a Y axis, and a Z axis, and the receiving antenna is A plurality of antenna elements are constituted by an array antenna arranged two-dimensionally along the XY plane with respect to the origin, and the direction estimating means analyzes the reception mode of the signal by the array antenna, With respect to the arrival direction of the signal, an elevation angle or depression angle that is an angle between the arrival direction of the signal and the XY plane, and a virtual line that appears on the XY plane when the arrival direction of the signal is orthogonally projected onto the XY plane; The gist is to estimate an azimuth angle, which is an angle between the origin and a positive X-axis.

  According to the same configuration, the elevation angle or depression angle and the azimuth angle are estimated with respect to the direction of arrival of the signal from the portable device, and when these indicate the direction from the second region toward the receiving antenna, the portable device is outside the vehicle. It is determined that it is located. On the other hand, when they indicate the direction from the third region toward the receiving antenna, it is determined that the portable device is located in the vehicle. For this reason, it is possible to more accurately determine whether the portable device is located inside or outside the vehicle by estimating the arrival direction of the signal from the portable device in a three-dimensional manner.

  According to a third aspect of the present invention, in the position determination device according to the first or second aspect, the receiving antenna includes an inner surface of a radio wave shielding member including a ceiling of the vehicle, a vicinity of the surface, and a floor of the vehicle. The gist of the invention is that it is provided on at least one of the inner surface of the radio wave shielding member including the surface and the vicinity of the surface.

  According to this configuration, the area is divided into the vehicle inside and the vehicle outside, with the radio wave shielding member including the vehicle ceiling or the radio wave shielding member including the vehicle floor as a boundary. The signal transmitted from the portable device is received by the receiving antenna, and the arrival direction of the signal is estimated. On the other hand, since the signal transmitted from the portable device located in the area outside the vehicle is shielded by the radio wave shielding member, it is not received by the receiving antenna. For this reason, unlike the present configuration, in the configuration in which the receiving antenna is provided at a position away from the radio wave shielding member, the portable device is located in the area between the receiving antenna and the radio wave shielding member, and the reception Where the portable device is located in a region on the opposite side of the antenna from the region, it is possible to distinguish them in this configuration. Therefore, in this configuration, it is possible to accurately estimate the arrival direction of the signal from the portable device.

  If the ceiling or floor is covered with a radio wave shielding member such as metal and a radio wave transmitting part such as window glass is provided near the ceiling in the height direction of the vehicle as in a general vehicle, the inner surface of the ceiling If a receiving antenna is provided in the vicinity of the surface, the third area can be widened, and it can be erroneously determined that the portable device is located outside the vehicle even though it is located inside the vehicle. Can be reduced. On the other hand, when a radio wave transmission part such as a window glass is provided near the floor in the height direction of the vehicle as in a special vehicle, the third area can be widened by providing a receiving antenna on the inner surface of the floor and in the vicinity of the surface. Therefore, it is possible to reduce the possibility of erroneous determination that the portable device is located outside the vehicle even though the portable device is located inside the vehicle.

  According to a fourth aspect of the present invention, in the position determination device according to any one of the first to third aspects, the signal transmission source is analyzed by analyzing the reception mode of the signal by the reception antenna. The position estimation unit further includes a distance estimation unit that estimates a distance to the portable device, and the direction determination unit estimates a direction from the second region to the reception antenna as the arrival direction of the signal. The distance from the receiving antenna to the portable device along the direction is specified based on the estimation result by the distance estimating means, and the position determining means is a direction from the second area toward the receiving antenna. When the distance from the receiving antenna to the portable device along the line is equal to or less than the distance from the receiving antenna to the radio wave transmitting portion, the portable device is located in the vehicle The position determination means determines that the distance from the reception antenna to the portable device along the direction from the second region toward the reception antenna exceeds the distance from the reception antenna to the radio wave transmission unit. The gist of the present invention is to determine that the portable device is located outside the vehicle.

  According to the same configuration, when the distance from the reception antenna to the portable device along the direction from the second region toward the reception antenna is equal to or less than the distance from the reception antenna to the radio wave transmitting portion, the portable device is positioned in the vehicle. It is determined that On the other hand, when the distance from the receiving antenna to the portable device along the direction from the second region to the receiving antenna exceeds the distance from the receiving antenna to the radio wave transmitting portion, the portable device is located outside the vehicle. It is determined that For this reason, when the portable device is located in the first area like the former, it is determined that the portable device is located in the vehicle, and the portable device is located in the vehicle. The possibility that it is erroneously determined that it is located outside the vehicle can be reduced.

Since this invention is comprised as mentioned above, there exist the following effects.
According to the present invention, when accurately determining whether the portable device is located inside or outside the vehicle, it can be easily performed.

Hereinafter, an embodiment embodying the present invention will be described.
As shown in FIG. 1, an electronic key system 1 is applied to the automobile of this embodiment. The electronic key system 1 includes an electronic key 2 possessed by a vehicle user and a security device 3 provided on the vehicle side, and bidirectional communication between the two is possible. The electronic key 2 is called a portable device because of its possession.

  The electronic key 2 has a reception function by wireless communication and a transmission function by wireless communication, and includes a communication antenna 21, a communication circuit 22, a microcomputer 23, an unlocking switch 24, a locking switch 25, and an engine start switch 26.

  The communication antenna 21 is a medium for receiving a request signal transmitted from the security device 3, and in this case, the communication antenna 21 functions as a reception antenna. The communication circuit 22 demodulates the request signal received by the communication antenna 21 to generate a reception signal, and outputs the reception signal to the microcomputer 23. That is, in this case, the communication circuit 22 functions as a reception circuit (including a demodulation circuit). In this case, the communication antenna 21 and the communication circuit 22 constitute reception means.

  The microcomputer 23 includes a non-volatile memory 23a, and an ID code (ID code of the electronic key 2) individually set for the electronic key 2 is stored in the memory 23a. When the reception signal related to the request signal is input from the communication circuit 22, the microcomputer 23 generates a signal (ID code signal) including the ID code of the electronic key 2 in order to respond to the request signal. The code signal is output to the communication circuit 22.

  The unlocking switch 24 is operated to unlock the door by remote operation, and the locking switch 25 is operated to lock the door by remote operation, and the engine start switch 26 is operated. Is operated to start the engine remotely.

  When the unlock switch 24 is operated, the microcomputer 23 requests an operation code (unlock request operation code) to request unlocking of the door in order to request the vehicle to unlock the door. And an ID code of the electronic key 2 (an unlock request signal) are generated. Then, the microcomputer 23 outputs this unlock request signal to the communication circuit 22.

  Further, when the lock switch 25 is operated, the microcomputer 23 requests an operation code (locking request operation code) for requesting locking of the door and the electronic key 2 to request the vehicle to lock the door. A signal (locking request signal) including the ID code is generated. Then, the microcomputer 23 outputs this locking request signal to the communication circuit 22.

  Further, when the engine start switch 26 is operated, the microcomputer 23 requests an operation code (engine start request operation code) and an electronic key for requesting the start of the engine to request the vehicle to start the engine. 2 (an engine start request signal) including the ID code of 2 is generated. Then, the microcomputer 23 outputs this engine start request signal to the communication circuit 22.

  The communication circuit 22 modulates various signals (ID code signal, unlock request signal, lock request signal, engine start request signal) input from the microcomputer 23 into radio waves having a predetermined frequency (2.45 GHz in this embodiment). . That is, in this case, the communication circuit 22 functions as a transmission circuit (including a modulation circuit). The communication antenna 21 is a medium for transmitting the various signals modulated by the communication circuit 22. In this case, the communication antenna 21 functions as a transmission antenna. In this case, the communication circuit 22 and the communication antenna 21 constitute a transmission unit.

The security device 3 has a transmission function by wireless communication and a reception function by wireless communication, and includes a communication circuit 31, a communication antenna 32, and a verification device 33.
The communication circuit 31 modulates the request signal input from the verification device 33 into a radio wave having a predetermined frequency (2.45 GHz in the present embodiment). That is, in this case, the communication circuit 31 functions as a transmission circuit (including a modulation circuit). The communication antenna 32 is a medium for transmitting a request signal modulated by the communication circuit 31. In this case, the communication antenna 32 functions as a transmission antenna. In this case, the communication circuit 31 and the communication antenna 32 constitute transmission means.

  Here, as shown in FIGS. 2 and 3, the communication antenna 32 is a central portion of the inner surface of a ceiling (corresponding to a roof panel forming a roof of a vehicle body) made of a radio wave shielding member such as metal in the vehicle. Is provided. The roof panel is provided with a reinforcing material (roof bow) that connects a pair of roof rails extending in the vehicle front-rear direction along the vehicle left-right direction of the roof panel in order to prevent the dent of the roof panel. When providing 32 in the center part of the inner surface of the roof panel, the roof bow may be an obstacle.

  The communication antenna 32 is preferably provided at the center of the inner surface of the roof panel in view of the stability of the directivity of the request signal transmitted from the communication antenna 32. However, if the roof bow is present, the roof antenna is avoided. Thus, the communication antenna 32 may be provided at a position slightly deviated from the center of the inner surface of the roof panel. Alternatively, the communication antenna 32 may be provided on the roof bow. Rather, it is preferable to provide the communication antenna 32 on the lower surface of the roof bow, which is located slightly lower than the inner surface of the roof panel, because the request signal transmitted from the communication antenna 32 is deployed outside the vehicle without any obstacles.

  Further, the communication antenna 32 is brought into direct contact with a radio wave shielding member such as a roof panel or a roof bow so that the electronic key 2 cannot exist in a region between the communication antenna 32 and the radio wave shielding member. It is desirable to consider. However, the communication antenna 32 is not necessarily in contact with the radio wave shielding member. Preferably, the communication antenna 32 is shielded from radio waves in a range where the electronic key 2 cannot exist in the region between the communication antenna 32 and the radio wave shielding member. It is allowed to be provided near the surface of the member.

  The request signal transmitted from the communication antenna 32 is a window glass that is a radio wave transmitting part in addition to the entire vehicle interior area (including those provided at each door, those provided at the front part, and those provided at the back part). It is designed to be extended to the area outside the vehicle via.

  In FIG. 3, as the window glass of the vehicle, an area connecting the radio wave transmitting portion including the window glass of the driver's seat door and the window glass of the passenger seat door and the communication antenna 32 is denoted by reference numeral A <b> 1. This is defined as the first region A1. Further, as an extension of the first area A1 on the driver's seat side of the two first areas A1 shown in FIG. This is indicated by A2 and is defined as the second area A2 (omitted for the passenger side). Further, of all the areas in the vehicle, the area excluding the first area A1 is indicated by reference numeral A3, and this is defined as the third area A3.

  The first region A1 and the second region A2 are not only for the window glass (radio wave transmission part) of the driver's seat door and the window glass (radio wave transmission part) of the passenger seat door, but also for the rear left seat door. It is also formed on the window glass (radio wave transmission part), the window glass (radio wave transmission part) of the rear right seat door, the windshield (radio wave transmission part), and the back glass (radio wave transmission part). Accordingly, the third region A3 is formed in the region excluding all the first regions A1 among all the regions in the vehicle.

  A request signal is transmitted from the communication antenna 32 to each of the areas A1 to A3, and a shadow area in which the request signal does not propagate originally because the metal part of the driver's seat door becomes a radio wave shield (obstacle). The request signal is also transmitted to the fourth region A4, which is a characteristic of radio wave diffraction that the request signal has. That is, the request signal transmitted from the communication antenna 32 extends in each area indicated by reference signs A1 to A4 in FIG. The fourth area A4 is formed not only for the driver's seat door, but also for the passenger's seat door and the rear left and right seat doors, and also for the front and rear of the vehicle. In addition, a request signal is transmitted due to the characteristics of radio wave diffraction. In short, the request signal is transmitted to the entire area in the vehicle and the area around the vehicle.

  In such a request signal transmission area, bidirectional communication between the electronic key 2 and the security device 3 is possible. That is, when the electronic key 2 is brought into the request signal transmission area, the request signal is received by the electronic key 2 and the ID code signal is transmitted from the electronic key 2.

  Returning to FIG. 1, the communication antenna 32 receives an ID code signal transmitted from the electronic key 2 as a response signal to the request signal, and an unlock request signal transmitted from the electronic key 2 regardless of the request signal. In this case, the communication antenna 32 functions as a receiving antenna. The communication circuit 31 demodulates various signals (ID code signal, unlock request signal, lock request signal, engine start request signal) received by the communication antenna 32 to generate a receive signal and verify the received signal Output to the device 33. That is, in this case, the communication circuit 31 functions as a receiving circuit (including a demodulating circuit). In this case, the communication antenna 32 and the communication circuit 31 constitute reception means.

  Here, the communication circuit 31 analyzes the reception mode of the various signals by the communication antenna 32, thereby estimating the direction of arrival of the signal and the electronic key 2 that is the transmission source of the signal. Distance estimation for estimating the distance is performed to determine whether the electronic key 2 is located inside or outside the vehicle. Then, the communication circuit 31 adds the determination result to the received signal and outputs it to the verification device 33. A direction estimation method and a distance estimation method by the communication circuit 31 will be described later.

  The verification device 33 includes a non-volatile memory 33a, and the memory 33a has the same ID code as the ID code of the electronic key 2 (= the regular electronic key 2) that is suitable for the vehicle on which the security device 3 is mounted. A code (reference ID code) is stored.

  When the vehicle is in a parked state (engine switch OFF, door lock state), the verification device 33 approaches the vehicle (second area A2 or fourth area) when the vehicle is “ridden” by the owner of the authorized electronic key 2. A request signal is intermittently output to the communication circuit 31 in order to monitor entry into the area A4.

  In addition, when the driver's seat door is opened and closed, the verification device 33 monitors the boarding (entrance into the first area A1 and the third area A3) by the owner of the proper electronic key 2, so that the communication circuit 31 Request signal intermittently.

  Furthermore, the collating device 33 is configured to escape from the vehicle (second area A2 or second area A2) when the door lock switch provided on the door outside handle is operated and the owner of the authorized electronic key 2 gets off the vehicle. 4), and the request signal is intermittently output to the communication circuit 31 in order to monitor whether the electronic key 2 has been left in the vehicle.

  As a result, when the vehicle is parked, when the driver's seat door is opened and closed, and when the door lock switch is further operated, a request signal is intermittently transmitted from the communication antenna 32 to each of the areas A1 to A4. The

  When the verification device 33 intermittently outputs a request signal to the communication circuit 31, various signals (ID code signal, unlock request signal, lock request signal) transmitted from the electronic key 2 during a pause period during which the request signal is not output. , An engine start request signal) standby state. That is, the collation device 33 monitors whether or not each received signal related to the various signals from the communication circuit 31 is input during the pause period.

  Then, when a received signal related to any of the various signals is input from the communication circuit 31, the verification device 33 stops outputting the request signal to the communication circuit 31, and receives the received signal input from the communication circuit 31. To analyze. That is, in this case, the collation device 33 determines whether or not the ID code included in the received signal matches the reference ID code. That is, in this case, the collation device 33 performs ID code collation.

  Then, the collation device 33 recognizes that the legitimate electronic key 2 has been used (both affirms the existence of the legitimate electronic key 2) when both ID codes are matched by the collation of the ID code, and is not shown. An ID code match signal is output on the in-vehicle communication network, and the received signal is further analyzed. That is, in this case, the collation device 33 specifies whether the electronic key 2 is located inside or outside the vehicle based on the determination result regarding the position of the electronic key 2 included in the received signal.

  Then, when the collation device 33 identifies that the electronic key 2 is located outside the vehicle, the collation device 33 outputs a portable device outside existence specifying signal that suggests that the electronic key 2 is located outside the vehicle, while the electronic key 2 is located within the vehicle. When it is determined that the mobile device is present, the portable device in-vehicle presence specifying signal is output on the in-vehicle communication network.

  Further, the verification device 33 receives an unlock request signal when the received signal includes an unlock request operation code, and indicates that there is a lock request when the received signal includes a lock request operation code. When an operation code for engine start request is included in the received signal, an engine start request signal is output on the in-vehicle communication network.

  Various signals output on the in-vehicle communication network (ID code coincidence signal, portable device outside vehicle identification signal, portable device vehicle presence identification signal, unlock request signal, locking request signal, engine start request signal) Are shared among various control devices including the verification device 33, the door control device 40, and the engine control device 50 that are electrically connected to the network. And each control apparatus performs vehicle control using these signals.

  For example, when the door control device 40 acquires an ID code match signal and a portable device outside vehicle presence identification signal through the in-vehicle communication network, the owner of the electronic key 2 touches the door outside handle and is built in the door. When it is detected by the touch sensor, the intention of boarding by the holder of the electronic key 2 is recognized. In this case, the door is unlocked.

  In addition, when the door control device 40 acquires the ID code match signal and the portable vehicle outside presence specifying signal, the owner of the electronic key 2 operates the door lock switch provided on the door outside handle to Is detected, the owner of the electronic key 2 is willing to get off the vehicle. In this case, the door is locked. In addition, since the door is locked in such a situation that the electronic key 2 is recognized to have been taken out of the vehicle, the door is locked without leaving the electronic key 2 in the vehicle. Can be prevented.

  Furthermore, when the door control device 40 acquires the ID code coincidence signal and the unlock request signal (lock request signal), the intention of the owner of the electronic key 2 to unlock the door (lock) is recognized. In this case, the door is unlocked (locked) regardless of the acquisition of the portable device outside presence specifying signal or the portable device inside presence specifying signal.

  On the other hand, the engine control device 50 detects the ID code coincidence signal and the portable device vehicle presence identification signal by turning on the engine switch while the owner of the electronic key 2 depresses the brake pedal. In this case, since the intention of starting the engine by the holder of the electronic key 2 is recognized, the engine is started in this case.

  In addition, when the engine control device 50 acquires the ID code coincidence signal and the engine start request presence signal, the engine control device 50 intends to start the engine by the owner of the electronic key 2 on the condition that the mobile device vehicle presence specifying signal is also acquired. In this case, the engine is started. In other words, the engine control device 50 acquires the ID code match signal and the engine start request presence signal, but also acquires the portable device outside presence specifying signal without acquiring the portable device presence specifying signal. The intention of starting the engine by the owner of 2 is invalidated, and in this case, the engine is not started. Accordingly, when the engine start switch 26 of the electronic key 2 is operated outside the vehicle, the engine start is prohibited, that is, the engine start is prohibited under the situation where the electronic key 2 is not located in the vehicle.

Next, a direction estimation method and a distance estimation method by the communication circuit 31 will be described.
As shown in FIG. 4, when the three axes extending perpendicular to each other with respect to a common origin O are defined as an X axis, a Y axis, and a Z axis, the communication antenna 32 includes a plurality of antenna elements that define the origin O. As a reference, it is constituted by an array antenna arranged two-dimensionally along the XY plane. In the present embodiment, the communication antenna 32 is configured by an adaptive array antenna arranged at each intersection of orthogonal matrices so that M × N antenna elements are arranged in M rows and N columns at equal intervals. ing.

  The communication circuit 31 orthogonally projects an elevation angle or depression angle, which is an angle between the arrival direction of the signal and the XY plane, and the arrival direction of the signal with respect to the arrival direction of the signal received by the communication antenna 32 on the XY plane. An azimuth angle, which is an angle formed by an imaginary line that sometimes appears on the XY plane, and the positive X axis line with respect to the origin O is estimated.

  In the present embodiment, since the communication antenna 32 is provided on the inner surface of the ceiling of the vehicle (which coincides with the XY plane), the angle formed between the arrival direction of the signal received by the communication antenna 32 and the XY plane. As shown in FIG. 4, the depression angle is indicated by the symbol θ. Also, in FIG. 4, a virtual line that appears on the XY plane when the direction of arrival of the signal is orthogonally projected on the XY plane is indicated by a symbol L, and is positive with respect to the virtual line L and the origin O. An azimuth angle that is an angle formed with the X-axis line is indicated by a symbol φ. Incidentally, the range of the depression angle θ is 0 degree ≦ θ ≦ 90 degrees, and the range of the azimuth angle φ is −180 degrees ≦ φ ≦ 180 degrees.

  Examples of methods for estimating the depression angle θ and the azimuth angle φ include beamformer methods, Capon methods, MUSIC methods, linear prediction methods, minimum norm methods, ESPRIT methods, and the like. Further, as a method for estimating the distance from the origin O, which is the reference point of the communication antenna 32, to the signal transmission source (the code d is given thereto), a method by inverse Fourier transform or the like can be cited. The main part of the present invention is not in these methods themselves, but based on the depression angle θ and the azimuth angle φ obtained through these methods, and the distance d, the electronic key 2 that is the transmission source of the signal is inside and outside the vehicle. Therefore, the details of each of the methods listed above are omitted here.

Next, the operation when the communication circuit 31 determines whether the electronic key 2 is located inside or outside the vehicle will be described.
As shown in FIG. 5, the communication circuit 31 has a depression angle θ and an azimuth angle φ with respect to the arrival direction of the signal received by the communication antenna 32, and a distance d from the communication antenna 32 to the transmission source of the signal. Mobile device position determination data associated with portable device position information indicating whether the electronic key 2 is located inside or outside the vehicle is set.

  When the communication circuit 31 obtains the depression angle θ, the azimuth angle φ, and the distance d by analyzing the reception mode of the signal by the communication antenna 32, the communication circuit 31 refers to the portable device position determination data, and the depression angle θ And the azimuth angle φ and the portable device position information associated with the distance d, it is determined whether the electronic key 2 is located inside or outside the vehicle. When the communication circuit 31 determines that the electronic key 2 is located inside the vehicle (outside the vehicle), the communication circuit 31 adds a determination result suggesting that to the above-described received signal and outputs the result to the verification device 33. The operation after the collation device 33 receives such a received signal is as described above.

  When a specific example of position determination by the communication circuit 31 is described, as a first premise, the upper edge of the window glass (radio wave transmitting portion) of the driver's seat door of the vehicle is at a height of depression angle θ = θ1. In addition, the front end of the window glass is located at the azimuth angle φ = φ1 at the height, and the distance from the origin O to that is d1.

  Under such a first premise, the communication circuit 31 analyzes the reception mode of the signal by the communication antenna 32, thereby making θ1 as the depression angle θ and the azimuth angle φ as shown in the first stage of FIG. When φ1 is obtained as a distance d that is less than or equal to d1, it is determined that the electronic key 2 is located in the vehicle. That is, in this case, the electronic key 2 is located in the first area A1 shown in FIG. 3, and the communication circuit 31 accurately determines it.

  On the other hand, as shown in the second stage of FIG. 5, when the communication circuit 31 obtains a value that exceeds θ1 as the depression angle θ, φ1 as the azimuth angle φ, and a distance d that exceeds d1, the electronic key 2 is outside the vehicle. Is determined to be located. In other words, in this case, the electronic key 2 is located in the second area A2 shown in FIG. 3, and the communication circuit 31 accurately determines it.

  As a second premise, the upper edge of the window glass (radio wave transmitting portion) of the driver's seat door of the vehicle is at a height of depression angle θ = θ1 (same as the first premise), and at that height It is assumed that the location of the window glass slightly deviated to the vehicle rear side from the first premise is located at the azimuth angle φ = φ2, and the distance from the origin O to that is d2.

  Under such a second premise, the communication circuit 31 obtained θ1 as the depression angle θ, φ2 as the azimuth angle φ, and values less than d2 as the distance d, as shown in the third stage of FIG. It is determined that the electronic key 2 is located in the vehicle. That is, in this case, the electronic key 2 is located in the first area A1 shown in FIG. 3, and the communication circuit 31 accurately determines it.

  On the other hand, as shown in the fourth row of FIG. 5, when the communication circuit 31 obtains θ1 as the depression angle θ, φ2 as the azimuth angle φ, and a value exceeding d2 as the distance d, the electronic key 2 is outside the vehicle. Is determined to be located. In other words, in this case, the electronic key 2 is located in the second area A2 shown in FIG. 3, and the communication circuit 31 accurately determines it.

  Further, as a third premise, the upper edge of the window glass (radio wave transmitting portion) of the driver's seat door of the vehicle is at a height of depression angle θ = θ1 (the same as the first premise and the second premise), The rear end of the window glass is located at the azimuth angle φ = φx at that height, and the distance from the origin O to that is dx.

  Under such a third premise, the communication circuit 31 obtained θ1 as the depression angle θ, φx as the azimuth angle φ, and a value less than dx as the distance d, as shown in the fifth stage of FIG. It is determined that the electronic key 2 is located in the vehicle. That is, in this case, the electronic key 2 is located in the first area A1 shown in FIG. 3, and the communication circuit 31 accurately determines it.

  On the other hand, when the communication circuit 31 obtains a value exceeding θ1 as the depression angle θ, φx as the azimuth angle φ, and a distance d exceeding dx, as shown in the sixth row of FIG. Is determined to be located. In other words, in this case, the electronic key 2 is located in the second area A2 shown in FIG. 3, and the communication circuit 31 accurately determines it.

  As described above, when a signal arriving from each direction determined by the depression angle θ = θ1 (fixed) and the azimuth angle φ = φ1 to φx is received by the communication antenna 32, the signal is transmitted from the communication antenna 32 along the direction. It is understood that the communication circuit 31 determines whether the electronic key 2 is located inside or outside the vehicle depending on the distance to the electronic key 2 that is a signal transmission source.

  When it is assumed that the window glass (radio wave transmitting portion) of the driver's seat door of the vehicle exists at the height of the depression angle θ = θ1 to θx when viewed from the origin O, the above-mentioned also at each height. Similarly, when a signal arriving from each direction determined by the values of the depression angle θ and the azimuth angle φ is received by the communication antenna 32, from the communication antenna 32 along the direction to the electronic key 2 that is the transmission source of the signal Depending on the distance, the communication circuit 31 determines whether the electronic key 2 is located inside or outside the vehicle (the same applies to other window glasses).

Next, as a fourth premise, it is assumed that the vicinity of the driver's seat of the vehicle is at the height of the depression angle θ = θy and is positioned at the azimuth angle φ = φy.
Under such a fourth premise, the communication circuit 31 has the electronic key 2 positioned in the vehicle when θy is obtained as the depression angle θ and φy is obtained as the azimuth angle φ, as shown in the seventh row of FIG. It is determined that That is, in this case, the electronic key 2 is located in the third area A3 shown in FIG. 3 and is accurately determined by the communication circuit 31.

  In this case, there is a floor made of a radio wave shielding member such as a metal in the vehicle from the origin O along the direction thereof (a floor pan which is a floor board of the passenger compartment and the luggage compartment corresponds to this). There is no traffic signal inside or outside the vehicle through the floor. Accordingly, when a signal arriving from the direction is received by the communication antenna 32, the communication circuit 31 does not estimate the distance from the communication antenna 32 along the direction to the electronic key 2 that is the transmission source of the signal. It is determined that the electronic key 2 is located in the vehicle.

  In summary, when the communication circuit 31 estimates that the direction from the second region A2 toward the communication antenna 32 is the arrival direction of the signal, the communication circuit 31 determines the distance from the communication antenna 32 to the electronic key 2 along the direction. Identifies through estimation.

  In the communication circuit 31, the distance from the communication antenna 32 to the electronic key 2 along the direction from the second region A2 to the communication antenna 32 is the distance from the communication antenna 32 to the window glass (radio wave transmitting portion). When it is below, it determines with the electronic key 2 being located in the vehicle. Therefore, when the signal transmitted from the electronic key 2 located in the first area A1 that is the area inside the vehicle reaches the communication antenna 32 and is received by the communication antenna 32, the electronic key 2 is placed inside the car. It is determined that it is located.

  In the communication circuit 31, the distance from the communication antenna 32 to the electronic key 2 along the direction from the second area A2 to the communication antenna 32 is the distance from the communication antenna 32 to the window glass (radio wave transmitting portion). When it exceeds, it is determined that the electronic key 2 is located outside the vehicle. Therefore, a signal transmitted from the electronic key 2 located in the second area A2 which is an area outside the vehicle reaches the communication antenna 32 through the window glass (radio wave transmission unit), and the signal is transmitted by the communication antenna 32. When received, it is determined that the electronic key 2 is located outside the vehicle.

  Furthermore, when the communication circuit 31 estimates that the direction from the third area A3 toward the communication antenna 32 is the arrival direction of the signal, the electronic key 2 is located in the vehicle without performing distance estimation. judge. Therefore, when the signal transmitted from the electronic key 2 located in the third area A3 which is the area inside the vehicle reaches the communication antenna 32 and is received by the communication antenna 32, the electronic key 2 is placed in the car. It is determined that it is located.

  When the electronic key 2 is located in the fourth area A4, an ID code signal is sent from the electronic key 2 in response to a request signal transmitted to the fourth area A4 due to the characteristics of radio wave diffraction. Is sent. The ID code signal reaches the communication antenna 32 due to the characteristics of radio wave diffraction, and is received by the communication antenna 32. In this case, since the direction from the second area A2 toward the communication antenna 32 is estimated to be the arrival direction of the signal, the distance from the communication antenna 32 along the direction to the electronic key 2 is determined through the distance estimation. Identified. In this case, since the distance exceeds the distance from the communication antenna 32 to the window glass (radio wave transmission portion), it is determined that the electronic key 2 is located outside the vehicle. Incidentally, the same applies to the case where an unlock request signal, a lock request signal, and an engine start request signal not related to the request signal are transmitted from the electronic key 2 located in the fourth area A4.

  In the present embodiment, the communication circuit 31 corresponds to direction estimation means for estimating the arrival direction of the signal by analyzing the reception mode of the signal by the communication antenna 32. The communication circuit 31 corresponds to distance estimation means for estimating the distance to the electronic key 2 that is a transmission source of the signal by analyzing the reception mode of the signal by the communication antenna 32. Further, the communication circuit 31 corresponds to a position determination unit that determines whether the electronic key 2 is located inside or outside the vehicle based on the arrival direction of the signal or the distance to the signal transmission source.

As described above, according to the present embodiment, the following operations and effects can be obtained.
(1) The request is transmitted from the electronic key 2 in response to the request signal without necessarily considering that the request signal is transmitted from the security device 3 of the vehicle only to a predetermined area outside the vehicle or only to a predetermined area inside the vehicle. By estimating the arrival direction of the incoming signal, it can be accurately determined whether the electronic key 2 is located inside or outside the vehicle. That is, the work necessary for setting the transmission area of the request signal is sufficient. Therefore, when accurately determining whether the electronic key 2 is located inside or outside the vehicle, it can be easily performed.

  (2) Based on the depression angle θ and the azimuth angle φ, the arrival direction of the signal from the electronic key 2 is estimated in a three-dimensional manner, so that the electronic key 2 is located in or outside the vehicle. It can be determined accurately.

  (3) Although the area is divided into the vehicle inner side and the vehicle outer side with the radio wave shielding member including the ceiling of the vehicle as a boundary, the signal transmitted from the electronic key 2 located in the vehicle inner area is: Received by the communication antenna 32, the direction of arrival of the signal is estimated. On the other hand, since the signal transmitted from the electronic key 2 located in the area outside the vehicle is shielded by the radio wave shielding member, it is not received by the communication antenna 32. For this reason, unlike the present configuration, in the configuration in which the communication antenna 32 is provided at a position away from the radio wave shielding member, the electronic key 2 is located in an area between the communication antenna 32 and the radio wave shielding member. In this configuration, it is possible to distinguish between the case where the electronic key 2 is located in a region opposite to the region with respect to the communication antenna 32. Therefore, in this configuration, the arrival direction of the signal from the electronic key 2 can be accurately estimated.

  In the other configuration, the reason why the two cannot be distinguished from each other is that there are two equal angles, that is, the depression angle θ and the elevation angle θ, with respect to the common azimuth angle φ. Incidentally, in this configuration, there is only one angle with respect to the azimuth angle φ, that is, the depression angle θ, and there is no elevation angle θ. That is, this is the technical significance of providing the communication antenna 32 on the inner surface of the vehicle's ceiling (radio wave shielding member) and in the vicinity of the surface.

  (4) When the ceiling or floor is covered with a radio wave shielding member such as metal and a radio wave transmitting part such as window glass is provided near the ceiling in the height direction of the vehicle as in a general vehicle, this configuration As described above, by providing the communication antenna 32 on the inner surface of the ceiling and in the vicinity of the surface, the third area A3 can be widened, and the electronic key 2 is located outside the vehicle even though the electronic key 2 is located inside the vehicle. It is possible to reduce the possibility of being erroneously determined to be located.

  (5) When the distance from the communication antenna 32 to the electronic key 2 along the direction from the second region A2 toward the communication antenna 32 is equal to or less than the distance from the communication antenna 32 to the window glass (radio wave transmitting portion) It is determined that the electronic key 2 is located in the vehicle. On the other hand, when the distance from the communication antenna 32 to the electronic key 2 along the direction from the second region A2 to the communication antenna 32 exceeds the distance from the communication antenna 32 to the window glass (radio wave transmitting portion) It is determined that the electronic key 2 is located outside the vehicle. For this reason, when the electronic key 2 is located in the first area A1 as in the former case, it is determined that the electronic key 2 is located in the vehicle, and the electronic key 2 is located in the vehicle. Nevertheless, it is possible to reduce the possibility of erroneous determination that it is located outside the vehicle. That is, by using both direction estimation and distance estimation, it is possible to determine more accurately whether the electronic key 2 is located inside or outside the vehicle.

  (6) Common frequency used for exchanging various signals (request signal, ID code signal, unlock request signal, lock request signal, engine start request signal) between the electronic key 2 and the security device 3 ( 2.45 GHz), the communication antenna can be used as a medium for both transmission and reception on both the electronic key 2 side and the security device 3 side. For this reason, on both the electronic key 2 side and the security device 3 side, the configuration can be simplified by reducing the number of parts, and the size and weight can be reduced. Therefore, productivity and portability can be expected on the electronic key 2 side, and productivity and fuel efficiency can be expected on the vehicle side on which the security device 3 is mounted.

  (7) The door is locked and unlocked when the unlocking switch 24 and the locking switch 25 are operated outside the vehicle, and the engine is started only when the engine start switch 26 is operated inside the vehicle, and the engine start switch 26 is operated outside the vehicle. When is operated, the engine start can be prohibited. This prevents the engine from starting even though the electronic key 2 is located outside the vehicle. That is, appropriate vehicle control according to the position of the electronic key 2 can be performed.

  (8) When the electronic key 2 is positioned in the vehicle, once the door is locked, if the door cannot be opened from the outside of the vehicle, It is avoided that the doors are opened without permission by the three parties, and the security can be improved. This can also be counted as one of the appropriate vehicle controls according to the position of the electronic key 2.

In addition, the said embodiment can also be changed and actualized as follows.
・ Similar to general vehicles, the ceiling and floor are covered with a radio wave shielding member such as metal, and unlike general vehicles, the radio wave transmission part such as window glass is the floor in the height direction of the vehicle. The present invention may be applied to a special vehicle provided nearby. In this case, by providing the communication antenna 32 on the inner surface of the floor and in the vicinity of the surface, the third area A3 can be widened, and the electronic key 2 is positioned outside the vehicle even though the electronic key 2 is positioned inside the vehicle. It is possible to reduce the possibility of being erroneously determined as being.

  In this case, for example, when the communication antenna 32 is provided on the inner surface of the floor of the vehicle (which coincides with the XY plane), the angle formed between the arrival direction of the signal received by the communication antenna 32 and the XY plane The “elevation angle θ” is employed instead of the “decline angle θ”.

  In this case, the area is divided into the vehicle inner side and the vehicle outer side with the radio wave shielding member including the floor of the vehicle as a boundary, but the signal transmitted from the electronic key 2 located in the vehicle inner area. Is received by the communication antenna 32, and the direction of arrival of the signal is estimated. On the other hand, since the signal transmitted from the electronic key 2 located in the area outside the vehicle is shielded by the radio wave shielding member, it is not received by the communication antenna 32. For this reason, unlike the present configuration, in the configuration in which the communication antenna 32 is provided at a position away from the radio wave shielding member, the electronic key 2 is located in an area between the communication antenna 32 and the radio wave shielding member. In this configuration, it is possible to distinguish between the case where the electronic key 2 is located in a region opposite to the region with respect to the communication antenna 32. Therefore, in this configuration, the arrival direction of the signal from the electronic key 2 can be accurately estimated.

  In the other configuration, the reason why the two cannot be distinguished from each other is that there are two equal angles, that is, a depression angle θ and an elevation angle θ, with respect to a common azimuth angle φ. Incidentally, in this configuration, there is only one angle with respect to the azimuth angle φ, that is, the elevation angle θ, and there is no depression angle θ. That is, this is the technical significance of providing the communication antenna 32 on the inner surface of the vehicle floor (radio wave shielding member) and in the vicinity of the surface.

  The present invention is not limited to the electronic key system 1 (communication system) in which bidirectional communication is performed between the portable device (electronic key 2) and the vehicle (security device 3), but is unidirectional with the portable device as the transmission side. The present invention can also be applied to a communication system in which communication is performed. For example, in the above-described embodiment, the exchange regarding the request signal and the ID code signal is not essential, and the present invention may be applied to a case where it is omitted. In this case, the portable device (electronic key 2) does not necessarily have a reception function, and may have at least a transmission function. On the other hand, the vehicle (security device 3) does not necessarily have a transmission function, and may have at least a reception function.

  -When arranging a plurality of antenna elements constituting the communication antenna 32 (adaptive array antenna) in a two-dimensional manner, the plurality of antenna elements are arranged in a cross shape instead of the arrangement in which the plurality of antenna elements are arranged at each intersection of the matrix. Or a configuration in which a plurality of antenna elements are arranged in an L shape may be employed.

  It is not always necessary to use distance estimation together, and it may be omitted and it may be determined whether the electronic key 2 is located inside or outside the vehicle only by direction estimation. Note that when only the direction estimation is performed in this way, the communication circuit 31 determines that when the electronic key 2 is present in the third area A3 shown in FIG. It is determined that it is located. When only the direction estimation is performed, the communication circuit 31 cannot distinguish between the direction from the first area A1 toward the communication antenna 32 and the direction from the second area A2 toward the communication antenna 32. When the electronic key 2 is present in the first area A1, it is determined that the electronic key 2 is located outside the vehicle even though the electronic key 2 is located inside the vehicle.

  However, the possibility that the electronic key 2 is located in the first area A1 is extremely low in the use of the vehicle. Therefore, the electronic key 2 is located outside the vehicle while the electronic key 2 is located inside the vehicle. From the determination that 2 is located, there is a low possibility that an inconvenience such as the engine not starting will occur, and it does not matter so much.

  In the first place, it is needless to say that the direction estimation and the distance estimation are used together in the embodiment, in light of the fact that such a possibility cannot be completely denied. This point is described in the effect (5) in the above embodiment.

The block diagram which shows the structure of the electronic key system applied to the motor vehicle of this embodiment. The perspective view of the vehicle which shows a mode that the communication antenna is provided in the vehicle. A first region that is a region connecting the communication antenna and the window glass provided in the vehicle, a second region that is a region that extends from the window glass to the outside of the vehicle as an extension of the first region, FIG. 4 is a schematic cross-sectional view of a vehicle showing a third region that is a region excluding the first region in all regions in the vehicle, and a fourth region that is a shadow region as viewed from a communication antenna provided in the vehicle. An X-axis, a Y-axis, and a Z-axis are defined with reference to the origin, and an array antenna is provided along the XY plane with the origin as a reference, and indicates a depression angle and an azimuth angle with respect to the arrival direction of a signal received by the array antenna Illustration. The conceptual diagram which shows the data for portable machine position determination set to the communication circuit of a security apparatus.

Explanation of symbols

  2 ... Electronic key (portable device), 3 ... Security device (position determining device), 31 ... Communication circuit (direction estimating means, distance estimating means, position determining means), 32 ... Communication antenna (receiving antenna), A1 ... First A2 ... second region, A3 ... third region, L ... virtual line on XY plane, O ... origin, θ ... depression angle, φ ... azimuth angle.

Claims (4)

In the position determination device for determining whether the portable device possessed by the vehicle user is located inside or outside the vehicle,
A receiving antenna which is provided in a vehicle and serves as a medium for receiving a signal transmitted from the portable device;
Direction estimation means for estimating the arrival direction of the signal by analyzing the reception mode of the signal by the reception antenna;
Position determining means for determining whether the portable device is located inside or outside the vehicle based on the arrival direction of the signal estimated by the direction estimating means;
The area connecting the radio wave transmission part including the window glass of the vehicle and the receiving antenna is defined as a first area,
As an extension of the first area, a second area is defined as an area that is expanded from the radio wave transmitting portion to the outside of the vehicle,
Of all the areas in the vehicle, the area excluding the first area is defined as the third area,
The position determination means determines that the portable device is located outside the vehicle when the direction from the second region toward the reception antenna is estimated by the direction estimation means as the arrival direction of the signal,
The position determining means determines that the portable device is located in the vehicle when the direction from the third region toward the receiving antenna is estimated by the direction estimating means as the arrival direction of the signal. A position determination device characterized by the above. Three axes extending orthogonally to each other with respect to a common origin are defined as an X axis, a Y axis, and a Z axis,
The receiving antenna is constituted by an array antenna in which a plurality of antenna elements are arranged two-dimensionally along the XY plane with the origin as a reference,
The direction estimation means analyzes the reception mode of the signal by the array antenna, thereby, with respect to the arrival direction of the signal, an elevation angle or depression angle that is an angle formed by the arrival direction of the signal and the XY plane, and the signal The azimuth angle, which is an angle formed between a virtual line appearing on the XY plane and the positive X-axis line with respect to the origin when the direction of arrival is orthogonally projected onto the XY plane, is estimated. Position determination device. 3. The receiving antenna is provided on at least one of an inner surface of a radio wave shielding member including a ceiling of the vehicle and the vicinity thereof, and an inner surface of a radio wave shielding member including a floor of the vehicle and the vicinity of the surface thereof. The position determination apparatus described in 1. In the position determination apparatus as described in any one of Claims 1-3,
Further comprising distance estimation means for estimating a distance to the portable device that is a transmission source of the signal by analyzing a reception mode of the signal by the reception antenna;
When the direction from the second region toward the reception antenna is estimated by the direction estimation unit as the arrival direction of the signal, the position determination unit is configured to receive the signal from the reception antenna along the direction to the portable device. A distance is specified based on the estimation result by the distance estimation means,
When the distance from the reception antenna to the portable device along the direction from the second region to the reception antenna is equal to or less than the distance from the reception antenna to the radio wave transmitting unit, Determine that the mobile device is in the car,
When the distance from the reception antenna along the direction from the second region toward the reception antenna to the portable device exceeds the distance from the reception antenna to the radio wave transmission unit, It is determined that the portable device is located outside the vehicle.

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