JP5437959B2 - Communication terminal position determination device - Google Patents

Description

  The present invention relates to a communication terminal position determination apparatus that determines the position of a communication terminal (communication device).

  2. Description of the Related Art Conventionally, an electronic key system that performs ID collation by transmitting an ID code wirelessly from an electronic key as a vehicle key has been widely used. This electronic key system includes a key operation smart system that transmits a request as an ID code return request from a vehicle and performs ID collation using an ID code returned from the electronic key in response to the request. The key operation-free system includes a smart entry system in which door lock locking / unlocking is permitted or executed when ID verification is established outside the vehicle, and when the ID verification is established in the vehicle, the engine can be started simply by pressing the engine switch inside the vehicle. There is a one-push engine start system.

  As shown in FIG. 10, the electronic key system includes an antenna 83 arranged on the driver's seat door 81 side (vehicle body right side) of the vehicle 80 and an antenna 84 installed on the passenger seat door 82 side (vehicle body left side). A technique (Patent Documents 1, 2, etc.) for determining the key position by logical determination of the response returned from the electronic key 85 to the radio waves transmitted from the antennas 83 and 84 has been devised. In this logical determination key position detection method, a request is transmitted in order from the driver's seat antenna 83 on the right side of the vehicle body and the passenger's seat antenna 84 on the left side of the vehicle body, and a driver's seat antenna area 86 and a passenger's seat antenna area 87 are formed in order. The key position is determined by the ID code returned by the electronic key 85 in response to these requests, that is, the logical determination of the response.

  For example, if there is a response from the electronic key 85 to the request for the driver's seat antenna 83 and there is no response from the electronic key 85 to the request for the passenger seat antenna 84, it is determined that the electronic key 85 is located outside the vehicle. If there is no response from the electronic key 85 to the request from the driver's seat antenna 83 and there is a response from the electronic key 85 to the request from the passenger seat antenna 84, it is determined that the electronic key 85 is located outside the vehicle. Furthermore, if there is a response to both the request for the driver's seat antenna 83 and the request for the passenger's seat antenna 84, it is determined that the electronic key 85 is located in the vehicle.

  In the logic determination key position detection method shown in FIG. 10, the positions of both the outside and the inside of the vehicle can be seen with a pair of antennas provided on the right side and the left side of the vehicle. Therefore, the logical determination key position detection method is, for example, compared with the case where an antenna is installed at each door as an antenna outside the vehicle and a plurality of antennas are installed inside the vehicle as antennas inside the vehicle to detect the position of the electronic key. There is an advantage that the number of antennas can be reduced to the extent that it only needs to be installed on the left and right of the vehicle body.

JP 2004-84406 A JP 2005-76329 A

  By the way, the antenna areas 86 and 87 of the antennas 83 and 84 do not necessarily have the same boundary between the inside and outside of the vehicle. Therefore, in the logic determination key position determination method, as shown in FIG. 11, the antenna area 86 of the driver's seat antenna 83 leaks to the outside of the passenger seat door 82 or the antenna area 87 of the passenger seat antenna 84 operates as shown in FIG. In some cases, the seat door 81 leaks outside. In this case, for example, when the electronic key 85 is located in the leakage area 88 on the passenger seat side of the driver's seat antenna area 86, the electronic key 85 is located on the passenger seat door 82 side, but the electronic key 85 is located. There is a problem that 85 is determined to be on the driver's seat door 81 side and the key position is erroneously determined.

  Here, in order to prevent the driver's seat antenna area 86 from leaking to the outside of the passenger seat door 82 and the passenger seat antenna area 87 from leaking from the outside of the driver seat door 81, the antenna areas 86, 87 are provided. Should be set narrowly. However, if the antenna areas 86 and 87 are set to be narrow, a null area will be generated in the interior of the vehicle, which causes a problem that the electronic key 85 located in the interior of the vehicle cannot be detected accurately.

  Here, as a place where the null area is likely to occur, for example, there is a seat surface in the vehicle. The seat surface is a place where electronic keys can be easily placed, but because the seat frame is made of iron (made of magnetic material), the seat frame absorbs transmission radio waves that are exchanged during communication. There is a high possibility of being. Therefore, the communication area is limited as a result of being affected by the seat frame, which leads to a problem that this occurs as a null area. This problem also occurs on the floor surface in the vehicle.

Note that this problem is not limited to the electronic key system, and can be similarly applied to various systems in which two parties communicate wirelessly.
The objective of this invention is providing the communication terminal position determination apparatus which can determine the position of a communication terminal more accurately.

  In order to solve the above problems, in the present invention, in the key position determination device of an electronic key system that performs ID collation by an ID code returned from an electronic key in response to an ID reply request from the communication master, the communication master When radio waves are transmitted alternately from one antenna and another antenna, the first reception intensity when the electronic key receives the radio wave from the one antenna, and the electronic key receives the radio wave from the other antenna. Reception strength calculation means for calculating the second reception strength at the time, and a line for dividing the combination value of the first reception strength and the second reception strength into areas on a plane coordinate, on one axis side of the plane coordinate When the electronic key is viewed, a determination line formed by a line connecting at least two different points, and the combination value with respect to the determination line is And gist that a position determining means for determining location.

  According to this configuration, when radio waves are alternately transmitted from one antenna and the other antenna and the electronic key receives the radio waves from the one antenna, and when the electronic key receives the radio waves from the other antenna. The second received intensity is calculated, and a combination value using the received intensity as a coordinate value is obtained. Then, the position of the electronic key is determined by confirming which position the combination value takes with respect to a determination line that is not just a straight line, that is, a unique determination line. For this reason, when the key position is viewed using a simple determination line on a straight line, it is possible to correctly view the key position by using a unique determination line for a portion that has been erroneously determined. Therefore, the position of the electronic key can be determined with higher accuracy.

In the present invention, the communication terminal is an electronic key, the wireless system is an electronic key system in which the communication master performs ID verification with the electronic key, and the position determination unit determines the position of the electronic key. This is the gist.
According to this configuration, the position of the electronic key can be accurately determined.

In the present invention, the determination line is provided with an indoor / outdoor determination line that divides the position of the electronic key indoors and outdoors, and the position determination means looks at the magnitude of the position of the combination value with respect to the indoor / outdoor determination line. Thus, the gist is to determine whether the electronic key is located indoors or outdoors.
According to this configuration, since the key position determination is used for the indoor / outdoor determination, it is possible to determine more accurately whether the electronic key is located outdoors or indoors.

  In the present invention, the determination line is provided with an indoor / outdoor determination line for dividing the position of the electronic key indoors and outdoors and an outdoor position determination line for dividing the position of the electronic key outdoors. The position determination uses the indoor / outdoor determination line to determine whether the electronic key is located inside or outside the room, and when the electronic key is located outside the room, the outdoor position determination line is used. The gist of the invention is that two determinations are performed, that is, an outdoor position determination in which the electronic key is located at an outdoor position.

  According to this configuration, it is possible to determine where the electronic key is located indoors or outdoors, and when the electronic key is present outdoors, it is also possible to determine the outdoor position of the electronic key. Therefore, the position of the electronic key can be subdivided and determined, so that the position of the electronic key can be determined with higher accuracy.

  The gist of the present invention is that the determination line is provided with a second determination line for preventing an act of illegally establishing communication between the communication master and the electronic key using a repeater. .

  According to this configuration, even if an electronic key that is not located in the communication area of the communication master is used by a third party to connect to the communication master without permission using a repeater, This communication is processed as not established. Accordingly, since it is not necessary to illegally establish ID verification between the communication master and the electronic key, unauthorized use of the communication master can be prevented.

  In the present invention, the determination line is formed symmetrically about a coordinate bisector passing through the origin of the plane coordinate, and the vicinity of the coordinate bisector is connected to the communication master using a repeater. The gist of the invention is that it is set as a region for preventing an act of illegally establishing communication with the electronic key.

  According to this configuration, even if an electronic key that is not located in the communication area of the communication master is used by a third party to connect to the communication master without permission using a repeater, this communication is not established. It is processed. Accordingly, since it is not necessary to illegally establish ID verification between the communication master and the electronic key, unauthorized use of the communication master can be prevented.

The gist of the present invention is that the determination line is formed by a plurality of straight lines having different inclinations at least before and after connecting.
According to this configuration, since the determination line is formed from a line connecting a plurality of straight lines, the expression of the determination line can be constructed with a simple expression called a linear function.

  In the present invention, the communication terminal is a tire communication device attached to each tire of a vehicle, and the wireless system is a tire pressure monitoring system that wirelessly acquires tire pressure from the tire communication device, and the position determination The means is to determine the position of the tire by determining the position of the tire communication device.

  According to this configuration, it is possible to accurately determine in which tire the tire communication device for which communication has been established is installed.

In the present invention, an electronic key system as the wireless system that collates ID with the electronic key as the communication terminal, and a tire pressure monitoring system as the wireless system that acquires tire pressure wirelessly from a tire communication device as the communication terminal The gist is to share one communication master.
According to this configuration, common parts can be used in both the electronic key system and the tire pressure monitoring system, so that the number of parts can be reduced.

  According to the present invention, the position of a communication terminal can be determined with higher accuracy.

The block diagram which shows schematic structure of the key position determination apparatus in 1st Embodiment. The XY orthogonal coordinate diagram which shows the pattern of a vehicle inside / outside determination line. The XY orthogonal coordinate diagram which shows the pattern of a vehicle exterior position determination line. The conceptual diagram which shows the image of the antenna area of a vehicle. The conceptual diagram which shows the image of the repeater use verification fraud establishment act. The timing chart which shows the communication sequence of smart communication. The XY orthogonal coordinate diagram which shows the pattern of the conventional determination line. The block diagram which shows the outline of the tire pressure monitoring system in 2nd Embodiment. The XY orthogonal coordinate diagram which shows the pattern of the determination line used for tire position determination. The schematic diagram which shows schematic structure of the conventional electronic key system. The schematic diagram which shows the state in which the leak area of the antenna was formed in the vehicle.

(First embodiment)
Hereinafter, a first embodiment of a communication terminal position determination apparatus embodying the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the vehicle 1 has a key operation free system 3 that automatically performs ID (Identification) verification when the electronic key 2 approaches the vehicle 1 as a kind of electronic key system that performs key verification wirelessly. Is provided. This key operation free system 3 includes a smart entry system in which a door lock is unlocked and unlocked in a series of door opening and closing operations without actually performing a key operation, and a push type engine installed in the vehicle. There is a one-push engine start system that can start the engine only by pressing the switch 4. The electronic key 2 constitutes a communication terminal, and the key operation free system 3 constitutes a wireless system and an electronic key system.

In this case, the vehicle 1 includes a key verification device 5 that performs ID verification with the electronic key 2, a door lock device 6 that manages a door lock operation, and an engine start device 7 that manages the operation of the engine. These are provided and connected by an in-vehicle bus 8. The key verification device 5 is provided with a verification ECU (Electronic Control Unit) 9 as a control unit of the device 5. In the memory (not shown) of the verification ECU 9, the ID code of the electronic key 2 that forms a pair with the vehicle 1 is registered. In addition, collation ECU9 comprises a communication master.

  The verification ECU 9 includes a driver-seat exterior vehicle transmitter (hereinafter referred to as a driver-seat antenna 11) that transmits radio waves in the LF (Low Frequency) band around a driver-seat door 10 (see FIG. 4), and a passenger-seat door 12 A passenger-seat exterior transmitter (hereinafter referred to as “passenger seat antenna 13”) that transmits LF band radio waves around (see FIG. 4) and a vehicle tuner 14 that receives UHF (Ultra High Frequency) band radio waves. It is connected. These antennas 11 and 13 are provided, for example, on the left and right pillars of the vehicle body, respectively, and can transmit a request signal Srq as an ID reply request to the electronic key 2. The driver's seat antenna 11 corresponds to one antenna, and the passenger seat antenna 13 corresponds to another antenna.

  As shown in FIG. 4, the driver's seat antenna 11 transmits radio waves at a transmission intensity that forms a communication area (driver's seat antenna area Kd) outside and inside the driver's seat. The passenger seat antenna 13 transmits radio waves at a transmission intensity that forms a communication area (passenger seat antenna area Kp) outside and inside the passenger seat side vehicle. In the case of this example, as a basic position determination of the electronic key 2, when the electronic key 2 strongly receives a radio wave from the driver's seat antenna 11, the position of the electronic key 2 is determined to be outside the driver's seat side vehicle, and the passenger's seat antenna When the electronic key 2 strongly receives the radio wave from 13, the position of the electronic key 2 is determined to be outside the driver's seat side vehicle. Further, when the radio wave from the driver's seat antenna 11 and the radio wave from the passenger seat antenna 13 are received with the same strength, the position of the electronic key 2 is determined to be in the vehicle.

  As shown in FIG. 1, the electronic key 2 is provided with a communication control unit 15 that performs overall control of the operation of the electronic key 2. An ID code is registered in the memory (not shown) of the communication control unit 15 as an ID unique to the key. The communication control unit 15 is connected to an LF receiver 16 capable of receiving LF band radio waves and a UHF transmitter 17 capable of transmitting UHF band radio waves. The LF receiver 16 is a three-axis receiving antenna including an X-axis antenna, a Y-axis antenna, and a Z-axis antenna, and each antenna is formed by a coil antenna. When the electronic key 2 receives the request signal Srq by the LF receiver 16, the electronic signal 2 transmits the ID signal Sid including the ID code by the UHF transmitter 17 using radio waves in the UHF band.

  When the verification ECU 9 receives the ID signal Sid from the electronic key 2 as a response to the request signal Srq, the verification ECU 9 executes smart verification as ID verification. When the collation ECU 9 confirms that smart collation with the electronic key 2 outside the vehicle, that is, collation outside the vehicle, is established, the door lock device 6 performs door lock / unlock operation or permits. Further, the verification ECU 9 permits the engine start and the power supply transition by the push operation of the engine switch 4 when confirming that the smart verification with the electronic key 2 in the vehicle, that is, the vehicle verification, is established.

  The key operation free system 3 of this example is provided with a key position determination device 18 that determines the position of the electronic key 2 using a determination line L as shown in FIGS. Yes. The key position determination device 18 of this example uses the magnetic field intensity Hx (denoted as the driver's seat side magnetic field intensity Hd) when the electronic key 2 receives the radio wave from the driver's seat antenna 11 and the radio wave from the passenger seat antenna 13 as an electronic signal. Calculate the magnetic field strength Hx (denoted as the passenger-side magnetic field strength Hp) when the key 2 is received, and see which position the magnetic field strengths Hd and Hp take with respect to the two-dimensional determination line L Thus, the position of the electronic key 2 is determined. The driver's seat side magnetic field strength Hd corresponds to the first reception strength, and the passenger seat side magnetic field strength Hp corresponds to the second reception strength.

  In this case, the verification ECU 9 is provided with an alternate transmission operation unit 19 that alternately transmits radio waves to the driver's seat antenna 11 and the passenger seat antenna 13. For example, the alternate transmission operation unit 19 first transmits the request signal Srq from the driver's seat antenna 11 to form the driver's seat antenna area Kd around the driver's seat antenna 11, and subsequently receives the request signal Srq from the passenger seat antenna 13. Then, the passenger seat antenna area Kp is formed around the passenger seat antenna 13. Then, the alternate transmission operation unit 19 repeatedly performs this alternate transmission.

  The communication control unit 15 is provided with a magnetic field strength calculation unit 20 that calculates a received signal strength indicator (RSS I) received by the electronic key 2 as a magnetic field strength Hx. When the request signal Srq from the driver's seat antenna 11 is received by the electronic key 2, the magnetic field strength calculation unit 20 calculates the magnetic field strength Hx at this time as the driver's seat side magnetic field strength Hd, and the request signal from the passenger seat antenna 13. When Srq is received by the electronic key 2, the magnetic field strength Hx at this time is calculated as the passenger seat side magnetic field strength Hp. Further, the magnetic field strength calculation unit 20 calculates the magnetic field strengths Hd and Hp by using the vector composite value of the three-axis reception strengths of the LF receiver 16 (three-axis antenna). The magnetic field strength calculation unit 20 constitutes reception strength calculation means.

  The communication control unit 15 is provided with a magnetic field strength notification unit 21 that notifies the vehicle 1 of the magnetic field strengths Hd and Hp received by the electronic key 2 in the process of smart communication. When the electronic key 2 transmits the ID signal Sid to the vehicle 1 in response to the request signal Srq, the magnetic field strength notification unit 21 transmits the ID signal Sid including the data of the magnetic field strength Hx. That is, the ID signal Sid includes the ID code of the electronic key 2 and the data (digital value) of the magnetic field strength Hx. When returning the ID signal Sid in response to the request signal Srq from the driver's seat antenna 11, the magnetic field strength notifying unit 21 notifies the vehicle 1 by putting the driver's seat side magnetic field strength Hd on the ID signal Sid, and the passenger seat. When the ID signal Sid is returned in response to the request signal Srq from the antenna 13, the passenger's seat side magnetic field strength Hp is put on the ID signal Sid and notified to the vehicle 1. The magnetic field strength notification unit 21 constitutes reception strength calculation means.

The verification ECU 9 is provided with a magnetic field strength acquisition unit 22 that acquires the magnetic field strength Hx from the electronic key 2 during smart communication. The magnetic field strength acquisition unit 22 refers to the magnetic field strength Hx included in the ID signal Sid and acquires the magnetic field strength Hx during smart communication. The magnetic field strength acquisition unit 22 acquires a driver seat side magnetic field strength Hd when the driver seat antenna 11 is used as a vehicle transmission antenna and a passenger seat side magnetic field strength Hp when the passenger seat antenna 13 is used as a vehicle transmission antenna. To do. The magnetic field strength acquisition unit 22 constitutes reception strength calculation means.

  The determination line L shown in FIGS. 2 and 3 is registered in the memory 23 of the verification ECU 9. The determination line L includes, for example, a plurality of determination lines in an orthogonal coordinate system (XY orthogonal coordinate system) in which the axis of the driver's seat side magnetic field strength Hd is the X coordinate and the axis of the passenger seat side magnetic field strength Hp is the Y coordinate. It consists of a group of unique lines combined. Then, with the driver's seat side magnetic field strength Hd as the X coordinate value and the passenger seat side magnetic field strength Hp as the Y coordinate value, this coordinate point P (XY coordinate plot point) is XY with respect to the determination line L. The position of the electronic key 2 is determined by looking at which position on the plane coordinates of the electronic key 2 is taken. The determination line L is formed by a line passing through at least two different points in the viewed coordinate system when viewed from the X axis or the Y axis, for example. The coordinate point P corresponds to the combination value.

  The determination line L in this example is provided with an in-vehicle / out-of-vehicle determination line La for determining whether the electronic key 2 is located outside the vehicle (outdoor) or in the vehicle (indoor). The in-vehicle / out-of-vehicle determination line La is formed of a line group in which a plurality of linear in-vehicle / in-vehicle unit determination lines La1, La2,. The vehicle inside / outside determination line La is composed of seven vehicle inside / outside unit determination lines La1 to La7. The line groups of the vehicle inside / outside unit determination lines La1 to La7 are formed symmetrically with respect to the diagonal Rk of the linear function that passes through the origin 0 of the XY orthogonal coordinate system and has a gradient equal to “1”. Has been. This is because the vehicle body has a symmetrical shape. The in-vehicle / outside determination line La corresponds to the indoor / outdoor determination line, the sixth in-vehicle / outside unit determination line La6 and the seventh in-vehicle / outside unit determination line La7 constitute the second determination line, and the diagonal line Rk is a coordinate bisector. It corresponds to.

  The vehicle inside / outside determination line La is provided with first to fifth in-vehicle / outside unit determination lines La1 to La5 that are used when the inside / outside determination of the electronic key 2 is performed. The first in-vehicle / outside unit determination line La1 is a straight line having an inclination of “−” and intersecting the diagonal line Rk. The second vehicle inside / outside unit determination line La2 is a linear type along the Y axis. The third in-vehicle / outside unit determination line La3 is a linear equation having a relatively large value of “+” and a y-intercept having a relatively small value. The fourth vehicle inside / outside unit determination line La4 is a linear type along the X axis. The fifth in-vehicle / outside unit determination line La5 is a linear equation having a relatively small value of “+” and a y-intercept having a relatively large value. The second in-vehicle / outside unit determination line La2 and the fourth in-vehicle / outside unit determination line La4 are symmetric with respect to the diagonal line Rk. The third in-vehicle / outside unit determination line La3 and the fifth in-vehicle / outside unit determination line La5 are symmetric with respect to the diagonal line Rk.

  In the case of this example, a substantially triangular area surrounded by the first in-vehicle unit determination line La1 to the seventh in-vehicle unit determination line La7 (hereinafter, referred to as an in-vehicle determination area Ei: a downward slanted diagonal area in FIG. 2) Apparently, it is set as an area where the electronic key 2 can be recognized as being present in the vehicle. An area surrounded by the first in-vehicle / outside unit determination line La1 to the fifth in-vehicle / outside unit determination line La5, the X-axis and the Y-axis (hereinafter referred to as an out-of-vehicle determination area Eo; Apparently, it is set as an area where it can be recognized that the electronic key 2 exists outside the vehicle.

  Here, for example, when the electronic key 2 is located outside the driver's seat side vehicle or the passenger's seat side vehicle, the electronic key 2 extremely approaches one side of the driver's seat antenna 11 and the passenger seat antenna 13. Therefore, as a result, one of the driver-seat-side magnetic field strength Hd and the passenger-seat-side magnetic field strength Hp takes an extremely large value with respect to the other. Therefore, if it can be confirmed that one of the driver seat side magnetic field strength Hd and the passenger seat side magnetic field strength Hp is significantly different from the other, that is, the coordinate point P is located in the vehicle exterior determination area Eo in FIG. It can be seen that 2 is located outside the vehicle.

  On the other hand, when the electronic key 2 is located in the vehicle, the electronic key 2 approaches the driver seat antenna 11 and the passenger seat antenna 13 substantially equally. Therefore, as a result, the driver's seat side magnetic field strength Hd and the passenger seat side magnetic field strength Hp settle to values similar to each other. Therefore, if it can be confirmed that the driver-seat-side magnetic field strength Hd and the passenger-seat-side magnetic field strength Hp are close to each other, that is, if the coordinate point P is located in the in-vehicle determination area Ei in FIG. You can see that

  Incidentally, as shown in FIG. 5, as a kind of vehicle theft, there is a relay use verification fraud establishment act that uses the repeater 24 to carry out a vehicle theft. For example, when the electronic key 2 is located outside the communication area of the antennas 11 and 13, the repeater use verification fraud is performed by placing a repeater 24 in the communication area, and using the repeater 24 to move the vehicle 1 outside the area. This is an act of connecting to the key 2 and establishing ID verification. If the vehicle is stolen due to the act of improper use of repeater use verification, ID verification will be established without permission from the user, so the door lock may be unlocked or the engine may be started by the theft It leads to.

  Therefore, the vehicle inside / outside determination line La is provided with sixth and seventh in-vehicle / outside unit determination lines La6 and La7 for preventing an illegal use of repeater use verification. The sixth in-vehicle / outside unit determination line La6 is a linear expression having a relatively large value of “−” and a y-intercept having a relatively large value. In addition, the seventh in-vehicle / outside unit determination line La7 is a linear equation in which the slope of “−” having a small value is relatively regular and the y-intercept has a relatively small value.

  Here, although the repeater 24 can repeat the signal data, there is a current situation where the repeater 24 cannot repeat the signal strength. Therefore, when the radio wave from the electronic key 2 is transmitted to the vehicle 1 by the act of improperly using the repeater use verification, this appears as a very large reception intensity. Therefore, as a result, the radio wave due to the illegal use of repeater use verification should have a high value in both the driver's seat side magnetic field strength Hd and the passenger seat side magnetic field strength Hp. For this reason, as shown in FIG. 2, coordinates are set in an area (hereinafter referred to as unauthorized communication determination area Ee: horizontal oblique line area in FIG. 2) that is greater than or equal to the sixth in-vehicle unit determination line La6 and the seventh in-vehicle unit determination line La7. If it is known that the point P is located, it can be understood that the electronic key 2 has been illegally communicated.

  The verification ECU 9 is provided with a position determination unit 25 that performs the position determination of the electronic key 2 using the determination line L. The position determination unit 25 also performs key position determination at the time of smart communication, and determines whether the smart verification that is being performed is external verification or in-vehicle verification. When the position determination unit 25 acquires the coordinate point P, the position determination unit 25 confirms in which region the coordinate point P is located among the vehicle outside determination region Eo, the vehicle interior determination region Ei, and the unauthorized communication determination region Ee. Carry out position in-vehicle / outside determination. The position determination unit 25 corresponds to a position determination unit.

  When the position determination unit 25 confirms that the coordinate point P is located in the in-vehicle determination area Ei shown in FIG. 2, the position determination unit 25 determines that the electronic key 2 is in the vehicle. When the position determination unit 25 confirms that the coordinate point P is located within the vehicle outside determination area Eo shown in FIG. 2, the position determination unit 25 determines that the electronic key 2 is outside the vehicle. When the position determination unit 25 confirms that the coordinate point P is located in the unauthorized communication determination area Ee shown in FIG. 2, the position determination unit 25 determines that the electronic key 2 has been illegally communicated.

  The determination line L in this example is provided with an out-of-vehicle position determination line Lb for determining whether the electronic key 2 is positioned on the driver's seat side or the passenger seat side when the electronic key 2 is positioned outside the vehicle. The vehicle outside position determination line Lb is also formed from a line group in which a plurality of linear vehicle outside position unit determination lines Lb1, Lb2,. The vehicle exterior position determination line Lb is composed of eight vehicle exterior position unit determination lines Lb1 to Lb8. The line groups of the vehicle exterior position unit determination lines Lb1 to Lb8 are also formed symmetrically with respect to the diagonal line Rk of the linear function having a slope of “1” that bisects the XY rectangular coordinate system. The vehicle outside position determination line Lb corresponds to the outdoor position determination line, and the fourth vehicle outside position unit determination line Lb4 and the eighth vehicle outside position unit determination line Lb8 constitute a second determination line.

  The vehicle exterior position determination line Lb is provided with four vehicle exterior position unit determination lines Lb1 to Lb4 that are used when checking whether the electronic key 2 is located on the driver's seat side. The first vehicle exterior position unit determination line Lb1 is a linear type along the Y axis. The second vehicle exterior position unit determination line Lb2 is a linear expression having an inclination parallel to the diagonal line Rk and a value having a smaller y-intercept than the diagonal line Rk. The third vehicle outside position unit determination line Lb3 is a linear equation having an inclination parallel to the second vehicle outside position unit determination line Lb2 and having a y-intercept smaller than that of the line Lb2. The fourth vehicle exterior position unit determination line Lb4 is a linear type along the X axis.

  The vehicle exterior position determination line Lb is provided with four vehicle exterior position unit determination lines Lb5 to Lb8 that are used when checking whether the electronic key 2 is located on the passenger seat side. The fifth vehicle exterior position unit determination line Lb5 is a linear type along the X axis. The sixth out-of-vehicle position unit determination line Lb6 is a linear equation having an inclination parallel to the diagonal line Rk and a value having a larger y-intercept than the diagonal line Rk. The seventh outside vehicle position unit determination line Lb7 is a linear equation having a slope parallel to the sixth outside vehicle position unit determination line Lb6 and a value having a larger y-intercept than the line Lb6. The eighth out-of-vehicle position unit determination line Lb8 is a linear type along the Y axis.

  In the case of this example, a substantially trapezoidal region (hereinafter referred to as a driver-seat-side vehicle exterior determination region Ed: a left-slanted hatched region in FIG. 3) surrounded by the four vehicle exterior position unit determination lines Lb1 to Lb4 is apparently It is set as an area where it can be recognized that the electronic key 2 exists outside the driver's seat side vehicle. This is because, when the electronic key 2 is located outside the driver's seat side vehicle, the electronic key 2 is closer to the driver's seat antenna 11 than the passenger's seat antenna 13, and as a result, the driver's seat side magnetic field strength is higher than the passenger seat side magnetic field strength Hp. This is because Hd takes a larger value. Therefore, if it can be confirmed that the coordinate point P is located in the driver's seat side vehicle exterior determination area Ed, it can be understood that the electronic key 2 is located outside the driver's seat side vehicle.

  In addition, a substantially trapezoidal region surrounded by the four vehicle exterior position unit determination lines Lb5 to Lb8 (referred to as a passenger seat side vehicle exterior determination region Ed: a right-downward oblique line region in FIG. 3) appears to be an electronic key 2 as an assistant. It is set as an area that can be recognized as being outside the seat side vehicle. This is because when the electronic key 2 is located outside the passenger seat side vehicle, the electronic key 2 is closer to the passenger seat antenna 13 than to the driver seat antenna 11, and as a result, the passenger seat side magnetic field strength is higher than the driver seat side magnetic field strength Hd. This is because Hp takes a larger value. Therefore, if it can be confirmed that the coordinate point P is located in the passenger seat side outside vehicle determination area Ep, it can be understood that the electronic key 2 is located outside the passenger seat side vehicle.

  Further, the fourth vehicle outside position unit determination line Lb4 and the eighth vehicle outside position unit determination line Lb8 are also used as lines for determining the presence or absence of the repeater use verification fraud. The fourth vehicle exterior position unit determination line Lb4 is an X-axis parallel line in which the passenger seat side magnetic field strength Hp takes a high value. The eighth vehicle exterior position unit determination line Lb8 is a Y-axis parallel line in which the driver's seat side magnetic field strength Hd takes a high value.

  Here, in this example, the area beyond the fourth vehicle position unit determination line Lb4 and the eighth vehicle position unit determination line Lb8 (unauthorized communication determination area Er: horizontal hatched area in FIG. 3) apparently performs smart communication. It is set as an area for judging unauthorized communication. As described above, in the case of the act of improper use of repeater use verification, the radio wave from the electronic key 2 can reach the vehicle 1 by the repeater 24, but the radio wave intensity cannot be duplicated. As a result, it reaches the vehicle 1 with high transmission intensity. Therefore, if it can be confirmed that the coordinate point P is located in the unauthorized communication determination area Er, it is determined that the communication is unauthorized communication.

  In the case of this example, the region surrounded by the second outside vehicle position unit determination line Lb2 and the sixth outside vehicle position unit determination line Lb6, that is, the region near the diagonal Rk, also becomes the unauthorized communication determination region Er. . As described above, the radio wave transmitted to the vehicle 1 by the repeater 24 reaches the vehicle 1 with a large magnetic field strength. As a result, the driver's seat antenna 11 and the passenger seat antenna 13 have the same magnetic field strength Hx. To. For this reason, since the driver's seat side magnetic field strength Hd and the passenger seat side magnetic field strength Hp have substantially the same value, the point on the diagonal line Rk of the XY coordinate system can be determined as a radio wave from the repeater 24.

  When the position determination unit 25 confirms that the coordinate point P is located within the driver seat side vehicle exterior determination area Ed shown in FIG. 3, the position determination unit 25 determines that the electronic key 2 is outside the driver seat vehicle. When the position determination unit 25 confirms that the coordinate point P is located in the passenger seat side out-of-vehicle determination area Ep shown in FIG. 3, the position determination unit 25 determines that the electronic key 2 is outside the passenger seat side vehicle. When the position determination unit 25 confirms that the coordinate point P is located within the unauthorized communication determination area Er shown in FIG. 3, the position determination unit 25 determines that the radio wave of the electronic key 2 has been illegally communicated.

Next, the operation of the key position determination device 18 of this example will be described with reference to FIG.
Here, first, it is assumed that the driver gets on the driver's seat door 10 when the vehicle 1 is in a parked state (door lock locking, engine stop). At this time, when the alternate transmission operation unit 19 confirms that the outside door handle knob of the driver's seat door is touch-operated by the driver, the driver's seat antenna 11 switches the electronic key 2 in the standby state to the activated state. The wake signal 26 is alternately transmitted from the passenger seat antenna 13. At this time, the alternate transmission operation unit 19 first transmits the first wake signal 26 a from the driver's seat antenna 11.

  Since the electronic key 2 is in the driver's seat antenna area Kd, the first wake signal 26a can be received. When the electronic key 2 receives the first wake signal 26a, the electronic key 2 is switched to the activated state by the first wake signal 26a. At this time, the magnetic field strength calculation unit 20 calculates the reception strength of the first wake signal 26a, that is, the driver seat side magnetic field strength Hd. In addition, when the electronic key 2 switches to the activated state, the electronic key 2 transmits a first ACK signal 27 to the vehicle 1.

  When the verification ECU 9 transmits the first wake signal 26a and receives an ACK response within the time limit, the verification ECU 9 recognizes that the electronic key 2 exists around the vehicle. When the verification ECU 9 confirms that the electronic key 2 is present around the vehicle, the verification ECU 9 transmits a vehicle ID 28 from the driver's seat antenna 11. The vehicle ID 28 is a unique ID of the vehicle 1. When the electronic key 2 receives the vehicle ID 28, the electronic key 2 executes vehicle ID verification, and confirms whether or not the communication partner vehicle 1 at this time is a regular communication partner. When the electronic key 2 confirms that vehicle ID verification is established, the electronic key 2 transmits a second ACK signal 29 to the vehicle 1.

  When the verification ECU 9 receives the second ACK signal 29 within the time limit after the transmission of the vehicle ID 28, the verification ECU 9 subsequently transmits a challenge 30 from the driver's seat antenna 11. The challenge 30 includes a key number for inquiring what registration key the electronic key 2 is and a challenge code for challenge response authentication. When the electronic key 2 receives the challenge 30, the electronic key 2 executes number verification with the key number in the challenge 30. When the electronic key 2 confirms that the number verification is established, the electronic key 2 passes the challenge code through its own encryption key and calculates a response code. When the calculation of the response code is completed, the electronic key 2 transmits a response 31 to the vehicle 1. The response 31 includes the ID code of the electronic key 2 and the calculated response code. When the transmission of the response 31 is completed, the electronic key 2 returns to the original standby state.

  In addition, when the electronic key 2 transmits the response 31 to the vehicle 1, the magnetic field strength notification unit 21 causes the response 31 to include the ID code and the response code together with data on the driver's seat side magnetic field strength Hd. That is, as the response 31, the ID code, the response code, and the driver's seat side magnetic field strength Hd are transmitted from the electronic key 2 to the vehicle.

  When transmitting the challenge 30, the verification ECU 9 also passes the challenge code through its encryption key and calculates the response code. When the verification ECU 9 receives the response 31 from the electronic key 2, the verification ECU 9 performs response verification using the response code included in the response 31. If it is confirmed that the verification is established, the verification ECU 9 verifies the ID code using the ID code included in the response 31. Execute. When the verification ECU 9 confirms that both verifications are established, the verification ECU 9 processes the smart verification as establishment.

  Further, when confirming that the smart verification is established, the magnetic field strength acquisition unit 22 acquires the driver seat side magnetic field strength Hd included in the response 31 and outputs the driver seat side magnetic field strength Hd to the position determination unit 25. That is, the magnetic field strength acquisition unit 22 recognizes that the response 31 received at this time is the response of the electronic key 2 to the inquiry from the driver's seat antenna 11, so the received strength data included in the response 31 is obtained. This is taken in as the driver's seat side magnetic field strength Hd, and this is notified to the position determination unit 25.

  When the alternate transmission operation unit 19 confirms that the smart collation by the driver's seat antenna 11 is completed, the alternate transmission operation unit 19 starts transmission of the second wake signal 26b from the passenger seat antenna 13 and uses the passenger seat antenna 13 as a vehicle transmission antenna. Smart communication with the electronic key 2 is performed. When receiving the second wake signal 26b, the electronic key 2 enters the activated state again by the second wake signal 26b. At this time, the magnetic field strength calculation unit 20 calculates the reception strength of the second wake signal 26b, that is, the passenger seat side magnetic field strength Hp.

  Further, when the electronic key 2 is switched to the activated state by the second wake signal 26b, the electronic key 2 transmits a third ack signal 32 to the vehicle 1. When the verification ECU 9 transmits the second wake signal 26b and receives an ACK response within the time limit, the verification ECU 9 continues the smart communication using the passenger seat antenna 13 as the vehicle transmission antenna.

  The subsequent smart communication is executed by the same communication sequence as when the driver's seat antenna 11 is a vehicle transmission antenna. That is, when the third ACK signal 32 reaches the vehicle 1, the vehicle ID 33 is transmitted from the passenger seat antenna 13, and the vehicle ID verification is executed. When the fourth ACK signal 34 arrives from the electronic key 2 to the vehicle 1 as a vehicle ID verification establishment notification, a challenge 35 is transmitted from the passenger seat antenna 13.

  When the electronic key 2 receives the challenge 35, the electronic key 2 executes key number verification and response code calculation in the challenge 35. When the response code calculation is completed, the electronic key 2 transmits a response 36 to the vehicle 1. The response 36 includes the ID code of the electronic key 2, the calculated response code, and data on the passenger seat side magnetic field strength Hp.

  When the verification ECU 9 receives the response 36, the verification ECU 9 performs response authentication and ID code verification. When the verification ECU 9 confirms that both verifications are established, the verification ECU 9 processes the smart verification as establishment. Further, when confirming that smart verification is established, the magnetic field strength acquisition unit 22 acquires the passenger seat side magnetic field strength Hp from the response 36 and outputs the passenger seat side magnetic field strength Hp to the position determination unit 25. That is, the magnetic field strength acquisition unit 22 recognizes that the response 36 received at this time is the response of the electronic key 2 to the inquiry from the passenger seat antenna 13, and therefore the reception strength included in the response 36 is determined as the assistant. This is taken in as the seat-side magnetic field strength Hp and output to the position determination unit 25.

  When the position determination unit 25 acquires the driver-seat-side magnetic field strength Hd and the passenger-seat-side magnetic field strength Hp, the position-determining unit 25 uses the driver-seat-side magnetic field strength Hd as the X-coordinate value and the passenger-seat-side magnetic field strength Hp as the Y-coordinate value. P is calculated. And the position determination part 25 performs the vehicle inside / outside determination which sees whether the electronic key 2 is outside a vehicle or a vehicle inside first. At this time, since the position determination unit 25 recognizes that the vehicle 1 is in the parking state, the position determination unit 25 performs an out-of-vehicle determination to confirm whether or not the electronic key 2 is positioned outside the vehicle.

  In this case, the position determination unit 25 reads the vehicle inside / outside determination line La from the memory 23, and whether or not the coordinate point P is located in the vehicle outside determination region Eo among the regions Ei, Eo, Ee determined from the vehicle inside / outside determination line La. By checking whether or not the vehicle is inside / outside when parked. Here, since it is assumed that the driver gets on from the driver's seat door 10 side, the coordinate point P is plotted as the coordinate point P1 in the outside determination area Eo, for example, as shown in FIG. Therefore, the position determination part 25 recognizes that the electronic key 2 exists outside a vehicle by the coordinate point P being located in the vehicle outside determination area | region Eo.

  Subsequently, the position determination unit 25 performs vehicle exterior position determination to see whether the electronic key 2 existing outside the vehicle is on the driver seat side or the passenger seat side. At this time, the position determination unit 25 reads the vehicle outside position determination line Lb from the memory 23 and sees in which region the coordinate point P is located in the regions Ed, Ep, Er determined from the vehicle outside position determination line Lb. Thus, the position of the electronic key 2 outside the vehicle is determined.

  Here, since it is assumed that the driver gets on from the driver's seat door 10 side, the coordinate point P is plotted as a coordinate point P2 in the driver's seat side vehicle exterior determination area Ed as shown in FIG. . Therefore, the position determination unit 25 recognizes that the electronic key 2 is positioned outside the driver's seat side vehicle by the coordinate point P being positioned in the driver's seat side vehicle exterior determination area Ed. For this reason, when the collation ECU 9 confirms that the smart collation with the electronic key 2 is established and that the vehicle exterior determination is also correct, the collation ECU 9 causes the door lock device 6 to unlock the door lock.

  On the other hand, when the position determination unit 25 determines that the vehicle is outside the vehicle, if the coordinate point P is not located in the vehicle outside determination region Eo, the vehicle outside determination is not established and the door lock is unlocked. In addition, even when the position determination unit 25 determines that the coordinate point P is located in the vehicle outside determination area Eo and the electronic key 2 exists outside the vehicle at the time of vehicle outside position determination, the coordinate point P is in the driver seat side vehicle outside determination area. If it is not correctly positioned in Ed or the passenger's seat side vehicle exterior determination area Ep, the vehicle exterior determination is not established and the door lock unlocking is disabled.

  Subsequently, it is assumed that the driver gets into the vehicle after unlocking the door lock. When the verification ECU 9 confirms that the driver has entered the vehicle by using, for example, a courtesy switch or the like, the verification ECU 9 executes the same smart communication in the same communication sequence as when the door lock is unlocked. Therefore, also in this case, the reception intensity of the electronic key 2 when performing smart communication with the electronic key 2 using the driver's seat antenna 11 as a vehicle transmission antenna is acquired as the driver's seat side magnetic field strength Hd, and the passenger's seat antenna 13 is transmitted to the vehicle. The reception strength of the electronic key 2 when performing smart communication with the electronic key 2 as an antenna is acquired as the passenger seat side magnetic field strength Hp, and the coordinate point P described above is calculated.

  When the position determination unit 25 acquires the coordinate point P during in-vehicle verification, the position determination unit 25 performs in-vehicle determination as a determination as to whether or not the electronic key 2 is positioned in the vehicle. Also at this time, the position determination unit 25 reads out the vehicle inside / outside determination line La from the memory 23, and of the regions Ei, Eo, Ee determined from the vehicle inside / outside determination line La, is the coordinate point P located in the vehicle inside determination region Ei? Car interior determination is executed by confirming whether or not.

  At this time, if the driver carrying the electronic key 2 gets on the vehicle, the coordinate point P is plotted as the coordinate point P3 in the in-vehicle determination area Ei as shown in FIG. Therefore, the position determination part 25 recognizes that the electronic key 2 exists in the vehicle by the coordinate point P being located in the vehicle interior determination area Ei. For this reason, when it is confirmed that the smart communication with the electronic key 2 is established and the in-vehicle determination is also established, the verification ECU 9 permits the power supply transition operation and the engine start operation by the engine start device 7.

  Then, the case where the driver who got off locks a door lock is assumed. When the verification ECU 9 detects that the lock button (not shown) of the outside door handle knob of the driver's door 10 is pressed when the vehicle 1 is stopped (door lock unlocked, engine stopped), the communication described above is performed. Performs smart matching similar to a sequence. Also at this time, smart communication is alternately performed by the driver's seat antenna 11 and the passenger's seat antenna 13, the driver's seat side magnetic field strength Hd and the passenger's seat side magnetic field strength Hp are acquired, and the coordinate point P described above is calculated.

  If the position determination part 25 acquires the coordinate point P at the time of collation outside a vehicle, it will perform a vehicle exterior determination this time as a determination whether the electronic key 2 is located outside a vehicle. Also at this time, the position determination unit 25 reads the vehicle inside / outside determination line La from the memory 23, and among the regions Ei, Eo, Ee determined from the vehicle inside / outside determination line La, is the coordinate point P positioned in the vehicle outside determination region Eo? By checking whether or not, the inside / outside determination at the time of parking is executed. Here, since it is assumed that the driver locks the door from the driver's seat door 10 side, the coordinate point P is plotted in the vehicle exterior determination area Eo. Therefore, the position determination part 25 recognizes that the electronic key 2 exists outside a vehicle by the coordinate point P being located in the vehicle outside determination area | region Eo.

  And the position determination part 25 continues and performs the vehicle exterior position determination which sees whether the electronic key 2 which exists outside a vehicle exists in the driver's seat side or a passenger seat side. Also at this time, the position determination unit 25 reads the vehicle outside position determination line Lb from the memory 23, and the coordinate point P in the regions Ed, Ep, Er determined from the vehicle outside position determination line Lb is in the driver side vehicle outside determination region Ed. By determining whether or not the vehicle is positioned, vehicle exterior position determination is executed.

  Here, since it is assumed that the driver locks the door from the driver's seat door 10 side, the coordinate point P is plotted in the driver's seat-side vehicle exterior determination area Ed. Therefore, the position determination unit 25 recognizes that the electronic key 2 is positioned outside the driver's seat side vehicle by the coordinate point P being positioned in the driver's seat side vehicle exterior determination area Ed. When the verification ECU 9 confirms that the smart communication with the electronic key 2 is established and the vehicle exterior determination is also established, the verification ECU 9 causes the door lock device 6 to perform door lock locking.

  Although the example in which the vehicle 1 is boarded from the driver's seat door 10 has been described above, the basic operation of the driver's seat door 10 is also the operation when getting on and off the passenger seat door 12, the rear right door, and the left door. Since these are the same as when getting on and off, details of these specific examples are omitted.

  By the way, when the position of the electronic key 2 is determined from the values of the driver-seat-side magnetic field strength Hd and the passenger-seat-side magnetic field strength Hp, for example, as shown in FIG. 7, the driver-seat-side magnetic field strength Hd and the passenger-seat-side magnetic field strength Hp In addition, it is assumed that one threshold value H1, H2 is provided, and the position of the electronic key 2 is determined by checking the magnitude relationship of the coordinate point P with respect to the threshold values H1, H2. In this case, for example, if the driver's seat side magnetic field strength Hd is greater than or equal to the threshold value H1, and the passenger's seat side magnetic field strength Hp is greater than or equal to the threshold value H2, it is determined that the electronic key 2 is located in the vehicle. If it is smaller than the threshold value H1 or the passenger seat side magnetic field strength Hp is smaller than the threshold value H2, it is determined that the electronic key 2 is located outside the vehicle. However, in this determination method, as is well known from the results of actual measurement, the coordinate points Pe, Pe,... In the broken-line circle in FIG. There was a problem.

  However, in the case of this example, the position of the electronic key 2 is determined by providing a unique determination line L that is a combination of a plurality of linear expressions, and grading the coordinate point P with respect to the determination line L. The coordinate points Pe, Pe... Can be determined as out of the vehicle without any problem. Therefore, if the key position is determined by the unique determination line L as in this example, the key position can be determined with higher accuracy.

  Further, when a third party tries to illegally establish smart verification by an act of illegally using repeater use verification, the coordinate point P calculated at this time is the illegal communication determination area Ee in FIG. Plotted in the communication determination area Er. Therefore, the smart communication at this time is not processed as established, and the vehicle 1 does not operate. For this reason, even if a third party tries to steal the vehicle with the repeater 24, it is not necessary to operate the vehicle 1, so that security against the vehicle theft can be ensured.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) In this example, the key position is determined by observing which position the coordinate point P on the XY coordinates determined from the driver's seat side magnetic field strength Hd and the passenger seat side magnetic field strength Hp is relative to the determination line L. In the key operation free system 3, the determination line L serving as a reference for position determination is a unique line constructed from a plurality of linear expressions. For this reason, since the key position is not determined by using a simple straight line as shown in FIG. 7 as the thresholds H1 and H2, it is possible to accurately determine a position erroneously determined by this method. Therefore, the position of the electronic key 2 can be subdivided to determine the position, so that the position of the electronic key 2 can be determined with higher accuracy.

  (2) The inside / outside determination line La is provided as the determination line L, and the inside / outside determination of the electronic key 2 is executed by looking at the coordinate point P with respect to the inside / outside determination line La. For this reason, since the inside / outside determination of the electronic key 2 is performed by the in-vehicle / outside determination line La with high determination accuracy, it is possible to more accurately determine whether the electronic key 2 is located outside the vehicle or inside the vehicle.

  (3) A vehicle interior / exterior determination line La and a vehicle exterior position determination line Lb are provided as the determination line L. When the electronic key 2 is located outside the vehicle, the vehicle interior / exterior determination line La performs vehicle interior / exit determination. The vehicle outside position determination line Lb also performs vehicle outside position determination as to whether the electronic key 2 is outside the driver's seat side vehicle or the passenger seat side vehicle. Therefore, the vehicle inside / outside position determination can be performed with high accuracy, and when the electronic key 2 is located outside the vehicle, it may be determined whether the electronic key 2 is located outside the driver side vehicle or the passenger side vehicle. It can be determined accurately.

(4) Since the judgment line L is constructed from a plurality of straight lines, the formula (judgment formula) of the judgment line L can be constructed by a simple formula called a linear function (primary straight line).
(5) A sixth in-vehicle / outside unit determination line La6 and a seventh in-vehicle / outside unit determination line La7 are provided as one of the in-vehicle / out-of-vehicle determination lines La, which can identify the repeater use verification fraud establishment. When the coordinate point P is located in the formed unauthorized communication determination area Ee, the communication is processed as not established. For this reason, even if a third party tries to establish smart communication illegally using the repeater 24, communication is not established as a result, and therefore unauthorized vehicle operation using the repeater 24 can be prevented. Thus, security against vehicle theft can be improved. This also applies to the fourth vehicle outside position unit determination line Lb4 and the eighth vehicle outside position unit determination line Lb8 of the vehicle outside position determination line Lb.

  (6) When determining the key position on the vehicle outside position determination line Lb, when the coordinate point P is on the diagonal line Rk whose inclination passing through the origin 0 of the orthogonal coordinate system (XY orthogonal coordinate system) is “1”, the repeater The communication is regarded as unsuccessful, assuming that the communication is caused by an illegal use verification. For this reason, unauthorized vehicle operation using the repeater 24 can be prevented, and as a result, security against vehicle theft can be improved.

  (7) Since the driver's seat side magnetic field strength Hd and the passenger seat side magnetic field strength Hp are calculated from the vector composite value of the three-axis antenna, these magnetic field strengths Hd and Hp can be calculated with higher accuracy.

  (8) The driver-side magnetic field strength Hd and the passenger-side magnetic field strength Hp calculated by the electronic key 2 are transmitted to the vehicle 1 as digital values, and the final key position determination is executed on the vehicle 1 side. By the way, since the verification ECU 9 of the vehicle 1 often uses a computer having a higher calculation speed than the communication control unit 15 of the electronic key 2, it is shorter if the key position determination is performed on the vehicle 1 side. The key position can be determined by time.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. In this example, the technical idea of the present invention is applied to the tire pressure monitoring system 50. Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals, detailed description thereof is omitted, and only different parts are described in detail.

  As shown in FIG. 8, the vehicle 1 is equipped with a tire air pressure monitoring system 50 that monitors the air pressure of each tire 51 by attaching a wireless valve (tire sensor) 52 to each tire 51. When the tire pressure monitoring system 50 detects a tire whose tire pressure is lower than the threshold value, the tire pressure monitoring system 50 notifies the driver of the tire, for example, with an in-vehicle instrument panel. The tire 51 includes a right front tire 51a, a left front tire 51b, a right rear tire 51c, and a left rear tire 51d. The tire pressure monitoring system 50 constitutes a wireless system.

  Valves 52 (52a to 52d) capable of wirelessly transmitting tire air pressure information Stp are attached to the tires 51a to 51d. The valve 52 in this example includes an LF receiver that can receive LF radio waves, a UHF transmitter that can transmit UHF radio waves, a pressure sensor that detects tire air pressure, a temperature sensor that detects tire temperature, and an acceleration applied to the tire. An acceleration sensor that performs this operation, a microcomputer that controls the above components, and the like are mounted. The microcomputer of each valve 52 is also provided with the magnetic field strength calculation unit 20 and the magnetic field strength notification unit 21 as described above. The valve 52 forms a communication terminal and a tire communication device.

  When the valve 52 receives the trigger signal Str from the antennas 11 and 13, the valve 52 transmits tire pressure information Stp by UHF radio waves. The tire pressure information Stp includes, for example, information such as a valve-specific identification ID, tire pressure, tire temperature, acceleration applied to the tire, and the like. The trigger signal Str is an LF radio wave and includes an operation execution request for requesting the valve 52 to transmit a radio wave. The trigger signal Str is transmitted at a predetermined timing when the antennas 11 and 13 do not communicate with the electronic key 2 while the vehicle is traveling.

  In the memory 23 of the verification ECU 9, a determination line L shown in FIG. 9 capable of specifying the tire position is registered. The determination line L of this example is composed of three Lk1, Lk2, and Lk3. These determination lines Lk1 to Lk3 have the same slope and different y-intercepts. In this example, the largest y-intercept is Lk1, the next largest y-intercept is Lk2, and the smallest y-intercept is Lk3.

  The position determination unit 25 specifies the tire position by confirming in which region Et1 to Et4 the coordinate point P of each valve 52a to 52d is positioned by the determination lines Lk1 to Lk3. In this example, the region Et1 above the determination line Lk1 in the XY coordinate region is a region that can be determined as the left front tire 51b, and the region Et2 surrounded by the determination lines Lk1 and Lk2 can be determined as the left rear tire 51d. It is an area. An area Et3 surrounded by the determination lines Lk2 and Lk3 is an area that can be determined as the right rear tire 51c, and an area Et4 that is lower in the XY coordinate area than the determination line Lk3 is an area that can be determined as the right front tire 51a. It has become.

Next, operation | movement of the tire pressure monitoring system 50 of this example is demonstrated.
The verification ECU 9 transmits trigger signals Str at different timings in the order of the driver's seat antenna 11 and the passenger's seat antenna 13, for example. When each of the valves 52a to 52d receives the trigger signal Str transmitted from the driver's seat antenna 11, first, in addition to calculating the tire pressure at that time, the magnetic field strength of the trigger signal Str transmitted from the driver's seat antenna 11, That is, the magnetic field intensity calculation unit 20 calculates Hd. The valves 52a to 52d transmit tire pressure information Stp including the magnetic field strength Hd to the vehicle 1 by UHF radio waves.

  At this time, among the valves 52a to 52d, the valves 52a and 52c on the driver's seat side are close to the driver's seat antenna 11, so that a high magnetic field strength Hd is obtained. On the other hand, since the valves 52b and 52d on the passenger seat side are far from the driver seat antenna 11, the magnetic field strength Hd lower than that on the driver seat side is obtained.

  Subsequently, each of the valves 52 a to 52 d receives the trigger signal Str transmitted from the passenger seat antenna 13. When each of the valves 52a to 52d receives the trigger signal Str transmitted from the passenger seat antenna 13, in addition to calculating the tire pressure at that time, the magnetic field strength of the trigger signal Str transmitted from the passenger seat antenna 13, that is, Hp is calculated by the magnetic field strength calculator 20. And each valve | bulb 52a-52d transmits the tire pressure information Stp including this magnetic field intensity | strength Hp to the vehicle 1 by a UHF electromagnetic wave.

  At this time, among the valves 52a to 52d, the valves 52a and 52c on the driver's seat side are far from the passenger seat antenna 13, and thus obtain a low magnetic field strength Hp. On the other hand, since the valves 52b and 52d on the passenger seat side are close to the passenger seat antenna 13, a high magnetic field strength Hp that is good on the passenger seat side is obtained.

  The verification ECU 9 specifies the tire position when the tire pressure information Stp is acquired as a response from each of the antennas 11 and 13. At this time, the position determination part 25 calculates the coordinate point P in identification ID1-ID4 of each valve | bulb 52a-52d. And the position determination part 25 pinpoints a tire position by confirming which identification ID is located in which area | region Et1-Et4.

  At this time, for example, if the coordinate point P of the identification ID1 is located in the region Et4, it is determined that the valve 52a of the identification ID1 is attached to the right front tire 51a, and the coordinate point P of the identification ID2 is located in the region Et1. Then, it is determined that the valve 52b with the identification ID 2 is attached to the left front tire 51b. If the coordinate point P of the identification ID3 is located in the region Et3, it is determined that the valve 52c of the identification ID3 is attached to the right rear tire 51c, and the coordinate point P of the identification ID4 is located in the region Et2. For example, it is determined that the valve 52d with the identification ID 4 is attached to the left rear tire 51d.

  The determination lines Lk1 to Lk3 are lines derived from experiments in a predetermined vehicle type. For this reason, how to draw the determination lines Lk1 to Lk3 differs depending on the vehicle type. The determination lines Lk1 to Lk3 can be obtained theoretically, but since the vehicle body has a complicated structure, it is difficult to obtain it logically as it is, and it is actually obtained by actual vehicle measurement.

  Further, if the driver's seat antenna 11 and the passenger seat antenna 13 are arranged in the middle in the vehicle front-rear direction, the reception intensity is the same between the front and rear, making determination difficult. In this case, it is preferable to provide a difference in reception intensity by adjusting the mounting position and mounting angle of the driver's seat antenna 11 and the passenger seat antenna 13.

According to the configuration of the present embodiment, in addition to the effects (1) to (8) described in the embodiment, the following effects can be obtained.
(9) Since it is possible to specify the positions of the tires 51a to 51d without arranging an initiator in each tire house, the number of parts required for the tire pressure monitoring system 50 can be reduced. In addition, tire specification can be performed with high accuracy.

  (10) Since the communication infrastructure on the vehicle body side (mainly, the verification ECU 9, the antennas 11 and 13, the vehicle tuner 12, etc.) in the key operation free system 3 is also shared by the tire pressure monitoring system 50, the number of components mounted on the vehicle 1 Can be reduced.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
-In 1st and 2nd embodiment, the determination line L is not limited to the line which consists of a several straight line, For example, you may form from a curve. Further, the determination line L may be a line obtained by combining a straight line and a straight line.

In the first and second embodiments, the antenna is not limited to the driver seat antenna 11 and the passenger seat antenna 13. For example, a trunk antenna mounted on a luggage may be used.
In the first and second embodiments, the position determination (electronic key 2, tire 51) is not limited to a form in which only one pair of antennas is provided to determine the position. For example, a plurality of sets of a pair of antennas may be provided, and the determination result for each set may be integrated to determine the position.

  -In 1st and 2nd embodiment, key position determination is not limited to seeing a vehicle inside / outside or vehicle outside position. That is, if the position of the electronic key 2 is viewed, the position determination target position is not particularly limited.

In the first and second embodiments, the key position determination is not limited to viewing both the inside and outside of the vehicle and the outside position of the vehicle, and may be either one.
-In 1st and 2nd embodiment, the wake signal 26 is not limited to transmission starting with a driver | operator's predetermined operation as a trigger. For example, when the vehicle 1 is in a parked state, the electronic key 2 approaching the vehicle 1 may be constantly monitored so that the transmission is always performed.

In the first and second embodiments, the magnetic field strengths Hd and Hp are not limited to being calculated using the three-axis vector composite value, and for example, the maximum value among the three axes may be used.
-In 1st and 2nd embodiment, the receiving antenna of the electronic key 2 or the valve | bulb 52 is not limited to a triaxial antenna, For example, a uniaxial antenna may be sufficient.

  In the first and second embodiments, the calculation of the magnetic field strength Hx is not limited to the wake signals 26a and 26b, and may be calculated by the vehicle IDs 28 and 33 and the challenges 30 and 35, for example.

  -In 1st and 2nd embodiment, position determination is not limited to the format which the vehicle 1 receives the data of the magnetic field intensity | strength Hx from a communication terminal (electronic key 2, valve | bulb 52), and performs on the vehicle 1 side. For example, all the steps up to the position determination are performed on the communication terminal side (electronic key 2, valve 52), and the determination result is notified to the vehicle 1.

In the first and second embodiments, the reception intensity is not limited to the magnetic field intensity Hx of the received radio wave, and may be an electric field intensity.
In the first and second embodiments, the request is not limited to the request signal Srq that is an ID reply request, but may be a signal that requests a response from the electronic key 2.

In the first and second embodiments, the smart verification is not limited to the condition that both the driver's seat antenna 11 and the passenger's seat antenna 13 are established, and only one of them may be used.
-In 1st and 2nd embodiment, the electronic key 2 is not limited to a vehicle key, Various terminals (a mobile phone, an IC card, etc.) can be used. Further, the electronic key 2 is not necessarily limited to one having a key function, and widely includes communication terminals (authentication terminals) that perform an authentication operation in a broad sense.

  In the first and second embodiments, the key operation free system 3 is not limited to having different frequencies in the forward path and the return path of mutual communication, and may have the same frequency. The communication frequency of the key operation free system 3 is not limited to LF and UHF, and other frequencies such as HF (High Frequency) may be used.

-In 1st and 2nd embodiment, a radio | wireless system and an inquiry are not limited to the example described in embodiment, It can change suitably according to the application place of this thought.
-In 1st and 2nd embodiment, the electric key 2 of the electronic key 2 is transmitted from the vehicle 1 in the process of smart communication, and the electronic key 2 is driven by this electric power electric wave, and it is good also considering the electronic key 2 as a battery-less. .

  -In 2nd Embodiment, the vehicle tuner 14 will obtain the same signal many times from the same valve 52 at the time of tire position specification, but if the tire pressure is determined by using a specific one among them, You may take an average value.

-In 2nd Embodiment, the control unit of the tire pressure monitoring system 50 is not limited to what collation ECU9 serves, and you may provide a dedicated ECU.
In the first or second embodiment, the key operation free system 3 and the tire pressure monitoring system 50 are not limited to sharing the communication infrastructure on the vehicle body side, and the functions may be independent in each system. In addition, the technical idea of this example is not limited to being mounted on the vehicle 1 but can be applied to other devices and apparatuses.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.
(A) In any one of claims 1 to 9, the determination line is formed symmetrically about a diagonal line with an inclination “1” passing through the origin of the plane coordinates. According to this configuration, it is only necessary to prepare an equation in which XY is reversed with the diagonal line as the center as a determination line, so that the determination line equation can be simplified.

  (B) In any one of claims 1 to 9 and the technical idea (a), the reception antenna of the communication terminal is formed by a multi-axis antenna, and the reception intensity calculation unit is configured to perform vector synthesis of the multi-axis antenna. The received strength is calculated using the value. According to this configuration, the reception intensity can be calculated with higher accuracy.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Electronic key which comprises a communication terminal, 3 ... Key operation free system which comprises a wireless system and an electronic key system, 9 ... Verification ECU as a communication master, 11 ... Driver's seat antenna as one antenna, 13 A passenger seat antenna as another antenna, 18 a position determination device, 20 a magnetic field strength calculation unit constituting a reception strength calculation unit, 21 a magnetic field strength notification unit constituting a reception strength calculation unit, and 22 a reception strength calculation unit. Constructing magnetic field intensity acquisition unit, 24 ... repeater, 26 ... position determination unit as position determination means, 50 ... tire pressure monitoring system configuring wireless system, 51 (51a-51d) ... tire, 52 (52a-52d) ... Valve constituting the communication terminal and the tire communicator, Hd ... Driver side magnetic field strength as the first reception strength, Hp ... Assistance as the second reception strength Seat side magnetic field strength, P: coordinate point as combination value, L: determination line, La: in-vehicle / outside determination line as indoor / outdoor determination line, Lb: outside position determination line as outdoor position determination line, La6: second determination 6th in-vehicle / outside unit determination line constituting the line, La7 ... 7th in-vehicle / outside unit determination line constituting the second determination line, Lb4 ... 4th outside-vehicle position unit judgment line constituting the second determination line, Lb8 ... second Eighth vehicle position unit determination line constituting the determination line, Lk1 to Lk3... Determination line, 0... Origin, Rk... Diagonal line as coordinate bisector.

Claims (9)

In the communication terminal position determination device used in the wireless system in which the communication terminal responds to the inquiry from the communication master and these communicate bidirectionally,
When radio waves are transmitted alternately from one antenna and another antenna of the communication master, a first reception intensity when the communication terminal receives radio waves from the one antenna, and radio waves from the other antennas are transmitted to the communication terminal. Receiving strength calculating means for calculating the second receiving strength at the time of receiving,
A combination value of the first reception intensity and the second reception intensity is provided as a line for dividing the area on a plane coordinate, and is formed by a line connecting at least two different points when viewed from one axis side of the plane coordinate. Judgment line,
A communication terminal position determination device comprising: position determination means for determining the position of the communication terminal according to the magnitude of the combination value with respect to the determination line. The communication terminal is an electronic key;
The wireless system is an electronic key system in which the communication master performs ID verification with the electronic key,
The communication terminal position determining apparatus according to claim 1, wherein the position determining unit determines a position of the electronic key. The determination line is provided with an indoor / outdoor determination line that divides the position of the electronic key indoors and outdoors, and the position determination means looks at the magnitude of the position of the combination value with respect to the indoor / outdoor determination line. The communication terminal position determining apparatus according to claim 2, wherein it is determined whether the electronic key is located indoors or outdoors. The determination line is provided with an indoor / outdoor determination line for dividing the position of the electronic key indoors and outdoors, and an outdoor position determination line for dividing the position of the electronic key outdoors.
The position determination of the electronic key is performed by using the indoor / outdoor determination line to determine whether the electronic key is located indoors or outdoors, and when the electronic key is located outdoors, the outdoor position 4. The communication terminal position determination apparatus according to claim 2, wherein two determinations are performed, that is, an outdoor position determination in which the electronic key is located at an outdoor position using a determination line. The second determination line is provided in the determination line to prevent an act of illegally establishing communication between the communication master and the electronic key using a repeater. 4. The communication terminal position determination device according to claim 1. The determination line is formed symmetrically about a coordinate bisector that passes through the origin of the plane coordinate, and the vicinity of the coordinate bisector uses a repeater to connect the communication master and the electronic key. The communication terminal position determination device according to any one of claims 2 to 4, wherein the communication terminal position determination device is set as a region that prevents an act of illegally establishing communication. The communication terminal position determination device according to any one of claims 1 to 6, wherein the determination line is formed by a plurality of straight lines having different inclinations at least before and after connecting. The communication terminal is a tire communication device attached to each tire of a vehicle,
The wireless system is a tire pressure monitoring system that wirelessly acquires tire pressure from the tire communication device,
The communication terminal position determination device according to any one of claims 1 to 7, wherein the position determination unit specifies a position of a tire by determining a position of the tire communication device. An electronic key system as the wireless system for ID verification with an electronic key as the communication terminal, and a tire pressure monitoring system as the wireless system for acquiring tire pressure wirelessly from a tire communication device as the communication terminal are: The said communication master is shared, The communication terminal position determination apparatus as described in any one of Claims 1-8 characterized by the above-mentioned.

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