JP6907711B2 - Electronic key position estimator - Google Patents

Description

The present invention relates to an electronic key position estimation device that estimates the position of an electronic key.

There is known an electronic key position estimation device that determines whether or not an electronic key exists in a collation area set inside and outside the vehicle by communicating with the electronic key. The electronic key position estimation device is a component of the electronic key system together with the electronic key.

The electronic key system can be used as an electronic key when the electronic key is located in the vehicle interior verification area set outside the vehicle and when the electronic key is located in the vehicle interior verification area set inside the vehicle interior. Communicate and verify the code.

The in-vehicle device to be operated when the collation is established differs depending on whether the electronic key is present in the out-of-vehicle collation area or the interior collation area. Therefore, it is necessary to distinguish whether the electronic key exists in the vehicle interior verification area or the vehicle interior verification area.

For this distinction, Patent Document 1 separately includes an antenna for forming an exterior collation area and an antenna for forming an interior collation area.

In order to form these collation areas, LF band antennas that easily form these collation areas are used as the vehicle exterior antenna and the vehicle interior antenna. These exterior antennas and interior antennas are transmission antennas. The electronic key includes a receiving antenna for receiving radio waves in the LF band.

On the other hand, the electronic key uses radio waves in the RF band for transmitting radio waves to the vehicle. Therefore, the electronic key also includes an antenna for transmission that transmits radio waves in the RF band. The vehicle also has an antenna for receiving radio waves in the RF band.

Japanese Unexamined Patent Publication No. 2012-180707

As described above, in the conventional electronic key system, the vehicle is an antenna that transmits radio waves in the LF band in order to distinguish whether the electronic key is present in the outside verification area or the interior verification area. It is necessary to prepare for each collation area. Of course, not only the antenna but also the transmission circuit is required. Further, the electronic key also requires an antenna and a receiving circuit for receiving radio waves in the LF band. For these reasons, it has been desired to further simplify the configuration of the electronic key system.

The present disclosure has been made based on this circumstance, and an object of the present disclosure is to provide an electronic key position estimation device capable of simplifying the configuration of an electronic key system.

The above object is achieved by a combination of the features described in the independent claims, and the sub-claims provide further advantageous specific examples. The reference numerals in parentheses described in the claims indicate, as one embodiment, the correspondence with the specific means described in the embodiments described later, and do not limit the disclosed technical scope.

One disclosure to achieve the above objectives is
An electronic key position estimation device that determines whether or not an electronic key exists in a matching area set inside and outside the vehicle by communicating with the electronic key (2).
A plurality of array antenna mounted on a vehicle,
A direction estimation unit (S25) that estimates the arrival direction of radio waves for each array antenna based on the radio waves received from the electronic keys by a plurality of array antennas.
An arrival direction line, which is a straight line extending from the array antenna in the arrival direction of the radio wave estimated by the direction estimation unit based on the radio wave received by the array antenna, is determined for each array antenna, and is based on the intersection of a plurality of arrival direction lines. , Position estimation units (S26, S27) that estimate the position of the electronic key,
Area determination unit (S28) that determines whether or not the electronic key exists in the collation area set inside the vehicle and the collation area set outside the vehicle based on the position of the electronic key estimated by the position estimation unit. equipped with a door,
Each of the plurality of array antennas includes a plurality of antenna elements (111, 131).
The direction estimation unit uses one of the plurality of array antennas as the first array antenna (110), the antenna element (111) included in the first array antenna, and an array antenna different from the first array antenna. For the additional array antenna (190), which is configured by combining with the antenna element provided in, the arrival direction of the radio wave is estimated.
The position estimation unit also determines the arrival direction line for the additional array antenna, and estimates the position of the electronic key using the arrival direction line determined for the additional array antenna .

The disclosed electronic key position estimation device estimates the arrival direction of the radio wave received from the electronic key by using a plurality of array antennas. Then, the position of the electronic key is estimated based on the intersection of a plurality of arrival direction lines. Further, based on the estimated position of the electronic key, it is determined whether or not the electronic key is located in the collation area set inside the vehicle and the collation area set outside the vehicle.

Therefore, the electronic key position estimation system does not need to provide an antenna for each collation area for collation with the electronic key. Therefore, the configuration of the electronic key position estimation device is simplified. Further, the electronic key does not need to be provided with a dedicated antenna for receiving the radio wave transmitted by the antenna for forming the collation area by the electronic key position estimation device. Therefore, the configuration of the electronic key system can be simplified.

It is an overall block diagram of the electronic key system 1 of embodiment. It is a block diagram which shows the structure of the electronic key 2 of FIG. It is a flowchart which shows the process which the matching ECU 150 executes in a distance estimation mode. It is a flowchart which shows the process which the collation ECU 150 executes in a position estimation mode. It is a figure explaining the method of estimating the position of the electronic key 2. It is a figure which shows the additional array antenna 190 and the arrival direction line L3.

<First Embodiment>
Hereinafter, embodiments will be described with reference to the drawings.

[overall structure]
FIG. 1 is an overall configuration diagram of the electronic key system 1. The electronic key system 1 includes an electronic key 2 carried by a user and an in-vehicle collation system 100 mounted on a vehicle 3. The in-vehicle collation system 100 has a function as an electronic key position estimation device.

The electronic key system 1 is determined based on the fact that the electronic key 2 and the in-vehicle collation system 100 communicate with each other to perform code collation without the user operating the electronic key 2, and the code collation is established. It is a system that permits the operation of in-vehicle devices. The predetermined in-vehicle device is, for example, a driving force source such as a door lock mechanism provided on the door of the vehicle 3 or an engine.

[Configuration of in-vehicle collation system 100]
The in-vehicle collation system 100 includes a first array antenna 110, a first communication unit 120, a second array antenna 130, a second communication unit 140, a collation ECU 150, an unlock sensor 160, a lock sensor 170, and a push start button 180.

The first array antenna 110 is an array antenna including three antenna elements 111a, 111b, 111c. Hereinafter, when the three antenna elements 111a, 111b, and 111c are not distinguished, they are referred to as antenna elements 111. The antenna element 111 is adjusted to have an electrical length for transmitting and receiving radio waves in the RF band. Specifically, the RF band is, for example, 315 MHz or 920 MHz. A dielectric may be arranged at the end of the antenna element 111 for the purpose of reducing the height.

The first array antenna 110 has a known configuration, and the three antenna elements 111a and 111b are arranged at intervals that are determined based on the wavelengths of the radio waves transmitted and received. Specifically, the three antenna elements 111a, 111b, and 111c are arranged at equal angular intervals in a circle having a radius determined based on the wavelength of the transmitted and received radio waves.

The first communication unit 120 is a transmission / reception circuit that transmits / receives radio waves using the first array antenna 110. The first communication unit 120 includes a modulation unit, a demodulation unit, an amplification unit, an AD conversion unit, and the like.

The second array antenna 130 has the same configuration as the first array antenna 110, and includes three antenna elements 131a, 131b, and 131c. Hereinafter, when the three antenna elements 131a, 131b, and 131c are not distinguished, they are described as the antenna element 131. The electrical length and the arrangement of the three antenna elements 131a, 131b, and 131c are the same as those of the antenna element 111 included in the first array antenna 110.

The second communication unit 140 is a transmission / reception circuit that transmits / receives radio waves using the second array antenna 130, and has the same configuration as the first communication unit 120.

The first array antenna 110 and the second array antenna 130 can be installed at various positions. It is preferable that the first array antenna 110 and the second array antenna 130 are arranged at positions different from each other in the front-rear direction of the vehicle 3. The reason for this is as follows.

When the user carrying the electronic key 2 approaches the vehicle 3, the user approaches the vehicle 3 from the side of the vehicle 3. If the positions of the first array antenna 110 and the second array antenna 130 in the front-rear direction of the vehicle 3 are different, the two array antennas 110 and 130 are used when the electronic key 2 is located on the side of the vehicle 3. The difference in the direction of the electronic key 2 estimated by the above can be increased. As a result, the position accuracy of the electronic key 2 estimated from the two directions can be improved. Therefore, it is preferable that the first array antenna 110 and the second array antenna 130 are arranged at positions where the positions of the vehicle 3 in the front-rear direction are different from each other.

For example, the first array antenna 110 is arranged on the front side of the vehicle 3 with respect to the center in the front-rear direction of the vehicle 3, and the second array antenna 130 is arranged on the rear side of the vehicle 3 with respect to the center in the front-rear direction of the vehicle 3. .. The first array antenna 110 is arranged on the front side of the vehicle 3 as much as possible. For example, it is arranged on the upper surface of the bonnet of the vehicle 3. When it is difficult to arrange the first array antenna 110, the front end of the outer surface of the roof, the front end of the back side of the roof in the vehicle interior, or the like is an example of arrangement of the first array antenna 110.

On the other hand, the second array antenna 130 is arranged on the rear side of the vehicle 3 as much as possible. For example, it is arranged on the upper surface of the trunk of the vehicle 3. Alternatively, the rear end of the outer surface of the roof, the rear end of the back side of the roof in the vehicle interior, and the like are examples of arrangement of the second array antenna 130.

The unlock sensor 160 is a sensor that is installed at or near the door handle of the vehicle 3 and is touched by the user when unlocking the door of the vehicle 3. The lock sensor 170 is a sensor that is installed at or near the door handle of the vehicle 3 and is touched by the user when locking the door of the vehicle 3. The push start button 180 is a button operated by the user when the drive source of the vehicle 3 is set to the drive state or the drive permission state, and is arranged in the passenger compartment of the vehicle 3. The drive source of the vehicle 3 is, for example, one or both of the engine and the motor.

The collation ECU 150 is a computer provided with a CPU, ROM, RAM, etc., and the CPU executes a program stored in a non-transitional substantive recording medium such as a ROM while using the temporary storage function of the RAM. .. As a result, the collation ECU 150 executes various controls. The functions executed by the collation ECU 150 will be described later with reference to FIGS. 3 and 4. Note that the CPU executing the above program means that the method corresponding to the program is executed. Further, a part or all of the functions executed by the collation ECU 150 may be configured in hardware by one or a plurality of ICs or the like.

[Configuration of electronic key 2]
As shown in FIG. 2, the electronic key 2 includes a communication unit 21, a lock switch 22, an unlock switch 23, and a key control unit 24. In addition to this, a door open / close switch, a mechanical key, and the like may be provided.

The communication unit 21 has a configuration capable of communicating with the first communication unit 120 and the second communication unit 140 included in the vehicle-mounted collation system 100. Specifically, the communication unit 21 includes an antenna for transmitting and receiving the same frequency as the first array antenna 110 and the second array antenna 130, a modulation unit, a demodulation unit, an amplification unit, an AD conversion unit, and the like.

The lock switch 22 and the unlock switch 23 are arranged on the surface of the electronic key 2 and can be pressed by the user. The lock switch 22 is a switch pressed by the user when instructing to unlock the door lock of the vehicle 3. The unlock switch 23 is a switch pressed by the user when instructing to lock the door lock of the vehicle 3.

The key control unit 24 is a computer provided with a CPU, ROM, RAM, etc., and the CPU uses the temporary storage function of the RAM to store a program stored in a non-transitional substantive recording medium such as a ROM. Execute. As a result, the key control unit 24 performs various controls. When the CPU executes the above program, it means that the method corresponding to the program is executed. Further, a part or all of the functions executed by the key control unit 24 may be configured in hardware by one or a plurality of ICs or the like.

The key control unit 24 analyzes the received data, for example. Specifically, the communication unit 21 analyzes the demodulated signal and determines whether or not the signal is a request signal. Further, the key control unit 24 generates a transmission signal and outputs the generated signal to the communication unit 21. The transmitted signal to be generated is, for example, a response signal transmitted in response to the request signal. The response signal includes an ID code stored in advance. Further, when the lock switch 22 is pressed, a transmission signal instructing to lock the door lock of the vehicle 3 is generated, and when the unlock switch 23 is pressed, the door lock of the vehicle 3 is released. A transmission signal is generated instructing the lock.

[Functions executed by the collation ECU 150]
The collation ECU 150 executes processing according to two modes, a position estimation mode and a distance estimation mode. The position estimation mode is a mode in which it is determined that the distance from the vehicle 3 to the electronic key 2 is shorter than the position estimation upper limit distance. On the other hand, the distance estimation mode is a mode in which it is determined that the electronic key 2 does not exist within the circle of the radius of the position estimation upper limit distance from the vehicle 3.

In the position estimation method in the present embodiment, if the distance to the electronic key 2 is too long, the position estimation accuracy is lowered. Further, when the distance to the electronic key 2 is long, the distance to the electronic key 2 may be estimated, and the need to estimate the position is low. In consideration of these points, the position estimation upper limit distance is appropriately set. The position estimation upper limit distance is, for example, 20 m.

In the distance estimation mode, the collation ECU 150 executes the process shown in FIG. In FIG. 3, in step S11, it is determined whether or not the distance estimation timing has been reached. The steps will be omitted below.

The distance estimation timing is the time when the distance estimation cycle has elapsed since the request signal was transmitted last time. In the present embodiment, two types of cycles, a long-distance estimation cycle and a medium-distance estimation cycle, are set as the distance estimation cycle. The long-distance estimation cycle is longer than the medium-range estimation cycle.

The long-distance estimation cycle is a cycle used when the distance to the electronic key 2 can be estimated to be a long distance, and the medium-distance estimation cycle is a cycle used when the distance to the electronic key 2 can be estimated to be a medium distance. The cycle to use.

The lower limit of the medium range is the upper limit of position estimation. A distance range shorter than the position estimation upper limit distance is a short distance range. The upper limit of the medium distance range is a predetermined distance longer than the position estimation upper limit distance. The long range is farther than the upper limit of the medium range. If it is farther than the upper limit of the medium range, it shall be a long distance as long as the distance can be estimated.

If the determination in S11 is NO, S11 is repeated. If the determination in S11 is YES, the process proceeds to S12. In S12, the request signal is output to a predetermined side of the first communication unit 120 and the second communication unit 140. For example, the collation ECU 150 outputs a request signal to the first communication unit 120. The first communication unit 120 transmits this request signal as a radio wave from the first array antenna 110. As a result, the request signal is transmitted from the first array antenna 110 toward the entire periphery of the vehicle 3. S11 and S12 are processes as a transmission control unit.

In S13, after the request signal is transmitted, it is determined whether or not the response signal is received within a preset time. If it is determined that the response signal has not been received, the process of FIG. 3 is terminated. When the process of FIG. 3 is completed, S11 is executed again. Further, in this case, it can be estimated that the electronic key 2 does not exist in a range capable of communicating with the in-vehicle collation system 100.

If the determination in S13 is YES, the process proceeds to S14. In S14, the distance to the electronic key 2 is estimated from the preset relationship between the magnitude of RSSI (that is, the intensity of the received radio wave) and RSSI, and the magnitude of RSSI of the response signal. The distance that can be estimated by RSSI is often not as accurate as the distance that can be calculated from the position estimated in FIG. 4, which will be described later. However, the distance estimated in S14 is a distance for determining whether the electronic key 2 exists in the short-range range, the medium-range range, or the long-range range. Therefore, the distance estimated from RSSI can be used. S14 corresponds to the distance estimation unit of the claim.

In S15, it is determined whether or not the distance estimated in S14 is shorter than the position estimation upper limit distance. If this determination is YES, the process proceeds to S16. In S16, the mode shifts to the position estimation mode. When S16 is executed, the process shown in FIG. 4 is executed next.

On the other hand, if the judgment of S15 is NO, the process proceeds to S17. In S17, the distance estimation cycle used in the next S11 is set based on the distance estimated in S14. After that, it returns to S11.

Next, the process executed by the matching ECU 150 in the position estimation mode shown in FIG. 4 will be described. In S21, it is determined whether or not the position estimation timing has been reached. The position estimation timing is the time when the position estimation cycle has elapsed since the request signal was transmitted last time. The position estimation cycle is set to be shorter than the distance estimation cycle described above. When a plurality of types of distance estimation cycles can be set, the position estimation cycle is set to a period shorter than the shortest distance estimation cycle.

If the determination in S21 is NO, S21 is repeated. If the determination in S21 is YES, the process proceeds to S22. In S22, a request signal is transmitted. The processing of S22 is the same as that of S12. S21 and S22 are processes as a transmission control unit.

In S23, it is determined whether or not the response signal has been received. The processing of S23 is the same as that of S13. If the judgment in S23 is NO, the process proceeds to S24. In S24, the mode shifts to the distance estimation mode. When S24 is executed, the process shown in FIG. 3 is executed.

On the other hand, if the determination in S23 is YES, the process proceeds to S25. S25 corresponds to the direction estimation unit of the claim. In this S25, the arrival direction of the response signal is estimated for each of the array antennas 110 and 130. Various known methods can be used for estimating the arrival direction by the array antennas 110 and 130. For example, a method of estimating the arrival direction from the distance between the antenna elements 111 and 113 and the phase difference or arrival time difference of the radio waves received by the antenna elements 111 and 113, the MUSIC method, the ESPRIT method, and the like can be used. Further, when the array antennas 110 and 130 are used as adaptive array antennas, a beam former or the like can also be used.

In S26, the arrival direction line L is determined. The arrival direction line L is a straight line extending from the array antennas 110 and 130 in the arrival direction of the response signal estimated based on the radio waves received by the array antennas 110 and 130.

FIG. 5 shows the arrival direction line L1 corresponding to the first array antenna 110 and the arrival direction line L2 corresponding to the second array antenna 130. The base point of the arrival direction line L1 is the center of gravity of the first array antenna 110, and the base point of the arrival direction line L2 is the center of gravity of the second array antenna 130.

In S27, it is estimated that the intersection of the arrival direction lines L1 and L2 determined in S26 is the position where the electronic key 2 exists. S26 and S27 correspond to the position estimation unit of the claim.

In S28, it is determined whether or not the position of the electronic key 2 estimated in S27 is in the preset in-vehicle collation area Ai or the out-of-vehicle collation area Ao. S28 corresponds to the area determination unit of the claim.

FIG. 5 also shows the in-vehicle verification area Ai and the out-of-vehicle verification area Ao. The in-vehicle verification area Ai is set in the vehicle as an area that does not exit from the vehicle 3. This in-vehicle collation area Ai corresponds to the conventional in-vehicle collation area, and may be set in the same range as the in-vehicle collation area conventionally formed by using the LF antenna installed in the vehicle interior. .. The vehicle exterior verification area Ao may be set to an area in the same range as the vehicle exterior verification area conventionally formed by using the LF antenna installed in the door handle.

If the determination in S28 is NO, the position of the electronic key 2 is neither in the in-vehicle verification area Ai nor in the out-of-vehicle verification area Ao. If the determination in S28 is NO, the process of FIG. 4 ends. In this case, S21 and below are executed again.

If the determination in S28 is YES, the process proceeds to S29. In S29, the collation process is performed by communicating with the electronic key 2. This collation process is a known collation process after receiving the response signal.

In S30, it is determined whether or not the collation is OK as a result of the collation process in S29. If the collation is not established, the process of FIG. 4 is terminated. On the other hand, if the verification is OK, the process proceeds to S31.

In S31, the operation of the in-vehicle device determined according to the collation area is permitted. If the area where the electronic key 2 exists is an outside verification area, the in-vehicle device that is permitted to operate is a door lock mechanism. If the area where the electronic key 2 exists is the vehicle interior verification area, the in-vehicle device that is permitted to operate is the driving force source.

When the unlock sensor 160 or the lock sensor 170 is operated while the operation of the door lock mechanism is permitted, the collation ECU 150 transmits a signal instructing the door lock ECU 5 to operate the door lock mechanism.

When the push start button 180 is operated while the operation of the driving force source is permitted, the collating ECU 150 transmits a signal instructing the power supply ECU 6 to operate the driving force source.

[Summary of the first embodiment]
The vehicle-mounted collation system 100 of the first embodiment described above includes a first array antenna 110 and a second array antenna 130, and the array antennas 110 and 130 are used to determine the direction of arrival of radio waves transmitted by the electronic key 2. Estimate (S25). Then, the intersection of the arrival direction lines L1 and L2 is estimated to be the position where the electronic key 2 exists (S27), and it is determined whether or not this position is in the in-vehicle verification area Ai or the out-of-vehicle verification area Ao. (S28).

In this way, it is determined whether or not the electronic key 2 is in the in-vehicle verification area Ai or the out-of-vehicle verification area Ao. Therefore, in the electronic key system 1, the antenna for transmitting and receiving radio waves for the LF band, which has been conventionally required, is used. It becomes unnecessary. Therefore, the configuration of the electronic key system 1 can be simplified. Further, even if the vehicle 3 is a resin body, it is possible to determine whether or not the electronic key 2 is in the in-vehicle verification area Ai or the out-of-vehicle verification area Ao.

Further, in the present embodiment, the distance from the vehicle 3 to the electronic key 2 is estimated based on the magnitude of RSSI of the radio wave transmitted by the electronic key 2 and received by the vehicle-mounted collation system 100 (S14). Then, when it is determined that the estimated distance is shorter than the position estimation upper limit distance, the position shifts to the position estimation mode and the position of the electronic key 2 is estimated.

In the method of estimating the position of the electronic key 2 from the intersection of the arrival direction lines L1 and L2, the smaller the angle difference between the arrival direction lines L1 and L2, the larger the error. Further, the farther the electronic key 2 is, the smaller the angle difference between the arrival direction lines L1 and L2 is. Therefore, when the electronic key 2 is far away, the estimation accuracy of the position of the electronic key 2 estimated from the intersection of the arrival direction lines L1 and L2 is lowered. On the other hand, the distance estimated from RSSI is not so high in accuracy regardless of the distance, but the distance estimation accuracy does not decrease so much even if the electronic key 2 is far away.

Therefore, in the present embodiment, the distance from the vehicle 3 to the electronic key 2 is estimated based on the magnitude of RSSI, and when it is determined that the estimated distance is shorter than the position estimation upper limit distance, the position of the electronic key 2 is set. presume. As a result, it is possible to prevent the estimation of a position with low accuracy.

Further, when the position of the electronic key 2 is far, it is less necessary to estimate the distance of the electronic key 2 with high frequency. Therefore, in the present embodiment, in the distance estimation mode in which the process of estimating the distance of the electronic key 2 is performed, the cycle for transmitting the request signal is longer than in the position estimation mode. As a result, it is possible to prevent the position of the electronic key 2 from being estimated more frequently than necessary and unnecessary power consumption.

<Second Embodiment>
Next, the second embodiment will be described. In the following description of the second embodiment, the elements having the same number as the codes used so far are the same as the elements having the same code in the previous embodiments, unless otherwise specified. Further, when only a part of the configuration is described, the embodiment described above can be applied to the other parts of the configuration.

In the second embodiment, in S25, in addition to estimating the arrival direction of the response signal using the first array antenna 110 and the second array antenna 130, respectively, the arrival direction of the response signal is estimated by using the additional array antenna 190. To estimate.

The additional array antenna 190 is configured by combining an antenna element 111 included in the first array antenna 110 and an antenna element 131 included in an array antenna different from the first array antenna, that is, the second array antenna 130. FIG. 6 shows the additional array antenna 190.

The additional array antenna 190 shown in FIG. 6 includes two antenna elements 111b and 111c included in the first array antenna 110 and one antenna element 131c included in the second array antenna 130. The method of estimating the arrival direction using the additional array antenna 190 is the same as the method of estimating the arrival direction using the first array antenna 110 and the second array antenna 130.

In S26, in addition to the arrival direction lines L1 and L2, the arrival direction line L3 determined from the arrival direction estimated by using the additional array antenna 190 is also determined. FIG. 6 also shows this arrival direction line L3. The base point of the arrival direction line L3 is the position of the center of gravity of the additional array antenna 190.

In S27, the position of the electronic key 2 is estimated from the three arrival direction lines L1, L2, and L3. If there are three arrival direction lines L1, L2, L3, there is a possibility that two intersections will be formed. When two intersections are formed, the average position of the two intersections is estimated as the position of the electronic key 2.

In this second embodiment, the antenna elements 111 and 131 provided in the first array antenna 110 and the second array antenna 130 are combined to form an additional array antenna 190. Then, the arrival direction of the radio wave is estimated for this additional array antenna 190 as well, and the third arrival direction line L3 is determined. Since the position of the electronic key 2 is estimated using the arrival direction line L3 as well, the position accuracy of the electronic key 2 can be improved without additionally providing an array antenna.

Although the embodiments have been described above, the disclosed technology is not limited to the above-described embodiments, and the following modifications are also included in the disclosed scope, and further, within a range other than the following that does not deviate from the gist. It can be implemented with various changes.

<Modification example 1>
In the first embodiment and the second embodiment, two array antennas 110 and 130 are provided, but three or more array antennas may be provided. As a result, when a plurality of intersections of the arrival direction lines L are formed, the position of the electronic key 2 is estimated based on the center of gravity of the intersections.

<Modification 2>
In the first embodiment, two types of cycles, a long-distance estimation cycle and a medium-distance estimation cycle, are set as the distance estimation cycle, but the distance estimation cycle may be one type or three or more types.

<Modification example 3>
In the second embodiment, an example in which the additional array antenna 190 is configured by the antenna elements 111b, 111c, 131c is shown. However, other antenna elements may be used as elements of the additional array antenna 190. Further, the number of antenna elements included in the additional array antenna 190 may be different from that of the first array antenna 110 and the second array antenna 130.

<Modification example 4>
In addition to determining that the electronic key 2 is located in the in-vehicle collation area Ai or the out-of-vehicle collation area Ao, the collation process of S29 may be executed when the collation condition is further satisfied. As the collation condition, a collation condition outside the vehicle and a collation condition inside the vehicle can be provided.

The external verification conditions are, for example, the power off and the door locked state. The fact that the unlock sensor 160 is turned on and that the lock sensor 170 is turned on may be added to the external collation conditions.

The vehicle interior collation condition is, for example, a condition that a predetermined operation that is possible while the driver is in the vehicle interior is performed. This predetermined operation is, for example, a depressing operation of the brake pedal. The operation of the push start button 180 is also an example of a predetermined operation.

1: Electronic key system 2: Electronic key 3: Vehicle 5: Door lock ECU 6: Power supply ECU 21: Communication unit 22: Locking switch 23: Unlocking switch 24: Key control unit 100: In-vehicle collation system 110: First array antenna 111: Antenna element 113: Antenna element 120: First communication unit 130: Second array antenna 131: Antenna element 140: Second communication unit 150: Matching ECU 160: Unlock sensor 170: Lock sensor 180: Push start button 190: Additional array antenna Ai: In-vehicle verification area Ao: Out-of-vehicle verification area L: Arrival direction line S11, S12: Transmission control unit S14: Distance estimation unit S21, S22: Transmission control unit S25: Direction estimation unit S26, S27: Position estimation unit, S28: Area determination unit

Claims (4)

An electronic key position estimation device that determines whether or not the electronic key exists in a collation area set inside and outside the vehicle by communicating with the electronic key (2).
A plurality of array antenna mounted on the vehicle,
A direction estimation unit (S25) that estimates the arrival direction of radio waves for each of the array antennas based on the radio waves received by the plurality of array antennas from the electronic key.
An arrival direction line, which is a straight line extending from the array antenna in the arrival direction of the radio wave estimated by the direction estimation unit based on the radio wave received by the array antenna, is determined for each array antenna, and a plurality of the arrival direction lines of the plurality of arrival direction lines are determined. Position estimation units (S26, S27) that estimate the position of the electronic key based on the intersection, and
Based on the position of the electronic key estimated by the position estimation unit, it is determined whether or not the electronic key exists in the collation area set inside the vehicle and the collation area set outside the vehicle. It is equipped with an area determination unit (S28) to be used .
Each of the plurality of array antennas includes a plurality of antenna elements (111, 131).
The direction estimation unit uses one of the plurality of array antennas as the first array antenna (110), the antenna element (111) included in the first array antenna, and the first array antenna. For the additional array antenna (190) configured by combining with the antenna element provided in the array antenna other than the above, the arrival direction of the radio wave is estimated.
Wherein the position estimation unit, the additional array antennas to determine the direction of arrival line for the additional array the DOA line determined for the antenna be used position estimation to electronic key position estimation device of the electronic key. A distance estimation unit (S14) for estimating the distance from the vehicle to the electronic key based on the intensity of radio waves transmitted by the electronic key and received by the array antenna is provided.
The electronic key position estimation device according to claim 1, wherein the position estimation unit estimates the position of the electronic key based on the distance estimated by the distance estimation unit being shorter than a preset position estimation upper limit distance. A transmission control unit (S11, S12, S21, S22) that periodically transmits a request signal from the array antenna is provided in order to transmit a response signal to the electronic key.
When the distance to the electronic key estimated by the distance estimation unit is longer than the position estimation upper limit distance, the transmission control unit is when the distance from the vehicle to the electronic key is shorter than the position estimation upper limit distance. The electronic key position estimation device according to claim 2, wherein the transmission cycle of the request signal is lengthened. The electronic key position estimation device according to any one of claims 1 to 3 , wherein the plurality of the array antennas are arranged at different positions in the front-rear direction of the vehicle.

Images