Vehicle side unit and positional relationship identification system

Abstract

To make it possible and easier to receive electric power of a desired intensity even when a positional relation between a portable device and a vehicle is specified by using high-frequency radio waves.SOLUTION: A vehicle side unit 3 includes at least one vehicle side antenna part 31 that can be used by being provided in a vehicle, and transmits and receives high-frequency signals being signals carried by high-frequency radio waves. The vehicle antenna part 31 includes: a vertically polarized wave antenna 311 provided to be able to transmit and receive polarized waves perpendicular to an object surface being a metal surface of a predetermined part of the vehicle; and a first horizontally polarized wave antenna 313 and a second horizontally polarized wave antenna 314 provided so as to be able to transmit and receive polarized waves that are horizontal to the object surface and orthogonal to each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a vehicle-side unit and a positional relationship specifying system. [Background technology]

[0002] There is known a technology for identifying the positional relationship of a portable device with respect to a vehicle by using radio waves transmitted between the portable device carried by a user and a vehicle unit including an antenna provided on the vehicle side. For example, Patent Document 1 discloses a technology for determining the position of a portable device based on the RSSI of a request signal transmitted as LF band radio waves from antennas arranged at multiple locations on the vehicle. Patent Document 1 uses the fact that the RSSI correlates with the distance between the portable device and the antenna to determine the position of the portable device by the principle of triangulation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-124477 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a multi-function mobile phone or the like is used as the portable device, it is possible to use communication between the portable device and the vehicle unit according to a communication standard using high-frequency radio waves such as Bluetooth (registered trademark) Low Energy (hereinafter, BLE). Radio waves in the LF band have a low frequency of 125 kHz. Therefore, attenuation in radio wave propagation is small, and the problem of insufficient strength is unlikely to occur. On the other hand, when high-frequency radio waves are used, attenuation in radio wave propagation is large, and there is a risk of insufficient strength. In particular, when the antenna of the portable device is a single-axis antenna, the orientation of the antenna changes arbitrarily, so simply installing multiple antennas on the vehicle side may not be able to receive radio waves of sufficient strength to estimate the positional relationship of the portable device.

[0005] One object of this disclosure is to provide a vehicle-side unit and a positional relationship determination system that makes it easier to receive power of the desired strength, even when high-frequency radio waves are used to determine the positional relationship of a portable device to a vehicle. [Means for solving the problem]

[0006] The above object is achieved by the combination of features recited in the independent claims, and the subclaims define further advantageous embodiments of the disclosure. The reference characters in parentheses in the claims indicate a correspondence with specific means described in the following embodiment as one aspect, and do not limit the technical scope of the present disclosure.

[0007] In order to achieve the above object, the vehicle side unit of the present disclosure is a device that can be installed in a vehicle and used to transmit and receive high-frequency signals that are signals carried on high-frequency radio waves. Rua The vehicle-side unit includes an antenna section (31, 31b), and the antenna section includes at least a vertically polarized antenna (311) that is provided so as to be capable of transmitting and receiving polarized waves perpendicular to a target surface, which is a metal surface of a predetermined part of the vehicle, and one or two horizontally polarized antennas (312, 312b) that are provided so as to be capable of transmitting and receiving polarized waves that are horizontal to the target surface and perpendicular to each other. The portable device includes a positional relationship determination unit (331) that determines the positional relationship of the portable device that transmits the high-frequency signal with respect to the vehicle using the high-frequency signal received by the antenna unit, and a reception strength determination unit (334) that determines the antenna having the strongest reception strength of the same high-frequency signal among the antennas of the antenna unit, and the positional relationship determination unit determines the positional relationship of the portable device with respect to the vehicle using only the high-frequency signal received by the antenna that is determined by the reception strength determination unit to have the strongest reception strength among the antennas of the antenna unit. .

[0008] This makes it possible to increase the directions in which the antenna unit that transmits and receives a high-frequency signal, which is a signal carried on high-frequency radio waves, can easily receive polarized waves beyond the directions of three mutually orthogonal axes. When it becomes easier to receive at least polarized waves in the directions of three mutually orthogonal axes, it becomes easier to receive a high reception strength even if the direction of the polarized waves from the transmission source of the high-frequency signal changes. Therefore, it becomes easier to receive power of the desired strength even if the high-frequency signal is attenuated. As a result, it becomes easier to receive power of the desired strength even when high-frequency radio waves are used to identify the positional relationship of the portable device to the vehicle.

[0009] In order to achieve the above-mentioned object, the positional relationship determination system of the present disclosure includes the above-mentioned vehicle side unit (3, 3a, 3b) and a portable device (2) carried by a user for transmitting and receiving a high-frequency signal, which is a signal transmitted over high-frequency radio waves.

[0010] According to this, since the vehicle-side unit described above is included, it becomes possible to more easily receive power of the desired strength even when high-frequency radio waves are used to identify the positional relationship of the portable device with respect to the vehicle. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a vehicle system 1. FIG. [Diagram 2] 2 is a diagram showing an example of a schematic configuration of a portable device 2. FIG. [Diagram 3] 2 is a diagram showing an example of a schematic configuration of a vehicle-side unit 3. FIG. [Figure 4] 1 is a top view partially showing an area in which a horizontally polarized antenna 312 is provided. [Diagram 5] FIG. 5 is a cross-sectional view taken along line II-II in FIG. [Figure 6] 13 is a flowchart showing an example of the flow of positional relationship specification-related processing in a control unit 33. [Figure 7] FIG. 2 is a diagram showing an example of a schematic configuration of a vehicle-side unit 3a. [Figure 8] 2 is a diagram showing an example of a schematic configuration of a vehicle-side unit 3b. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A number of embodiments for disclosure will be described with reference to the drawings. For convenience of description, in a number of embodiments, parts having the same functions as parts shown in the drawings used in the previous description may be given the same reference numerals and their description may be omitted. For parts given the same reference numerals, the description in other embodiments may be referred to.

[0013] <Overall configuration of vehicle system 1> As shown in Fig. 1, the vehicle system 1 includes a portable device 2 carried by a user and a vehicle unit 3 used in a vehicle. Note that "carried by a user" does not necessarily mean a state in which the device is carried by the user, but also includes a state in which the device is not carried by the user, such as when the device is left behind. "Used in a vehicle" does not necessarily mean a state in which the device is mounted on a vehicle, but also includes a state before the device is mounted on a vehicle. This vehicle system 1 corresponds to a positional relationship identification system.

[0014] The portable device 2 and the vehicle-side unit 3 are capable of transmitting and receiving signals via wireless communication. When the portable device 2 and the vehicle-side unit 3 are within each other's communication range, the signal transmitted by one of them via wireless communication is received by the other. The transmission and reception of signals via wireless communication between the portable device 2 and the vehicle-side unit 3 is performed by superimposing the signal on high-frequency radio waves. The high-frequency radio waves referred to here may be, for example, radio waves of 1 GHz or higher. The high-frequency radio waves may be high-frequency radio waves used for wireless communication in accordance with a short-range wireless communication standard such as Bluetooth (registered trademark) Low Energy (hereinafter, BLE). In the following, a case where the portable device 2 and the vehicle-side unit 3 transmit and receive signals via wireless communication in accordance with the BLE short-range wireless communication standard (hereinafter, BLE communication) will be described as an example. In this case, the high-frequency radio waves are radio waves in the 2.4 GHz band.

[0015] <General configuration of portable device 2> Next, the portable device 2 will be described with reference to Fig. 2. The portable device 2 may be a so-called Fob or a multi-function mobile phone. In the following, a case where the portable device 2 is a multi-function mobile phone will be described as an example. As shown in Fig. 2, the portable device 2 includes a mobile antenna unit 21 and a BLE transceiver 22 for BLE communication.

[0016] The mobile antenna unit 21 receives signals transmitted from the vehicle unit 3 on high-frequency radio waves, and transmits signals on high-frequency radio waves. The mobile antenna unit 21 uses, for example, a single-axis antenna. The BLE transceiver 22 demodulates signals received by the mobile antenna unit 21, modulates the signals, and outputs them to the mobile antenna unit 21 to be radiated as high-frequency radio waves.

[0017] <Schematic configuration of vehicle side unit 3> Next, a schematic configuration of the vehicle-side unit 3 will be described with reference to Fig. 3. As shown in Fig. 3, the vehicle-side unit 3 includes a vehicle-side antenna unit 31, a BLE transceiver 32, and a control unit 33.

[0018] The vehicle-side antenna unit 31 receives a signal transmitted from the portable device 2 on a high-frequency radio wave, and transmits a signal on a high-frequency radio wave. This vehicle-side antenna unit 31 corresponds to an antenna unit. The vehicle-side antenna unit 31 can be provided in a vehicle and used. The vehicle-side antenna unit 31 is installed on a part of the surface of the vehicle. The vehicle-side antenna unit 31 may be provided inside the vehicle cabin or on the outer surface of the vehicle. For example, the vehicle-side antenna unit 31 may be configured to be installed on a pillar, a bumper, a door handle, a roof, a door mirror, a back door, or the like. The vehicle-side antenna unit 31 may be configured to be provided in one vehicle or in a plurality of vehicles. In this embodiment, an example will be described in which three vehicle-side antenna units 31 are provided in the vehicle so that the position of the portable device can be identified by the principle of triangulation.

[0019] As shown in FIG. 3, the vehicle-side antenna unit 31 has a vertically polarized antenna 311 and a horizontally polarized antenna 312. The horizontally polarized antenna 312 has a first horizontally polarized antenna 313 and a second horizontally polarized antenna 314. The vertically polarized antenna 311 and the horizontally polarized antenna 312 are preferably arranged on the same plane. This is to prevent each antenna of the vehicle-side antenna unit 31 from interfering with the directivity of the other. The vertically polarized antenna 311 and the horizontally polarized antenna 312 are arranged on a metal surface of a predetermined part of the vehicle (hereinafter, the target surface). That is, the vehicle-side antenna unit 31 is arranged on the target surface. The multiple vehicle-side antenna units 31 may be configured to be provided on different target surfaces. The predetermined part of the vehicle may be the pillar, bumper, door handle, roof, door mirror, back door, etc., as described above.

[0020] The vertically polarized antenna 311 and the horizontally polarized antenna 312 may be configured to be provided in contact with the target surface, but are preferably provided at a distance of λ / 4 from the target surface, because this makes it possible to increase the antenna gain by using the target surface as a reflector.

[0021] The vertically polarized antenna 311 is provided so as to be capable of transmitting and receiving polarized waves perpendicular to the target surface. It is preferable to use a zero-order resonant antenna as the vertically polarized antenna 311. This is because a low-profile antenna configuration is possible. The zero-order resonant antenna is an antenna having a flat plate structure that utilizes zero-order resonance, which is an application technology of metamaterials.

[0022] The zero-order resonant antenna may be an antenna including a ground plate, which is a plate-shaped conductive member, a patch section, which is a plate-shaped conductive member, disposed so as to face the ground plate at a predetermined interval, and a short-circuiting section, which is a conductive member that electrically connects the patch section and the ground plate. The ground plate may be connected to the external conductor of the power supply cable to function as a ground. The patch section may be provided with a feeding point at an arbitrary position. Furthermore, it is more preferable to further include an additional conductor, which is a plate-shaped conductive member disposed so as to face the patch section at a predetermined interval, on the side of the patch section where the ground plate is not disposed, and to perform parallel resonance using the inductance of the short-circuiting section, the capacitance formed by the ground plate and the patch section, and the capacitance formed by the patch section and the additional conductor. Note that an inverted-F antenna may be used as the vertically polarized antenna 311.

[0023] The horizontally polarized antenna 312 is provided so as to be capable of transmitting and receiving polarized waves that are horizontal to the target surface and perpendicular to each other. The first horizontally polarized antenna 313 is provided so as to be capable of transmitting and receiving polarized waves that are horizontal to the target surface. This first horizontally polarized antenna 313 corresponds to the first horizontally polarized antenna. The second horizontally polarized antenna 314 is provided so as to be capable of transmitting and receiving polarized waves that are horizontal to the target surface and perpendicular to the polarized waves that can be transmitted and received by the first horizontally polarized antenna 313. This second horizontally polarized antenna 314 corresponds to the second horizontally polarized antenna. The vertically polarized antenna 311, the first horizontally polarized antenna 313, and the second horizontally polarized antenna 314 have antenna axes that are perpendicular to each other. That is, the vehicle-side antenna unit 31 has a three-axis antenna that is perpendicular to each other. In this embodiment, the vehicle-side antenna unit 31 will be described by taking as an example a configuration in which the vehicle-side antenna unit 31 has this three-axis antenna, but the vehicle-side antenna unit 31 may have more antennas.

[0024] The horizontally polarized antenna 312 may be a pattern antenna formed by printing or etching on a circuit board, for example. It is also preferable that a ground layer is formed directly below the horizontally polarized antenna 312 in a lower layer, which is a layer located closer to the target surface than the layer on which the horizontally polarized antenna 312 is provided. Here, explanation will be made with reference to Figs. 4 and 5. Fig. 4 is a top view partially showing the area where the horizontally polarized antenna 312 is provided. Fig. 5 is a cross-sectional view taken along line II-II in Fig. 4. GNDa and GNDb in Fig. 5 are grounds. Sub in Fig. 5 is a substrate. U in Fig. 5 is the upper layer side, and L is the lower layer side that corresponds to the target surface side.

[0025] As shown in FIG. 5, a horizontally polarized antenna 312 is formed as a pattern antenna on the surface of the upper layer of the substrate Sub. GNDa and GNDb are located below the layer on which the horizontally polarized antenna 312 is formed. GNDa is a ground to which the vertically polarized antenna 311, which is omitted in FIG. 4 and FIG. 5, is grounded. GNDa is not provided directly below the horizontally polarized antenna 312. GNDb is located in a layer below GNDa. GNDb is provided directly below the horizontally polarized antenna 312. The presence of GNDb directly below the horizontally polarized antenna 312 makes it possible to direct the directivity toward the surface of the circuit board opposite to the side on which the horizontally polarized antenna 312 is provided. Therefore, the gain in a single surface direction is improved. In addition, it is preferable that the GNDb and the horizontally polarized antenna 312 are provided at a distance of λ / 4. This is because the GNDb can be used as a reflector to increase the gain of the horizontally polarized antenna 312. The target surface of the vehicle may be used as GNDb.

[0026] The BLE transceiver 32 demodulates the signal received by the vehicle-side antenna unit 31, or modulates the signal and outputs it to the vehicle-side antenna unit 31 to be radiated as high-frequency radio waves. The BLE transceiver 32 may also measure the reception strength of the signal received by the vehicle-side antenna unit 31, for example. The BLE transceiver 32 may determine that the signal has been received when the reception strength of the signal received by the vehicle-side antenna unit 31 is equal to or greater than a threshold. The threshold may be set arbitrarily, and may be a value that distinguishes between noise and signals.

[0027] The control unit 33 includes a processor, a memory, an I / O, and a bus connecting these, and executes various processes related to authentication in the vehicle by executing a control program stored in the memory. The memory referred to here is a non-transitory tangible storage medium that non-temporarily stores computer-readable programs and data. The non-transitory tangible storage medium is realized by a semiconductor memory, a magnetic disk, or the like. The control unit 33 controls the transmission of a signal from the vehicle-side antenna unit 31 in the BLE transceiver 32. The control unit 33 identifies the positional relationship of the portable device 2 with respect to the vehicle based on the signal received by the vehicle-side antenna unit 31.

[0028] The control unit 33 includes a position measurement unit 331, a storage unit 332, and a reception timing determination unit 333 as functional blocks for identifying the positional relationship of the portable device 2 with respect to the vehicle. Note that some or all of the functions executed by the control unit 33 may be configured as hardware using one or more ICs or the like. Also, some or all of the functional blocks included in the control unit 33 may be realized by a combination of software execution by a processor and hardware members.

[0029] The positioning unit 331 identifies the positional relationship of the portable device 2 with respect to the vehicle by using the high-frequency signal received by the vehicle-side antenna unit 31. This positioning unit 331 corresponds to a positional relationship identification unit. The positioning unit 331 identifies the distance between the portable device 2 and the vehicle-side antenna unit 31 provided on the vehicle (hereinafter, portable device distance) as the positional relationship of the portable device 2 with respect to the vehicle. The positioning unit 331 may identify the portable device distance based on the reception strength of the signal received by the vehicle-side antenna unit 31 measured by the BLE transceiver 32. In this case, the positioning unit 331 may identify the portable device distance from the reception strength and the distance attenuation characteristic of the reception strength. Alternatively, the positioning unit 331 may identify the portable device distance based on the propagation time from when a signal is transmitted from the vehicle-side antenna unit 31 to when a response to the signal is received by the BLE transceiver 32.

[0030] The position measuring unit 331 may also specify the position of the portable device 2 relative to the vehicle by the principle of triangulation based on the portable device distances specified for each of the multiple vehicle-side antenna units 31. Note that, in a configuration in which only one vehicle-side antenna unit 31 is provided for the vehicle instead of multiple ones, the position of the portable device 2 may not be specified. The position measuring unit 331 may also specify the position of the portable device 2 relative to the vehicle by the principle of triangulation based on the reception strength measured by the BLE transceiver 32 for each of the multiple vehicle-side antenna units 31 without specifying the portable device distance. The position measuring unit 331 may also specify a rough position of the portable device 2 relative to the vehicle based on the portable device distances specified for each of the two vehicle-side antenna units 31.

[0031] When determining the positional relationship of the portable device 2 with respect to the vehicle, the position measurement unit 331 determines which of the multiple antennas of the vehicle-side antenna unit 31 to use for the signal received, based on the determination result of the reception timing determination unit 333.

[0032] It is preferable that the storage unit 332 stores in advance delay characteristics of signals received by the antennas of the vehicle-side antenna unit 31. In this embodiment, the antennas of the vehicle-side antenna unit 31 are the vertically polarized antenna 311, the first horizontally polarized antenna 313, and the second horizontally polarized antenna 314. The delay characteristics referred to here refer to a difference in delay time that occurs between a signal received by an antenna and being received by the BLE transceiver 32, depending on the length of the antenna and the length from the antenna to the power supply unit. The storage unit 332 may store in advance delay characteristics obtained by simulation, experiment, or the like. The storage unit 332 may store in advance delay characteristics for each of the multiple vehicle-side antenna units 31. A non-volatile memory may be used as the storage unit 332.

[0033] The reception timing determination unit 333 determines which antenna has the earliest timing of receiving the same high frequency signal among the antennas of the vehicle-side antenna unit 31. In a configuration in which multiple vehicle-side antenna units 31 are provided on the vehicle, the reception timing determination unit 333 determines which antenna has the earliest timing of receiving the same high frequency signal for each of the multiple vehicle-side antenna units 31. For the vehicle-side antenna unit 31 instructed to transmit by the control unit 33, the reception timing determination unit 333 may determine that the antenna that outputs a signal received the earliest after the transmission instruction is given is the antenna that has the earliest timing of receiving the same high frequency signal.

[0034] It is preferable that the reception timing determination unit 333 corrects the delay of the signal received by each antenna using the delay characteristics of each antenna stored in the storage unit 332, and determines the antenna that has the earliest reception timing of the same high frequency signal. The delay can be corrected by subtracting the delay time corresponding to the delay characteristics of each antenna from the above-mentioned propagation time. This makes it possible to specify a more accurate propagation time and more accurately determine the antenna that has the earliest reception timing of the same high frequency signal. Note that when the propagation time is corrected, the corrected propagation time can be used as the propagation time for subsequent processing.

[0035] Since the in-vehicle environment is an environment where multiple multipaths exist, the high-frequency radio waves transmitted from the portable device 2 arrive as multiple radio waves with varying propagation times. The variations vary depending on the polarization. However, the radio waves that arrive earliest from the portable device 2 can be said to be the radio waves that arrive via the route with the shortest distance to the actual distance. Therefore, with the above configuration, it is possible to determine the antenna that receives the radio waves that can identify the portable device distance that is closest to the actual distance.

[0036] It is preferable that the position measurement unit 331 specifies the positional relationship of the portable device 2 with respect to the vehicle by using only the high frequency signal received by the antenna determined by the reception timing determination unit 333 to have the earliest reception timing, among the high frequency signals received by the antennas of the vehicle-side antenna unit 31. This makes it possible to use radio waves that can specify the portable device distance closer to the actual distance, and therefore makes it possible to specify the positional relationship of the portable device 2 with respect to the vehicle with higher accuracy.

[0037] <Positional Relationship Identification-Related Processing in the Control Unit 33> Here, the process related to the determination of the positional relationship of the portable device 2 with respect to the vehicle in the control unit 33 (hereinafter, the positional relationship determination related process) will be described with reference to the flowchart in Fig. 6. In the example of Fig. 6, the process up to the determination of the portable device distance for each vehicle-side antenna unit 31 will be described as the positional relationship determination related process. The flowchart in Fig. 6 may be configured to be started when the control unit 33 requests the BLE transceiver 32 to transmit a high-frequency signal from the vehicle-side antenna unit 31. In the case where a plurality of vehicle-side antenna units 31 are provided in the vehicle, for example, the BLE transceivers 32 corresponding to those vehicle-side antenna units 31 may be requested to transmit in order.

[0038] First, in step S1, the control unit 33 causes the BLE transceiver 32, which has requested transmission of a high-frequency signal, to wait for reception. When the BLE transceiver 32 waits for reception, high-frequency signals received by each antenna of the vehicle-side antenna unit 31 are output to the BLE transceiver 32, and signals with reception strength equal to or greater than a threshold are received as the target high-frequency signals.

[0039] In step S2, if a predetermined time has elapsed since the request for transmission of a high-frequency signal (YES in S2), the process proceeds to step S3. The "predetermined time" here refers to a time during which it is assumed that the portable device 2 will reply to the signal transmitted from the vehicle-side antenna unit 31. On the other hand, if the predetermined time has not elapsed since the request for transmission of a high-frequency signal (NO in S2), the process of S2 is repeated. As a result, for any antenna of the vehicle-side antenna unit 31 that can receive a high-frequency signal equal to or higher than the threshold within the predetermined time, the BLE transceiver 32 receives a signal from that antenna.

[0040] In step S3, the reception timing determination unit 333 determines, based on the signal received in S2, which antenna of the vehicle-side antenna unit 31 has the earliest reception timing of the same high-frequency signal. In step S4, the position positioning unit 331 determines the portable device distance using only the high-frequency signal received by the antenna determined in S3 to have the earliest reception timing among the high-frequency signals received by the antennas of the vehicle-side antenna unit 31. Then, the positional relationship determination related process ends.

[0041] <Summary of the First Embodiment> According to the configuration of the first embodiment, it is possible to increase the directions in which the vehicle-side antenna unit 31, which transmits and receives a high-frequency signal carried on a high-frequency radio wave, can easily receive polarized waves in three mutually orthogonal axial directions. When it becomes easier to receive polarized waves in three mutually orthogonal axial directions, it becomes easier to receive a high reception intensity even if the direction of the polarized waves from the portable device 2 changes. Therefore, even if the high-frequency signal is attenuated, it becomes easier to receive power of a desired intensity. As a result, it becomes easier to receive power of a desired intensity even when a high-frequency radio wave is used to specify the positional relationship of the portable device 2 with respect to the vehicle. As a result, it becomes possible to specify the positional relationship of the portable device 2 with respect to the vehicle with higher accuracy.

[0042] In the first embodiment, the control unit 33 includes the reception timing determination unit 333. However, the present invention is not limited to this. For example, the reception timing determination unit 333 may be included in the BLE transceiver 32.

[0043] In the first embodiment, the portable device distance may be determined by using high-frequency signals received by antennas other than the antenna having the earliest reception timing of the same high-frequency signal among the high-frequency signals received by the antennas of the vehicle-side antenna unit 31. For example, information such as the propagation time and reception strength of the high-frequency signals received by each antenna of the vehicle-side antenna unit 31 may be averaged and used. In this case, the weighting of the information of the antenna having the earliest reception timing of the same high-frequency signal may be increased.

[0044] (Embodiment 2) In the first embodiment, the configuration is shown in which the positional relationship of the portable device 2 with respect to the vehicle is identified using a high-frequency signal received by an antenna determined to have the earliest reception timing of the same high-frequency signal, but the present invention is not necessarily limited to this. For example, a configuration (hereinafter, referred to as the second embodiment) may be used in which the positional relationship of the portable device 2 with respect to the vehicle is identified using a high-frequency signal received by an antenna determined to have the strongest reception strength of the same high-frequency signal. The configuration of the second embodiment will be described below.

[0045] The vehicle system 1 of the second embodiment includes a portable device 2 carried by a user and a vehicle-side unit 3a used in a vehicle. The vehicle system 1 of the second embodiment is similar to the vehicle system of the first embodiment, except that the vehicle system 1 of the second embodiment includes the vehicle-side unit 3a instead of the vehicle-side unit 3.

[0046] <Schematic configuration of vehicle side unit 3a> Next, a schematic configuration of the vehicle-side unit 3a will be described with reference to Fig. 7. As shown in Fig. 7, the vehicle-side unit 3a includes a vehicle-side antenna unit 31, a BLE transceiver 32, and a control unit 33a. The vehicle-side unit 3a is similar to the vehicle-side unit 3 of the first embodiment, except that the vehicle-side unit 3a includes the control unit 33a instead of the control unit 33.

[0047] The control unit 33a includes, as functional blocks, a position measurement unit 331, a storage unit 332, and a reception strength determination unit 334 for determining the positional relationship of the portable device 2 with respect to the vehicle. The control unit 33a is similar to the control unit 33 of the first embodiment, except that the control unit 33a includes the reception strength determination unit 334 instead of the reception timing determination unit 333.

[0048] The reception strength determination unit 334 determines which antenna has the strongest reception strength of the same high frequency signal among the antennas of the vehicle-side antenna unit 31. In the case where a plurality of vehicle-side antenna units 31 are provided in the vehicle, the reception strength determination unit 334 determines which antenna has the strongest reception strength of the same high frequency signal for each of the plurality of vehicle-side antenna units 31. The reception strength determination unit 334 may determine that the antenna having the highest reception strength measured by the BLE transceiver 32 is the antenna having the highest reception strength of the same high frequency signal for each antenna of the vehicle-side antenna unit 31 instructed to transmit by the control unit 33a. The BLE transceiver 32 may measure the reception strength at each antenna of the vehicle-side antenna unit 31. In the second embodiment, this process may be performed instead of the process of S3 of the positional relationship specification related process described in FIG. 6.

[0049] A radio wave with a strong reception strength is said to be a radio wave with high reliability. Therefore, with the above configuration, it is possible to determine the antenna that received the radio wave that can identify the portable device distance that is closer to the actual distance.

[0050] It is preferable that the position measurement unit 331 specifies the positional relationship of the portable device 2 with respect to the vehicle by using only the high-frequency signal received by the antenna determined by the reception strength determination unit 334 to have the strongest reception strength among the high-frequency radio waves received by the antennas of the vehicle-side antenna unit 31. In the second embodiment, this process may be performed instead of the process of S4 among the positional relationship specification-related processes described in Fig. 6. This makes it possible to use radio waves that can specify the portable device distance closer to the actual distance, and therefore makes it possible to specify the positional relationship of the portable device 2 with respect to the vehicle with higher accuracy.

[0051] In the second embodiment, the control unit 33a includes the reception strength determination unit 334. However, the present invention is not limited to this. For example, the reception strength determination unit 334 may be included in the BLE transceiver 32.

[0052] In the second embodiment, the portable device distance may be determined by using high-frequency signals received by antennas other than the antenna with the strongest reception strength of the same high-frequency signal among the high-frequency signals received by the antennas of the vehicle-side antenna unit 31. For example, information such as the propagation time and reception strength of the high-frequency signals received by each antenna of the vehicle-side antenna unit 31 may be averaged and used. In this case, the information of the antenna with the strongest reception strength of the same high-frequency signal may be weighted more heavily.

[0053] (Embodiment 3) In the above-described third embodiment, the horizontally polarized antenna 312 has the first horizontally polarized antenna 313 and the second horizontally polarized antenna 314, but the present invention is not necessarily limited to this. For example, a circularly polarized antenna may be used instead of the first horizontally polarized antenna 313 and the second horizontally polarized antenna 314 (hereinafter, the third embodiment). The configuration of the third embodiment will be described below.

[0054] The vehicle system 1 of the third embodiment includes a portable device 2 carried by a user and a vehicle-side unit 3b used in a vehicle. The vehicle system 1 of the third embodiment is similar to the vehicle system of the first embodiment, except that the vehicle system 1 of the third embodiment includes the vehicle-side unit 3b instead of the vehicle-side unit 3.

[0055] <Schematic configuration of vehicle side unit 3b> Next, a schematic configuration of the vehicle-side unit 3a will be described with reference to Fig. 8. As shown in Fig. 7, the vehicle-side unit 3a includes a vehicle-side antenna section 31b, a BLE transceiver 32, and a control section 33. The vehicle-side unit 3b is similar to the vehicle-side unit 3 of the first embodiment, except that the vehicle-side unit 3b includes a vehicle-side antenna section 31b instead of the vehicle-side antenna section 31.

[0056] The vehicle-side antenna unit 31b has a vertically polarized antenna 311 and a horizontally polarized antenna 312b. The vehicle-side antenna unit 31b is similar to the vehicle-side antenna unit 31 of the first embodiment, except that it has the horizontally polarized antenna 312b instead of the horizontally polarized antenna 312. The horizontally polarized antenna 312b has a circularly polarized antenna 315. The circularly polarized antenna 315 is a single antenna that is horizontal to the target surface and can transmit and receive polarized waves that are orthogonal to each other.

[0057] According to the configuration of the third embodiment, instead of using two antennas, it is possible to transmit and receive both polarized waves that are horizontal to the target surface and orthogonal to each other with one circularly polarized antenna 315. Therefore, it is possible to reduce the configuration required for transmitting and receiving antennas such as RF switches by the amount of antennas that use this configuration.

[0058] The present disclosure is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims. The embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present disclosure. The control unit and the method described in the present disclosure may be realized by a dedicated computer constituting a processor programmed to execute one or more functions embodied by a computer program. Alternatively, the device and the method described in the present disclosure may be realized by a dedicated hardware logic circuit. Alternatively, the device and the method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor that executes a computer program and one or more hardware logic circuits. The computer program may be stored in a computer-readable non-transient tangible recording medium as instructions executed by the computer. [Explanation of symbols]

[0059] 1 Vehicle system (positional relationship determination system), 2 Portable device, 3, 3a, 3b Vehicle side unit, 31, 31b Vehicle side antenna unit (antenna unit), 33, 33a Control unit, 311 Vertically polarized antenna, 312, 312b Horizontally polarized antenna, 313 First horizontally polarized antenna (first horizontally polarized antenna), 314 Second horizontally polarized antenna (second horizontally polarized antenna), 315 Circularly polarized antenna, 331 Position measurement unit (positional relationship determination unit), 332 Memory unit, 333 Reception timing determination unit, 334 Reception strength determination unit

Claims

1. A vehicle-side unit including an antenna section (31, 31b) for transmitting and receiving a high-frequency signal carried on a high-frequency radio wave, the vehicle-side unit being capable of being installed in a vehicle and used in the vehicle, The antenna unit includes: A vertically polarized antenna (311) that is provided so as to be capable of transmitting and receiving polarized waves perpendicular to a target surface that is a metal surface of a predetermined part of the vehicle; At least one or two horizontally polarized antennas (312, 312b) that are arranged to be capable of transmitting and receiving polarized waves that are horizontal to the target surface and perpendicular to each other, a positional relationship determination unit (331) that determines a positional relationship of a portable device that transmits the high-frequency signal with respect to the vehicle, using the high-frequency signal received by the antenna unit; a reception strength determination unit (334) for determining an antenna having the strongest reception strength of the same high frequency signal among the antennas included in the antenna unit, The positional relationship determination unit is a vehicle-side unit that determines the positional relationship of the portable unit with respect to the vehicle using only the high-frequency signal received by the antenna that the reception strength determination unit determines to have the strongest reception strength among the antennas of the antenna unit.

2. In claim 1, A plurality of the antenna units are provided, The plurality of antenna units are vehicle-side units provided on the same vehicle for each of the different target surfaces.

3. In claim 1 or 2, The antenna section is a vehicle-side unit having, as the horizontally polarized antenna, a first horizontally polarized antenna (313) that is configured to be capable of transmitting and receiving polarized waves horizontal to the target surface, and a second horizontally polarized antenna (314) that is configured to be capable of transmitting and receiving polarized waves that are horizontal to the target surface and perpendicular to the polarization.

4. In claim 1 or 2, The antenna section is a vehicle-side unit having, as the horizontally polarized antenna, one circularly polarized antenna (315) capable of transmitting and receiving both polarized waves that are horizontal to the target surface and perpendicular to each other.

5. In any one of claims 1 to 4, The vertically polarized antenna is a vehicle-side unit that is a zero-order resonance antenna.

6. In any one of claims 1 to 5, The antenna section is provided on the target surface, and is a vehicle side unit in which a ground layer is formed directly below the horizontally polarized antenna in a lower layer, which is a layer located on the target surface side of the layer on which the horizontally polarized antenna is provided.

7. In any one of claims 1 to 6, The antenna portion is a vehicle-side unit provided at a distance of λ / 4 from the target surface.

8. A vehicle side unit (3, 3a, 3b) according to any one of claims 1 to 7, A positional relationship specifying system including a portable device (2) carried by a user for transmitting and receiving a high-frequency signal, which is a signal carried on high-frequency radio waves.

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