Vehicle-side unit and position relationship determination system
By setting vertical and horizontal polarization wave antennas in the vehicle side unit and using the vehicle's metal surface as a reflector, the problem of high-frequency radio wave signal attenuation is solved, and higher accuracy in determining the location of the portable device is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DENSO CORP
- Filing Date
- 2021-11-12
- Publication Date
- 2026-06-09
AI Technical Summary
When using high-frequency radio waves to determine the positional relationship of a portable device relative to a vehicle, existing technologies struggle to receive sufficient signal strength, especially when the orientation of the portable device's antenna is uncertain, and multiple vehicle antenna setups cannot effectively receive radio waves.
The antenna design employs a vehicle-side unit, including a vertically polarized wave antenna and at least two horizontally polarized wave antennas, which are set to be orthogonal to each other, increasing the direction of receiving polarized waves to three axes, and using the vehicle's metal surface as a reflector to improve signal strength.
Even with high-frequency signal attenuation, the required power intensity can be received more easily, improving the accuracy of determining the positional relationship of the portable device relative to the vehicle.
Smart Images
Figure CN116648549B_ABST
Abstract
Description
[0001] Cross-references to related applications
[0002] This application claims priority to Japanese Patent Application No. 2020-211523, filed on December 21, 2020, the entire contents of which are incorporated herein by reference. Technical Field
[0003] This disclosure relates to a vehicle-side unit and a positional relationship determination system. Background Technology
[0004] It is known to utilize techniques for determining the positional relationship of a portable device relative to a vehicle by transmitting and receiving radio waves between a user-carried portable device and a vehicle-side unit containing an antenna located on the vehicle side. For example, Patent Document 1 discloses a technique for determining the position of a portable device based on RSSI (Request Signal Indicator Signal) of a request signal transmitted from antennas located at multiple locations on the vehicle in the LF band. In Patent Document 1, the position of the portable device is determined by using the principle of triangulation, which correlates RSSI with the distance between the portable device and the antenna.
[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-124477
[0006] When using multi-functional mobile phones or similar portable devices, communication between the portable device and the vehicle-side unit is considered to utilize communication standards using high-frequency radio waves, such as Bluetooth Low Energy (BLE). The LF band radio waves are 125kHz, a relatively low frequency. Therefore, the attenuation during wave propagation is minimal, reducing the likelihood of insufficient signal strength. On the other hand, when using high-frequency radio waves, the attenuation during propagation is greater, raising concerns about insufficient signal strength. In particular, if the portable device's antenna is a single-axis antenna, the antenna's orientation can change arbitrarily, raising concerns that simply setting multiple antennas on the vehicle side may not be sufficient to receive radio waves with sufficient strength to estimate the portable device's positional relationship. Summary of the Invention
[0007] One objective of this disclosure is to provide a vehicle-side unit and a position determination system that can more easily receive power of the desired intensity, even when high-frequency radio waves are used to determine the positional relationship of a portable device relative to a vehicle.
[0008] The aforementioned objectives are achieved through a combination of features described in the independent technical solutions. Furthermore, dependent technical solutions specify more advantageous specific examples. The reference numerals enclosed in parentheses in the claims indicate a correspondence with specific units described in the embodiments described later as an example, and do not limit the technical scope of this disclosure.
[0009] To achieve the above objectives, the vehicle-side unit disclosed herein is a vehicle-side unit that can be installed in a vehicle and is equipped with at least one antenna section for transmitting and receiving signals carried on high-frequency radio waves, i.e., high-frequency signals. The antenna section has at least: a vertically polarized wave antenna configured to transmit and receive polarized waves that are perpendicular to an object surface, the object surface being a metal surface that is a defined part of the vehicle; and one or two horizontally polarized wave antennas configured to transmit and receive mutually orthogonal polarized waves that are horizontal to the object surface.
[0010] Accordingly, the direction in which the antenna section transmitting and receiving signals carried on high-frequency radio waves (i.e., high-frequency signals) easily receives polarized waves can be increased to at least three mutually orthogonal axes. If polarized waves in at least three mutually orthogonal axes are easily received, then even if the direction of the polarized wave from the high-frequency signal source changes, a higher reception strength is easily received. Therefore, even with high-frequency signal attenuation, it is easier to receive the desired power intensity. As a result, even when high-frequency radio waves are used to determine the positional relationship of the portable device relative to the vehicle, it is easier to receive the desired power intensity.
[0011] In addition, in order to achieve the above objectives, the position relationship determination system disclosed herein includes the vehicle-side unit described above, and a portable device carried by a user that transmits and receives signals carried on high-frequency radio waves, i.e., high-frequency signals.
[0012] Therefore, since the vehicle-side unit mentioned above is included, even when high-frequency radio waves are used to determine the positional relationship of the portable device relative to the vehicle, it is easier to receive the desired power intensity. Attached Figure Description
[0013] Figure 1 This is a diagram illustrating an example of the general configuration of system 1 for a vehicle.
[0014] Figure 2 This is a diagram illustrating an example of the general structure of the portable device 2.
[0015] Figure 3 This is a diagram showing an example of the general configuration of the vehicle side unit 3.
[0016] Figure 4 This is a top view that partially shows the area where the horizontally polarized wave antenna 312 is installed.
[0017] Figure 5 It is along Figure 4 A sectional view along line II-II.
[0018] Figure 6 This is a flowchart illustrating an example of the process for determining the positional relationship in the control unit 33.
[0019] Figure 7 This is a diagram showing an example of the general configuration of the vehicle side unit 3a.
[0020] Figure 8 This is a diagram showing an example of the schematic configuration of the vehicle side unit 3b. Detailed Implementation
[0021] The various embodiments disclosed will be described with reference to the accompanying drawings. Furthermore, for ease of explanation, sometimes the same reference numerals are used between various embodiments for parts having the same function as those shown in the figures used in the description so far, and their descriptions are omitted. Parts with the same reference numerals can be referred to in the description of other embodiments.
[0022] <Brief Structure of System 1 for Vehicles>
[0023] like Figure 1 As shown, the vehicle system 1 includes a user-carried portable device 2 and a vehicle-side unit 3 used in the vehicle. Furthermore, "user-carried" is not limited to a state where the user carries it, but also includes a state where it is not carried by the user, such as being left behind. "Used in the vehicle" is not limited to a state where it is mounted on the vehicle, but also includes a state where it was mounted before being mounted on the vehicle. This vehicle system 1 is equivalent to a positional relationship determination system.
[0024] The portable device 2 and the vehicle-side unit 3 can each transmit and receive signals wirelessly. Furthermore, when the portable device 2 and the vehicle-side unit 3 are within each other's communication range, one party receives signals transmitted by the other via wireless communication. The transmission and reception of signals between the portable device 2 and the vehicle-side unit 3 based on wireless communication is achieved by carrying the signals onto high-frequency radio waves. The high-frequency radio waves referred to here are, for example, any radio waves above 1 GHz. Additionally, the high-frequency radio waves are those used in wireless communication according to short-range wireless communication standards such as Bluetooth Low Energy (hereinafter referred to as BLE). The following description illustrates the case where the portable device 2 and the vehicle-side unit 3 transmit and receive signals via wireless communication according to the BLE short-range wireless communication standard (hereinafter referred to as BLE communication). In this case, the high-frequency radio wave is a radio wave in the 2.4 GHz band.
[0025] <Brief Components of the Portable 2>
[0026] Next, use Figure 2 The portable phone 2 will be explained below. The portable phone 2 can be either a so-called Fob (Fob) or a multi-function mobile phone. The following example illustrates the case where the portable phone 2 is a multi-function mobile phone. For example... Figure 2As shown, the portable device 2, regarding BLE communication, includes a portable side antenna section 21 and a BLE transceiver 22.
[0027] The portable antenna section 21 receives signals transmitted via high-frequency radio waves from the vehicle-side unit 3, or transmits signals via high-frequency radio waves. The portable antenna section 21 may use a single-axis antenna, for example. The BLE transceiver 22 demodulates the signals received by the portable antenna section 21, or modulates the signals and outputs them to the portable antenna section 21 for high-frequency radio wave radiation.
[0028] <Brief Structure of Vehicle Side Unit 3>
[0029] Next, use Figure 3 The general structure of vehicle-side unit 3 will be described. For example... Figure 3 As shown, the vehicle-side unit 3 includes a vehicle-side antenna section 31, a BLE transceiver 32, and a control section 33.
[0030] The vehicle-side antenna section 31 receives signals transmitted from the portable device 2 via high-frequency radio waves, or transmits signals via high-frequency radio waves. This vehicle-side antenna section 31 is equivalent to an antenna section. The vehicle-side antenna section 31 can be installed in a vehicle for use. The vehicle-side antenna section 31 is installed on a portion of the surface of the vehicle. The vehicle-side antenna section 31 can be installed inside the vehicle compartment or outside the vehicle. For example, the vehicle-side antenna section 31 can be configured to be installed on a pillar, bumper, door handle, roof, rearview mirror, rear door, etc. The vehicle-side antenna section 31 can be configured as one or multiple. In this embodiment, in order to determine the position of the portable device using the principle of triangulation, a configuration of three vehicle-side antenna sections 31 will be described as an example.
[0031] like Figure 3 As shown, the vehicle-side antenna unit 31 includes a vertically polarized wave antenna 311 and a horizontally polarized wave antenna 312. The horizontally polarized wave antenna 312 includes a first horizontally polarized wave antenna 313 and a second horizontally polarized wave antenna 314. Preferably, the vertically polarized wave antenna 311 and the horizontally polarized wave antenna 312 are arranged on the same plane. This is to prevent the antennas in the vehicle-side antenna unit 31 from obstructing each other's directivity. The vertically polarized wave antenna 311 and the horizontally polarized wave antenna 312 are arranged on a metal surface (hereinafter referred to as the target surface) of a defined portion of the vehicle. In other words, the vehicle-side antenna unit 31 is arranged on the target surface. Multiple vehicle-side antenna units 31 can be configured to be respectively disposed on different target surfaces. The defined portion of the vehicle can be the aforementioned pillar, bumper, door handle, roof, rearview mirror, rear door, etc.
[0032] While the vertically polarized wave antenna 311 and the horizontally polarized wave antenna 312 can also be configured to be in contact with the object surface, it is preferable to configure them to be separated from the object surface by λ / 4. This is so as to utilize the object surface as a reflector to improve the antenna gain.
[0033] The vertically polarized wave antenna 311 is configured to transmit and receive polarized waves perpendicular to the target plane. A zero-order resonant antenna is preferably used as the vertically polarized wave antenna 311. This is to allow for a low-background antenna configuration. A zero-order resonant antenna refers to an antenna with a planar structure that utilizes zero-order resonance as a metamaterial application technology.
[0034] As a zero-order resonant antenna, an antenna can be used that has a base plate as a plate-shaped conductor member, a plate-shaped conductor member, i.e., a patch portion, positioned opposite the base plate at a predetermined interval, and a conductor member, i.e., a short-circuit portion, electrically connecting the patch portion to the base plate. The base plate only needs to be connected to the external conductor of the power supply cable to function as a ground wire. A power supply point can be provided at any position in the patch portion. Furthermore, it is more preferable to have a plate-shaped conductor member, i.e., an additional conductor, positioned opposite the patch portion at a predetermined interval on the side of the patch portion where the base plate is not located, and to use the inductance of the short-circuit portion, the electrostatic capacitance formed by the base plate and the patch portion, and the electrostatic capacitance formed by the patch portion and the additional conductor to achieve parallel resonance. In addition, an inverted F-shaped antenna can also be used as a vertical polarization wave antenna 311.
[0035] The horizontally polarized wave antenna 312 is configured to transmit and receive mutually orthogonal polarized waves that are horizontal relative to the target surface. The first horizontally polarized wave antenna 313 is configured to transmit and receive polarized waves that are horizontal relative to the target surface. This first horizontally polarized wave antenna 313 is equivalent to a first horizontally polarized wave antenna. The second horizontally polarized wave antenna 314 is configured to transmit and receive polarized waves that are horizontal relative to the target surface and orthogonal to the polarized waves transmitted and received by the first horizontally polarized wave antenna 313. This second horizontally polarized wave antenna 314 is equivalent to a second horizontally polarized wave antenna. The antenna axes of the vertically polarized wave antenna 311, the first horizontally polarized wave antenna 313, and the second horizontally polarized wave antenna 314 are mutually orthogonal. In other words, the vehicle-side antenna section 31 has three mutually orthogonal antenna axes. Although this embodiment exemplifies the configuration of the vehicle-side antenna section 31 with these three-axis antennas, the vehicle-side antenna section 31 may also have more antennas.
[0036] The horizontally polarized wave antenna 312 can be, for example, a patterned antenna formed on a circuit board by printing or etching. Furthermore, it is preferable to form a ground line directly below the horizontally polarized wave antenna 312 in a layer located on the object plane side compared to the layer where the horizontally polarized wave antenna 312 is disposed. Here, using... Figure 4as well as Figure 5 Please provide an explanation. Figure 4 This is a top view that partially shows the area where the horizontally polarized wave antenna 312 is installed. Figure 5 It is along Figure 4 A sectional view along line II-II. Figure 5 GND and GNDb are ground wires, respectively. Figure 5 Sub is the substrate. Figure 5 U is the upper layer side, and L is the lower layer side, which is equivalent to the object face side.
[0037] like Figure 5 As shown, a horizontally polarized wave antenna 312, serving as a patterned antenna, is formed on the surface of the upper layer of the substrate Sub. GNDa and GNDb are located in a layer lower than the layer in which the horizontally polarized wave antenna 312 is formed. GNDa is... Figure 4 , Figure 5 The ground wire of the vertically polarized wave antenna 311 is omitted. GNDa is not positioned directly below the horizontally polarized wave antenna 312. GNDb is located on a lower layer than GNDa. GNDb is positioned directly below the horizontally polarized wave antenna 312. Because GNDb is located directly below the horizontally polarized wave antenna 312, the directivity is not directed towards the side of the circuit board opposite to the side where the horizontally polarized wave antenna 312 is positioned. This improves the gain in a single-plane direction. Furthermore, it is preferable that GNDb and the horizontally polarized wave antenna 312 are separated by λ / 4. This is so that GNDb can be used as a reflector to improve the gain of the horizontally polarized wave antenna 312. Alternatively, the surface of the vehicle can be used as GNDb.
[0038] The BLE transceiver 32 demodulates the signal received by the vehicle-side antenna section 31, or modulates the signal and outputs it to the vehicle-side antenna section 31, causing it to be radiated as a high-frequency radio wave. The BLE transceiver 32 can also, for example, measure the received signal strength through the vehicle-side antenna section 31. The BLE transceiver 32 can receive signals when the received signal strength through the vehicle-side antenna section 31 is above a threshold. The threshold can be arbitrarily set, and a value can be set to distinguish between noise and signal.
[0039] The control unit 33 includes a processor, memory, I / O, and a bus connecting them. It executes various authentication-related processes within the vehicle by executing control programs stored in the memory. The memory referred to here is a non-transitory tangible storage medium that can be read by a computer and stores programs and data. Alternatively, non-transitory tangible storage media can be implemented using semiconductor memory or a hard disk. The control unit 33 controls the transmission of signals from the vehicle-side antenna unit 31 in the BLE transceiver 32. Based on the signals received through the vehicle-side antenna unit 31, the control unit 33 determines the positional relationship of the portable device 2 relative to the vehicle.
[0040] The control unit 33, which determines the positional relationship of the portable device 2 relative to the vehicle, includes a position measuring unit 331, a storage unit 332, and a receiving timing determination unit 333 as functional modules. Alternatively, some or all of the functions performed by the control unit 33 can be implemented in hardware using one or more ICs. Furthermore, some or all of the functional modules of the control unit 33 can be implemented through a combination of software execution by a processor and hardware components.
[0041] The position measurement unit 331 uses the high-frequency signal received by the vehicle-side antenna unit 31 to determine the positional relationship of the portable device 2 relative to the vehicle. This position measurement unit 331 is equivalent to a positional relationship determination unit. The position measurement unit 331 determines the distance (hereinafter referred to as the portable device distance) between the vehicle-side antenna unit 31 and the portable device 2 as the positional relationship of the portable device 2 relative to the vehicle. The position measurement unit 331 determines the portable device distance based on the received signal strength measured by the BLE transceiver 32 and received by the vehicle-side antenna unit 31. In this case, the position measurement unit 331 can determine the portable device distance based on the received signal strength and the distance attenuation characteristics of the received signal strength. Alternatively, the position measurement unit 331 may also determine the portable device distance based on, for example, the propagation time from the start of signal transmission by the vehicle-side antenna unit 31 to the receipt of the response to the signal by the BLE transceiver 32.
[0042] Alternatively, the position measuring unit 331 can determine the position of the portable device 2 relative to the vehicle based on the distances to the portable device determined for each of the multiple vehicle-side antenna units 31, using the principle of triangulation. Furthermore, if only one portable device is provided instead of multiple vehicle-side antenna units 31, the position of the portable device 2 can be configured to be uncertain. Alternatively, the position measuring unit 331 can also determine the position of the portable device 2 relative to the vehicle based on the received strength measured by the BLE transceiver 32 for each of the multiple vehicle-side antenna units 31, using the principle of triangulation, without knowing the distance to the portable device. The position measuring unit 331 can also determine the approximate position of the portable device 2 relative to the vehicle based on the distances to the portable device determined for each of the two vehicle-side antenna units 31.
[0043] When determining the positional relationship between the portable device 2 and the vehicle, the position measuring unit 331 determines which of the multiple antennas of the vehicle-side antenna unit 31 to use to receive the signal based on the determination result in the receiving timing determination unit 333.
[0044] Preferably, the storage unit 332 pre-stores the delay characteristics of the received signals of each antenna of the vehicle-side antenna unit 31. In this embodiment, the vehicle-side antenna unit 31 includes a vertically polarized wave antenna 311, a first horizontally polarized wave antenna 313, and a second horizontally polarized wave antenna 314. The delay characteristic referred to here is the difference in delay time from the length of the antenna (the length from the antenna to the power supply unit) until the signal received by the antenna is received by the BLE transceiver 32. The storage unit 332 can pre-store the values of the delay characteristics obtained through simulation, experimentation, etc. The storage unit 332 can pre-store the delay characteristics of each antenna of the plurality of vehicle-side antenna units 31. As the storage unit 332, a non-volatile memory can be used.
[0045] The timing determination unit 333 determines the antenna with the earliest reception timing for the same high-frequency signal among the antennas provided by the vehicle-side antenna unit 31. In the case where the vehicle is configured with multiple vehicle-side antenna units 31, the timing determination unit 333 determines the antenna with the earliest reception timing for the same high-frequency signal for each of these multiple vehicle-side antenna units 31. For the vehicle-side antenna unit 31 that has been instructed to transmit by the control unit 33, the timing determination unit 333 determines the antenna with the earliest output of the signal instructed to be transmitted for reception as the antenna with the earliest reception timing for the same high-frequency signal.
[0046] The preferred timing determination unit 333 uses the delay characteristics of each antenna stored in the storage unit 332 to correct the delay of the signal received by each antenna and determine the antenna with the earliest reception timing for the same high-frequency signal. The delay correction is achieved by subtracting the delay time corresponding to the delay characteristics of each antenna from the propagation time. This allows for a more accurate determination of the propagation time and more precise identification of the antenna with the earliest reception timing for the same high-frequency signal. Furthermore, after correcting the propagation time, the corrected propagation time can be used as the propagation time for subsequent processing.
[0047] The in-vehicle environment is a multi-path environment, so the high-frequency radio waves transmitted from the portable device 2 arrive as multiple radio waves with varying propagation times. These variations differ depending on the polarization of the wave. However, the earliest radio wave arriving from the portable device 2 can be considered to have arrived via the path that most closely approximates the actual distance. Therefore, based on the above configuration, it is possible to determine the antenna that receives the radio wave that best indicates the portable device's distance to the correct path.
[0048] The preferred position measuring unit 331 uses only the high-frequency signal received by the antenna on the vehicle side antenna unit 31, which is determined by the receiving timing determination unit 333 to be the earliest received antenna, to determine the positional relationship of the portable device 2 relative to the vehicle. Therefore, radio waves that can determine a portable device distance closer to the actual distance can be used, thus enabling a more accurate determination of the positional relationship of the portable device 2 relative to the vehicle.
[0049] <Related processing for determining positional relationships in control unit 33>
[0050] Here, using Figure 6 The flowchart below explains the processing related to determining the positional relationship of the portable device 2 relative to the vehicle in the control unit 33 (hereinafter referred to as positional relationship determination related processing). Figure 6 In the example, as part of the positional relationship determination process, the process up to determining the portable distance to each vehicle-side antenna section 31 will be described. This is configured to begin when the control unit 33 requests the BLE transceiver 32 to transmit a high-frequency signal from the vehicle-side antenna section 31. Figure 6 The flowchart is sufficient. In the case where the vehicle is equipped with multiple vehicle-side antenna sections 31, for example, sequential transmission can be required for the BLE transceivers 32 corresponding to these vehicle-side antenna sections 31.
[0051] First, in step S1, the control unit 33 puts the BLE transceiver 32, which requests the transmission of high-frequency signals, into reception standby mode. When the BLE transceiver 32 is in reception standby mode, the 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 above a threshold are received as the target high-frequency signals.
[0052] In step S2, if a predetermined time has elapsed since the transmission of the requested high-frequency signal (S2: Yes), the process proceeds to step S3. This predetermined time can be pre-assumed as the time required for the portable device 2 to receive a response from the signal transmitted from the vehicle-side antenna unit 31. Conversely, if the predetermined time has not elapsed since the transmission of the requested high-frequency signal (S2: No), the process in S2 is repeated. Thus, within the predetermined time, the BLE transceiver 32 receives the signal from the antenna of the vehicle-side antenna unit 31 that is capable of receiving high-frequency signals above a certain threshold.
[0053] In step S3, the timing determination unit 333 determines, based on the signal that can be received in S2, the antenna with the earliest reception timing among the antennas of the vehicle-side antenna unit 31 that receives the same high-frequency signal. In step S4, the position measurement unit 331 determines the distance to the portable device using only the high-frequency signal received by the antenna determined to have the earliest reception timing in S3 from the high-frequency signals received by the antennas of the vehicle-side antenna unit 31. Then, the position relationship determination process ends.
[0054] <Summary of Implementation Method 1>
[0055] According to the configuration of Embodiment 1, the direction in which the vehicle-side antenna section 31, which transmits and receives signals carried on high-frequency radio waves (i.e., high-frequency signals), easily receives polarized waves can be increased to the directions of three mutually orthogonal axes. If polarized waves in mutually orthogonal three-axis directions are easily received, then even if the direction of the polarized wave from the portable device 2 changes, a higher reception strength is easily received. Therefore, even if the high-frequency signal attenuates, it is easier to receive the desired power intensity. As a result, even when high-frequency radio waves are used to determine the positional relationship of the portable device 2 relative to the vehicle, it is easier to receive the desired power intensity. Consequently, the positional relationship of the portable device 2 relative to the vehicle can be determined with greater accuracy.
[0056] Furthermore, although Embodiment 1 shows a configuration in which the control unit 33 includes a receiving timing determination unit 333, it is not necessarily limited to this. For example, the BLE transceiver 32 may also be configured to include a receiving timing determination unit 333.
[0057] Alternatively, in Embodiment 1, the distance to the portable device can also be determined using high-frequency signals received by antennas other than the antenna with the earliest reception timing for the same high-frequency signal, from the high-frequency signals received by the antennas included in 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 included in the vehicle-side antenna unit 31 can be averaged. In this case, the weight of the information from the antenna with the earliest reception timing for the same high-frequency signal can also be increased.
[0058] (Implementation Method 2)
[0059] Although Embodiment 1 shows a configuration in which the positional relationship of the portable device 2 relative to the vehicle is determined using a high-frequency signal received by the antenna with the earliest reception timing, which is determined to be the same high-frequency signal, this configuration is not necessarily limited to this. For example, the positional relationship of the portable device 2 relative to the vehicle may also be determined using a high-frequency signal received by the antenna with the strongest reception strength, which is determined to be the same high-frequency signal (hereinafter referred to as Embodiment 2). The configuration of Embodiment 2 will be described below.
[0060] The vehicle system 1 of Embodiment 2 includes a user-carried portable device 2 and a vehicle-side unit 3a used in a vehicle. The vehicle system 1 of Embodiment 2 is the same as the vehicle system of Embodiment 1, except that it includes a vehicle-side unit 3a instead of a vehicle-side unit 3.
[0061] <Brief Structure of Vehicle Side Unit 3a>
[0062] Next, use Figure 7 The general structure of the vehicle-side unit 3a will be explained. For example... Figure 7 As shown, the vehicle-side unit 3a includes a vehicle-side antenna section 31, a BLE transceiver 32, and a control section 33a. The vehicle-side unit 3a is the same as the vehicle-side unit 3 in Embodiment 1, except that it has a control section 33a instead of a control section 33.
[0063] The control unit 33a, which determines the positional relationship of the portable device 2 relative to the vehicle, includes a position measuring unit 331, a storage unit 332, and a reception strength determination unit 334 as functional modules. The control unit 33a is the same as the control unit 33 in Embodiment 1, except that it has a reception strength determination unit 334 instead of a reception timing determination unit 333.
[0064] The reception strength determination unit 334 determines the antenna with the strongest reception strength for the same high-frequency signal among the antennas of the vehicle-side antenna unit 31. In the case where the vehicle is configured with multiple vehicle-side antenna units 31, the unit determines the antenna with the strongest reception strength for the same high-frequency signal for each of these multiple vehicle-side antenna units 31. The reception strength determination unit 334 determines the antenna with the highest reception strength measured by the BLE transceiver 32 as the antenna with the highest reception strength for the same high-frequency signal for each antenna of the vehicle-side antenna unit 31 that has been instructed to transmit by the control unit 33a. The BLE transceiver 32 measures the reception strength of each antenna of the vehicle-side antenna unit 31. In Embodiment 2, instead of... Figure 6 The positional relationship determination process described in the text involves processing S3, which can be performed accordingly.
[0065] A strong reception capacity for radio waves generally indicates a high reliability. Therefore, based on the above configuration, it is possible to determine whether an antenna is receiving radio waves that can accurately determine the distance to a portable device, closer to the actual distance.
[0066] The preferred position measuring unit 331 uses only the high-frequency signal received by the antenna with the strongest reception strength, determined by the reception strength determination unit 334, from the high-frequency radio waves received by the antenna on the vehicle side antenna unit 31, to determine the positional relationship of the portable device 2 relative to the vehicle. In Embodiment 2, Figure 6 In the positional relationship determination process described in the previous section, this process can be performed instead of the process in S4. Accordingly, radio waves that can determine the distance of the portable device more closely to the actual distance can be used, so the positional relationship of the portable device 2 relative to the vehicle can be determined with greater accuracy.
[0067] Furthermore, although Embodiment 2 shows a configuration in which the control unit 33a includes a reception strength determination unit 334, it is not necessarily limited to this. For example, the BLE transceiver 32 may also be configured to include a reception strength determination unit 334.
[0068] Alternatively, in Embodiment 2, the distance to the portable device can also be determined using high-frequency signals received by antennas other than the antenna with the strongest reception strength for the same high-frequency signal, among the high-frequency signals received by the antennas included in 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 included in the vehicle-side antenna unit 31 can be averaged. In this case, the weight of the information from the antenna with the strongest reception strength for the same high-frequency signal can be increased.
[0069] (Implementation Method 3)
[0070] Although the above-described Embodiment 1 shows a configuration where the horizontally polarized wave antenna 312 has a first horizontally polarized wave antenna 313 and a second horizontally polarized wave antenna 314, it is not necessarily limited to this configuration. For example, it may be configured to use a circularly polarized wave antenna instead of the first horizontally polarized wave antenna 313 and the second horizontally polarized wave antenna 314 (hereinafter referred to as Embodiment 3). Hereinafter, the configuration of Embodiment 3 will be described.
[0071] The vehicle system 1 of Embodiment 3 includes a user-carried laptop 2 and a vehicle-side unit 3b used in a vehicle. The vehicle system 1 of Embodiment 3 is the same as the vehicle system of Embodiment 1, except that it includes a vehicle-side unit 3b instead of a vehicle-side unit 3.
[0072] <Brief Structure of Vehicle Side Unit 3b>
[0073] Next, use Figure 8 The general structure of the vehicle-side unit 3b will be explained. For example... Figure 8 The vehicle-side unit 3b shown includes a vehicle-side antenna section 31b, a BLE transceiver 32, and a control section 33. The vehicle-side unit 3b is the same as the vehicle-side unit 3 in Embodiment 1, except that it has a vehicle-side antenna section 31b instead of a vehicle-side antenna section 31.
[0074] The vehicle-side antenna section 31b includes a vertically polarized wave antenna 311 and a horizontally polarized wave antenna 312b. The vehicle-side antenna section 31b is identical to the vehicle-side antenna section 31 of Embodiment 1, except that it has a horizontally polarized wave antenna 312b instead of the horizontally polarized wave antenna 312. The horizontally polarized wave antenna 312b includes a circularly polarized wave antenna 315. The circularly polarized wave antenna 315 is an antenna capable of transmitting and receiving any one of mutually orthogonal polarized waves that are horizontally aligned with the target plane.
[0075] According to the configuration of Embodiment 3, instead of using two antennas, one circularly polarized wave antenna 315 can be used to transmit and receive either a mutually orthogonal polarized wave that is horizontal relative to the target plane. This reduces the amount of configuration required for transmitting and receiving antennas such as RF switches, and thus reduces the amount of antenna reduction required by using this configuration.
[0076] Furthermore, this disclosure is not limited to the embodiments described above, and various modifications can be made within the scope shown in the technical solution. Embodiments obtained by appropriately combining the technical units disclosed in different embodiments are also included within the technical scope of this disclosure. Additionally, the control unit and method described in this disclosure can be implemented using a dedicated computer configured to execute one or more functions embodied in a computer program. Alternatively, the apparatus and method described in this disclosure can be implemented using dedicated hardware logic circuits. Alternatively, the apparatus and method described in this disclosure can be implemented using one or more dedicated computers composed of a processor executing a computer program and one or more hardware logic circuits. Furthermore, the computer program can also be stored as instructions executable by a computer on a non-transferable tangible recording medium readable by a computer.
Claims
1. A vehicle-side unit, which can be installed and used in a vehicle, the vehicle-side unit having an antenna section for transmitting and receiving signals carried on high-frequency radio waves, i.e., high-frequency signals, wherein, The aforementioned antenna section has at least the following features: A vertically polarized wave antenna, configured to transmit and receive polarized waves perpendicular to an object surface, which is a metallic surface that is a defined part of the vehicle; and The first and second horizontally polarized wave antennas are configured to transmit and receive mutually orthogonal polarized waves that are horizontal relative to the aforementioned object plane, respectively. The aforementioned vertically polarized wave antenna, the aforementioned first horizontally polarized wave antenna, and the aforementioned second horizontally polarized wave antenna are triaxial antennas whose respective antenna axes are orthogonal to each other. The aforementioned vehicle-side unit includes: The positional relationship determination unit uses the high-frequency signal received by the antenna unit to determine the positional relationship between the portable device transmitting the high-frequency signal and the vehicle; and The reception strength determination unit determines the antenna with the strongest reception strength for the same high-frequency signal among the vertically polarized wave antenna, the first horizontally polarized wave antenna, and the second horizontally polarized wave antenna. The aforementioned positional relationship determination unit uses only the high-frequency signal received by the antenna with the strongest reception strength determined by the aforementioned reception strength determination unit among the antennas provided by the aforementioned antenna unit to determine the positional relationship of the portable device relative to the aforementioned vehicle.
2. The vehicle-side unit according to claim 1, wherein, Equipped with multiple of the aforementioned antenna sections, The plurality of antennas described above are disposed on different object surfaces of the same vehicle described above.
3. The vehicle-side unit according to claim 1 or 2, wherein, The antenna section described above includes the first horizontally polarized wave antenna and the second horizontally polarized wave antenna. The first horizontally polarized wave antenna is configured to transmit and receive polarized waves that are horizontal relative to the object surface, and the second horizontally polarized wave antenna is configured to transmit and receive polarized waves that are horizontal relative to the object surface and orthogonal to the polarized waves.
4. The vehicle-side unit according to claim 1 or 2, wherein, The aforementioned vertically polarized wave antenna is a zero-order resonant antenna.
5. The vehicle-side unit according to claim 1 or 2, wherein, The aforementioned antenna portion is disposed on the aforementioned object surface, and a ground wire is formed directly below the aforementioned first horizontal polarization wave antenna and the aforementioned second horizontal polarization wave antenna in the layer located on the object surface side, i.e., the lower layer, compared to the layer where the aforementioned first horizontal polarization wave antenna and the aforementioned second horizontal polarization wave antenna are disposed.
6. The vehicle-side unit according to claim 1 or 2, wherein, The antenna section is configured to be separated from the object surface by λ / 4.
7. The vehicle-side unit according to claim 1, wherein, Equipped with multiple of the aforementioned antenna sections, The plurality of antenna sections are disposed on different object surfaces of the same vehicle. The aforementioned positional relationship determination unit determines the position of the portable device relative to the vehicle based on the distances between the portable device and each of the multiple vehicle-side antenna units determined separately, using the principle of triangulation.
8. The vehicle-side unit according to claim 1, wherein, The aforementioned antenna section includes a first antenna section and a second antenna section. The aforementioned positional relationship determination unit determines the position of the portable device based on a first distance between the portable device and the vehicle, and a second distance between the portable device and the vehicle. The first distance mentioned above is the distance determined by using only the high-frequency signal received by the antenna with the strongest reception strength, which is determined by the reception strength determination unit among the vertically polarized wave antenna, the first horizontally polarized wave antenna, and the second horizontally polarized wave antenna in the first antenna section. The second distance mentioned above is the distance determined by using only the high-frequency signal received by the antenna with the strongest reception strength, which is determined by the reception strength determination unit among the vertically polarized wave antenna, the first horizontally polarized wave antenna, and the second horizontally polarized wave antenna in the second antenna section.
9. A system for determining positional relationships, comprising: The vehicle-side unit as described in claim 1 or 2; and A portable device is carried by the user and sends and receives signals carried on high-frequency radio waves, i.e., high-frequency signals.