Wireless communication machine, and substrate

Abstract

To provide a wireless communication machine including a plurality of antennas for communicating with a mobile device, in which a substrate is reduced in a size while suppressing occurrence of a reverse phenomenon of reception intensity.SOLUTION: A wireless communication machine includes a substrate 3 on which a first antenna 4, a second antenna 5, a transmission / reception unit 8, and a controller 9 are mounted. The first antenna 4 is formed on the substrate 3 as a half-wavelength dipole antenna. The second antenna 5 is patterned on the substrate 3 as a monopole antenna. The controller 9 collects first antenna intensity, which is reception intensity of a mobile device about a wireless signal transmitted from the first antenna 4, but does not collect second antenna intensity, which is reception intensity of the mobile device of the signal transmitted from the second antenna 5. The controller 9 acquires a distance to the mobile device by performing a distance measurement process for each antenna, and outputs the distance to a smart ECU together with the first antenna intensity.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a wireless communication device and a board that are connected to an electronic control device via a cable. [Background technology]

[0002] Patent Document 1 discloses a configuration in which a portable device observes the reception strength of signals transmitted from an exterior antenna and an interior antenna, and an electronic control device determines the location of the portable device using the reception strength information observed by the portable device. The exterior antenna is an antenna provided on the exterior of the vehicle, such as an exterior door handle. The interior antenna is an antenna disposed inside the vehicle cabin. A communication module including an antenna can be called a wireless communication device. Generally, wireless communication devices disposed in various places in the vehicle are often connected to the electronic control device by communication cables.

[0003] However, depending on the configuration of the wireless communication device, the current involved in wireless transmission from the wireless communication device may flow into the communication cable as leakage current, radiating noise toward the inside of the vehicle. As a technology for suppressing such leakage current, Patent Document 1 discloses a configuration in which a strip line as a leakage current blocking section having a length of about one-quarter of the wavelength (hereinafter also referred to as λ) of the target radio wave is formed to branch off from the power feed line. The target radio wave refers to the radio wave to be transmitted and received, in other words, the radio wave in the frequency band used for communication with a mobile device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-170162 A [Patent Document 2] Patent No. 4992762 Summary of the Invention [Problem to be solved by the invention]

[0005] The developers of the present disclosure have considered a configuration for determining whether or not a portable device is present inside a vehicle based on the indoor unit strength and the outdoor unit strength as a first configuration for determining the position of a portable device relative to a vehicle. The indoor unit strength here refers to the reception strength at the portable device of a signal transmitted from the indoor unit, which is a wireless communication device installed inside the vehicle cabin. The outdoor unit strength here refers to the reception strength at the portable device of a signal transmitted from the outdoor unit, which is a wireless communication device mounted on the exterior of the vehicle. In both cases, the subject of observation of the reception strength is the portable device, and the observed reception strength information can be returned from the portable device to the wireless communication device.

[0006] However, since it was difficult to achieve a desired level of accuracy in determining the location with the above first configuration, we investigated a system for determining the location of a mobile device using distance information to the mobile device determined based on a distance-related value in addition to the reception strength as a second configuration. As a result, we obtained the following findings (1) to (3).

[0007] The distance-related value here refers to a parameter other than reception strength that takes a value corresponding to the device distance, such as a round trip time or a transmission / reception phase difference for each frequency. The transmission / reception phase difference is the phase difference between a transmission signal and a reception signal. The distance-related value is calculated by having the wireless communication device carry out a predetermined communication for distance measurement with the portable device. The communication for distance measurement is communication for measuring the distance-related value, and may include a process in which the wireless communication device and the portable device transmit and receive signals to each other.

[0008] (1) In order to improve the accuracy of measuring the distance to a mobile device, it is preferable to provide multiple antennas on one wireless communication device and average the distance measurement results for each antenna.

[0009] (2) When multiple antennas are mounted on one board, λ / 4 antennas are preferable from the viewpoint of miniaturizing the board. However, these types of antennas may increase the leakage current into the communication cable. Note that the λ / 4 antenna here refers to an antenna that has an electrical length of λ / 4, such as an L-shaped antenna or an inverted F antenna.

[0010] (3) Because the communication cable connected to the outdoor unit itself passes through the vehicle, if there is a large leakage current from the outdoor unit to the communication cable, a reversal in reception strength may occur when the mobile device receives a noise signal radiated from the communication cable connected to the outdoor unit.

[0011] The inversion of reception strength here refers to a situation where the outdoor unit strength is higher than the indoor unit strength when the portable device is inside the vehicle, i.e., in a situation where the indoor unit strength should be higher than the outdoor unit strength. As one solution to the problem of (3) above, a configuration in which a strip line / stub having a length of λ / 4 is provided near the power supply point of each antenna as a leakage current blocking section, following the configuration disclosed in Patent Document 1, is considered. However, this assumed configuration may lead to an increase in the board area and an increase in costs.

[0012] However, because the propagation path of a wireless signal is reversible, the inversion of the reception strength can occur even when the receiver of the reception strength is not a portable device but a wireless communication device mounted on the vehicle. For example, when a signal transmitted from a portable device in a vehicle is received by a communication cable connected to the outdoor unit, the outdoor unit strength can become higher than the indoor unit strength.

[0013] The present disclosure has been made based on the above considerations or points of view, and one of its objectives is to miniaturize the board in a wireless communication device equipped with multiple antennas for communicating with a mobile device while suppressing the occurrence of a reception strength inversion phenomenon. [Means for solving the problem]

[0014] The first wireless communication device disclosed herein is a wireless communication device that is mounted on the exterior of a vehicle and used for wireless communication with a portable device, and is equipped with multiple antennas and a control module (9) that controls the operation of the multiple antennas, where the multiple antennas include a first antenna (4) that is a half-wavelength antenna and a second antenna (5) that is not a half-wavelength antenna, and the control module performs the following operations: acquires a first antenna strength, which is the reception strength at the portable device of a wireless signal transmitted from the first antenna; performs ranging communication using the first antenna, which is communication for measuring a distance-related value that is a parameter different from the reception strength and takes a value according to the distance to the portable device; performs ranging communication using the second antenna; calculates the distance to the portable device based on a first distance-related value, which is the distance-related value obtained in the ranging communication using the first antenna, and a second distance-related value, which is the distance-related value obtained in the ranging communication using the second antenna; and transmits data indicating the distance to the portable device to a position determination device mounted on the vehicle in association with data indicating the first antenna strength.

[0015] According to the above configuration, a half-wave antenna is used as the first antenna to measure the reception strength. A half-wave antenna is less likely to generate current in the ground plane than a λ / 4 antenna, so it is possible to reduce leakage current to the communication cable. This reduces the risk of an inversion of reception strength caused by noise due to leakage current to the communication cable.

[0016] In addition, among the multiple antennas, the second antenna that is not used to measure the reception strength does not need to be a half-wave antenna, and may be, for example, a λ / 4 antenna. Also, since the second antenna does not transmit a signal for strength measurement, there is no need to add a strip line having a length of λ / 4 to the second antenna as a leakage current blocking section. Therefore, in a wireless communication device equipped with multiple antennas for direct communication with a mobile device, it is possible to achieve both miniaturization of the board and suppression of the occurrence of the reception strength inversion phenomenon. Also, the distance-related value is measured for each antenna. Therefore, the measurement accuracy of the distance to the mobile device can also be improved.

[0017] The second wireless communication device disclosed herein is a wireless communication device that is mounted on and used in a vehicle and is used to perform wireless communication with a mobile device, and is equipped with multiple antennas and a control module (9) that controls the operation of the multiple antennas, where the multiple antennas include a first antenna (4) that is a half-wavelength antenna and a second antenna (5) that is not a half-wavelength antenna, and the control module is configured to acquire a first antenna strength, which is the reception strength at the mobile device of a radio signal transmitted from the first antenna, perform ranging communication for each antenna, which is communication by which the mobile device calculates a device distance, which is the distance from the mobile device to the wireless communication device, receive data indicating the device distance from the mobile device, and transmit a signal indicating the reception strength and distance to a position determination device.

[0018] The difference between the second wireless communication device and the first wireless communication device is that the portable device has a function for calculating the distance from the wireless communication device to the portable device. The configuration of the second wireless communication device also provides the same effects as the first wireless communication device.

[0019] A third wireless communication device disclosed herein is a wireless communication device that is mounted on the exterior of a vehicle and used for wireless communication with a portable device, and is equipped with multiple antennas and a control module (9) that controls the operation of the multiple antennas, where the multiple antennas include a first antenna (4) that is a half-wavelength antenna and a second antenna (5) that is not a half-wavelength antenna, and the control module performs the following operations: acquires a first antenna strength, which is the reception strength of a wireless signal from the portable device received by the first antenna; performs ranging communication using the first antenna, which is communication for measuring a distance-related value that is a parameter different from the reception strength and takes a value corresponding to the distance to the portable device; performs ranging communication using the second antenna; calculates the distance to the portable device based on a first distance-related value that is the distance-related value obtained in the ranging communication using the first antenna and a second distance-related value that is the distance-related value obtained in the ranging communication using the second antenna; and transmits data indicating the distance to the portable device to a position determination device mounted on the vehicle in association with data indicating the first antenna strength.

[0020] The difference between the third wireless communication device and the first wireless communication device is that the wireless communication device observes the reception strength. Since the transmission and reception of wireless signals is reversible, the configuration of the third wireless communication device also provides the same effects as the first wireless communication device.

[0021] In addition, the substrate of the present disclosure is a substrate for a wireless communication device mounted on an outer door handle of a vehicle and used, and includes a ground layer (31), a first antenna (4) which is a half-wavelength antenna for performing wireless communication with a portable device, a second antenna (5) which is an antenna for performing wireless communication with a portable device of a type different from the first antenna and is an ungrounded antenna that does not have a portion for electrically connecting to the ground layer, and a control module (9) which controls the operation of the multiple antennas, and the control module includes an intensity acquisition unit (F5) which acquires a first antenna intensity, which is the reception intensity at the portable device of a wireless signal transmitted from the first antenna, a distance acquisition unit (F4) which acquires data indicating the distance from the portable device to the wireless communication device by having the multiple antennas communicate with the portable device in sequence, and a report processing unit (F6) which associates the data indicating the distance to the portable device with data indicating the first antenna intensity and transmits it to a position determination device.

[0022] The above-mentioned board is a board on which various components constituting the first wireless communication device are mounted, and provides the same effects as the first wireless communication device.

[0023] In addition, the reference characters in parentheses in the claims indicate the corresponding relationship with the specific means described in the embodiments described later as one aspect, and do not limit the technical scope of the present disclosure. In addition, the present disclosure considers the leakage current blocking unit to be an optional element, and does not prohibit the introduction of the leakage current blocking unit. [Brief description of the drawings]

[0024] [Figure 1] 1 is a diagram for explaining an overall view of a vehicle electronic key system; [Diagram 2] FIG. 2 is a block diagram of a smart ECU. [Diagram 3] FIG. 2 is a functional block diagram of the radio device. [Figure 4] 4A to 4C are diagrams illustrating examples of arrangement of a first antenna and a second antenna on a substrate. [Diagram 5]13 is a flowchart illustrating an example of an intensity measurement process. [Figure 6] 13 is a flowchart illustrating an example of a distance measurement process. [Figure 7] FIG. 13 is a diagram showing an example of a flow of communication between a communication device and a portable device for intensity measurement and distance measurement. [Figure 8] 10 is a flowchart illustrating an example of a position determination process performed by a smart ECU. [Figure 9] FIG. 1 is a diagram for explaining an overview of an active two-way system. [Figure 10] FIG. 1 is a diagram for explaining an overview of a passive two-way system. [Figure 11] FIG. 1 is a diagram for explaining an overview of a one-way system. [Figure 12] 11A and 11B are diagrams illustrating modified examples of the antenna shape. [Figure 13] FIG. 2 is a diagram showing a configuration including a plurality of first antennas. [Figure 14] 10 is a flowchart for explaining an example of an intensity measurement process when a plurality of first antennas are present. [Figure 15] FIG. 13 is a diagram showing a configuration including a plurality of second antennas. [Figure 16] 13 is a diagram for explaining another example of a method for calculating the second phase difference. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of a vehicle electronic key system to which the wireless communication device of the present disclosure is applied will be described with reference to the drawings. The present disclosure is not limited to the following embodiment, and various modified examples described below are also included in the technical scope of the present disclosure. In addition, in addition to the following, various modifications can be made without departing from the gist of the present disclosure. Various supplements and modified examples can be appropriately combined and implemented as long as no technical contradiction occurs. Components having the same function are given the same reference numerals, and their description may be omitted. In addition, when only a part of the configuration is mentioned, the description given elsewhere can be applied to the other parts.

[0026] 1, the electronic key system for a vehicle according to this embodiment includes an in-vehicle system VS and a portable device Md. The in-vehicle system VS includes a smart ECU 1 and multiple wireless devices 2. ECU is an abbreviation for Electronic Control Unit and refers to an electronic control device.

[0027] The wireless device 2 is a communication module for performing two-way wireless communication with a portable device Md, which is a device carried by a user of the vehicle Hv, using radio waves in a predetermined frequency band. Each wireless device 2 complies with the same communication standard. Here, as an example, each wireless device 2 is configured to be able to perform wireless communication with the portable device Md in accordance with Bluetooth (registered trademark) Low Energy (hereinafter, BLE communication). In other words, the wireless device 2 and the portable device Md are configured to be able to transmit and receive radio waves in the 2.4 GHz band.

[0028] In the following, a case will be described in which the in-vehicle system VS is configured to act as a master / scanner in data communication with the portable device Md, and the portable device Md is configured to act as a slave / advertiser. That is, the in-vehicle system VS establishes a communication connection with the portable device Md by receiving an advertisement signal from the portable device Md, and detects the presence of the portable device Md (and thus the user) in the vicinity of the vehicle Hv. The advertisement signal is a BLE signal for notifying (i.e. advertising) the presence of the portable device Md itself to other devices. The BLE signal is a wireless signal conforming to BLE. The BLE signal may include a code indicating a source or destination. The source or destination may be expressed by a device ID or the like. Note that the descriptions of wireless signal / BLE signal / data / message / packet / frame / package / data set / information and the like in this disclosure may be read as mutually interchangeable. Note that, as another aspect, the portable device Md may be configured to operate as a master in communication with the in-vehicle system VS.

[0029] The in-vehicle system VS includes radios 2A to 2D as the radio 2. The radio 2A is the radio 2 arranged in the vehicle cabin. The radio 2A is arranged, for example, on the instrument panel, the upper end of the windshield, or the center of the ceiling in the vehicle. The radio 2A may be housed inside the housing of the smart ECU 1. The radio 2A corresponds to an indoor unit. The radios 2B to 2D are the radios 2 arranged on the outer surface of the vehicle Hv. The radio 2B is built into the outer door handle for the right front seat. The right front seat is a seat located to the right of the center console among the front seats. When the handle is provided on the right side of the instrument panel, the right front seat corresponds to the driver's seat. The radio 2B may be arranged on the right B-pillar, the right side mirror, or the right side sill. The radio 2B can be called a right outdoor unit.

[0030] The wireless device 2C is built into the outer door handle for the left front seat. The wireless device 2C may be disposed on the left B-pillar, the left side mirror, or the left side sill. The wireless device 2C can be called the left outdoor unit. The wireless device 2D is disposed near the rear bumper or the trunk door. The wireless device 2D can be called the rear outdoor unit. The wireless devices 2B to 2D correspond to outdoor units.

[0031] The smart ECU1 is connected to each of the multiple wireless devices 2 via a communication cable C. The communication cable Ca shown in FIG. 1 is a communication cable that connects the smart ECU1 and the wireless device 2A. The communication cable Cb is a communication cable that connects the smart ECU1 and the wireless device 2B. The communication cable Cc is a communication cable that connects the smart ECU1 and the wireless device 2C. The communication cable Cd is a communication cable that connects the smart ECU1 and the wireless device 2D. Each communication cable C is wired in a gap in the vehicle, for example, under a seat or inside a plastic door panel. In other words, various communication cables C connected to the wireless devices 2B to 2D as outdoor units are wired inside the vehicle. The communication cable C may include a configuration as a power cable for supplying power from the vehicle Hv / smart ECU1 to the wireless device 2. The multiple communication cables C may be bundled as a harness.

[0032] <About the mobile device Md> The portable device Md is a portable and general-purpose information processing terminal equipped with a BLE communication function. As the portable device Md, various communication terminals such as a smartphone and a wearable device can be adopted. The wearable device is a device that is worn on the user's body and can be of various shapes such as a wristband type, a watch type, a finger ring type, a glasses type, and an earphone type. The portable device Md can also be called a user device, a key device, or the like.

[0033] The mobile device Md includes a display, a BLE communication module, and a device control unit. The display is, for example, a liquid crystal display or an organic EL display. The display displays an image according to an input signal from the device control unit.

[0034] The BLE communication module is a communication module for implementing BLE communication. The BLE communication module has a reception strength detection unit, which is a functional unit that measures the reception strength of a received signal. The measurement value of reception strength itself can also be called RSSI (Received Signal Strength Indicator / Indication). In addition to the received data, the BLE communication module transmits data indicating the measured reception strength together with transmission source information to the device control unit.

[0035] The BLE communication module is configured to be capable of transmitting and receiving a continuous wave (CW) signal of a predetermined waveform as a signal for distance measurement in addition to a modulated signal for data communication. The CW signal may be a sine wave or a triangular wave. The signal for distance measurement is a signal for measuring the distance from the portable device Md to the wireless device 2.

[0036] The BLE communication module also includes a reception phase detection unit, which detects the reception phase, which is the phase angle of the reception signal relative to the output signal of the local oscillator, when the CW signal is received, as a function unit for distance measurement. The reception phase corresponds to the output value of an arctangent whose input value is the ratio of the Q (Quadrature-Phase) component to the I (In-Phase) component of the reception signal. The magnitude of the I component corresponds to the strength of the in-phase component of the reception signal. The magnitude of the Q component corresponds to the strength of the quadrature component of the reception signal. The I component is obtained by multiplying the reception signal by a carrier wave output by the local oscillator. The Q component is obtained by multiplying the reception signal by a phase-shifted signal in which the phase of the output signal of the local oscillator is shifted by 90°. The phase-shifted signal can be obtained by passing the output signal of the local oscillator through a phase shift circuit, which is a circuit that shifts the phase by 90°. The local oscillator is a circuit that generates a sine wave or cosine wave of a carrier frequency, and is realized using, for example, a voltage-controlled oscillator (VCO) or the like. The reception phase may be determined based on an IQ signal whose frequency has been down-converted to baseband. The detected reception phase information is used for distance measurement processing as described below.

[0037] The device control unit is configured to execute various types of arithmetic processing. The device control unit is configured as a computer equipped with, for example, a processor, a RAM (Random Access Memory), a storage, etc. A device ID is stored in the storage. A key code used in wireless authentication processing with the smart ECU 1 may be stored in the storage. The key code may also be called an encryption key, etc.

[0038] The device control unit causes the BLE communication module to transmit the advertising signal at a predetermined transmission interval. Furthermore, based on the BLE communication module receiving a connection request from the in-vehicle system VS, the device control unit performs a communication connection process with the in-vehicle system VS. Based on the establishment of the communication connection with the in-vehicle system VS, the mobile device Md may perform an authentication process by wireless communication (hereinafter, wireless authentication process). The wireless authentication process may be performed, for example, by a challenge-response method.

[0039] When the device control unit of this embodiment receives a BLE signal transmitted from the vehicle Hv, it returns a response signal corresponding to the received signal. When the portable device Md receives a BLE signal transmitted from the in-vehicle system VS (actually, the wireless device 2), it acquires the reception strength of the received signal from the BLE communication module. Then, it returns a message including data indicating the reception strength. In the present disclosure, the reception strength of the signal transmitted from the wireless device 2 detected by the portable device Md is also referred to as device strength. A message including the device strength may also be referred to as a device strength message.

[0040] The portable device Md executes a communication sequence for distance measurement based on a request from the in-vehicle system VS. For example, the portable device Md causes the BLE communication module to transmit a CW signal of a specified channel based on a request from the in-vehicle system VS. The interaction between the portable device Md and the in-vehicle system VS (actually the wireless device 2) will be described later.

[0041] The portable device Md may be a smart key, which is a dedicated device as an electronic key for the vehicle Hv. The smart key is a device that is transferred to the owner together with the vehicle Hv when the vehicle Hv is purchased. The smart key can be understood as one of the accessories of the vehicle Hv. The smart key can adopt various shapes, such as a flat rectangular parallelepiped type, a flat ellipsoid type (so-called fob type), and a card type. The smart key can be called a vehicle portable device, a key fob, a key card, an access key, etc.

[0042] <About Smart ECU> The smart ECU 1 is an ECU that determines a device position in cooperation with the wireless device 2. In the present disclosure, the device position means a relative position of the portable device Md with respect to the vehicle Hv. For example, the smart ECU 1 determines whether or not the portable device Md is present inside the vehicle based on the communication status between the multiple wireless devices 2 and the portable device Md. The smart ECU 1 corresponds to a position determination device. Since the portable device Md corresponds to a user, determining the device position corresponds to determining the user's position. The smart ECU 1 may detect that the portable device Md is present within a predetermined range outside the vehicle based on at least one wireless device 2 receiving a BLE signal transmitted from the portable device Md, and may start a process of determining the device position.

[0043] The smart ECU 1 is realized by using a computer. That is, as shown in Fig. 2, the smart ECU 1 includes a processor 11, a memory 12, a storage 13, an input / output circuit (hereinafter, I / O) 14, and a bus line connecting these components. The processor 11 is, for example, a CPU (Central Processing Unit). The processor 11 accesses the memory 12 to execute various processes for realizing the functions of each functional unit described below. The memory 12 is a volatile storage medium, for example, a RAM.

[0044] The storage 13 includes a non-volatile storage medium such as a flash memory. The storage 13 stores a control program executed by the processor 11. The processor 11 executes the control program, which corresponds to the execution of a vehicle control method corresponding to the control program. The storage 13 also stores a device ID of the portable device Md. The storage 13 also stores data indicating the mounting position of each wireless device 2 in the vehicle Hv. The I / O 14 is a circuit module for communicating with other devices. The smart ECU 1 will be described in detail later.

[0045] The smart ECU 1 is disposed in the vehicle interior, for example, in the instrument panel. The smart ECU 1 may be attached to an overhead console, a right or left C-pillar, under the driver's seat, etc. The C-pillar refers to the third pillar from the front among the pillars provided on the vehicle Hv.

[0046] Various in-vehicle devices can be directly or indirectly connected to the smart ECU 1. For example, the smart ECU 1 is connected to a door sensor, a start switch, a body ECU, a power supply ECU, and the like so as to be able to communicate with each other via an in-vehicle network.

[0047] The door sensor is a sensor for detecting a user operation for unlocking and locking the doors of the vehicle Hv. The door sensor may be a touch sensor or a push-type switch. The start switch is a push switch that allows the user to turn the running power source on and off. The start switch may also be called a power switch. The body ECU is an ECU that controls the door lock motor and the in-vehicle lighting equipment. The power source ECU is an ECU that controls the on / off of the running power source mounted on the vehicle Hv. The running power source is a power source for running the vehicle Hv, and refers to the ignition power source if the vehicle Hv is an engine vehicle. If the vehicle Hv is an electric vehicle, the running power source refers to the system main relay.

[0048] The smart ECU 1 detects unlocking and locking operations based on various data / signals input from sensors, ECUs, switches, etc. mounted on the vehicle Hv. The unlocking operation is a user operation for unlocking the vehicle Hv. The locking operation is an operation for locking the vehicle Hv. The smart ECU 1 can detect a touch operation on a door sensor as an unlocking / locking operation.

[0049] The smart ECU 1 controls the operation of the wireless devices 2A to 2D. The smart ECU 1 also uses the wireless devices 2A to 2D depending on the purpose. The smart ECU 1 uses the wireless device 2A for both data communication with the portable device Md and distance measurement. Meanwhile, the other wireless devices 2 are used as anchors. An anchor is a wireless device 2 that is used only for determining the position of the portable device Md. In other words, an anchor refers to a wireless device 2 that is not used for data communication. Here, data communication refers to communication for sending and receiving, for example, audio data, files, and the like.

[0050] In the present disclosure, a communication device used for data communication is referred to as a gateway communication device. In this embodiment, the wireless device 2A corresponds to the gateway communication device. The gateway communication device may be a communication device that is in a standby state either constantly or intermittently while the vehicle Hv is parked. In one aspect, the gateway communication device may be understood as a wireless device 2 that represents a plurality of wireless devices 2. In another aspect, the gateway communication device may be understood as a wireless device 2 that starts up before the anchor. Such a gateway communication device may have a longer startup frequency / startup time than the anchor.

[0051] The settings of the gateway communication device may be dynamically changed by the smart ECU 1. For example, when the smart ECU 1 detects a malfunction in the wireless device 2A, the smart ECU 1 may cause the wireless device 2B to function as the gateway communication device. The gateway communication device may also be called a representative device, a central device, a data communication device, or the like.

[0052] While the driving power supply is off, the smart ECU 1 sets the wireless device 2A as a gateway communication device to a scan mode. The scan mode is a state in which advertisements can be received. The scan mode may be a mode in which the wireless device 2A intermittently enters a standby state at a predetermined scan interval. The wireless device 2A searches for the portable device Md by a passive scan or active scan method.

[0053] The smart ECU 1 can reduce power consumption during parking by turning off the power of the anchor wireless devices 2B to 2D while the driving power is off. Of course, the smart ECU 1 may keep the wireless devices 2B to 2D in the scan mode as with the wireless device 2A. In addition, the smart ECU 1 may react to a user operation (e.g., unlocking operation) on the vehicle Hv and cause the wireless device 2 to search for the portable device Md according to the operation.

[0054] The smart ECU 1 starts up the other wireless devices 2B to 2D based on the fact that the wireless device 2A has been connected to the portable device Md for communication. Then, the smart ECU 1 causes each of the wireless devices 2A to 2D to perform a distance measurement process and an intensity measurement process in a predetermined order. The distance measurement process and the intensity measurement process will be described separately later.

[0055] The smart ECU 1 acquires communication status data generated as a result of distance measurement processing and intensity measurement processing from each wireless device 2. The acquired communication status data is stored in the memory 12 together with information indicating the acquisition source (e.g., wireless device number). The communication status data includes distance information and reception strength. The smart ECU 1 determines the device position by combining the distance information and reception strength provided by multiple wireless devices 2. An example of the operation of the processor 11 related to determining the device position will be described separately later. The functional block related to the position determination can also be called a position determination unit.

[0056] In addition, the smart ECU 1 may cooperate with other ECUs to execute control / processing according to the device position in response to a user operation on the vehicle Hv. For example, when the smart ECU 1 determines that the portable device Md is present near a door outside the vehicle and detects that the door sensor has been touched by a user, the smart ECU 1 may execute processing to lock or unlock the door. A functional block that executes control related to locking and unlocking the door can be called a vehicle control unit. The vehicle control unit may be provided in the smart ECU 1 or in another ECU called a zone ECU, domain ECU, body ECU, or the like.

[0057] <About communication devices> The wireless device 2 is a communication module for performing wireless communication with the mobile device Md in accordance with the BLE standard. The wireless devices 2 have roughly the same configuration. As shown in FIG. 3, each wireless device 2 includes a board 3, a first antenna 4, a second antenna 5, a transceiver unit 8, a controller 9, an in-vehicle communication unit 7, and a switch 6.

[0058] The substrate 3 is a rectangular printed circuit board. The substrate 3 has dimensions that fit the mounting location. The substrate 3 is provided with electronic components, analog elements, signal lines, and the like that constitute the radio device 2. For example, the substrate 3 is provided with a first antenna 4, a second antenna 5, a switch 6, an in-vehicle communication unit 7, a transceiver unit 8, and a controller 9. In the present disclosure, the two surfaces of the substrate 3 are referred to as a first surface and a second surface, respectively. As described separately below, the first surface is a surface on which the first antenna 4 and the second antenna 5 are formed. The first surface can also be referred to as an antenna forming surface. The second surface is a surface opposite to the first surface. The second surface can also be referred to as a back surface.

[0059] In addition, in the present disclosure, the four edges of the substrate 3 are referred to in a clockwise direction as the first edge E31, the second edge E32, the third edge E33, and the fourth edge E34. The first edge E31 is an edge extending in the longitudinal direction of the substrate 3. The second edge E32 is an edge extending in the lateral direction of the substrate 3. The second edge E32 is an edge perpendicular to the first edge E31 among the four edges of the substrate 3. The third edge E33 is an edge on the opposite side to the first edge E31. The fourth edge E34 is an edge on the climbing single unit side of the second edge E32. In another embodiment, an edge extending in the lateral direction of the substrate 3 may be set to the first edge E31. In that case, the second edge E32 can be an edge extending in the longitudinal direction of the substrate 3.

[0060] The substrate 3 includes a ground layer 31 inside or on the back side. The ground layer 31 is a conductor layer that provides a ground potential (so-called ground). The conductor layer can also be called a conductor plate. The plate shape here includes a thin film shape. The ground layer / conductor layer can be read as a ground plate / conductor plate, respectively. The ground layer 31 is electrically connected to a ground line of a communication cable or a power cable that connects the smart ECU 1 and the wireless device 2. The ground layer 31 is also electrically connected to ground terminals of various electronic components. In addition to the above configuration, the substrate 3 may be provided with a power supply circuit that converts a voltage supplied from the vehicle Hv into a voltage suitable for the operation of the controller 9, etc.

[0061] Both the first antenna 4 and the second antenna 5 are antenna elements for transmitting and receiving radio waves in the frequency band used in BLE communication, i.e., the 2.4 GHz band. The 2.4 GHz band can be understood as a frequency band that includes multiple channels (Ch 0 to 39) used in BLE communication. In the present disclosure, when there is no need to distinguish between the first antenna 4 and the second antenna 5, such as in the description of parts common to the first antenna 4 and the second antenna 5, the first antenna 4 and the second antenna 5 may be simply referred to as antennas.

[0062] The first antenna 4 and the second antenna 5 are each electrically connected to the transceiver unit 8 via the switch 6. The switch 6 is a circuit / component for switching the antenna used by the controller 9 for communication with the portable device Md. The switch 6 has a plurality of connection states. For example, the switch 6 has a first connection state and a second connection state as connection states. The first connection state is a state in which the first antenna 4 is connected to the transceiver unit 8. The second connection state is a state in which the second antenna 5 is connected to the transceiver unit 8. The connection state of the switch 6 is switched by the controller 9. Hereinafter, the antenna connected to the transceiver unit 8 out of the first antenna 4 and the second antenna 5 will also be referred to as the used antenna or the effective antenna.

[0063] The first antenna 4 is configured as a dipole antenna having an electrical length of λ / 2, for example, as shown in FIG. 4. λ refers to the wavelength of the target radio wave, which is the radio wave that the antenna transmits and receives. Since the target radio wave here is 2.4 GHz, λ in a vacuum corresponds to approximately 125 mm. The electrical length is an effective length taking into account the effects of wavelength shortening due to dielectrics and the like. The electrical length can be called the effective length. The actual dimension at which the electrical length is λ / 2 can vary depending on the material of the substrate 3, etc. Here, as an example, λ corresponds to 72 mm. Therefore, the length equivalent to λ / 2 is 36 mm, and the length equivalent to λ / 4 is 18 mm.

[0064] The first antenna 4 is patterned on the first surface in a position parallel to the first edge E31 of the substrate 3, for example. The first antenna 4 is formed in a straight line, for example. That is, the first antenna 4 is formed along the first edge E31. The configuration shown in FIG. 4 corresponds to a configuration in which the first antenna 4 is provided along the longitudinal direction of the substrate 3. Note that the switch 6, the transceiver 8, and the controller 9 are not shown in FIG. 4.

[0065] The first antenna 4 includes a feed element A41 and a ground element A42 as a segmented configuration. The feed element A41 and the ground element A42 are linear conductors each having a length of λ / 4. The feed element A41 and the ground element A42 are arranged on the same straight line with a predetermined interval therebetween. In the present disclosure, of the two ends of the linear feed element A41, the end adjacent to the ground element A42 is referred to as a feed end T41. Also, of the two ends of the linear ground element A42, the end adjacent to the feed element A41 is referred to as a ground end T42. The interval between the feed end T41 and the ground end T42 can be appropriately designed to be 1 mm, 2 mm, 4 mm, or the like.

[0066] The feed element A41 is electrically connected to the transceiver 8 via a feed line L1, a switch 6, and the like. The feed line L1 is a microstrip line for feeding power to the feed element A41. One end of the feed line L1 is connected to the feed element A41 at a feed end T41. The other end of the feed line L1 is electrically connected to a signal input / output terminal of the transceiver 8.

[0067] The ground element A42 is connected to the ground layer 31 via a ground line L2 extending from the ground end T42 toward the ground layer 31. The ground line L2 is a microstrip line for connecting the ground element A42 to the ground layer 31. The power feed line L1 and the ground line L2 are formed parallel to each other. The power feed line L1 and the ground line L2 have the same length. The first antenna 4 has a shape in which the power feed element A41 and the ground element A42 extend in opposite directions from the ends of the power feed line L1 and the ground line L2. Lfd in the figure indicates the power feed line length, which is the length of the power feed line L1 and the ground line L2. In this embodiment, Lfd is set to 8 mm as an example. The power feed line length may be 5 mm, 7 mm, 10 mm, etc.

[0068] The second antenna 5 is an L-shaped linear element having an electrical length of λ / 4. The second antenna 5 is configured as an inverted L antenna, which is a variation of a monopole antenna. The second antenna 5 is patterned on the first surface with its polarization plane perpendicular to that of the first antenna 4. For example, the second antenna 5 is patterned on the first surface with most of it parallel to the second edge E32 of the substrate 3. For convenience, the portion of the second antenna 5 that is along the second edge E32 is referred to as the second edge parallel portion.

[0069] The second antenna 5 has a second edge orthogonal portion extending at a right angle from one end of the second edge parallel portion. The second antenna 5 is L-shaped overall by the second edge orthogonal portion and the second edge parallel portion. For example, the second edge parallel portion is set to 28 mm, and the second edge orthogonal portion is set to 8 mm. The second antenna 5 only needs to have a total length of λ / 4 (=36 mm), and the ratio of the length of the second edge parallel portion and the second edge orthogonal portion can be adjusted as appropriate.

[0070] In addition, the longer the second edge parallel portion, the easier it becomes for the second antenna 5 to transmit and receive radio waves that are orthogonal to the first antenna 4 in terms of the plane of polarization. According to the above antenna arrangement, the plane of polarization of the second antenna 5 is orthogonal to the plane of polarization of the first antenna 4. The second antenna 5 is provided at a position that is λ / 8 or more away from the first antenna 4.

[0071] The in-vehicle communication unit 7 is a circuit module for communicating with the smart ECU 1 via the communication cable C. The in-vehicle communication unit 7 includes analog circuit elements and ICs, a PHY chip conforming to a communication method with the smart ECU 1, and a connector 71 to which the communication cable C is connected. The in-vehicle communication unit 7 corresponds to a cable connection unit. The connector 71 is disposed, for example, along the fourth edge portion E34 of the substrate 3.

[0072] The transmitting / receiving unit 8 is a circuit module that performs signal processing related to the transmission and reception of wireless signals. The transmitting / receiving unit 8 may include a modulation circuit, a demodulation circuit, a frequency conversion circuit, an amplifier circuit, a local oscillator, and the like. The transmitting / receiving unit 8 also includes an input / output terminal for outputting a signal to an antenna and receiving a signal from the antenna. The transmitting / receiving unit 8 is connected to the controller 9 so as to be able to communicate with each other. The transmitting / receiving unit 8 demodulates a data signal received by the antenna in use and provides the demodulated signal to the controller 9. The data signal refers to a modulated signal for data communication. The transmitting / receiving unit 8 also modulates the transmission data input from the controller 9 and causes it to be radiated as radio waves from the antenna in use. The transmitting / receiving unit 8 may be realized as an IC chip (i.e., a transmitting / receiving IC).

[0073] The transceiver 8 also includes an automatic gain control (AGC) circuit that performs automatic gain control on the received signal. The transceiver 8 is configured to use the received voltage at the first antenna 4 as a reference voltage for the automatic gain control. The transceiver 8 includes an input terminal for the AGC. The input terminal for the automatic gain control is electrically connected to the power feed line L1. In other words, the transceiver 8 is configured to use the received voltage at the first antenna 4 as a reference voltage for the AGC.

[0074] Furthermore, the transceiver 8 is configured to be capable of transmitting a CW signal of an operating frequency in addition to a modulated signal for data communication. The operating frequency refers to a frequency (channel) used for communication. The operating frequency may be interpreted as a carrier frequency. The operating frequency changes over time by frequency hopping or in response to an instruction from the controller 9.

[0075] The transceiver 8 includes a reception phase detector 81 as a functional unit for distance measurement. The reception phase detector 81 is a circuit that detects the reception phase, which is the phase angle of the reception signal relative to the output signal of the local oscillator, when a CW signal is received. The transceiver 8 provides the controller 9 with the detection value of the reception phase of the CW signal in association with information indicating the frequency used (e.g., a channel number). Each time the frequency used is switched, the transceiver 8 detects the transmission and reception phase of the CW signal as part of the distance measurement process for the corresponding frequency. In other words, the controller 9 is provided with data indicating the reception phase for each frequency.

[0076] The controller 9 is a microcomputer that controls the transceiver unit 8 and the switch 6. The controller 9 includes a processor 91, a memory 92, a storage 93, and an I / O circuit. The controller 9 is connected to each of the transceiver unit 8, the in-vehicle communication unit 7, and the switch 6. The controller 9 corresponds to a control module.

[0077] The controller 9 plays a role in controlling the transfer of data with the smart ECU 1. Specifically, the controller 9 provides the received data input from the transmitting / receiving unit 8 to the smart ECU 1 sequentially or based on a request from the smart ECU 1. The controller 9 also outputs the transmission data input from the smart ECU 1 to the transmitting / receiving unit 8.

[0078] The controller 9 includes, as functional units related to distance measurement, an antenna selection unit F1, a primary phase difference identification unit F2, a secondary phase difference acquisition unit F3, a distance acquisition unit F4, a device strength acquisition unit F5, and a report processing unit F6.

[0079] The antenna selection unit F1 is configured to switch the antenna to be used by outputting a predetermined control signal to the switch 6. Every time the antenna to be used is switched, the controller 9 performs communication for distance measurement with the portable device Md at multiple frequencies, thereby acquiring distance information and device strength for each antenna and frequency.

[0080] The primary phase difference identification unit F2 is configured to acquire a primary phase difference for each frequency. The primary phase difference is the phase difference between a CW signal transmitted from the antenna in use and a received CW signal. The primary phase difference can be called a transmission / reception phase difference or a single frequency phase difference. The primary phase difference is, for example, the average value or total value of the reception phases detected by the wireless device 2 and the portable device Md when they transmit and receive CW signals to each other.

[0081] The primary phase difference specifying unit F2 can specify the primary phase difference at the frequency used by using any one of various methods such as an active 2-way method, a passive 2-way method, or a 1-way method. Details of the active 2-way method, the passive 2-way method, and the 1-way method will be described later. The portable device Md operates so as to correspond to the method of specifying the primary phase difference used by the wireless device 2. In this embodiment, the active 2-way method is adopted as an example.

[0082] The primary phase difference identifying unit F2 may execute a process for acquiring a primary phase difference when the frequency in use is switched. When the active two-way system is employed, the process includes transmitting and receiving CW signals to and from the portable device Md, and receiving a message indicating the reception phase from the portable device Md. The communication for acquiring the primary phase difference corresponds to an example of distance measurement communication. The value of the primary phase difference acquired by the primary phase difference identifying unit F2 is stored in the memory 92 in association with the value of the frequency in use at that time. The calculation of the primary phase difference may be performed by the transmitting and receiving unit 8. The functional arrangement in the wireless device 2 may be changed as appropriate.

[0083] The secondary phase difference acquisition unit F3 is configured to calculate a secondary phase difference. The secondary phase difference is the difference between the primary phase differences observed at two different frequencies. The secondary phase difference can be called a two-frequency phase difference or an inter-frequency phase difference. The secondary phase difference corresponds to the amount of displacement of the phase angle due to a change in frequency. Since the primary phase difference itself is a parameter different from the reception intensity, the secondary phase difference is also a parameter different from the reception intensity.

[0084] The secondary phase difference acquisition unit F3 calculates a secondary phase difference for each combination of frequencies. In BLE communication, three or more frequencies are used over time, so the secondary phase difference acquisition unit F3 calculates two or more secondary phase differences with different combinations of frequencies, that is, multiple secondary phase differences. In the present disclosure, multiple secondary phase differences are sometimes referred to as multi-frequency phase differences. As will be described next, the distance acquisition unit F4 estimates the device distance based on the multi-frequency phase differences. The device distance is the distance from the wireless device 2 to the portable device Md.

[0085] The distance acquisition unit F4 performs a process of calculating a provisional value of the device distance using the differential frequency (Δf) which is the difference between the two frequencies and the secondary phase difference (Δφ) for each combination of frequencies for which the secondary phase difference is calculated. If the device distance is D, there is a relationship between D, Δf, and Δφ, which is D∝C·Δφ / (2π·Δf). The parameter "C" in the above formula indicates the propagation speed of radio waves (3×10^8 m / sec). The distance acquisition unit F4 calculates the provisional value of the device distance based on the relational formula. For example, the distance acquisition unit F4 calculates the provisional value of the device distance using the following formula 1. Note that the parameter k constituting formula 1 is a design value and is set to 1.0 or 0.5. The value of k can be determined depending on whether the transmission and reception phase difference is calculated as the phase change amount for one way or the phase change amount for round trip. D=k C Δφ / (2π Δf) Formula 1

[0086] The distance acquisition unit F4 adopts the average or median of the provisional values ​​of the device distance calculated for each combination of frequencies as the device distance for the antenna in use. For convenience, the device distance calculated using the first antenna 4 is referred to as the first distance, and the device distance calculated using the second antenna 5 is referred to as the second distance. The distance acquisition unit F4 may adopt the average value of the first distance and the second distance as the final value of the device distance.

[0087] The device strength acquisition unit F5 acquires the reception strength at the portable device Md for a signal transmitted from the antenna in use, that is, the device strength, by communicating with the portable device Md. For example, the device strength acquisition unit F5 may acquire the device strength from the portable device Md by transmitting a message to the portable device Md requesting a report of the device strength. In this case, the portable device Md may transmit a device strength message based on receiving a request from the wireless device 2. Each time the frequency in use changes, the device strength acquisition unit F5 acquires the device strength at that frequency. Note that the signal used by the portable device Md to measure the reception strength may be a CW signal or a data signal.

[0088] However, since the second antenna 5 is a monopole antenna, the leakage current to the communication cable C during signal transmission is relatively large. If the leakage current to the communication cable C is large, a reversal phenomenon of reception strength may occur due to noise radiated from the communication cable C toward the interior of the vehicle. In other words, the device strength for the signal transmitted from the second antenna 5 is not reliable as a criterion for determining the device position. For this reason, the device strength acquisition unit F5 of this embodiment acquires the device strength only when the first antenna 4 is in use. In other words, the device strength acquisition unit F5 collects only the first antenna strength, which is the device strength for the signal transmitted from the first antenna 4.

[0089] The portable device Md may transmit a device strength message every time it receives a predetermined signal from the wireless device 2. In this case, the controller 9 may receive a message indicating not only the first antenna strength but also the second antenna strength, which is the device strength for a signal transmitted from the second antenna 5. The device strength acquisition unit F5 may once acquire the device strength for each antenna and each frequency. The device strength acquisition unit F5 may be configured to substantially collect only the first antenna strength by deleting or ignoring data regarding the second antenna strength.

[0090] The report processing unit F6 is configured to transmit a data set including reception strength information and device distance information determined as a result of the strength measurement process and the distance measurement process to the smart ECU1 as communication status data. The reception strength information includes data on the first antenna strength. The device distance information includes an average value of the first distance and the second distance, or data on each of the first distance and the second distance. The reception status data is used by the smart ECU1 to determine the device position. The report processing unit F6 may transmit the reception strength information and the device distance information to the smart ECU1 as separate packets.

[0091] Each wireless device 2 operates according to instructions from the smart ECU 1. Each wireless device 2 sequentially performs intensity measurement processing and distance measurement processing based on instructions from the smart ECU 1. In other words, each wireless device 2 outputs data related to device intensity and device distance to the smart ECU 1 based on instructions from the smart ECU 1. Note that each wireless device 2 may be configured to autonomously attempt intensity measurement processing and distance measurement processing at a predetermined interval.

[0092] In addition, the wireless device 2 changes the operation state based on an instruction from the smart ECU 1. For example, the wireless device 2 switches the power on and off based on an instruction from the smart ECU 1.

[0093] <Intensity measurement processing> Here, the strength measurement process will be described with reference to Fig. 5. The controller 9 executes the strength measurement process based on an instruction from the smart ECU 1. The controller 9 may execute the strength measurement process spontaneously upon receiving a predetermined user operation (e.g., an unlocking operation) without an instruction or permission from the smart ECU 1. The controller 9 may also execute the strength measurement process periodically. The strength measurement process includes, as an example, steps S101 to S106. Each step is executed in order according to the direction of the arrow shown in the figure.

[0094] Step S101 is a step of setting the first antenna 4 as the used antenna. Step S102 is a step of transmitting a signal for strength measurement from the first antenna 4. The signal for strength measurement may be a predetermined message requesting a report of the device strength. Also, a CW signal for distance measurement may be used as the signal for strength measurement, as will be described later.

[0095] Step S103 is a step of acquiring the device strength as the first antenna strength by receiving a device strength message from the portable device Md. Step S104 is a step of judging whether the first antenna strength has been acquired at a predetermined number (N) of frequencies. N can be set to 3, 6, 10, etc. If the number of frequencies at which the first antenna strength has been acquired does not reach the predetermined number (S104 NO), the controller 9 executes step S105.

[0096] Step S105 is a step for changing the frequency in use. For example, the controller 9 switches the frequency in use after transmitting a message indicating the next frequency in use to the portable device Md. When the frequency in use is changed, the controller 9 executes steps S101 and thereafter in the new frequency in use. That is, steps S101 to S105 are repeated until the number of frequencies for which device strengths have been acquired reaches a predetermined number. The frequency in use may be changed automatically by frequency hopping.

[0097] When the first antenna strengths at a predetermined number of frequencies or more can be acquired, the controller 9 executes step S106. Step S106 is a step of calculating a representative value of the first antenna strength for each frequency as the report strength. The representative value of the first antenna strength for each frequency, i.e., the report strength, may be the average value or the median value of the multiple first antenna strengths. The report strength is a device strength to be reported to the smart ECU 1. The smart ECU 1 handles the device strength reported from each wireless device 2 as a criterion for determining whether the portable device Md is present inside the vehicle. Therefore, the report strength can also be called a position determination strength.

[0098] Note that step S104 may be a step of determining whether or not the device strength has been acquired for each of all frequencies (Ch 0 to 36) that can be used for data communication. In that case, N may be set to 37. Step S104 may also be a step of determining whether or not the device strength has been acquired for each of all frequencies (Ch 37 to 39) that are used for advertising. In that case, N may be set to 3.

[0099] <Distance measurement processing> Here, the distance measurement process will be described with reference to FIG. 6. The controller 9 executes the distance measurement process based on an instruction from the smart ECU 1. In another embodiment, the controller 9 may execute the distance measurement process spontaneously upon receiving a predetermined user operation (e.g., unlocking operation) without an instruction or permission from the smart ECU 1. Furthermore, the controller 9 may execute the distance measurement process periodically. In addition, the controller 9 may execute the intensity measurement process and the distance measurement process in sequence. Furthermore, the controller 9 may execute the intensity measurement process and the distance measurement process in parallel. The distance measurement process includes, as an example, steps S201 to S209. The controller 9 executes each step in sequence according to the direction of the arrow shown in FIG. 6.

[0100] Step S201 is a step of setting an antenna whose device distance has not been measured as an antenna to be used. An antenna whose device distance has not been measured corresponds to an antenna whose device distance has not been measured in steps S202 to S207.

[0101] Step S202 is a step of transmitting and receiving a phase measurement signal to and from the portable device Md. The phase measurement signal may be a CW signal of the currently used frequency. The phase measurement signal may also be another predetermined signal. Step S203 is a step of acquiring a primary phase difference. The wireless device 2 of this embodiment attempts to identify the primary phase difference by an active two-way system. Therefore, step S203 may include a step of receiving a reception phase message from the portable device Md. Note that, as described above, the wireless device 2 may identify the primary phase difference by a passive two-way system or a one-way system. In a configuration in which the wireless device 2 acquires the primary phase difference by a one-way system, steps S202 to S203 may be steps in which the portable device Md transmits a CW signal while sequentially changing the frequency, and the wireless device 2 identifies the reception phase for each frequency. Steps S202 to S203 are a series of processes for identifying the primary phase difference. Details of steps S202 to S203 can be changed as appropriate depending on the method of identifying the primary phase difference. The communication carried out in steps S202 and S203 corresponds to distance measurement communication.

[0102] Step S204 is a step for determining whether or not primary phase differences have been collected at a predetermined number (M) of frequencies. M is set to a value of 3 or more, such as 3, 6, or 10. M may be the same value as N described above, or may be different. If the number of frequencies for which primary phase differences have been identified does not reach the predetermined number (S204 NO), the controller 9 executes step S205.

[0103] Step S205 is a step of switching the operating frequency, similar to step S105. The frequency may be changed by frequency hopping. After the operating frequency is changed, the controller 9 executes step S202 and subsequent steps at the new operating frequency. That is, the controller 9 repeats steps S202 to S205 until the number of frequencies at which the first-order phase difference has been measured reaches a predetermined number.

[0104] Step S204 may be a step of determining whether or not the first-order phase difference has been measured at each of all frequencies (Ch 0 to 36) available for data communication. Step S204 may also be a step of determining whether or not the first-order phase difference has been measured at each of all frequencies (Ch 37 to 39) used in advertising.

[0105] Step S206 is a step of calculating secondary phase differences for a plurality of frequency combinations based on the primary phase differences for each frequency collected in steps S202 to S205. Since the primary phase differences for at least three frequencies have been acquired by the sequence of steps S202 to S205, two or more secondary phase differences are generated in step S206. The secondary phase differences for each frequency combination are stored in memory 92 together with frequency information.

[0106] In step S207, the distance acquisition unit F4 calculates the device distance for the currently used antenna. Specifically, the distance acquisition unit F4 calculates a provisional value of the device distance for each combination of frequencies based on a plurality of secondary phase differences using the above formula 1. Then, the average or median of these provisional values ​​is stored in the memory 92 as the device distance for the currently used antenna.

[0107] Step S208 is a step for judging whether or not the processing of steps S202 to S207 has been performed for all antennas equipped in the wireless device 2. If there are any antennas for which the above processing has not been performed, the processing of steps S201 and after is executed again. When the controller 9 calculates the device distances for all antennas (S208 YES), it executes step S209. In step S209, the device distance to be reported is determined based on the device distance for each antenna. The device distance to be reported refers to the device distance to be reported to the smart ECU 1. The controller 9 can adopt the average value or median value of the device distances for each antenna as the device distance to be reported.

[0108] <Additional information on communication between mobile devices and communication devices> The intensity measurement process may be performed as a part of the distance measurement process as shown in Fig. 7. For example, the wireless device 2 and the portable device Md execute a sequence including steps S31A to S39 in Fig. 7 based on the wireless device 2 receiving a communication status report request from the smart ECU 1. The sequence in Fig. 7 can be performed for each antenna included in the wireless device 2.

[0109] Step S31A is a step in which the wireless device 2 transmits a ranging start request signal to the portable device Md using any one of the antennas. The ranging start request signal is a message signal requesting the start of ranging processing. Upon receiving the ranging start request signal (S31B), the portable device Md returns a positive response signal (so-called Ack) (S32A).

[0110] Upon receiving an Ack from the portable device Md (S32B), the wireless device 2 transmits a CW signal at the currently used frequency (S33A). Upon receiving the CW signal (S33B), the portable device Md analyzes the received CW signal to obtain the reception strength and reception phase (S34), and transmits the CW signal back (S35A).

[0111] When the wireless device 2 receives the CW signal (S35B), it analyzes the received CW signal to identify the reception phase (S36). In addition, the wireless device 2 transmits an observation value request signal to the portable device Md (S37A). The observation value request signal is a signal that requests the transmission of the reception phase and device strength identified in S34. The portable device Md returns an observation result signal including the device strength and reception phase based on the reception of the observation value request signal (S37B) (S38A). When the wireless device 2 receives the observation result signal (S38B), it attempts to calculate the device strength and device distance to be reported using the reception phase and device strength included in the reception signal as a subsequent process (S39). The subsequent process may include changing the frequency and the antenna. Steps S31A to S39 are repeatedly performed while changing the antenna and frequency to be used so that the device strength and device distance to be reported can be calculated.

[0112] The portable device Md may transmit a message including the device strength to the wireless device 2 regardless of whether the source of the received CW signal is the first antenna 4 or not. The wireless device 2 may discard or ignore the device strength acquired while the second antenna 5 is in use. Ignoring here means not using it for calculating the device strength to be reported. The wireless device 2 may specify whether or not the device strength needs to be reported as an observation value request signal. The wireless device 2 may transmit a signal requesting both the reception phase and the device strength while the first antenna 4 is in use, but may transmit a signal not requesting the device strength while the second antenna 5 is in use.

[0113] Furthermore, if a passive two-way system is used to specify the transmission and reception phase difference, it is not necessary for the portable device Md to return the reception phase. Instead, the portable device Md can return a CW signal reflecting the reception phase to the wireless device 2, as described later.

[0114] <Position determination process> Here, the position determination process performed by the in-vehicle system VS (mainly the smart ECU1) will be described with reference to the flowchart shown in FIG. 8. The position determination process may include steps S401 to S417 as shown in FIG. 8. The in-vehicle system VS may perform the position determination process in response to a user operation such as an unlocking operation or a locking operation. The in-vehicle system VS may perform the position determination process periodically. The in-vehicle system VS may perform the position determination process periodically or in response to a predetermined user operation, on condition that the gateway communication device is communicatively connected to the portable device Md.

[0115] Step S401 is a step in which each wireless device 2 performs a strength measurement process and a distance measurement process in a predetermined order. Step S401 can be interpreted as a step in which the smart ECU1 causes each wireless device 2 to perform a strength measurement process and a distance measurement process in a predetermined order. Step S402 is a step in which each of the multiple wireless devices 2 transmits communication status data to the smart ECU1. Step S402 can be interpreted as a step in which the smart ECU1 aggregates the communication status data for each wireless device 2. Step S403 is a step in which the smart ECU1 determines whether the indoor unit strength is greater than the outdoor unit strength. In the figure, RSSI_IN means the indoor unit strength. Also, RSSI_OUT means the outdoor unit strength.

[0116] The indoor unit strength (RSSI_IN) is the reception strength observed by the portable device Md for a signal transmitted from the indoor unit. In this embodiment, since the only indoor unit present is the wireless unit 2A, the device strength provided by the wireless unit 2A corresponds to the indoor unit strength. If there are multiple indoor units present, the smart ECU 1 can handle the maximum value of the device strengths provided by the multiple indoor units as the indoor unit strength. If there are multiple indoor units present, the indoor unit strength may be the average value or median value of the device strengths provided by the multiple indoor units.

[0117] The outdoor unit strength (RSSI_OUT) is the reception strength observed by the portable device Md for a signal transmitted from an outdoor unit. Wireless devices 2B to 2D are connected to the smart ECU1 of this embodiment as outdoor units. In such a case, the smart ECU1 treats the maximum value of the device strengths provided by the multiple outdoor units as the indoor unit strength. In other words, the smart ECU1 of this embodiment regards the maximum value of the device strengths provided by the wireless devices 2B to 2D as the outdoor unit strength. Note that when multiple outdoor units are present, the outdoor unit strength may be the average value or median value of the device strengths provided by the multiple outdoor units.

[0118] As described above, the device strength reported by each wireless device 2 to the smart ECU 1 is the reception strength when a signal is transmitted from the first antenna 4, not the reception strength when a signal is transmitted from the second antenna 5. The device strength when the second antenna 5 is operating may be affected by leakage current from the communication cable C, but the possibility is relatively small when the first antenna 4 is operating. The above configuration corresponds to a configuration in which it is determined whether or not the portable device Md is present inside the vehicle without using the reception strength when the second antenna 5 is operating. The term "device strength" in the description of the position determination process can be read as "first antenna strength."

[0119] When the indoor unit strength is greater than the outdoor unit strength (S403 YES), the smart ECU1 executes step S404. Step S404 is a step for determining whether or not the minimum value of the indoor unit observation distance is less than a predetermined indoor determination value. The indoor unit observation distance is the device distance observed by the indoor unit. In this embodiment, the indoor unit is only the wireless unit 2A, so the device distance observed by the wireless unit 2A corresponds to the minimum value of the indoor unit observation distance. When there are multiple indoor units, the minimum value of the indoor unit observation distance can be the minimum value of the device distances observed by the multiple indoor units. minD(IN) in FIG. 8 represents the minimum value of the indoor unit observation distance. Th1 in FIG. 8 is the indoor determination value. The indoor determination value is set to, for example, 2 m, 2.5 m, or 3 m.

[0120] When the indoor unit observation distance is less than the indoor determination value (S404 YES), the smart ECU 1 determines that the device position is inside the vehicle (S405). The processing of steps S403 to S405 corresponds to the smart ECU 1 determining that the device position is inside the vehicle based on the fact that there is an indoor unit whose device distance is less than the indoor determination value and the indoor unit strength is greater than the outdoor unit strength.

[0121] When the indoor unit strength is equal to or less than the outdoor unit strength (NO in S403), the smart ECU 1 executes step S406. Also, even if the indoor unit strength is greater than the outdoor unit strength, the smart ECU 1 may execute step S406 when there is no indoor unit whose device distance is less than the indoor determination value.

[0122] Step S406 is a step for determining whether or not the device distance observed by wireless device 2B (i.e., right outdoor unit) disposed on the right outer surface of the vehicle Hv is the smallest among the device distances observed by multiple outdoor units. Hereinafter, the device distance reported from wireless device 2B will be referred to as the right observation distance. Also, below, the device distance observed by the outdoor unit will be referred to as the outdoor unit observation distance. D(B) in FIG. 8 represents the right observation distance.

[0123] If the right observation distance is the shortest among the outdoor unit observation distances (S406 YES), the smart ECU 1 executes step S407. On the other hand, if the right observation distance is not the shortest among the outdoor unit observation distances (S406 NO), the smart ECU 1 executes step S409.

[0124] Step S407 is a step for determining whether the right observation distance is less than a predetermined proximity determination value. Th2 in FIG. 8 is the proximity determination value. The proximity determination value is a parameter that defines a passive entry area outside the vehicle. The passive entry area corresponds to an area where the in-vehicle system VS can automatically unlock / lock the vehicle Hv based on wireless communication with the portable device Md. The proximity determination value is set to, for example, 1.0 m, 1.5 m, 2 m, or the like. If the right observation distance is less than the proximity determination value (S407 YES), the smart ECU1 determines that the device position is near the right door outside the vehicle (S408). Even if the right observation distance is the smallest among the outdoor unit observation distances, the smart ECU1 can execute step S415 if the right observation distance is equal to or greater than the proximity determination value (S407 NO).

[0125] Step S409 is a step for determining whether the device distance observed by wireless device 2C (i.e., the left outdoor unit) located on the left outer surface of the vehicle Hv is the smallest among the outdoor unit observation distances. Hereinafter, the device distance reported from wireless device 2C is also referred to as the left observation distance. D (C) in FIG. 8 represents the left observation distance.

[0126] If the left observation distance is the shortest among the outdoor unit observation distances (S409 YES), the smart ECU 1 executes step S410. On the other hand, if the left observation distance is not the shortest among the outdoor unit observation distances (S409 NO), the smart ECU 1 executes step S412.

[0127] Step S410 is a step for determining whether the left observation distance is less than the proximity determination value. If the left observation distance is less than the proximity determination value (S410 YES), the smart ECU 1 determines that the device position is near the left door outside the vehicle (S411). If the left observation distance is equal to or greater than the proximity determination value (S410 NO), the smart ECU 1 executes step S415.

[0128] Step S412 is a step for determining whether or not the device distance observed by the wireless device 2D (i.e., the rear outdoor unit) disposed on the rear outer surface of the vehicle Hv is the smallest among the outdoor unit observation distances. Hereinafter, the device distance reported from the wireless device 2D is also referred to as the rear observation distance. D (D) in FIG. 8 represents the rear observation distance.

[0129] If the rear observation distance is the shortest among the outdoor unit observation distances (S412 YES), the smart ECU 1 executes step S413. On the other hand, if the rear observation distance is not the shortest among the outdoor unit observation distances (S412 NO), the smart ECU 1 executes step S415.

[0130] In step S413, the smart ECU 1 determines whether the rear observation distance is less than the proximity determination value. If the rear observation distance is less than the proximity determination value (YES in S413), the smart ECU 1 determines that the device position is near the rear end outside the vehicle (e.g., the trunk door) (S414).

[0131] Step S415 is a step for determining whether the minimum value of the outdoor unit strength is smaller than a predetermined far-distance judgment value. In the figure, minD(OUT) represents the minimum value of the outdoor unit strength. The far-distance judgment value is a parameter for determining that the portable device Md is not present near the vehicle Hv. The far-distance judgment value is set to, for example, 5.0 m, 6.0 m, or 10 m.

[0132] In one aspect, the far-distance determination value can be understood as a parameter that defines an intermediate area located between the vicinity of the vehicle and the far-distance. The intermediate area may be a so-called welcome area where a predetermined welcome control, such as turning on the exterior lights, is executed upon entry of the portable device Md into the area. The intermediate area may be an area where a predetermined control that is not executed when the portable device Md is located far outside the vehicle is executed / started, such as authentication by wireless communication with the portable device Md, tracking of the device location, and shortening of the location determination period. The intermediate area may also be called a standby area, a surrounding area, or the like. In addition, the intermediate area may be an area where a user can use a function to remotely park / leave the vehicle Hv.

[0133] If the minimum value of the outdoor unit intensity is smaller than the predetermined far-distance judgment value (YES in S415), the smart ECU 1 judges that the device position is in the intermediate area outside the vehicle (S416). On the other hand, if the minimum value of the outdoor unit intensity is equal to or larger than the predetermined far-distance judgment value, the smart ECU 1 judges that the device position is in the far-distance area outside the vehicle.

[0134] <How to calculate the primary phase difference> Here, as examples of methods for calculating the primary phase difference, an active 2-way system, a passive 2-way system, and a 1-way system will be outlined.

[0135] First, the active 2-way system will be described. In the active 2-way system, as shown in Fig. 9, an initiator and a reflector transmit and receive CW signals to each other, and each detects the phase difference between the transmitted signal and the received signal. The initiator then collects the phase difference observed by the reflector, and identifies the primary phase difference. The active 2-way system includes a process of transmitting and receiving CW signals to each other, and a process of transmitting a received phase message indicating the received phase (θr) observed by the reflector to the initiator.

[0136] An initiator is a device that starts communication, in other words, a device that requests a response. A reflector is a device that returns a response. Here, the wireless device 2 corresponds to the initiator, and the portable device Md corresponds to the reflector. A reflector may also be called a responder. In another embodiment, the portable device Md may operate as an initiator.

[0137] CW_I in Fig. 9 is the CW signal transmitted by the initiator. CW_R is the CW signal transmitted by the reflector. RpMsg in Fig. 9 indicates the received phase message. If the initial phase of the initiator is δi, the initial phase of the reflector is δr, the first-order phase difference that should be observed according to the one-way distance between the initiator and reflector is φ, and the target frequency is f, then the relationships are θr=φ+δi-δr and θi=φ-δi+δr.

[0138] Based on the above relational expression, the average value of θi and θr is the primary phase difference (φ) in which the initial phase components of the initiator and reflector are cancelled out. The active two-way system corresponds to a system in which the average value of the reception phase at the initiator and the reception phase at the reflector is calculated as the primary phase difference. Note that since the phase difference due to one-way propagation is assumed here, the average value of θi and θr is taken as the primary phase difference. In another aspect, when the phase difference due to two-way propagation is assumed as the primary phase difference, the primary phase difference can be calculated as θi + θr.

[0139] As shown in Figure 10, the passive 2-way system is also a system in which an initiator and a reflector transmit and receive CW signals to each other. The difference from the active 2-way system is that the reflector reflects the reception phase of the CW signal transmitted from the initiator in the initial phase of the transmission signal before transmitting it. For example, when the reception phase at the reflector is θr, it transmits a CW signal expressed as z(t)=A·exp{-i(ωt+θr+2πn)}. A represents the amplitude. ω is the angular frequency corresponding to the target frequency (f) and has the relationship ω=2πf. n is a natural number and corresponds to the interval from when the reflector receives the CW signal to when it transmits the CW signal.

[0140] According to the above method, the reception phase observed by the initiator does not include the initial phase component of the reflector. The reception phase observed by the initiator is the same value as when a CW signal is received that is reflected and returned by a reflecting object OBJ such as a wall. As a result, the initiator can calculate the first-order phase difference without acquiring the reception phase from the reflector. The passive two-way method has an advantage over the active two-way method in that the reflector does not need to transmit a reception phase message.

[0141] The one-way method is a method in which the reception phase of the CW signal transmitted from the portable device Md is adopted as the primary phase difference as shown in FIG. 11, on the premise that the initial phase of the CW signal for each frequency transmitted from the portable device Md is constant. In the one-way method or the two-way method, the initiator and the reflector exchange messages indicating the parameters for performing the ranging communication prior to transmitting the CW signal for each frequency (i.e., as a preparation process). The parameters for performing the ranging communication refer to, for example, the setting value of the initial phase, the interval for switching the frequency, the frequency increment (so-called hopIncrement), the initial frequency, and the like. For example, when the one-way method is adopted, the portable device Md transmits a ranging setting notification message indicating the above setting values ​​to the wireless device 2. The portable device Md may start transmitting the CW signal based on receiving an Ack from the wireless device 2 in response to the ranging setting notification message. Of course, the wireless device 2, not the portable device Md, may determine the parameters for performing the ranging communication and transmit the ranging setting notification message.

[0142] <Explanation of the effect of the above configuration> The developers of this disclosure conducted a strength measurement test in two patterns to verify the effect of the type of antenna provided in the outdoor unit on the strength inside the vehicle cabin. The first pattern is a pattern in which a dipole antenna is placed on the right door handle. The second pattern is a pattern in which an inverted-F antenna is placed on the right door handle. The first pattern corresponds to a configuration in which a dipole antenna is used to measure the strength of the device. The second pattern corresponds to a configuration in which an inverted-F antenna is used to measure the strength of the device.

[0143] In both patterns, the portable device Md is placed on the seating surface of the right front seat. The orientation of the antenna in the right door handle is adjusted so that the polarization plane and the main beam direction are approximately the same. In addition, the test conditions other than the type of antenna, such as the transmission power, the placement location and posture of the portable device Md, and the wiring path of the communication cable C, are substantially the same. The above test corresponds to a test for verifying how much the device strength when the portable device Md is present in the vehicle cabin changes depending on the antenna type of the outdoor unit used for strength measurement.

[0144] As a result of the above test, when a dipole antenna is used for device strength measurement, the device strength at the right front seat is reduced by about 12 dB to 18 dB compared to when an inverted-F antenna is used for device strength measurement. In other words, it was confirmed that the reception strength at the portable device Md present in the vehicle cabin can be reduced by about 15 dB on average by using a dipole antenna for device strength measurement. Naturally, the smaller the reception strength at the portable device Md present in the cabin for the signal emitted from the outdoor unit, the less likely the reception strength inversion phenomenon will occur. The test result means that the risk of the reception strength inversion phenomenon occurring can be reduced by adopting a dipole antenna as the antenna type for the outdoor unit.

[0145] In addition, a monopole antenna and a λ / 4 antenna such as an inverted F antenna or an inverted L antenna operate by regarding the ground layer 31 as a grounded element of a dipole antenna. Therefore, when a λ / 4 antenna is operated, a current is also induced in the ground layer 31, and a relatively large leakage current may flow in the communication cable C. If the leakage current in the communication cable C is large, the noise radiated from the communication cable C toward the inside of the vehicle may increase the strength in the vehicle interior. As a result, the inversion phenomenon of the reception strength is likely to occur. In other words, the device strength for a signal transmitted from the second antenna 5 configured as a λ / 4 antenna is not reliable as a criterion for determining the device position.

[0146] The configuration of the present disclosure has been created based on the above findings and considerations. The in-vehicle system VS of the present disclosure uses only the first antenna strength among the first antenna strength and the second antenna strength to determine whether the portable device Md is present inside the vehicle (S403). In other words, the smart ECU1 does not use the second antenna strength to determine whether the portable device Md is present inside the vehicle. This is because, as described above, the second antenna strength is unreliable as a criterion for determining whether the portable device Md is present inside the vehicle. With this configuration, it is possible to reduce the risk of erroneously determining the device position due to radio waves originating from leakage current from the communication cable C connected to the outdoor unit.

[0147] Incidentally, if a linear conductor having a length of λ / 4 is connected to the ground layer 31 in addition to the first antenna 4, resonance may occur in the linear conductor due to a small amount of induced current flowing in the ground layer 31 when the first antenna 4 is in operation. For example, if the second antenna 5 is also a dipole antenna, resonance may also occur in the ground element of the second antenna 5 when the first antenna 4 is in operation. If resonance occurs in another linear conductor connected to the ground layer 31 when the first antenna 4 is in operation, leakage current may increase.

[0148] To address this issue, the second antenna 5 provided in each wireless device 2 is not a dipole antenna but a monopole antenna (specifically, an inverted L antenna). In other words, the second antenna 5 is an antenna type that is not connected to the ground layer 31. Therefore, there is little risk that resonance will occur in the second antenna 5 due to a minute induced current flowing in the ground layer 31 when the first antenna 4 is in operation. This also reduces the risk that the second antenna 5 will be excited when the first antenna 4 is in operation. As a result, it is possible to further suppress leakage current to the communication cable C when the first antenna 4 is in operation.

[0149] Furthermore, in calculating the device distance, the wireless device 2 determines the final device distance based on the device distances calculated by each of the first antenna 4 and the second antenna 5. This configuration can improve the accuracy of distance estimation compared to a configuration in which the device distance measured by only one antenna is directly adopted as the final device distance.

[0150] Furthermore, since the second antenna 5 is a λ / 4 antenna (specifically, an inverted L antenna), the size of the board is smaller than when both the first antenna 4 and the second antenna 5 are dipole antennas. By making the antennas that are not used to measure the reception strength out of the multiple antennas λ / 4 antennas, it is possible to further miniaturize the board 3. A λ / 4 antenna can be understood as a conductor having a structure in which the path length of the current is λ / 4.

[0151] In addition, the present disclosure includes a configuration in which, in at least the outdoor unit, an antenna used to measure the device strength is a half-wave antenna, while an antenna not used to measure the device strength is a non-half-wave antenna, in order to reduce the size of the board and improve the accuracy of determining the device position. A half-wave antenna is an antenna having a length half the wavelength (target wavelength: λ) of radio waves used for communication with the portable device Md. Half-wave antennas include dipole antennas, slot antennas, and patch antennas. The first antenna 4 may be a slot antenna or a patch antenna. A half-wave antenna can be understood as a conductor having a structure in which the path length of a current is λ / 2.

[0152] Moreover, the non-half-wavelength antenna is, for example, a λ / 4 antenna such as a monopole antenna, an inverted L antenna, or an inverted F antenna. In addition, a zero-order resonant antenna, which is an antenna that uses zero-order resonance, which is an application technology of metamaterials, can also be included in the non-half-wavelength antenna. The zero-order resonant antenna is a mushroom-shaped antenna that includes a patch part that is a flat metal conductor arranged opposite to the ground layer 31, and a short-circuit part that electrically connects the center of the patch part to the ground layer 31. The zero-order resonant antenna transmits and receives a desired radio wave by utilizing parallel resonance caused by the capacitance formed between the ground layer 31 and the patch part and the inductance of the short-circuit part. The zero-order resonant antenna can also be called a metamaterial antenna.

[0153] The above description of the first antenna can be rephrased as a half-wave antenna or a dual-purpose antenna. The dual-purpose antenna here refers to an antenna that is used not only for ranging but also for measuring device strength. The above description of the second antenna can be rephrased as a non-half-wave antenna or a dedicated antenna. Here, dedicated refers to an antenna that is used only for ranging, out of device strength measurement and ranging. Here, dedicated means that it is not intended to be used for measuring device strength related to device position determination. The dedicated antenna may be used for purposes other than strength measurement, such as data communication and wireless authentication.

[0154] The shapes, mounting positions, and types of the first antenna 4 and the second antenna 5 can be changed as appropriate. For example, as shown in Fig. 12, the first antenna 4 and the second antenna 5 may have a bent shape that is bent in multiple stages. The first antenna 4 may have a folded shape. The second antenna 5 may be formed in a meandering shape.

[0155] The feed line length Lfd may be set to a length equivalent to λ / 4 (for example, 36 mm). According to a configuration in which the feed line length Lfd is set to λ / 4, the amount / probability of current flowing to the ground layer 31 during operation of the first antenna 4 can be further reduced. Note that, when the feed line length Lfd to the first antenna 4 is set to λ / 4, leakage current to the communication cable C can be suppressed even if the second antenna 5 is a grounded antenna. A grounded antenna is an antenna that has a portion connected to the ground layer 31, and refers to an inverted F antenna, a dipole antenna, a zero-order resonant antenna, etc. Conversely, in the present disclosure, an antenna type that does not have a portion connected to the ground layer 31, such as a monopole antenna or an inverted L antenna, is called a non-grounded antenna.

[0156] Additionally, any reference to an element using a designation such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed. Nor does it imply that the first element must precede the second element in any way.

[0157] For example, there may be two first antennas 4, as indicated by reference numerals 4A and 4B in FIG. 13. The antennas are preferably arranged at a distance of λ / 8 or more from each other. The first antennas 4A and 4B may be formed along edges of the substrate 3 that face each other. According to this configuration, the distance between the first antennas 4A and 4B can be set relatively large. Providing a plurality of first antennas 4 corresponds to a configuration having a plurality of half-wave antennas. Although FIG. 13 illustrates a case in which both the first antennas 4A and 4B are dipole antennas, the types of the plurality of first antennas 4 may be different. For example, the first antenna 4B may be a slot antenna or a patch antenna. In addition, when a plurality of dipole antennas are provided as half-wave antennas, the feeder line lengths to the dipole antennas may be set to a length difference equivalent to λ / 4. According to this setting, the leakage current to the communication cable C can be further reduced.

[0158] In addition, when the wireless device 2 has a plurality of half-wave antennas, the controller 9 may measure the device strength for each half-wave antenna as shown in FIG. 14. Step S501 shown in FIG. 14 is a step in which the controller 9 sets the half-wave antenna whose device strength has not been measured as the used antenna. Step S502 is a step in which the controller 9 calculates the average value or the median value of the device strength for each frequency using the half-wave antenna selected in step S501. The content of step S502 may be the same as steps S102 to S106. Step S503 is a step in which it is determined whether the device strength has been measured for all the half-wave antennas. If there remains a half-wave antenna whose device strength has not yet been measured, the controller 9 sets the half-wave antenna whose strength has not yet been measured as the used antenna, and then performs step S502. Step S504 is a step in which the controller 9 calculates the average of the measured values ​​of the device strength for each half-wave antenna as the strength to be reported.

[0159] The wireless device 2 may include a plurality of second antennas 5. For example, as shown in FIG. 15, second antennas 5A and 5B may be formed on the substrate 3. In addition, it is preferable that the antennas provided on the substrate 3 are spaced apart from each other by λ / 8 or more. This configuration makes it possible to maintain good isolation between the antennas. As in FIG. 4, the switch 6, the transceiver 8, and the controller 9 are not shown in FIGS. 12, 13, and 15. Also, the connector 71 is not shown in FIGS. 13 and 15.

[0160] The secondary phase difference acquisition unit F3 may not calculate the secondary phase difference for each combination of frequencies individually. The secondary phase difference acquisition unit F3 may calculate a regression line L indicating the relationship between the frequency and the reception phase based on the reception phase for each frequency (i.e., the primary phase), and may adopt the slope of the regression line L as the secondary phase difference. FIG. 16 is a conceptual diagram showing the relationship between the regression line L and the reception phase for each frequency. This is because the slope of the regression line L indicates the amount of change in the reception phase relative to the amount of shift in the frequency. The regression line L and its slope can be calculated by various methods, such as the least square method. If the regression line is expressed as y=a·x+b, the coefficient a of x corresponds to the slope of the regression line L. The regression line L can also be referred to as an approximation line. The secondary phase difference acquisition unit F3 may also determine the secondary phase difference to be used in distance calculation by recalculating the approximation line after excluding values ​​(so-called outliers) whose distance from the regression line L temporarily calculated based on the observed values ​​is equal to or greater than a predetermined value. These configurations can reduce the processing load on the secondary phase difference acquisition unit F3 while improving the accuracy of the secondary phase difference, which in turn can be expected to improve the distance measurement accuracy.

[0161] In the above, the smart ECU 1 determines the device location using the reception strength observed by the portable device Md, but the present invention is not limited to this. The smart ECU 1 may determine the device location based on the reception strength of the signal from the portable device Md received by the first antenna 4. The smart ECU 1 may be configured to treat the reception strength of the signal from the portable device Md received by the first antenna 4 as the above-mentioned first antenna strength. With this configuration, the smart ECU 1 and the wireless device 2 do not need to collect reception strength information for each frequency from the portable device Md. In addition, since the transceiver 8 is configured to use the reception voltage at the first antenna 4 as the reference voltage for AGC, the risk of overestimating the reception strength due to noise propagating from the communication cable can be reduced.

[0162] The controller 9 may calculate the device distance using a round-trip time (RTT) instead of or in addition to the transmission and reception phase difference. The RTT is the time from when a response request signal is transmitted to when a response signal is received. The RTT and the transmission and reception phase difference correspond to distance-related values. Transmitting and receiving a signal for measuring the RTT also corresponds to an example of distance measurement communication.

[0163] The above embodiment is applicable to various vehicles that run on roads. That is, the present disclosure can be installed in various vehicles that can run on roads, such as two-wheeled vehicles, three-wheeled vehicles, etc., in addition to four-wheeled vehicles. Motorized bicycles can also be included in two-wheeled vehicles.

[0164] The in-vehicle system VS may be configured such that each wireless device 2 operates as a master device of the portable device Md by using a multipoint technique. Also, the in-vehicle system VS may be configured such that each wireless device 2 operates as a slave device of the portable device Md.

[0165] The communication method between the wireless device 2 and the portable device Md is not limited to BLE, and may be Bluetooth Classic, Wi-Fi (registered trademark), EnOcean (registered trademark), Zigbee (registered trademark), UWB-IR (Ultra Wide Band - Impulse Radio), etc. Various communication methods can be adopted between the wireless device 2 and the portable device Md. Various standards such as IEEE802.11n and IEEE802.11ax can also be adopted as the Wi-Fi standard.

[0166] <Additional remarks (1)> The present disclosure also includes the following technical ideas. Furthermore, the present disclosure also includes within its scope a program for causing a computer to function as a controller (control module), and a non-transient tangible recording medium such as a semiconductor memory on which the program is recorded. The present disclosure also includes within its scope an in-vehicle system including a plurality of wireless communication devices and a position determination device, as well as a position determination method implemented by a smart ECU, as described below.

[0167] [Technical thought 1] A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on an exterior surface of a vehicle and used therewith, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include a first antenna (4) which is a half-wave antenna; a second antenna (5) that is not a half-wave antenna; The control module includes: Obtaining a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; performing distance measurement communication using the first antenna, the distance measurement communication being communication for measuring a distance-related value that is a parameter different from the reception strength and that takes a value corresponding to a distance to the mobile device; performing the ranging communication using the second antenna; and Calculating a distance to the portable device based on a first distance-related value obtained in the ranging communication using the first antenna and a second distance-related value obtained in the ranging communication using the second antenna; and transmitting data indicating the distance to the portable device to a position determination device mounted on the vehicle, the data corresponding to the first antenna strength.

[0168] [Technical thought 2] The device further includes a substrate (3) including a ground layer (31), The wireless communication device described in technical idea 1, wherein the second antenna is not connected to the ground layer.

[0169] [Technical thought 3] The wireless communication device described in Technical Idea 1 or 2, wherein the control module performs communication for measuring the distance-related value by using each of the multiple antennas in sequence.

[0170] [Technical thought 4] A wireless communication device described in any one of technical ideas 1 to 3, wherein the control module is configured not to receive data indicating the second antenna strength, which is the receiving strength at the mobile device for the signal transmitted from the second antenna, from the mobile device, or to ignore the data even if received.

[0171] [Technical thought 5] A transceiver unit (8) is connected to each of the first antenna and the second antenna by a signal line and performs automatic gain control on a received signal, A wireless communication device described in any one of technical ideas 1 to 4, wherein the transceiver unit is configured to use the received voltage at the first antenna as a reference voltage for the automatic gain control.

[0172] [Technical Thought 6] A wireless communication device described in any one of technical ideas 1 to 5, wherein the first antenna and the second antenna are positioned at a distance from each other of at least one-eighth of a target wavelength, which is the wavelength of radio waves used for communication with the mobile device.

[0173] [Technical Thought 7] The device further includes a substrate (3) including a ground layer (31), A wireless communication device described in any one of technical ideas 1 to 6, wherein the second antenna and the first antenna are mounted on the substrate in such a manner that the polarization planes for transmission and reception are perpendicular to each other.

[0174] [Technical Thought 8] The distance-related value is a phase difference between a continuous wave signal transmitted to the portable device and the continuous wave signal received from the portable device, The wireless communication device described in any one of Technical Ideas 1 to 7, wherein the control module is configured to acquire the phase difference at each of a plurality of frequencies.

[0175] [Technical Thought 9] A wireless communication device described in any one of technical ideas 1 to 7, wherein the distance-related value is a round-trip time, which is the time from sending a response request signal to the portable device to receiving a response signal from the portable device.

[0176] [Technical Thought 10] A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on a vehicle and used therein, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include a first antenna (4) which is a half-wave antenna; a second antenna (5) that is not a half-wave antenna; The control module includes: Obtaining a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; performing distance measurement communication for the portable device to calculate a device distance, which is a distance from the portable device to the wireless communication device, for each of the antennas; receiving data from the portable device indicative of the device distance; and transmitting a signal indicative of said reception strength and said distance to a position determining device.

[0177] [Technical Thought 11] A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on an exterior surface of a vehicle and used therewith, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include a first antenna (4) which is a half-wave antenna; a second antenna (5) that is not a half-wave antenna; The control module includes: Obtaining a first antenna strength, which is a reception strength of a wireless signal from the portable device received by the first antenna; performing distance measurement communication using the first antenna, the distance measurement communication being communication for measuring a distance-related value that is a parameter different from the reception strength and that takes a value corresponding to a distance to the mobile device; performing the ranging communication using the second antenna; and Calculating a distance to the portable device based on a first distance-related value obtained in the ranging communication using the first antenna and a second distance-related value obtained in the ranging communication using the second antenna; and transmitting data indicating the distance to the portable device to a position determination device mounted on the vehicle, the data corresponding to the first antenna strength.

[0178] [Technical Thought 12] A wireless communication device according to any one of technical ideas 1 to 11, which is built into an outer door handle, pillar, side mirror, side sill, or bumper of the vehicle.

[0179] [Technical Thought 13] A substrate for a wireless communication device mounted on an outer door handle of a vehicle, A ground layer (31); a first antenna (4) which is a half-wave antenna for performing wireless communication with a mobile device; A second antenna (5) is an antenna for performing wireless communication with a portable device of a type different from that of the first antenna, and is an ungrounded antenna that does not have a portion electrically connected to the ground layer; a control module (9) for controlling the operation of the plurality of antennas; The control module includes: a strength acquisition unit (F5) that acquires a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; a distance acquisition unit (F4) for acquiring data indicating a distance from the portable device to the wireless communication device by sequentially causing the plurality of antennas to communicate with the portable device; a report processing unit (F6) that associates data indicating the distance to the mobile device with data indicating the first antenna strength and transmits the data to a position determination device.

[0180] [Technical Thought 14] A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on a vehicle and used therein, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include a first antenna (4) which is a half-wave antenna; a second antenna (5) that is not a half-wave antenna; The control module includes: Obtaining a first antenna strength, which is a reception strength of a wireless signal from the portable device received by the first antenna; performing distance measurement communication for the portable device to calculate a device distance, which is a distance from the portable device to the wireless communication device, for each of the antennas; receiving data from the portable device indicative of the device distance; and transmitting a signal indicative of said reception strength and said distance to a position determining device.

[0181] The configuration described in any one of the above technical ideas 2 to 10 can be appropriately introduced into the configurations described as technical ideas 11 and 13. Technical idea 14 corresponds to a configuration in which the configuration described as technical idea 10 in which the portable device Md calculates distance is applied to technical idea 11.

[0182] <Additional remarks (2)> The various flowcharts shown in this disclosure are all examples, and the number of steps constituting the flowchart and the order of execution of the processes can be changed as appropriate. In this disclosure, "acquire" can be read as "calculate", "receive", and "detect". The device, system, and method thereof described in this disclosure may be realized by a dedicated computer constituting a processor programmed to execute one or more functions embodied by a computer program. The device and method described in this disclosure may be realized using a dedicated hardware logic circuit. The device and method described in this 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. Some or all of the functions of the controller 9 may be realized as hardware. A mode in which a certain function is realized as hardware includes a mode in which it is realized using one or more ICs, etc. As the processor (computation core), a CPU, an MPU, a GPU, a DFP (Data Flow Processor), etc. can be adopted. Some or all of the functions of the controller 9 may be realized using any one of a system-on-chip (SoC), an integrated circuit (IC), and a field-programmable gate array (FPGA). The concept of an IC also includes an application specific integrated circuit (ASIC). The computer program may be stored in a computer-readable non-transitive tangible storage medium as instructions executed by a computer. As the program storage medium, a hard-disk drive (HDD), a solid state drive (SSD), a flash memory, etc. may be used. [Explanation of symbols]

[0183] 1 Smart ECU (position determination device), 2 Radio (wireless communication device), 3 Board, 4 First antenna, 5 Second antenna, 6 Switch, 7 In-vehicle communication unit, 8 Transmitter / receiver unit, 9 Controller (control module), 31 Ground layer, C Communication cable, F4 Distance acquisition unit, F5 Strength acquisition unit, F6 Report processing unit.

Claims

1. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on an exterior surface of a vehicle and used therewith, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; a transceiver unit (8) connected to each of the first antenna and the second antenna by a signal line and performing automatic gain control on a received signal; the transceiver is configured to use a received voltage at the first antenna as a reference voltage for the automatic gain control; The control module includes: Obtaining a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; performing distance measurement communication using the first antenna, the distance measurement communication being communication for measuring a distance-related value that is a parameter different from the reception strength and that takes a value corresponding to a distance to the mobile device; performing the ranging communication using the second antenna; and Calculating a distance to the portable device based on a first distance-related value obtained in the ranging communication using the first antenna and a second distance-related value obtained in the ranging communication using the second antenna; A wireless communication device that associates data indicating the distance to the portable device with data indicating the first antenna strength and transmits the data to a position determination device installed in the vehicle.

2. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on an exterior surface of a vehicle and used therewith, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; The first antenna and the second antenna are arranged apart from each other by at least one-eighth of a target wavelength, which is a wavelength of a radio wave used for communication with the mobile device; The control module includes: Obtaining a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; performing distance measurement communication using the first antenna, the distance measurement communication being communication for measuring a distance-related value that is a parameter different from the reception strength and that takes a value corresponding to a distance to the mobile device; performing the ranging communication using the second antenna; and Calculating a distance to the portable device based on a first distance-related value obtained in the ranging communication using the first antenna and a second distance-related value obtained in the ranging communication using the second antenna; A wireless communication device that associates data indicating the distance to the portable device with data indicating the first antenna strength and transmits the data to a position determination device installed in the vehicle.

3. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on an exterior surface of a vehicle and used therewith, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; A substrate (3) including a ground layer (31); the second antenna and the first antenna are provided on the substrate in such a manner that their polarization planes for transmission and reception are orthogonal to each other; The control module includes: Obtaining a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; performing distance measurement communication using the first antenna, the distance measurement communication being communication for measuring a distance-related value that is a parameter different from the reception strength and that takes a value corresponding to a distance to the mobile device; performing the ranging communication using the second antenna; and Calculating a distance to the portable device based on a first distance-related value obtained in the ranging communication using the first antenna and a second distance-related value obtained in the ranging communication using the second antenna; A wireless communication device that associates data indicating the distance to the portable device with data indicating the first antenna strength and transmits the data to a position determination device installed in the vehicle.

4. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on a vehicle and used therein, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; a transceiver unit (8) connected to each of the first antenna and the second antenna by a signal line and performing automatic gain control on a received signal; the transceiver is configured to use a received voltage at the first antenna as a reference voltage for the automatic gain control; The control module includes: Obtaining a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; performing distance measurement communication for the portable device to calculate a device distance, which is a distance from the portable device to the wireless communication device, for each of the antennas; receiving data from the portable device indicative of the device distance; and transmitting a signal indicative of said reception strength and said distance to a position determining device.

5. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on a vehicle and used therein, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; The first antenna and the second antenna are arranged apart from each other by at least one-eighth of a target wavelength, which is a wavelength of a radio wave used for communication with the mobile device; The control module includes: Obtaining a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; performing distance measurement communication for the portable device to calculate a device distance, which is a distance from the portable device to the wireless communication device, for each of the antennas; receiving data from the portable device indicative of the device distance; and transmitting a signal indicative of said reception strength and said distance to a position determining device.

6. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on a vehicle and used therein, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; A substrate (3) including a ground layer (31); the second antenna and the first antenna are provided on the substrate in such a manner that their polarization planes for transmission and reception are orthogonal to each other; The control module includes: Obtaining a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; performing distance measurement communication for the portable device to calculate a device distance, which is a distance from the portable device to the wireless communication device, for each of the antennas; receiving data from the portable device indicative of the device distance; and transmitting a signal indicative of said reception strength and said distance to a position determining device.

7. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on an exterior surface of a vehicle and used therewith, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; a transceiver unit (8) connected to each of the first antenna and the second antenna by a signal line and performing automatic gain control on a received signal; the transceiver is configured to use a received voltage at the first antenna as a reference voltage for the automatic gain control; The control module includes: acquiring a first antenna strength, which is a reception strength of a wireless signal from the portable device received by the first antenna; performing distance measurement communication using the first antenna, the distance measurement communication being communication for measuring a distance-related value that is a parameter different from the reception strength and that takes a value corresponding to a distance to the mobile device; performing the ranging communication using the second antenna; and Calculating a distance to the portable device based on a first distance-related value obtained in the ranging communication using the first antenna and a second distance-related value obtained in the ranging communication using the second antenna; A wireless communication device that associates data indicating the distance to the portable device with data indicating the first antenna strength and transmits the data to a position determination device installed in the vehicle.

8. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on an exterior surface of a vehicle and used therewith, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; The first antenna and the second antenna are arranged apart from each other by at least one-eighth of a target wavelength, which is a wavelength of a radio wave used for communication with the mobile device; The control module includes: acquiring a first antenna strength, which is a reception strength of a wireless signal from the portable device received by the first antenna; performing distance measurement communication using the first antenna, the distance measurement communication being communication for measuring a distance-related value that is a parameter different from the reception strength and that takes a value corresponding to a distance to the mobile device; performing the ranging communication using the second antenna; and Calculating a distance to the portable device based on a first distance-related value obtained in the ranging communication using the first antenna and a second distance-related value obtained in the ranging communication using the second antenna; A wireless communication device that associates data indicating the distance to the portable device with data indicating the first antenna strength and transmits the data to a position determination device installed in the vehicle.

9. A wireless communication device for wirelessly communicating with a mobile device, the wireless communication device being mounted on an exterior surface of a vehicle and used therewith, A plurality of antennas; a control module (9) for controlling the operation of the plurality of antennas; The plurality of antennas include A first antenna (4), which is a half-wave antenna; a second antenna (5) which is not a half-wave antenna; A substrate (3) including a ground layer (31); the second antenna and the first antenna are provided on the substrate in such a manner that their polarization planes for transmission and reception are orthogonal to each other; The control module includes: acquiring a first antenna strength, which is a reception strength of a wireless signal from the portable device received by the first antenna; performing distance measurement communication using the first antenna, the distance measurement communication being communication for measuring a distance-related value that is a parameter different from the reception strength and that takes a value corresponding to a distance to the mobile device; performing the ranging communication using the second antenna; and Calculating a distance to the portable device based on a first distance-related value obtained in the ranging communication using the first antenna and a second distance-related value obtained in the ranging communication using the second antenna; A wireless communication device that associates data indicating the distance to the portable device with data indicating the first antenna strength and transmits the data to a position determination device installed in the vehicle.

10. A substrate for a wireless communication device mounted on an outer door handle of a vehicle, A ground layer (31); a first antenna (4) which is a half-wave antenna for performing wireless communication with a mobile device; A second antenna (5) is an antenna for performing wireless communication with a portable device of a type different from that of the first antenna, and is an ungrounded antenna that does not have a portion electrically connected to the ground layer; a control module (9) for controlling the operation of the plurality of antennas; a transceiver unit (8) connected to each of the first antenna and the second antenna by a signal line and performing automatic gain control on a received signal; the transceiver is configured to use a received voltage at the first antenna as a reference voltage for the automatic gain control; The control module includes: a strength acquisition unit (F5) that acquires a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; a distance acquisition unit (F4) for acquiring data indicating a distance from the portable device to the wireless communication device by sequentially causing the plurality of antennas to communicate with the portable device; A board including a report processing unit (F6) that associates data indicating the distance to the mobile device with data indicating the first antenna strength and transmits the data to a position determination device.

11. A substrate for a wireless communication device mounted on an outer door handle of a vehicle, A ground layer (31); a first antenna (4) which is a half-wave antenna for performing wireless communication with a mobile device; A second antenna (5) is an antenna for performing wireless communication with a portable device of a type different from that of the first antenna, and is an ungrounded antenna that does not have a portion electrically connected to the ground layer; a control module (9) for controlling the operation of the plurality of antennas; The first antenna and the second antenna are arranged apart from each other by at least one-eighth of a target wavelength, which is a wavelength of a radio wave used for communication with the mobile device; The control module includes: a strength acquisition unit (F5) that acquires a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; a distance acquisition unit (F4) for acquiring data indicating a distance from the portable device to the wireless communication device by sequentially causing the plurality of antennas to communicate with the portable device; A board including a report processing unit (F6) that associates data indicating the distance to the mobile device with data indicating the first antenna strength and transmits the data to a position determination device.

12. A substrate for a wireless communication device mounted on an outer door handle of a vehicle, A ground layer (31); a first antenna (4) which is a half-wave antenna for performing wireless communication with a mobile device; A second antenna (5) is an antenna for performing wireless communication with a portable device of a type different from that of the first antenna, and is an ungrounded antenna that does not have a portion electrically connected to the ground layer; a control module (9) for controlling the operation of the plurality of antennas; the second antenna and the first antenna are provided on the substrate in such a manner that their polarization planes for transmission and reception are orthogonal to each other; The control module includes: a strength acquisition unit (F5) that acquires a first antenna strength, which is a reception strength at the mobile device of a wireless signal transmitted from the first antenna; a distance acquisition unit (F4) for acquiring data indicating a distance from the portable device to the wireless communication device by sequentially causing the plurality of antennas to communicate with the portable device; A board including a report processing unit (F6) that associates data indicating the distance to the mobile device with data indicating the first antenna strength and transmits the data to a position determination device.

Images