Position detecting system, position detecting method, and computer

Abstract

A DK-ECU 1 determines whether a portable device (9) supports wireless communication using a second communication scheme on the basis of wireless communication with the portable device (9) using a first communication scheme. If it is determined that the portable device supports wireless communication using the second communication scheme, a communication module (2) is caused to perform wireless communication with the portable device (9) using the second communication scheme, and a position-related value relating to the position of the portable device is acquired from a wireless communication signal in the second communication scheme. If it is determined that the portable device (9) does not support wireless communication using the second communication scheme, the position-related value is acquired from a wireless communication signal in the first communication scheme. The acquired position-related value is used to determine a position (area) of the portable device (9) relative to a vehicle (Hv).

Description

Position detection system, position detection method, and computer CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-206917 filed in Japan on December 7, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The present disclosure relates to a technology for detecting the position of a mobile device relative to an object by wirelessly communicating with the mobile device through a communication module installed in the object.

[0003] Patent Document 1 discloses a portable device configured to establish a Bluetooth (registered trademark, hereinafter the same) Low Energy (BLE) communication connection with a communication gateway in a vehicle, and then perform impulse radio ultra-wideband (IRUWB) communication with at least one sensor provided in the vehicle.

[0004] Patent No. 6988986

[0005] The mobile equipment (hereinafter also referred to as a mobile device) disclosed in Patent Document 1 is configured to perform BLE communication and IRUWB communication. However, not all mobile devices are equipped with BLE communication and IRUWB communication functions. The use of BLE channel sounding (CS) communication is also being considered as a technology for detecting the location of a mobile device. In BLECS communication, continuous waves, such as sine waves, whose frequency is periodically changed are transmitted and received. As such, there are multiple variations in communication methods for locating the position of a mobile device relative to an object (e.g., a vehicle). Even if a communication module installed in an object supports multiple communication methods for locating the position of the mobile device, as described above, not all mobile devices necessarily support these multiple communication methods. Therefore, there is a need for a technology that can absorb the differences and properly detect the location of a mobile device even when the communication methods supported by the communication module and the mobile device do not match.

[0006] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide a position detection system, a position detection method, and a computer that are capable of detecting the position of a mobile device even when the multiple communication methods supported by a communication module installed on an object do not match the communication method supported by the mobile device.

[0007] In order to achieve the above object, a position detection system according to the present disclosure is a position detection system for detecting a position of a portable device relative to an object, comprising: a communication module installed on the object and performing wireless communication with the portable device using a first communication method; the communication module configured to be able to perform wireless communication with the portable device also using a second communication method different from the first communication method; a determination unit that determines whether the portable device supports wireless communication using the second communication method based on the wireless communication with the portable device using the first communication method; an acquisition unit that, if the determination unit determines that the portable device supports wireless communication using the second communication method, causes the communication module to perform wireless communication with the portable device using the second communication method and acquires a position-related value related to the position of the portable device from the wireless communication signal with the portable device using the second communication method, and if the determination unit determines that the portable device does not support wireless communication using the second communication method, acquires a position-related value related to the position of the portable device from the wireless communication signal with the portable device using the first communication method; and a determination unit that determines the position of the portable device relative to the object or an area in which the portable device is located based on the position-related value acquired by the acquisition unit.

[0008] Further, a position detection method according to the present disclosure is a position detection method executed by a computer for detecting a position of a portable device relative to an object, the position detection method comprising: using a communication module installed on the object to perform wireless communication with the portable device using a first communication method; the communication module being configured to be able to perform wireless communication with the portable device also using a second communication method different from the first communication method; determining whether the portable device supports wireless communication using the second communication method based on the wireless communication with the portable device using the first communication method; if it is determined that the portable device supports wireless communication using the second communication method, causing the communication module to perform wireless communication with the portable device using the second communication method and acquiring a position-related value related to the position of the portable device from the wireless communication signal with the portable device using the second communication method; if it is determined that the portable device does not support wireless communication using the second communication method, acquiring a position-related value related to the position of the portable device from the wireless communication signal with the portable device using the first communication method; and determining the position of the portable device relative to the object or an area in which the portable device is located based on the acquired position-related value.

[0009] Furthermore, a computer according to the present disclosure is a computer that executes a process of detecting a position of a portable device relative to an object based on a wireless communication signal when a communication module installed on the object and the portable device perform wireless communication, wherein the communication module is configured to be able to perform wireless communication with the portable device using a second communication method different from the first communication method in addition to a first communication method, and the computer is configured to execute the following processes: a process of determining whether or not the portable device supports wireless communication using the second communication method, based on the wireless communication with the portable device using the first communication method; a process of causing the communication module to perform wireless communication with the portable device using the second communication method when it is determined that the portable device supports wireless communication using the second communication method, and acquiring a position-related value related to the position of the portable device from the wireless communication signal with the portable device using the second communication method; and a process of determining, based on the acquired position-related value, the position of the portable device relative to the object or an area in which the portable device is located.

[0010] According to the position detection system, position detection method, and computer disclosed herein, as described above, it is determined whether the portable device supports wireless communication using a second communication method based on wireless communication with the portable device using a first communication method. If it is determined that the portable device supports wireless communication using the second communication method, the communication module is caused to wirelessly communicate with the portable device using the second communication method, and a position-related value related to the position of the portable device is acquired from the wireless communication signal with the portable device using the second communication method. In this way, if the portable device supports the second communication method, the position-related value related to the position of the portable device can be acquired from the wireless communication signal with the portable device using the second communication method. On the other hand, if it is determined that the portable device does not support wireless communication using the second communication method, the position-related value related to the position of the portable device is acquired from the wireless communication signal with the portable device using the first communication method. The calculated position-related value is used to determine the position of the portable device relative to an object or the area in which the portable device is located. Therefore, according to the position detection system, position detection method, and computer disclosed herein, it is possible to detect the position of a mobile device even if the multiple communication methods supported by the communication module installed in the target object do not match the communication method supported by the mobile device.

[0011] The reference numbers in parentheses in the claims merely indicate an example of the correspondence with specific configurations in the embodiments described below, in order to facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

[0012] Furthermore, the technical features of the present disclosure other than those described above will become apparent from the following description of the embodiments and the accompanying drawings.

[0013] 1 is a diagram illustrating an overall view of a vehicle electronic key system to which a position detection system is applied. FIG. 2 is a block diagram illustrating the configuration of a portable device. FIG. 3 is a block diagram illustrating the configuration of an in-vehicle system. FIG. 4 is a diagram illustrating an example of the arrangement of a BLE module in a vehicle. FIG. 5 is a block diagram illustrating the configuration of the BLE module. FIG. 6 is a diagram schematically illustrating the flow of a CS ranging process. FIG. 7 is a diagram illustrating the operation of a portable device and an in-vehicle system when the portable device and the in-vehicle system are not yet communicatively connected. FIG. 8 is a diagram illustrating the operation of a portable device and an in-vehicle system when the portable device and the in-vehicle system periodically perform data communication via BLE communication after a communication connection between the portable device and the in-vehicle system is established. FIG. 9 is a diagram illustrating the operation of a portable device and an in-vehicle system when the portable device and the in-vehicle system perform CS ranging communication. FIG. 10 is a functional block diagram of a main controller. FIG. 11 is a diagram illustrating an example of areas set inside and outside a vehicle to determine the location of a device based on whether it belongs to an area. FIG. 12 is a flowchart illustrating an example of a process for determining whether a portable device is compatible with CS ranging communication. FIG. 13 is a flowchart illustrating an example of a process for detecting the location of a portable device, executed in an in-vehicle system. FIG. 14 is a block diagram illustrating the configuration of a portable device according to a second embodiment. FIG. 15 is a block diagram illustrating the configuration of an in-vehicle system according to a second embodiment. FIG. 10 is a diagram showing an example of the arrangement of a BLE module and a UWB module in a vehicle according to a second embodiment. FIG. 11 is a diagram for explaining the operation of a mobile device and an in-vehicle system when the mobile device and the in-vehicle system perform UWB ranging communication. FIG. 12 is a flowchart showing an example of a process for determining whether the mobile device supports CS ranging communication and UWB ranging communication according to a second embodiment. FIG. 13 is a flowchart showing an example of a process for detecting the position of the mobile device, executed in the in-vehicle system according to a second embodiment. FIG. 14 is a flowchart showing an example of a process for selectively using a plurality of ranging methods depending on the area in which the mobile device is located according to a second embodiment. FIG. 15 is a flowchart showing an example of a process for selectively using a plurality of ranging methods depending on the moving speed of the mobile device according to a second embodiment. FIG. 16 is a diagram showing the configuration of a modified example.

[0014] Hereinafter, an embodiment in which a location detection system, a location detection method, and a computer according to the present disclosure are applied to a vehicle electronic key system will be described with reference to the accompanying drawings. However, the present disclosure is not limited to the following embodiment, and various modifications described below are also included within the technical scope of the present disclosure. Furthermore, in addition to the following, various modifications can be implemented without departing from the gist of the present disclosure. Each embodiment and various modifications can be implemented in appropriate combinations as long as no technical contradictions arise. Components having the same function are given the same reference numerals, and their description may be omitted. Furthermore, when only a portion of the configuration is mentioned, descriptions provided elsewhere can apply to the other portions.

[0015] (First Embodiment) <Overall Configuration> As shown in Figure 1, the electronic key system for a vehicle according to this embodiment includes an in-vehicle system VS and a portable device 9. The in-vehicle system VS includes a digital key ECU (hereinafter referred to as DK-ECU) 1. ECU stands for Electronic Control Unit and refers to an electronic control device. The DK-ECU 1 can also be referred to as a computer, microcomputer, processor, etc.

[0016] <Regarding the DK-ECU 1> The DK-ECU 1 is configured to be able to perform wireless communication compliant with Bluetooth LE (hereinafter referred to as BLE communication), which corresponds to a first communication method, with a portable device 9 carried by a user of the vehicle Hv. Furthermore, the DK-ECU 1 is configured to be able to perform BLE channel sounding communication (hereinafter referred to as BLECS communication), which corresponds to a second communication method, with the portable device 9. BLECS communication will be described later. In the following, a case will be described in which the DK-ECU 1 is configured to act as a master in BLE communication with the portable device 9, and the portable device 9 is configured to act as a slave. The term "master" can be read as "central" or "scanner." The term "slave" can be read as "peripheral" or "advertiser."

[0017] The DK-ECU 1 establishes a communication connection with the portable device 9 by receiving an advertising signal from the portable device 9. The advertising signal is a signal for notifying (i.e., advertising) other devices of its presence. The advertising signal may include a code indicating the sender or destination. The sender or destination may be expressed by an identifier such as a device ID. In another embodiment, the vehicle electronic key system may be configured so that the portable device 9 acts as the master in communication with the DK-ECU 1, and the DK-ECU 1 acts as the slave. The roles of each device are interchangeable. Furthermore, the functions and configurations of the DK-ECU 1 and the portable device 9 can be changed as appropriate in accordance with the role interchange.

[0018] In the present disclosure, a wireless signal conforming to the BLE standard is referred to as a BLE signal. Furthermore, among BLE signals, an advertisement channel signal may be referred to as an advertisement signal, and a data channel signal may be referred to as a data signal. Of the 40 channels of BLE communication, channels with channel numbers 37 to 39 correspond to advertisement channels. Furthermore, channels with channel numbers 0 to 36 correspond to data channels. The definitions and specific frequency values ​​of advertisement channels and data channels are determined according to the BLE standard. Furthermore, in accordance with changes to the BLE standard, the configuration of the present disclosure may be appropriately modified and implemented so as to conform to the changed standard.

[0019] <About the Portable Device 9> The portable device 9 is a portable, general-purpose information processing terminal equipped with a BLE communication function. Various communication terminals, such as a smartphone or a wearable device, can be used as the portable device 9. A wearable device is a device worn on the user's body and can have a variety of shapes, such as a wristband, a watch, a ring, glasses, or earphones. The portable device 9 can also be called a user device or a key device.

[0020] The portable device 9 may be a smart key, which is a dedicated device serving as an electronic key for the vehicle Hv. The smart key is a device that is transferred to the owner along with the vehicle Hv when the vehicle Hv is purchased. The smart key can be considered one of the accessories of the vehicle Hv. The smart key may also be called a vehicle portable device, key fob, key card, access key, etc.

[0021] As shown in FIG. 2, the mobile device 9 includes a device control unit 90, a display 95, a touch panel 96, a BLE module 97, and the like.

[0022] The device control unit 90 is a module that controls the overall operation of the portable device 9. The device control unit 90 is configured as a computer that includes, for example, a device processor 91, a memory 92, a storage 93, an input / output circuit 94, and the like. The device processor 91 is, for example, a CPU (Central Processing Unit). The memory 92 is a volatile storage medium such as RAM (Random Access Memory). The storage 93 includes a non-volatile storage medium such as flash memory. The input / output circuit 94 is a circuit that allows the device control unit 90 to receive signals from other components within the portable device 9 and output signals to other components.

[0023] The storage 93 may store a device ID, a key code used in wireless authentication processing with the DK-ECU 1, and the like. The key code may also be called an encryption key, etc. A digital key app, which is application software that causes the portable device 9 to function as a vehicle key, may be installed in the storage 93. The digital key app is an app for securely communicating with the DK-ECU 1 and responding to inquiries / requests from the DK-ECU 1. In this disclosure, the application software may be simply referred to as an app.

[0024] The display 95 is, for example, a liquid crystal display or an organic EL display. The display 95 displays an image in response to an input signal from the device control unit 90. The touch panel 96 is, for example, a capacitive touch panel, and is layered on the display 95. The touch panel 96 is an input device provided in the portable device 9. The display 95 and the touch panel 96 correspond to interfaces through which the user inputs a password into the portable device 9 for logging in to the digital key app and inputs operations for pairing the portable device 9 with the in-vehicle system VS.

[0025] The BLE module 97 is a communication module for performing BLE communication. The BLE module 97 includes a reception strength detection unit, which is a functional unit that measures the reception strength of a received signal. The measurement value of the reception strength may also be called RSSI (Received Signal Strength Indicator). In addition to the received data, the BLE module 97 outputs data indicating the measured reception strength together with transmission source information to the device control unit 90.

[0026] Furthermore, the BLE module 97 may be configured to transmit and receive a continuous wave (CW) signal of a predetermined waveform as a signal for CS (Channel Sounding) ranging, which will be described later, in addition to a modulated signal for data communication. The CW signal may be a sine wave or a triangular wave. The BLE module 97 may have a configuration similar to that of a BLE module 2, which will be described later, and which is included in the in-vehicle system VS. The description of the BLE module 2 may be partially or entirely applicable to the BLE module 97.

[0027] In order to initiate BLE communication with the in-vehicle system VS, the device control unit 90 causes the BLE module 97 to transmit an advertising signal at a predetermined transmission interval (advertising interval). Furthermore, the device control unit 90 establishes a BLE communication connection with the in-vehicle system VS based on the BLE module 97 receiving a connection request transmitted from the in-vehicle system VS in response to the advertising signal. The device control unit 90 may perform authentication processing via wireless communication (hereinafter, wireless authentication processing) based on the establishment of the communication connection with the in-vehicle system VS. The wireless authentication processing may be performed, for example, using a challenge-response method. In this case, the device control unit 90 may generate a response code using a key code in response to receiving a challenge code from the in-vehicle system VS and return the response code to the in-vehicle system VS.

[0028] Furthermore, when the BLE module 97 has a CS ranging function, the device control unit 90 executes communication for CS ranging based on a request from the in-vehicle system VS. For example, based on a request from the in-vehicle system VS, the device control unit 90 causes the BLE module 97 to transmit a CW signal of a specified channel (or frequency). The interaction between the device control unit 90 and the in-vehicle system VS will be described separately below.

[0029] <Regarding the In-Vehicle System VS> As shown in FIG. 3 , the in-vehicle system VS includes a DK-ECU 1, a BLE module 2, a body ECU 4, an action sensor 5, and an actuator 6. The DK-ECU 1, the BLE module 2, and the body ECU 4 are connected to each other so as to be able to communicate with each other, for example, via an in-vehicle network. Various standards can be adopted for the in-vehicle network, such as Controller Area Network (CAN: registered trademark), Ethernet (registered trademark), and FlexRay (registered trademark). However, the following description will be given assuming that CAN is adopted as the in-vehicle network standard. The body ECU 4 is connected to the action sensor 5 and the actuator 6. The connection configuration between devices disclosed herein is an example and can be changed as appropriate.

[0030] The DK-ECU 1 executes processing to determine the position of the portable device 9 relative to the vehicle Hv based on the BLE signals (more specifically, the RSSI ranging results and CS ranging results of the BLE signals) communicated between the BLE module 2 of the in-vehicle system VS and the BLE module 97 of the portable device 9. For example, the DK-ECU 1 detects the position of the portable device 9 by determining whether the portable device 9 is located in an entry area EA outside the vehicle or in an engine start area ESA inside the vehicle based on the BLECS signals communicated between the multiple BLE modules 2 and the portable device 9. Because the portable device 9 corresponds to a user, detecting the device position corresponds to detecting the user's position.

[0031] 3, the DK-ECU 1 includes a main controller 11, a CAN controller 15, a power supply circuit 16, etc. The main controller 11 is a computer that executes various processes related to detecting the position of the portable device 9. The main controller 11 includes a main processor 12, a memory 13, and a storage 14. The main processor 12 is, for example, a CPU that executes predetermined processes according to software. The memory 13 is a volatile storage medium, for example, a RAM.

[0032] The storage 14 includes a non-volatile storage medium such as a flash memory. The storage 14 stores a device location detection program executed by the main processor 12. Execution of the device location detection program by the main processor 12 corresponds to execution of a location detection method corresponding to the device location detection program. The storage 14 also stores registration data in which the device ID of the portable device 9 (e.g., a unique Bluetooth address) is associated with a CS compatibility flag indicating whether the portable device 9 supports BLECS communication. The storage 14 also stores data indicating the installation position of each BLE module 2 in the vehicle Hv.

[0033] The CAN controller 15 executes communication processing according to the CAN protocol with other components of the in-vehicle system VS in response to instructions from the main controller 11, etc. The CAN controller 15 executes transmission processing, reception processing, and arbitration processing as communication processing. For example, when a data frame is stored in a reception buffer, the CAN controller 15 executes reception processing and transmits the received data to the main controller 11. The reception processing includes processing to determine whether the received data frame is an invalid data frame that has been damaged or the like through a form check, a stuff check, a cyclic redundancy check, etc.

[0034] The power supply circuit 16 is a circuit module that supplies power to the main controller 11, the CAN controller 15, etc. The power supply circuit 16 converts the voltage (e.g., battery voltage) input from the power cable into a voltage suitable for the operation of the main controller 11 and the CAN controller 15, and outputs it to each section.

[0035] The BLE module 2 is a communication module for performing BLE communication. In this embodiment, a plurality of BLE modules 2 are provided in the vehicle Hv. Each BLE module 2 is also referred to as an anchor. For example, as shown in FIG. 4 , the plurality of BLE modules 2 includes, for example, an interior front anchor 2A, an interior rear anchor 2B, a right front anchor 2C, a right rear anchor 2D, a left rear anchor 2E, and a left front anchor 2F. The interior front anchor 2A and the interior rear anchor 2B are BLE modules 2 disposed in the vehicle cabin. The right front anchor 2C, the right rear anchor 2D, the left rear anchor 2E, and the left front anchor 2F are BLE modules 2 disposed on the exterior surface of the vehicle Hv. The configuration and performance of each BLE module 2 may be substantially the same regardless of the installation location. Note that the example of the arrangement of the plurality of BLE modules 2 shown in FIG. 4 is merely an example, and the plurality of BLE modules 2 may be disposed in different locations.

[0036] The BLE module 2 is configured to be able to transmit and receive CW signals for each channel (or frequency) as signals for CS ranging using BLECS communication in addition to modulated signals for data communication as BLE communication. BLE communication corresponds to a first communication method, and BLECS communication corresponds to a second communication method. Furthermore, the BLE module 2 is configured to be able to scan for advertising signals using power supplied from an on-board battery even while the vehicle Hv is parked.

[0037] The body ECU 4 is an ECU that detects user operations (actions) on the vehicle Hv based on input signals from the action sensors 5 and operates the actuators 6 in response to the detected user operations. Examples of actions on the vehicle Hv include locking and unlocking operations, sitting down, pressing a start switch, and depressing a brake pedal. The action sensors 5 include, for example, door sensors provided on the exterior door handles, a start switch, a brake pedal sensor, and a seat sensor. The body ECU 4 can detect touch operations on the door sensors as unlocking and locking operations. The door sensors are sensors that detect user operations to unlock and lock the doors of the vehicle Hv. The door sensors may be touch sensors or push-button switches. The start switch is a push-button switch that the user uses to turn the driving power on and off.

[0038] The actuator 6 is, for example, a lock motor or an on / off switching mechanism for headlights and welcome lamps. The lock motor is a motor that switches between locking and unlocking the doors. The welcome lamp is an in-vehicle lighting device that illuminates the road surface near the doors. The welcome lamp is arranged on the side mirror, side sill, the lower end of the door panel, etc.

[0039] When the body ECU 4 detects a predetermined event that requires detection of the location of the portable device 9, such as an unlocking operation, the body ECU 4 may transmit an event occurrence notification signal to the DK-ECU 1. Based on the event occurrence notification signal input from the body ECU 4, the DK-ECU 1 may execute control and processing related to the detection of the device location.

[0040] <Configuration and Function of BLE Module> Next, a description will be given of an example of the configuration and function of the BLE module 2. The BLE module 2 includes an RF core 21, an antenna 22, and a BLE controller 23, as shown in FIG.

[0041] The antenna 22 is an antenna element for transmitting and receiving radio waves in the frequency band used for 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 for BLE communication. The antenna 22 is electrically connected to the RF core 21. The channel can also be referred to as a frequency. Of the multiple channels assigned to BLE, the channel used for actual communication (in other words, the frequency / channel in use) changes over time by frequency hopping or in response to an instruction from the BLE controller 23.

[0042] The RF core 21 is a circuit module that performs signal processing for transmitting and receiving radio signals. The RF core 21 may include a modulation circuit, a demodulation circuit, a frequency conversion circuit, an amplifier circuit, a local oscillator, etc. The RF core 21 also has input / output terminals for outputting signals to the antenna 22 and receiving signals from the antenna 22.

[0043] In this embodiment, the antenna 22 includes multiple antennas 22A and 22B with different polarization axes, such as horizontal polarization and vertical polarization. These multiple antennas 22A and 22B are provided to realize polarization diversity, which ensures the reception level of the CS ranging signal by switching between the multiple antennas 22A and 22B with different polarization axes during CS ranging communication. In the following description, when the two antennas 22A and 22B are collectively described, they will be simply referred to as antenna 22. For example, when performing data communication with the mobile device 9, the RF core 21 uses only one of the multiple antennas 22A and 22B. On the other hand, when performing CS ranging communication with the mobile device 9, the RF core 21 switches between the multiple antennas 22A and 22B. The switching between the multiple antennas 22A and 22B is performed by the antenna switching unit E3 while the CS ranging signal maintains the same frequency. This makes it possible to transmit and receive CS ranging signals via multiple signal paths, making it possible to measure the phase of the CS ranging signal with high accuracy through CS ranging communication.

[0044] The BLE module 97 of the portable device 9 may or may not have multiple antennas. For example, if the BLE module 97 of the portable device 9 has two antennas, the BLE module 2 of the in-vehicle system VS and the BLE module 97 of the portable device 9 can cooperatively switch between their two antennas while the CS ranging signal maintains the same frequency, thereby enabling transmission and reception of the CS ranging signal through four signal paths. Furthermore, if the BLE module 97 of the portable device 9 does not have multiple antennas, the CS ranging signal may be transmitted and received through multiple signal paths by simply switching between the multiple antennas 22A and 22B in the BLE module 2 of the in-vehicle system VS.

[0045] The RF core 21 is connected to the BLE controller 23 so as to be able to communicate with each other. The RF core 21 demodulates a signal received by the antenna 22 and provides the demodulated signal to the BLE controller 23. The RF core 21 also modulates transmission data input from the BLE controller 23 and emits the data as radio waves from the antenna 22. The RF core 21 may be realized as an IC chip (i.e., a transmission / reception IC).

[0046] The RF core 21 is configured to be able to transmit and receive modulated signals for data communication as well as CW signals for each channel (frequency) as a function for CS ranging. The RF core 21 also includes a reception strength detection unit E1 and a reception phase detection unit E2. The reception strength detection unit E1 is a functional unit that measures the reception strength of a received signal. The reception strength detection unit E1 outputs data indicating the detected reception strength to the BLE controller 23.

[0047] The reception phase detector E2 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 ranging signal is received. The phase angle of the reception signal relative to the output signal of the local oscillator corresponds to the reception phase. In other words, the reception phase can be interpreted as the output value of the 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 the carrier wave output by the local oscillator. The Q component is obtained by multiplying the reception signal by a phase-shifted signal, which is a 90° phase shifter of the output signal of the local oscillator. The phase-shifted signal can be obtained by passing the output signal of the local oscillator through a phase shift circuit, which shifts the phase by 90°.

[0048] 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). The reception phase may be determined based on an IQ signal whose frequency has been reduced to baseband. The detected reception phase information is used to calculate the device distance.

[0049] The RF core 21 provides the BLE controller 23 with the detected value of the reception phase of the CW ranging signal in association with information indicating the frequency in use (e.g., a channel number). The RF core 21 detects the reception phase of the CW signal as part of the ranging process every time the frequency in use is switched. That is, the BLE controller 23 is provided with data indicating the reception phase for each frequency. At this time, the data indicating the reception phase for each frequency may include multiple reception phases due to the above-mentioned polarization diversity.

[0050] The BLE controller 23 is a microcomputer that controls the RF core 21. The BLE controller 23 includes a processor 24, a memory 25, a storage 26, an input / output circuit 27, etc. The BLE controller 23 controls the exchange of data with the DK-ECU 1. Specifically, the BLE controller 23 provides the DK-ECU 1 with received data input from the RF core 21 sequentially or based on a request from the DK-ECU 1. The BLE controller 23 also outputs transmission data input from the DK-ECU 1 to the RF core 21.

[0051] The BLE controller 23 includes a CS ranging unit F1, a reception strength acquisition unit F2, and a report processing unit F3. The CS ranging unit F1, the reception strength acquisition unit F2, and the report processing unit F3 may each be a software module or a hardware module. The following descriptions of the CS ranging unit F1, the reception strength acquisition unit F2, and the report processing unit F3 can be replaced with the BLE module 2 or the BLE controller 23 as appropriate.

[0052] The CS ranging unit F1 is a functional unit that performs CS ranging. CS ranging here refers to a process of generating distance data indicating the device distance based on a position-related value (reception phase), which is a parameter indicating the length of the propagation path of a wireless signal from the BLE module 2 to the mobile device 9. CS ranging includes a process of performing bidirectional or unidirectional communication with the mobile device 9 to obtain a reception phase difference, which is a position-related value. CS ranging can also be called High Accuracy Distance Measurement (HADM) or phase difference ranging. In the present disclosure, a series of processes including communication for CS ranging may also be referred to as CS ranging processing.

[0053] In this embodiment, the CS ranging unit F1 acquires the reception phase for each frequency as a CS ranging process and calculates the device distance based on the reception phase. The reception phase is the phase difference between the CW ranging signal transmitted by the portable device 9 and the CW ranging signal received by the BLE module 2. The reception phase can be called the transmission / reception phase difference, the single frequency phase difference, or the first-order phase difference.

[0054] The CS ranging unit F1 can acquire the reception phase for each frequency using, for example, a one-way method. The one-way method is a method in which, assuming that the initial phase of the CW signal for each frequency transmitted from the portable device 9 is constant, the reception phase of the CW signal transmitted from the portable device 9 is used as the basis for calculating the inter-frequency phase difference. The reception phase (in other words, the single-frequency phase difference) used as the basis for calculating the inter-frequency phase difference can also be acquired using a so-called passive two-way method or active two-way method. The passive two-way method and active two-way method will be described later in a separate supplementary explanation.

[0055] 6 is a flowchart showing an example of a CS ranging process using a one-way method. The CS ranging process includes a preparation phase for adjusting the conditions for performing ranging, a collection phase for collecting reception phases by actually transmitting and receiving CW ranging signals, and a calculation phase for calculating distances based on the collected reception phases for each frequency. In this disclosure, wireless communication for acquiring position-related values ​​(reception phases), such as transmitting and receiving CW ranging signals, is also referred to as CW ranging communication.

[0056] Step S100 is a step in which the BLE module 2 transmits a CS ranging start request to the mobile device 9. The CS ranging start request is a BLE signal requesting the mobile device 9 to start CS ranging. The CS ranging start request can be transmitted using a data channel. In step S105, the mobile device 9 returns a positive response signal (so-called Ack) to the BLE module 2 based on receiving the CS ranging start request.

[0057] In step S110, the BLE module 2 transmits a ranging setting notification signal based on receiving an ACK in response to the CS ranging start request from the mobile device 9. The ranging setting notification signal indicates parameters for performing CS ranging communication. The parameters for performing ranging communication may include an initial phase setting value, a hopping interval, a frequency transition amount, and an initial frequency. The initial phase setting value is basically set to 0. The hopping interval indicates the time required for switching frequencies, in other words, the time required for maintaining one frequency. The hopping interval may be the same as or different from the connection interval used in data communication. The frequency transition amount is a parameter indicating the amount of frequency change when switching frequencies. The frequency transition amount may be the same value as the hop increment used in data communication or may be different. If the frequency transition amount is the same value as the hop increment used in data communication, the frequency transition amount in CS ranging communication may be determined by the hop increment. The initial frequency is the frequency of the CW ranging signal transmitted first in a series of ranging communications. The frequency information may be expressed, for example, by a channel number, or may be expressed separately from the channel number.

[0058] In step S115, upon receiving the ranging setting notification signal, the portable device 9 returns an Ack to the BLE module 2. In step S120, upon receiving the Ack from the portable device 9, the BLE module 2 transitions to a state in which it can receive a signal of the initial frequency, i.e., a reception standby state.

[0059] In step S125, the portable device 9 starts transmitting a CW ranging signal at the initial frequency when a predetermined time has elapsed since returning the Ack. The transmission of the CW ranging signal can be stopped, for example, when a certain time has elapsed since the start of the transmission. The CW transmission time, which is the time for which the CW ranging signal is continuously transmitted, may be set to be shorter than the hopping interval. Note that the portable device 9 may start transmitting the CW ranging signal after receiving the ranging setting notification signal and then receiving a CW ranging transmission request from the BLE module 2.

[0060] When the BLE module 2 receives the CW ranging signal from the portable device 9, in step S130, it detects the reception phase and stores the reception phase data together with frequency information (e.g., channel number) in the memory 25. In step S140, the BLE module 2 and the portable device 9 automatically switch the operating frequency at the hopping interval previously agreed upon in step S110. The changed frequency can be uniquely determined from the frequency before the change and the previously agreed frequency transition amount.

[0061] After switching the operating frequency, the portable device 9 transmits a CW ranging signal of the new operating frequency in step S145. The BLE module 2 also switches the operating frequency, thereby transitioning to a state in which it can receive a signal of the new operating frequency. Then, in step S150, the BLE module 2 observes and acquires the reception phase at the frequency after the switching.

[0062] The BLE module 2 and the portable device 9 repeat the frequency switching process and the reception phase acquisition process described above until they have collected the reception phases for all frequencies for which the reception phases should be acquired (for example, all channels (Ch 0 to 36) that can be used for data communication). The BLE module 2 and the portable device 9 may end the repeated process when they have collected the reception phases for all predetermined necessary frequencies. The required number here may be the same as the number of data channels, or may be more or less than that. The greater the number of frequencies for which the reception phases are collected, the higher the ranging accuracy, which will be described later. On the other hand, the time and power consumption required for ranging communication may increase. The required number may be 3, 4, 5, 8, 10, 16, 37, 81, etc.

[0063] In step S160, the BLE module 2 transmits a ranging end notification signal to the portable device 9 at the timing when the necessary number of reception phases for each frequency have been collected. The ranging end notification signal is a data signal for notifying the end of CW ranging communication. Upon receiving the ranging end notification signal, the portable device 9 transitions to a normal data communication mode. The normal data communication mode corresponds to a state in which predetermined data such as audio data can be transmitted and received. The transmission and reception of the ranging end notification signal is an optional element and may be omitted. Upon receiving the ranging end notification signal, the portable device 9 may return an ACK to the BLE module 2.

[0064] When the CS ranging unit F1 has completed collection of the reception phase for each frequency, it calculates a phase change coefficient (α) in step S170. The phase change coefficient is a parameter that indicates the degree to which the reception phase changes in response to a change in frequency. The phase change coefficient can also be called the phase change degree, the phase shift amount, or the correlation coefficient between phase and frequency.

[0065] The phase change coefficient is calculated based on the reception phase observed at two arbitrary frequencies, for example, a first frequency and a second frequency. If the difference frequency, which is the difference between the first frequency and the second frequency, is Δf, the inter-frequency phase difference, which is the difference between the reception phases observed at the first frequency and the second frequency, is Δφ, and the phase change coefficient is α, then the relationship is α = Δφ / Δf. The inter-frequency phase difference (Δφ) is the difference between the reception phases observed at two different frequencies. The inter-frequency phase difference can also be called a two-frequency phase difference or a quadratic phase difference. The inter-frequency phase difference corresponds to the amount of phase angle shift due to a change in the frequency used.

[0066] The CS ranging unit F1 of this embodiment calculates a regression line showing the relationship between frequency and reception phase based on the reception phase for each frequency, and uses the slope of the regression line as the phase change coefficient. This is because the slope of the regression line indicates the amount of change in reception phase relative to the amount of frequency change. The regression line can be calculated using various methods, such as the least squares method. If the regression line is expressed as y = ax + b, the coefficient a of x corresponds to the slope of the regression line. Note that in the above equation, "x" is a variable corresponding to frequency, and "y" is a variable corresponding to reception phase. The regression line can also be referred to as an approximate line.

[0067] The CS ranging unit F1 may provisionally calculate a first regression line based on all observed reception phase data, and then recalculate a second regression line after excluding values ​​(so-called outliers) whose distance from the provisionally calculated first regression line is equal to or greater than a predetermined value. In this case, the CS ranging unit F1 may use the slope of the second regression line as a phase change coefficient. In this way, the phase change coefficient used in distance calculation may be determined based on a regression line whose population is data excluding outliers. This configuration can improve the accuracy of the inter-frequency phase difference and, ultimately, the ranging accuracy.

[0068] The CS ranging unit F1 may calculate the inter-frequency phase difference (Δφ), the differential frequency (Δf), and the phase change coefficient for each combination of frequencies for which the reception phase can be observed. The CS ranging unit F1 may use the average or median of the phase change coefficients for each combination of frequencies as the phase change coefficient to be used in distance calculation.

[0069] In step S180, the CS ranging unit F1 calculates the device distance (D) using a phase change coefficient (α) generated based on reception phase information at multiple frequencies. If the device distance is D, the differential frequency Δf and the inter-frequency phase difference (Δφ) have the relationship D∝C·Δφ / (2π·Δf)=C·α / 2π. The parameter "C" in the above equation indicates the propagation speed of radio waves (3×10^8 m / sec). The CS ranging unit F1 calculates the device distance based on this relationship. For example, the CS ranging unit F1 can calculate the device distance using equation 1: D=k·C·α / 2π. The parameter k in equation 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 a phase change coefficient for one way or a round trip. The CS ranging unit F1 stores the calculated device distance data in memory 25.

[0070] In another aspect, when the CS ranging unit F1 calculates a hypothetical value (d) of the device distance using Δf and Δφ for each frequency combination and adopts the average or median value of these as the device distance, the hypothetical value (d) of the device distance for a certain frequency combination can be calculated using d = k·C·Δφ / (2π·Δf), etc.

[0071] 6, the steps executed by the BLE module 2 are executed in cooperation with the CS ranging unit F1 and the RF core 21. In the above, as an example, the BLE module 2 determines and notifies the implementation conditions for CS ranging communication, but this is not limiting. The portable device 9, rather than the BLE module 2, may determine the specifications for implementing ranging communication and transmit a ranging setting notification signal. Furthermore, the execution entity of each step can be interchanged. The above sequence may be executed by the portable device 9 acting as the master (in other words, the master).

[0072] The reception strength acquisition unit F2 is configured to acquire data indicating the reception strength of a signal from the mobile device 9 for each frequency, which is a location-related value for BLE communication, from the RF core 21. While the BLE module 2 is connected to and communicating with the mobile device 9, the BLE module 2 periodically transmits and receives a data signal for communication confirmation with the mobile device 9. The reception strength acquisition unit F2 acquires reception strength data when the data signal for communication confirmation is received. Communication for communication confirmation can be performed at connection intervals. Communication for communication confirmation may also be performed each time channel hopping is performed.

[0073] The signal used to detect the reception strength is not limited to a data signal for communication confirmation. It may be a normal data signal or an advertising signal. Furthermore, the signal used to detect the reception strength may be a signal for CS ranging communication. Unless otherwise noted, the reception strength in the following description refers to the reception strength of a signal transmitted from the mobile device 9.

[0074] The report processing unit F3 transmits the device distance calculated by the CS ranging unit F1 and reception strength data indicating the reception strength acquired by the reception strength acquisition unit F2 to the main controller 11. The transmission of various data may be performed periodically. The report processing unit F3 may also transmit various data in response to a request from the main controller 11.

[0075] <Interaction between the portable device 9 and the in-vehicle system VS> Here, the interaction between the portable device 9 and the in-vehicle system VS will be described. The interaction between the portable device 9 and the in-vehicle system VS is performed after the portable device 9 is registered (paired) as an owner device in the in-vehicle system VS. Therefore, first, an example of an owner device registration process for registering (pairing) the portable device 9 as an owner device in the in-vehicle system VS will be described.

[0076] In the owner device registration process, if the portable device 9 is a communication terminal such as a smartphone, the user performs biometric authentication, inputs a passcode, or the like on the portable device 9. This makes it possible to confirm that the portable device 9 is being operated by the user himself / herself in the owner device registration process.

[0077] The user uses the portable device 9 to request the start of the owner device registration process from a management server (not shown). In response to this request, the management server creates a password. The created password is distributed to the portable device 9 and the in-vehicle system VS via wireless communication.

[0078] In the in-vehicle system VS, when the vehicle's main switch is turned on, a button for starting pairing between the owner device and the in-vehicle system VS is displayed, for example, on a multimedia screen provided in the vehicle cabin. When the user operates the pairing start button, the pairing process is initiated. At this time, the in-vehicle system VS preferably authenticates the user by, for example, holding a smart key having a short-range wireless communication function such as NFC near the main switch. Alternatively, the user may be authenticated by entering a passcode identifying the user on the multimedia screen. The pairing start button may also be displayed on the display 95 of the portable device 9, rather than on the multimedia screen provided in the vehicle cabin.

[0079] When the pairing start button is operated, an advertising signal is transmitted from the slave (DK-ECU1 or portable device 9) in the BLE communication to the central (portable device 9 or DK-ECU1). The central in the BLE communication receives the advertising signal from the slave. Then, when the central confirms that the slave is a legitimate communication partner based on the password distributed by the management server, it responds to the advertising signal and returns a connection request. A BLE communication connection between the central and the slave is established based on the slave's receipt of the connection request from the central.

[0080] When a BLE communication connection between the central and the slave is established, the central and the slave mutually generate encryption keys and exchange them via BLE communication. After the authenticity of the exchanged encryption key is verified, the exchanged encryption key is stored in a storage medium such as each storage. After pairing, the data signal of the BLE communication is encrypted using the exchanged encryption key. This ensures the security of the BLE communication between the DK-ECU 1 and the portable device 9.

[0081] Next, the DK-ECU 1 determines whether the portable device 9 supports CS ranging communication. This determination method will be described in detail later. If the DK-ECU 1 determines that the portable device 9 supports CS ranging communication, the DK-ECU 1 associates the ID (portable device ID) of the portable device 9 with the set CS compatibility flag, registers it, and saves it.

[0082] Finally, the management server is notified that the portable device 9 has been registered as an owner device with the in-vehicle system VS of the vehicle Hv, thereby completing the owner device registration process. After the owner device registration process is completed, the slave in the BLE communication (the DK-ECU 1 or the portable device 9) starts transmitting an advertising signal. The central in the BLE communication (the portable device 9 or the DK-ECU 1) starts scanning for the corresponding advertising signal. Note that the following describes an example in which the portable device 9 is a slave in the BLE communication.

[0083] When the portable device 9 and the in-vehicle system VS are not yet connected for communication, the portable device 9 transmits an advertising signal at an interval equal to a predetermined advertising interval plus a random time (so-called advertising delay), as shown in Fig. 7. The BLE module 2 of the in-vehicle system VS enters a reception standby state at a predetermined scan interval and scans for signals from the portable device 9. The size of the scan window, which corresponds to the length of time for which the reception standby state is maintained, may be designed as appropriate.

[0084] The lengths of the scan interval and the advertising interval can also be set to various values. The various interval values ​​are preferably set to values ​​that enable a quick connection when the user approaches the vehicle Hv. The advertising interval can be set to a value from 20 milliseconds to 400 milliseconds, such as 37.5 milliseconds, 50 milliseconds, 80 milliseconds, or 100 milliseconds. Of course, the advertising interval may be set to a value greater than 400 milliseconds as long as it complies with the BLE standard. The advertising interval may also be set to a value shorter than the scan interval.

[0085] In response to the advertising signal from the portable device 9, the in-vehicle communication system VS returns a connection request, thereby establishing a communication connection between the portable device 9 and the in-vehicle system VS. After the BLE communication connection between the portable device 9 and the in-vehicle system VS is established, the BLE module 97 of the portable device 9 and the BLE module 2 of the in-vehicle system VS periodically perform data communication at a predetermined connection interval via BLE communication, as shown in FIG. 8 . The content of the communication may be various, such as a communication confirmation. The connection interval may be set to a value between 7.5 milliseconds and 200 milliseconds, such as 30 milliseconds or 40 milliseconds. The connection interval may also be set to a value greater than 200 milliseconds as long as it complies with the BLE standard.

[0086] Furthermore, after a BLE communication connection is established between the portable device 9 and the in-vehicle system VS, the DK-ECU 1 of the in-vehicle system VS performs CS ranging communication if the BLE module 97 of the portable device 9 supports CS ranging communication. The method by which the DK-ECU 1 determines whether the BLE module 97 of the portable device 9 supports CS ranging communication will be described later. Preferably, CS ranging communication is initiated when the received signal strength of the BLE signal exceeds a predetermined strength threshold or when the distance between the positions measured by the respective GPS receivers falls below a distance threshold. When any of the above-described conditions for starting CS ranging communication is satisfied, the DK-ECU 1 can transmit a request to start CS ranging to the BLE module 2.

[0087] FIG. 9 illustrates the interaction between the portable device 9 and the in-vehicle system VS when performing CS ranging communication. The CS ranging interval, which is the interval at which the BLE module 2 performs CS ranging communication, can be set to, for example, twice or three times the connection interval. By making the CS ranging interval longer than the interval at which periodic data communication is performed, power consumption can be reduced. However, the CS ranging interval may be the same as the connection interval. Note that "CS-Ranging Interval" in FIG. 9 indicates the CS ranging interval. In one CS ranging communication, CW signals may be transmitted and received at multiple frequencies. Furthermore, one CS ranging communication may transmit and receive a CW signal at a single frequency. The duration of one CS ranging communication can be adjusted depending on the length of the CW signal, etc.

[0088] When the portable device 9 and the in-vehicle system VS perform data communication and CS ranging communication via their respective BLE modules 2 and 97, as shown in Fig. 9, the DK-ECU 1 can, for example, perform received signal strength ranging based on the received signal strength of the signal for data communication, and can also perform CS ranging through CS ranging communication. On the other hand, if the portable device 9 does not support CS ranging communication, normal data communication is performed between the BLE module 2 and the portable device 9, as shown in Fig. 8, for example. In this case, the DK-ECU 1 can perform received signal strength ranging using the received signal strength for data communication.

[0089] The CS ranging communication may be terminated, for example, when the portable device 9 is powered off and the BLE communication connection is disconnected, or when the received signal strength of the BLE signal falls below a predetermined strength threshold. The strength threshold for terminating the CS ranging communication may be the same as or different from the strength threshold for starting the CS ranging communication. Furthermore, the CS ranging communication may be terminated if no action is taken on the vehicle for a predetermined time after the CS ranging communication is started. Alternatively, the CS ranging communication may be terminated when the user gets into the vehicle Hv and turns on the start switch. When any of the above-described conditions for terminating the CS ranging communication is satisfied, the DK-ECU 1 can transmit a request to stop CS ranging to the BLE module 2.

[0090] When the CS ranging communication is terminated in response to the user turning on the start switch, the CS ranging communication may be started in response to the opening and closing of the door of the vehicle Hv. This makes it possible to detect the position of the portable device 9 through the CS ranging communication when the portable device 9 is taken out of the vehicle while the vehicle is temporarily stopped with the start switch not turned off.

[0091] <Functions of Main Controller 11> As shown in Fig. 10, the main controller 11 of the DK-ECU 1 includes, as functional blocks, a communication control unit G1 and a position determination unit G2. The communication control unit G1 is a software or hardware module that controls the operation of the BLE module 2. For example, if the BLE module 97 of the portable device 9 supports CS ranging communication, the communication control unit G1 causes the BLE module 2 to perform CS ranging processing.

[0092] The position determination unit G2 detects the position of the portable device 9 by determining the device position relative to the vehicle Hv based on the CS ranging result and / or the received signal strength ranging result. The device position can be expressed by a plurality of areas / zones that are set in advance in the vehicle Hv, such as an engine start area ESA inside the vehicle, an entry area (nearby area) EA outside the vehicle, an intermediate area and a far area outside the vehicle.

[0093] The entry area EA outside the vehicle may include, for example, a first entry area EA1 near the driver's seat, a second entry area EA2 near the passenger seat, and a third entry area EA3 near the trunk, as shown in FIG. 11 . Thus, the entry area EA refers to, for example, an area outside the vehicle where the distance from the driver's seat, passenger seat, and trunk of the vehicle Hv is less than a predetermined proximity determination value. The proximity determination value may be set to, for example, 1.0 m, 1.5 m, or 2 m. The entry area EA is an area where the doors, trunk, and other doors of the vehicle Hv can be locked or unlocked. Regarding unlocking the vehicle Hv, only the doors and trunks corresponding to each entry area may be unlocked, or all doors and trunks may be unlocked in response to the detection of the presence of a portable device 9 within one entry area. Regarding locking the vehicle Hv, all doors and trunks may be locked when a portable device 9 is present within one entry area and a user holding the portable device 9 performs a locking operation.

[0094] The far area refers to an area where the distance from the vehicle Hv is equal to or greater than a predetermined far distance determination value (e.g., a distance corresponding to the outer edge of area EA4 in FIG. 11 ). The far distance determination value is a parameter for determining that the portable device 9 is not present around the vehicle Hv. The far distance determination value is set to, for example, 5.0 m, 6.0 m, 10 m, or 12 m. The intermediate area (e.g., area EA4 in FIG. 11 ) refers to an area intermediate between the far area and the entry area EA. The intermediate area may be a so-called welcome area in which predetermined welcome control, such as turning on exterior vehicle lights, is executed upon entry of the portable device 9 into the area. The intermediate area may also be an area in which predetermined control, such as authentication via wireless communication with the portable device 9, tracking of the device location, or shortening of the location determination cycle, is executed / started, which would not be executed if the portable device 9 is located far outside the vehicle. The intermediate area may also be referred to as a standby area, a peripheral area, or the like. Alternatively, the intermediate area may be an area in which a user can use a function to remotely park or exit the vehicle Hv.

[0095] The entry area EA, intermediate area, and far area are subdivisions of the outside area. Furthermore, the position determination unit G2 may determine whether the portable device 9 is located inside the vehicle as an engine start area ESA inside the vehicle, as shown in FIG.

[0096] As described above, the position determination unit G2 of this embodiment determines a stay area, which is an area where the portable device 9 is located. In another aspect, the position determination unit G2 may calculate device position coordinates instead of or in addition to determining the stay area. The device position coordinates refer to the position coordinates of the portable device 9 located in a two-dimensional / three-dimensional coordinate system based on a predetermined position of the vehicle Hv. The calculation of the device position coordinates can be performed using a method similar to three-point positioning or multi-point positioning in the technical fields of GPS and position estimation.

[0097] The main controller 11 transmits device position data, which is data indicating the determined device positions, to a predetermined ECU such as the body ECU 4. The main controller 11 may periodically update the device position data. The main controller 11 may also generate and update the device position data in response to the occurrence of a predetermined event.

[0098] <Process for Determining CS Ranging Communication Compatibility of Portable Device 9> Next, a process for determining whether the BLE module 97 of the portable device 9 is compatible with CS ranging communication, which is executed in the in-vehicle system VS of the vehicle electronic key system of this embodiment, will be described with reference to the flowchart of Fig. 12. Note that the process shown in the flowchart of Fig. 12 is executed when the portable device 9 is an owner device and is registered (paired) as the owner device with the in-vehicle system VS.

[0099] When the portable device 9 is registered as an owner device with the in-vehicle system VS, the BLE module 97 of the portable device 9 and the BLE module 2 of the in-vehicle system VS exchange various information, including each other's identification information (portable device ID). During this exchange, for example, information regarding the wireless communication method supported by the in-vehicle system VS may be transmitted to the portable device 9, or conversely, information regarding the wireless communication method supported by the portable device 9 may be transmitted to the in-vehicle system VS. By including whether or not the portable device 9 supports CS ranging communication in the information regarding the wireless communication method supported by the portable device 9, the in-vehicle system VS can determine whether or not the portable device 9 supports CS ranging communication based on the received information regarding the wireless communication method supported by the portable device 9.

[0100] Alternatively, during the above-described exchange between the portable device 9 and the in-vehicle system VS, the in-vehicle system VS can, for example, inquire about setting values ​​related to CS ranging communication from the portable device 9. If the portable device 9 responds to the inquiry from the in-vehicle system VS with a setting value related to CS ranging communication, the in-vehicle system VS can determine that the portable device 9 supports CS ranging communication. On the other hand, if the portable device 9 does not respond to the inquiry from the in-vehicle system VS or receives a response indicating that the portable device 9 does not support CS ranging communication, the in-vehicle system VS can determine that the portable device 9 does not support CS ranging communication.

[0101] In addition, confirmation of whether the portable device 9 supports CS ranging communication may be performed each time the DK-ECU 1 and the portable device 9 start BLE communication, rather than when the portable device 9 is registered as an owner device.

[0102] In step S200 of the flowchart in FIG. 12 , the DK-ECU 1 of the in-vehicle system VS determines whether the portable device 9 supports CS ranging communication based on the information about the wireless communication method supported by the portable device 9 received from the portable device 9 or the response result to the inquiry about the setting values ​​related to CS ranging communication. Note that when the portable device 9 is the master, the portable device 9 determines whether the BLE module 2 of the in-vehicle system VS supports CS ranging communication. If the portable device 9 supports CS ranging communication, the DK-ECU 1 proceeds to step S210 and sets the CS compatibility flag to "True" to indicate that the CS ranging communication is supported. On the other hand, if the portable device 9 does not support CS ranging communication, the DK-ECU 1 proceeds to step S220 and sets the CS compatibility flag to "False" to indicate that the CS ranging communication is not supported.

[0103] In step S230, the DK-ECU 1 links the ID (portable device ID) of the portable device 9 with the CS compatible flag set in step S210 or S220, registers it in a secure storage unit such as the storage 14, and stores it.

[0104] <Processing for detecting the position of the portable device 9> Next, the processing for detecting the position of the portable device 9, which is performed using the BLE module 2 in the in-vehicle system VS of the vehicle electronic key system of this embodiment, will be described with reference to the flowchart of Figure 13.

[0105] In step S300, the BLE controller 23 or the DK-ECU 1 determines whether a communication connection has been established with the portable device 9. If a communication connection with the portable device 9 has been established, the DK-ECU 1 proceeds to the processing of step S305, and acquires the ID of the portable device 9 (portable device ID) from the BLE signal communicated with the portable device 9 to establish the communication connection.

[0106] In step S310, the DK-ECU 1 determines whether the acquired portable device ID has been registered. As described above, if the device is registered as an owner device, the portable device ID has been registered. Therefore, in this case, the DK-ECU 1 determines "Yes" in step S310 and proceeds to step S325. On the other hand, if the acquired portable device ID has not been registered, the DK-ECU 1 determines "No" in step S310 and proceeds to step S315.

[0107] In step S315, the DK-ECU 1 determines, from the BLE signal communicated with the portable device 9 to establish a communication connection, whether the portable device 9 is a friend device that has been authorized by the user who owns the owner device to access and use the vehicle Hv.

[0108] The portable device 9, which is a friend device, can, for example, obtain and store information (e.g., an attestation package including an IRK, etc.) indicating that the portable device 9 is a friend device that has been granted vehicle access authority and usage authority from the portable device 9, which is the owner device, in advance via a management server. Therefore, when the portable device 9, which is a friend device, approaches the vehicle Hv, it can use the stored information to establish a communication connection between the in-vehicle system VS and the portable device 9 by returning a connection request in response to an advertising signal.

[0109] When a BLE communication connection is established between the portable device 9, which is a friend device, and the in-vehicle system VS, the in-vehicle system VS checks the attestation package held by the portable device 9. This allows the in-vehicle system VS to determine that the portable device 9 with which the communication connection has been established is a friend device. Thereafter, similar to when the owner device is registered, the two devices mutually generate encryption keys and exchange them via BLE communication. After the authenticity of the exchanged encryption keys is authenticated, the exchanged encryption keys are stored in storage media such as the respective storages.

[0110] Alternatively, in response to instructions from the user of the owner device, the DK-ECU 1 can acquire registration information by performing so-called V2X communication with a management server that registers the ID, authorized authority, and expiration date of the portable device 9, which is a friend device, and determine whether the portable device 9 with which a communication connection has been established is a friend device based on the acquired registration information.

[0111] If the DK-ECU 1 determines that the portable device 9 is a friend device, the DK-ECU 1 proceeds to step S320. If the DK-ECU 1 determines that the portable device 9 is not a friend device, the DK-ECU 1 disconnects the established communication connection and returns to step S300.

[0112] In step S320, the DK-ECU 1 performs BLE communication with the portable device 9, which is a friend device, to acquire information indicating whether the portable device 9 supports CS ranging communication. Acquisition of the information indicating whether the portable device 9 supports CS ranging communication can be performed using the same method as for the owner device described above. When it is determined whether the friend device supports CS ranging communication, the DK-ECU 1 associates and registers the ID (portable device ID) of the portable device 9 with the set CS compatibility flag, as in the case of the owner device. In this manner, the DK-ECU 1 registers (pairs) the portable device 9, which is a friend device. Therefore, if the portable device 9, which is a friend device, approaches the vehicle Hv for the second or subsequent time, the DK-ECU 1 can determine whether the portable device 9 supports CS ranging communication from the associated and registered portable device ID and CS compatibility flag.

[0113] In step S325, the DK-ECU 1 checks the CS compatibility flag of the portable device 9 with which the communication connection has been established. If the CS compatibility flag is "False" and the portable device 9 does not support CS ranging communication, the DK-ECU 1 proceeds to step S330. If the CS compatibility flag is "True" and the portable device 9 supports CS ranging communication, the DK-ECU 1 proceeds to step S345.

[0114] In step S330, the DK-ECU 1 performs distance measurement based on the received signal strength of a data signal transmitted to and received from the portable device 9. In this embodiment, as shown in FIGS. 4 and 11 , multiple anchors (BLE modules) 2A to 2F are provided inside and outside the vehicle Hv. Therefore, the approximate device distance between each of the anchors 2A to 2F and the portable device 9 can be calculated based on the received signal strength received by each of the anchors 2A to 2F. Therefore, in step S335, the DK-ECU 1 can detect the approximate location (area) of the portable device 9 from the device distances calculated for the multiple anchors 2A to 2F.

[0115] In step S345, the DK-ECU 1 performs CS ranging by transmitting and receiving a CS ranging signal to and from the portable device 9. At this time, the DK-ECU 1 may perform ranging based on the received signal strength of the BLE signal. This is because performing ranging using the received signal strength in addition to CS ranging can improve the accuracy of detecting the location of the portable device 9. For example, by periodically performing CS ranging and received signal strength ranging, the portable device 9 can be determined to be inside the vehicle if the received signal strength is equal to or greater than an intensity threshold indicating that the portable device 9 is inside the vehicle and the CS ranging result indicates that the portable device 9 is inside the vehicle (e.g., within 1 m from the in-vehicle BLE module 2). However, the DK-ECU 1 may perform only CS ranging without performing received signal strength ranging. As described above, CS ranging calculates the device distance based on the reception phase of the CW ranging signal, thereby enabling the device distance to be calculated with higher accuracy than ranging based on received signal strength. Therefore, in step S350, the DK-ECU 1 can detect the position (area) of the portable device 9 with high accuracy from the device distances calculated by CS ranging for the plurality of anchors 2A to 2F.

[0116] Then, when the DK-ECU 1 detects the position of the portable device 9, it transmits the detected position data of the portable device 9 to the body ECU 4. Based on the position data of the portable device 9 provided by the DK-ECU 1, the body ECU 4 can execute predetermined control such as unlocking / locking the vehicle Hv and turning on the power.

[0117] 13, the DK-ECU 1 determines whether or not positioning of the portable device 9 is complete. For example, the DK-ECU 1 may determine that positioning of the portable device 9 is complete when the vehicle Hv stops, the occupants get out, the vehicle Hv is locked, and the portable device 9 is separated from the vehicle, making it impossible to measure the position of the portable device 9. If positioning of the portable device 9 is not complete, the DK-ECU 1 returns to step S330 or S345 and repeatedly executes the above-described process. This repeatedly (periodically) executes distance measurement based on received signal strength or CS distance measurement.

[0118] Second Embodiment Overview of a Vehicle Electronic Key System According to a Second Embodiment Next, a vehicle electronic key system to which a position detection system, a position detection method, and a computer according to a second embodiment of the present disclosure are applied will be described.

[0119] Fig. 14 is a block diagram showing the configuration of a portable device 9 according to this embodiment. As shown in Fig. 14, the portable device 9 according to this embodiment is obtained by adding a UWB module 98 capable of implementing UWB communication corresponding to the third communication method to the portable device 9 according to the first embodiment. Fig. 15 is a block diagram showing the configuration of an in-vehicle system VS according to this embodiment. As shown in Fig. 15, the in-vehicle system VS according to this embodiment is obtained by adding a plurality of UWB modules 3 capable of implementing UWB communication to the in-vehicle system VS according to the first embodiment.

[0120] 16 shows an example of the arrangement of a BLE module 2 and a UWB module 3 according to this embodiment in a vehicle Hv. The BLE module 2 according to this embodiment is capable of performing BLE communication as well as BLECS communication. In the example shown in FIG. 16, anchors 2A and 2B of the BLE module 2 are arranged at the front and rear of the vehicle interior, respectively. Therefore, even if ranging or CS ranging based on received signal strength is performed by performing BLE communication or BLECS communication, the precise location of the portable device 9 cannot be determined, and only the area to which the portable device 9 belongs can be roughly detected.

[0121] 16, anchors 3A-3F of multiple UWB modules 3 are respectively arranged in the front and rear of the vehicle, the front right of the vehicle, the rear right of the vehicle, the rear left of the vehicle, and the front left of the vehicle. Therefore, when device distances between at least three UWB modules 3 and the portable device 9 are calculated by performing UWB communication, the position of the portable device 9 can be detected with high accuracy.

[0122] In this way, when the portable device 9 is compatible with UWB ranging communication, the in-vehicle system VS according to this embodiment is configured to be able to perform UWB communication, which is a wireless communication method using the UWB-IR (Ultra Wide Band - Impulse Radio) system, via the respective UWB modules 3 and 98. Specifically, the in-vehicle system VS and the portable device 9 are configured to be able to transmit and receive impulse-shaped radio waves (hereinafter, referred to as impulse signals) used in UWB communication via the respective UWB modules 3 and 98. The impulse signal used in UWB communication is a signal having an extremely short pulse width (e.g., 2 ns) and a bandwidth of approximately 500 MHz or greater (i.e., an ultra-wide bandwidth).

[0123] Note that UWB communication can utilize multiple channels as defined in IEEE 802.15.4z. The in-vehicle system VS can communicate with the portable device 9 using, for example, the fifth channel of UWB communication. Of course, the in-vehicle system VS can also be configured to communicate with the portable device 9 using other channels, such as the third and ninth channels. The third channel has a center frequency of 4492 MHz, the fifth channel has a center frequency of 6489.6 MHz, and the ninth channel has a center frequency of 7987.2 MHz. IEEE (registered trademark) stands for Institute of Electrical and Electronics Engineers. Each channel corresponds to a frequency band of ±250 MHz from the center frequency. Frequencies such as 3.1 GHz to 4.8 GHz and 6.0 GHz to 10.6 GHz can be used in UWB communication.

[0124] Various modulation methods can be used for UWB communication, including on-off keying (OOK), pulse position modulation (PPM), and pulse width modulation (PWM). The on-off keying method represents information (e.g., 0 and 1) by the presence or absence of an impulse signal. The pulse position modulation method modulates the position at which a pulse occurs. The pulse width modulation method represents information by the pulse width. Here, as an example, UWB communication between the in-vehicle system VS and the portable device 9 is performed using the OOK method. Data transmission via UWB communication can be achieved using multiple impulse signals. Hereinafter, a data signal exchanged via UWB communication will be referred to as a UWB signal. Because a UWB signal includes multiple impulse signals, it can also be called a pulse sequence signal.

[0125] The UWB modules 3 and 98 are communication modules for performing UWB communication. The UWB modules 3 and 98 output received data to the DK-ECU 1 and the device control unit 90, respectively. The UWB modules 3 and 98 also transmit UWB signals corresponding to transmission data based on instructions from the DK-ECU 1 and the device control unit 90, respectively. Furthermore, the UWB modules 3 and 98 can also transmit and receive UWB signals for ranging based on instructions from the DK-ECU 1 and the device control unit 90, respectively. In this way, the operations of the UWB modules 3 and 98 are controlled by the DK-ECU 1 and the device control unit 90, respectively.

[0126] For example, when performing UWB communication with the portable device 9, the DK-ECU 1 can instruct any UWB module 3 to transmit a UWB signal. When the device control unit 90 receives a UWB signal transmitted from the in-vehicle system VS via the UWB module 98, it returns a response signal corresponding to the received signal via the UWB module 98. For example, when the device control unit 90 receives a UWB signal as a search signal, it can return a UWB signal obtained by modulating a code including the device ID of the portable device 9 to the in-vehicle system VS as a response signal. The search signal is a signal used by the in-vehicle system VS to search for the portable device 9 and is a type of signal that requests the portable device 9 to return a response signal. The UWB signals transmitted by the portable device 9 and the in-vehicle system VS may include a code indicating the source or destination.

[0127] It is preferable that the DK-ECU 1 and the device control unit 90 stop the operation of the UWB modules 3, 98 and, for example, put them into a sleep state when a BLE communication connection is not established. In other words, for example, the device control unit 90 preferably activates the UWB module 98 and enables UWB communication based on the establishment of a BLE communication connection with the in-vehicle system VS. This configuration can reduce the power consumption of the UWB module 98. In this case, the device control unit 90 may be configured to activate the UWB module 98 on the condition that a UWB ranging start request is received from the DK-ECU 1 via BLE communication after the BLE communication connection with the in-vehicle system VS is established.

[0128] The DK-ECU 1 can also instruct the UWB modules 3 to perform UWB ranging, including UWB communication for ranging. For example, the DK-ECU 1 can perform a cyclic measurement process in which it instructs each of the multiple UWB modules 3 to perform UWB ranging in turn. The DK-ECU 1 can periodically perform the cyclic measurement process after a BLE communication connection is established between the vehicle Hv and the portable device 9. The DK-ECU 1 may determine the start timing of the cyclic measurement process or dynamically change the cyclic measurement interval based on the received signal strength value of the BLE signal observed within a predetermined period of time. Alternatively, the DK-ECU 1 may perform the cyclic measurement process based on the detection of a predetermined event that requires the location of the portable device 9 to be detected. The above-described UWB ranging process measures the device distance from each UWB module 3 to the portable device 9, and the location of the portable device 9 is detected based on this measured distance. Each UWB module 3 is also referred to as an anchor.

[0129] The UWB modules 3 and 98 are equipped with an antenna for UWB communication, a transmission / reception circuit, a UWB controller, etc. The transmission / reception circuit is a circuit that performs signal processing for modulation and demodulation. The UWB controller is a microcomputer that controls the operation of the UWB modules 3 and 98 and generates UWB ranging data, which will be described next.

[0130] Each UWB module 3 performs UWB ranging processing based on instructions from the DK-ECU 1. The UWB ranging processing is a process of acquiring the propagation time (in other words, the time of flight) of radio waves from each UWB module 3 to the portable device 9 as a position-related value of UWB communication, and measuring the device distance based on the acquired propagation time of the radio waves. The UWB ranging processing includes a process of transmitting a UWB signal of a predetermined pattern to the portable device 9 as UWB communication for ranging, and a process of receiving a UWB signal as a response signal from the portable device 9. In the UWB ranging processing, the UWB signal exchanged between the UWB module 3 and the portable device 9 may be a single impulse signal, or a pulse sequence signal in which multiple impulse signals are arranged in a predetermined pattern.

[0131] The UWB controller of each UWB module 3 measures the round trip time (RTT), which is the elapsed time from transmitting a UWB signal to receiving a response signal from the portable device 9, and calculates the device distance based on the RTT. In other words, the position-related value of UWB communication is the flight time of the communication signal between the UWB module 3 and the portable device 9. The RTT corresponds to the round-trip flight time of the UWB signal. For example, the UWB controller of this embodiment calculates the device distance by multiplying half of the value obtained by subtracting a predetermined correction value from the RTT by the propagation time of the radio waves. The correction value here is a parameter for offsetting the response processing time in the portable device 9 and delay time within the UWB module 3. The specific value of the correction value can be designed as appropriate. Each UWB module 3 transmits the calculated device distance to the DK-ECU 1 as UWB ranging data. After performing UWB ranging processing, the UWB module 3 stops operating either autonomously or upon instruction from the DK-ECU 1. The process of converting the RTT into a distance may be performed by the main controller 11 of the DK-ECU 1 .

[0132] 17 is a diagram showing an example of interaction when UWB ranging communication is performed between the portable device 9 and the in-vehicle system VS. Note that if the portable device 9 supports UWB ranging communication, when the portable device 9 is registered (paired) as an owner device or a friend device in the in-vehicle system VS, the following processing is executed in addition to the processing described in the first embodiment.

[0133] For example, after exchanging encryption keys for BLE communication, the portable device 9 and the in-vehicle system VS generate a UWB Ranging Secret Key (URSK), which is a key used in UWB ranging communication, and share the generated URSK via BLE communication. The URSK can be used to create information that proves that the other party in the UWB ranging communication is a valid party. By having the generated URSK shared between the ECU 1 and the portable device 9, the ECU 1 can perform UWB ranging communication with the portable device 9 as the other party.

[0134] The ECU 1 registers and stores the generated Ursk in association with the ID (portable device ID) of the portable device 9. Preferably, the ECU 1 confirms that UWB ranging communication with the portable device 9 is possible by performing UWB ranging using the generated Ursk.

[0135] As shown in Figure 17, the in-vehicle system VS periodically performs BLE data communication and UWB ranging communication with the portable device 9. For example, the UWB ranging interval, which is the interval at which the DK-ECU 1 causes the UWB module 3 to perform UWB ranging communication, can be set to three or four times the connection interval. By lengthening the UWB ranging interval in this way, it is expected that power consumption can be reduced. However, the CS ranging interval may be the same as the connection interval.

[0136] Note that "UWB-Ranging Interval" in FIG. 17 indicates the UWB ranging interval. One UWB ranging communication may include UWB ranging communications using multiple UWB modules 3. The UWB ranging interval may be set to a value between 150 milliseconds and 400 milliseconds, such as 180 milliseconds or 280 milliseconds. The UWB ranging interval may be longer than the CS ranging interval. The UWB ranging interval may also be the same as or shorter than the CS ranging interval.

[0137] Furthermore, it is preferable that the detection of the position of the mobile device using the UWB signal (UWB ranging) be started, for example, when the received signal strength of the BLE signal exceeds a predetermined strength threshold, or when the distance between the positions measured by each GPS receiver falls below a distance threshold, because this is expected to have the effect of reducing power consumption.

[0138] When any of the above-described UWB ranging start conditions is satisfied, the DK-ECU 1 can transmit a UWB ranging start request to the multiple UWB modules 3. In response to this UWB ranging start request, the multiple UWB modules 3 transition from a sleep state to an active state. This enables the multiple UWB modules 3 to transmit UWB ranging signals. In other words, the multiple UWB modules 3 are in a sleep state while not performing UWB ranging.

[0139] Like CS ranging communication, UWB ranging communication may be terminated when the portable device 9 is powered off and the BLE communication connection is disconnected, or when the received signal strength of the BLE signal falls below a predetermined strength threshold. The strength threshold for terminating UWB ranging communication may be the same as or different from the strength threshold for starting UWB ranging communication. Furthermore, UWB ranging communication may be terminated if no action is taken on the vehicle for a predetermined time after the start of UWB ranging communication. Furthermore, UWB ranging communication may be terminated when the user gets into the vehicle Hv and turns on the start switch.

[0140] When any of the above-described UWB ranging termination conditions is satisfied, the DK-ECU 1 can transmit a UWB ranging stop request to the multiple UWB modules 3. In response to this stop request, the multiple UWB modules 3 terminate UWB ranging communication. Then, for example, if the multiple UWB modules 3 do not receive a new UWB ranging start request within a predetermined time after terminating UWB ranging communication, they can transition to a sleep state.

[0141] Even when UWB ranging is terminated in response to the user turning on the start switch, UWB ranging communication may be started in response to the opening and closing of the door of the vehicle Hv. This makes it possible to detect through UWB ranging communication that the portable device 9 has been taken out of the vehicle when the vehicle is temporarily stopped with the start switch not turned off.

[0142] <Process for Determining Compatibility of Portable Device 9 with CS Ranging Communication and UWB Ranging Communication> Next, a process for determining whether the BLE module 97 of the portable device 9 is compatible with CS ranging communication and UWB ranging communication, which is executed in the in-vehicle system VS of the vehicle electronic key system of this embodiment, will be described with reference to the flowchart of Fig. 18. Note that, like the process shown in the flowchart of Fig. 12, the process shown in the flowchart of Fig. 18 may be executed when the portable device 9 is an owner device and is registered (paired) as an owner device with the in-vehicle system VS.

[0143] The processing from steps S200 to S220 in the flowchart of FIG. 18 is the same as that in the flowchart of FIG. 12 , and therefore description thereof will be omitted. In step S240, the DK-ECU 1 of the in-vehicle system VS determines whether the portable device 9 supports UWB ranging communication. This determination, similar to the determination of whether the portable device 9 supports CS ranging communication, can be made based on information received from the portable device 9 regarding the wireless communication method supported by the portable device 9 or the portable device 9's response to an inquiry about setting values ​​related to UWB ranging communication. If the portable device 9 supports UWB ranging communication, the DK-ECU 1 proceeds to step S250 and sets the UWB compatibility flag to "True" to indicate that the UWB ranging communication is supported. On the other hand, if the portable device 9 does not support UWB ranging communication, the DK-ECU 1 proceeds to step S260 and sets the UWB compatibility flag to "False" to indicate that the UWB ranging communication is not supported.

[0144] In step S270, the DK-ECU 1 associates the ID (mobile device ID) of the portable device 9 with the CS-compatible flag set in step S210 or S220 and the UWB-compatible flag set in step S250 or S260, and registers and stores them in a secure storage unit such as the storage 14. At this time, if the portable device 9 is compatible with UWB ranging communication, the above-mentioned URSK is also stored.

[0145] <Process for Detecting the Position of the Portable Device> Next, a process for detecting the position of the portable device 9, which is executed in the in-vehicle system VS of the vehicle electronic key system of this embodiment, will be described with reference to the flowchart of FIG.

[0146] The processing of steps S400 and S405 in the flowchart of Fig. 19 is similar to steps S300 and S305 in the flowchart of Fig. 13, and therefore description thereof will be omitted. Also, although the processing of steps S310 to S320 in the flowchart of Fig. 12 is omitted in the flowchart of Fig. 19, processing similar to these steps may be performed.

[0147] In step S410, the DK-ECU 1 determines the CS compatibility flag and UWB compatibility flag of the portable device 9 with which the communication connection has been established. If the UWB compatibility flag is "True" and the CS compatibility flag is "False," the DK-ECU 1 proceeds to step S415. If the UWB compatibility flag is "True" and the CS compatibility flag is "True," the DK-ECU 1 proceeds to step S430. If the UWB compatibility flag is "False" and the CS compatibility flag is "True," the DK-ECU 1 proceeds to step S445. If the UWB compatibility flag is "False" and the CS compatibility flag is "False," the DK-ECU 1 proceeds to step S460.

[0148] In step S415, the DK-ECU 1 performs UWB ranging by transmitting and receiving UWB ranging signals to and from the portable device 9. At this time, the DK-ECU 1 may perform ranging based on the received signal strength of the BLE signal (RSSI ranging). By performing RSSI ranging in addition to UWB ranging, the accuracy of detecting the position of the portable device 9 can be improved and power consumption can be reduced. For example, when the portable device 9 is located in a far area, RSSI ranging may be performed, and when the portable device 9 is located in an intermediate area or a nearby area, UWB ranging may be performed, which can detect the position more accurately. Furthermore, RSSI ranging may also be performed when the portable device 9 is located in an intermediate area or a nearby area. Then, in step S420, the DK-ECU 1 can accurately detect the position (area) of the portable device 9 based on the device distances calculated for the multiple anchors 3A to 3F that perform UWB ranging.

[0149] In step S430, the DK-ECU 1 performs UWB ranging by transmitting and receiving UWB ranging signals to and from the portable device 9. The DK-ECU 1 also performs CS ranging by transmitting and receiving CS ranging signals to and from the portable device 9. The DK-ECU 1 may also perform ranging based on the received signal strength of the BLE signal (RSSI ranging). For example, the DK-ECU 1 may simultaneously perform UWB ranging and CS ranging. In this case, the DK-ECU 1 may detect the location (area) of the portable device 9 by multilateration based on the device distance measured by UWB ranging and the device distance measured by CS ranging. Alternatively, the DK-ECU 1 may separately calculate the location of the portable device 9 based on the device distance measured by UWB ranging and the device distance measured by CS ranging, and then detect the final location (area) of the portable device 9 from the separately calculated portable device locations. Furthermore, when detecting the final location (area) of the mobile device 9, the results of received signal strength ranging may be taken into consideration.

[0150] Alternatively, the DK-ECU 1 may use multiple distance measurement methods depending on the location (area) of the portable device 9 and the moving speed of the portable device 9, rather than always using multiple distance measurement methods simultaneously. Below, an example of using multiple distance measurement methods depending on the location (area) of the portable device 9 and an example of using multiple distance measurement methods depending on the moving speed of the portable device 9 will be described.

[0151] FIG. 20 shows an example of a process for selectively using a plurality of distance measurement methods depending on the location (area) of the portable device 9, and is a flowchart showing in detail the process of step S430 in FIG.

[0152] In step S500, the DK-ECU 1 determines whether a predetermined time has elapsed since the distance measurement was performed to detect the location (area) of the portable device 9. If the predetermined time has elapsed, the location of the portable device 9 may have changed significantly from the location (area) detected based on the previous distance measurement, and the DK-ECU 1 proceeds to step S510 to detect the exact location of the portable device 9. On the other hand, if the predetermined time has elapsed, the location of the portable device 9 can be considered not to have changed significantly from the location (area) detected based on the previous distance measurement, and the DK-ECU 1 proceeds to step S520.

[0153] In step S510, the DK-ECU 1 instructs the UWB module 3 to perform UWB ranging, or instructs the UWB module 3 and the BLE module 2 to perform UWB ranging and CS ranging simultaneously. By performing UWB ranging or UWB ranging and CS ranging simultaneously, the DK-ECU 1 can detect the exact position (area) of the portable device 9 in step S435 of the flowchart in FIG. 19 .

[0154] In step S520, the DK-ECU 1 determines whether the previously detected location of the portable device 9 belonged to a nearby area (entry area), an intermediate area, or a distant area. If the previous area was determined to be a nearby area, the DK-ECU 1 proceeds to step S530. If the previous area was determined to be an intermediate area, the DK-ECU 1 proceeds to step S540. If the previous area was determined to be a distant area, the DK-ECU 1 proceeds to step S550.

[0155] In step S530, similar to step S510, the DK-ECU 1 instructs the UWB module 3 to perform UWB ranging, or instructs the UWB module 3 and the BLE module 2 to perform UWB ranging and CS ranging simultaneously. That is, if it is determined that the location of the portable device 9 belongs to the nearby area, multiple communication methods may be selected, and location-related values ​​may be acquired using the selected multiple communication methods. This makes it possible to detect the location (area) of the portable device 9 located near the vehicle Hv with high accuracy.

[0156] In step S540, the DK-ECU 1 instructs the BLE module 2 to perform CS ranging. This makes it possible to detect the location (area) of the portable device 9 located near the intermediate area with a certain degree of accuracy while saving power consumption. In step S550, the DK-ECU 1 performs RSSI ranging based on the received signal strength of the BLE data signal. This makes it possible to detect the approximate location of the portable device 9 located near the far area while saving power consumption and ensuring responsiveness in location detection. In this way, when the location of the portable device 9 does not belong to the near area but belongs to the intermediate area or far area, fewer communication methods may be selected than when the portable device 9 belongs to the near area, and location-related values ​​may be acquired using the selected multiple communication methods.

[0157] Next, an example of selectively using multiple distance measurement methods in consideration of the movement speed of the portable device 9 will be described. FIG. 21 is a flowchart illustrating in detail the process of step S430 in FIG. 19 , showing an example of a process of selectively using multiple distance measurement methods in consideration of the movement speed of the portable device 9. The flowchart shown in FIG. 21 adds step S525 to the flowchart shown in FIG. 20 . The steps other than step S525 in the flowchart of FIG. 21 are the same as those in the flowchart of FIG. 20 , and therefore their explanations will be simplified or omitted. Note that selectively using multiple distance measurement methods in consideration of the movement speed of the portable device 9 is performed when the current distance measurement is performed within a predetermined period of time since the previous distance measurement was performed to detect the position (area) of the portable device 9, similar to the selective use of multiple distance measurement methods according to the area in which the portable device 9 is located.

[0158] Step S525 is executed if it is determined in step S520 that the previously detected position of the portable device 9 is in the nearby area (entry area). In step S525, the DK-ECU 1 determines whether the moving speed of the portable device 9 at the time of distance measurement for the previous position detection is equal to or greater than a speed threshold. The moving speed of the portable device 9 can be calculated, for example, by dividing the distance between the position of the portable device 9 two positions before last and the previous position of the portable device 9 by the time corresponding to the position detection interval.

[0159] If the DK-ECU 1 determines that the moving speed is equal to or greater than the speed threshold, the DK-ECU 1 proceeds to the processing of step S530. In step S530, as described above, the DK-ECU 1 instructs the UWB module 3 to perform UWB ranging, or instructs the UWB module 3 and the BLE module 2 to simultaneously perform UWB ranging and CS ranging. In other words, when the moving speed of the portable device 9 is equal to or greater than the speed threshold, multiple communication methods may be selected, and position-related values ​​may be acquired using the selected multiple communication methods. This allows the DK-ECU 1 to detect the position (area) of the portable device 9 with high accuracy when the moving speed of the portable device 9 is equal to or greater than the speed threshold.

[0160] Conversely, if the DK-ECU 1 determines that the moving speed of the portable device 9 is less than the speed threshold, the DK-ECU 1 proceeds to the processing of step S540. In step S540, as described above, the DK-ECU 1 instructs the BLE module 2 to perform CS ranging. That is, when the moving speed of the portable device 9 is less than the speed threshold, a fewer number of communication methods may be selected than would be selected if the moving speed is equal to or greater than the speed threshold. As a result, when the moving speed is low and the amount of change in the position of the portable device 9 is considered small, it is possible to detect the position (area) of the portable device 9 with a certain degree of accuracy while saving power consumption.

[0161] 21 , for example, even if the previously detected position of the portable device 9 is determined to be in the intermediate area or the far area, the communication method for performing distance measurement to detect the position of the portable device 9 may be switched depending on the movement speed of the portable device 9. For example, if the previously detected position of the portable device 9 is determined to be in the intermediate area and the movement speed of the portable device 9 is determined to be equal to or greater than a speed threshold, the process of step S530 may be executed to detect the accurate position of the portable device 9. Furthermore, if the previously detected position of the portable device 9 is determined to be in the far area and the movement speed of the portable device 9 is determined to be equal to or greater than a speed threshold, the process of step S540 may be executed to detect the position of the portable device 9 with higher accuracy.

[0162] Steps S445, S450, S460, and S465 in the flowchart of Fig. 19 are similar to steps S345, S350, and S330, S335 in the flowchart of Fig. 13, and therefore their explanations will be omitted. Also, steps S425, S440, S455, and S470 in the flowchart of Fig. 19 are similar to steps S340 or S355 in the flowchart of Fig. 13, and therefore their explanations will be omitted.

[0163] <Modifications> Although preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modifications within the scope of the gist of the present disclosure.

[0164] <Modification of System Configuration (1)> In the above-described embodiment, the BLE module 2 is disposed outside the housing of the DK-ECU 1. However, this is not limiting. For example, the BLE module 2 may be disposed inside the housing of the DK-ECU 1.

[0165] <Variation (2) of System Configuration> The in-vehicle system VS may include, for example, multiple BLE modules 2A to 2F as the BLE module 2, as shown in FIG. 22 . In the example shown in FIG. 22 , the multiple BLE modules 2A to 2F are arranged in close proximity to multiple UWB modules 3A to 3F. In this case, the location of the portable device 9 may be detected based on a result combining UWB ranging results from multiple UWB modules 3 and CS ranging results from multiple BLE modules 2. Alternatively, the device location based on the UWB ranging results and the device location based on the CS ranging results may be calculated separately, and the final device location may be calculated based on the separately calculated device locations. For example, if the two calculated locations of the portable device 9 match, the matched location may be determined as the final location of the portable device 9. If the two calculated locations of the portable device 9 do not match, a more likely location of the portable device 9 may be selected based on parameters such as the signal strength at the time of each ranging.

[0166] When multiple BLE modules 2 are used to perform CS ranging, one BLE module 2 may distribute channel information and timing information for performing the CS ranging process to other BLE modules 2, thereby enabling the other BLE modules 2 to also intercept (sniff) the CW signal transmitted from the mobile device 9.

[0167] In BLE, frequency hopping is performed after a communication connection is established, and therefore, normally, only the BLE module 2 that is connected to the communication line can capture the data signal from the mobile device 9. In contrast, with the sniffer technology, by providing channel information and timing information to other BLE modules 2, the other BLE modules 2 can also capture the data signal and CW signal from the mobile device 9. As a result, the other BLE modules 2 can detect the reception strength, reception phase, reception time, etc. of the signal from the mobile device 9 without being connected to the mobile device 9. Therefore, a configuration that applies the sniffer technology has the advantage that multiple BLE modules 2 can perform CS ranging processing in parallel.

[0168] <Modification of System Configuration (3)> In the above embodiment, the ECU 1 is configured as an independent electronic control unit in the in-vehicle system VS, but this is not limiting. For example, the functions of the ECU 1 may be integrated with other ECUs configured to realize other functions.

[0169] <Example of a Change in UWB Ranging> In the above-described embodiment, the UWB module 3 measures the RTT, which is the elapsed time from transmitting a UWB signal to receiving a response signal from the portable device 9, and calculates the device distance based on the RTT. However, in addition to or instead of measuring the RTT, the UWB module 3 can measure the arrival angle or arrival time difference of the UWB signal as a position-related value of UWB communication, and detect the position of the portable device 9 based on the measured arrival angle or arrival time difference. For example, if the UWB module 3 is configured to measure the arrival angle of the UWB signal in addition to measuring the RTT of the UWB signal, it becomes possible to detect the position (or area) of the portable device 9 around the vehicle Hv with a smaller number of UWB modules 3.

[0170] <Supplementary Information on Method for Obtaining Single-Frequency Phase Difference> The BLE module 2 may obtain the single-frequency phase difference for each frequency using an active two-way system or a passive two-way system, and may use the obtained single-frequency phase difference to calculate the inter-frequency phase difference. Here, an overview of the active two-way system and the passive two-way system will be described.

[0171] The active two-way system is a system in which an initiator and a reflector transmit and receive CW signals to each other, detect the phase difference between the transmitted signal and the received signal, and use these two phase differences to identify the single-frequency phase difference. The active two-way system includes a process in which the initiator and the reflector transmit and receive CW signals to each other, and a process in which the reflector transmits the observed received phase (θr) to the initiator.

[0172] 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. In the above embodiment, the BLE module 2 corresponds to the initiator, and the mobile device 9 corresponds to the reflector.

[0173] If the initial phase of the initiator is δi, the initial phase of the reflector is δr, the single-frequency phase difference that should be observed according to the one-way distance between the initiator and the reflector is φ, and the target frequency is f, then the relationships θr = φ + δi - δr and θi = φ - δi + δr hold. Based on this relationship, the average value of θi and θr is the single-frequency phase difference (φ) in which the initial phase components of the initiator and the reflector are canceled 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 single-frequency 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 single-frequency phase difference. As another aspect, if the phase difference due to round-trip propagation is assumed as the single-frequency phase difference, the single-frequency phase difference can be calculated as θi + θr.

[0174] The passive two-way system also involves an initiator and a reflector transmitting and receiving CW signals to and from each other. The difference from the active two-way system is that the reflector reflects the received phase of the CW signal transmitted from the initiator in the initial phase of the transmitted signal. For example, if the received phase at the reflector is θr, the reflector transmits a CW signal expressed as z(t) = A·exp{-i(ωt + θr + 2πn)}. A represents amplitude. ω is the angular frequency corresponding to the target frequency (f), and has the relationship ω = 2πf. n is a natural number corresponding to the interval between when the reflector receives the CW signal and when it transmits the CW signal. In this system, the received phase observed by the initiator does not include the reflector's initial phase component. The received phase observed by the initiator is the same value as when the CW signal is received after being reflected by a reflective object such as a wall. As a result, the initiator can calculate the single-frequency phase difference without acquiring the reception phase from the reflector. The passive two-way system has the advantage over the active two-way system that the reflector does not need to transmit a reception phase message. As described above, the single-frequency phase difference and, therefore, the inter-frequency phase difference can be calculated using various methods.

[0175] <Variations of CS Ranging> The BLE controller 23 may calculate the device distance using the RTT instead of or in addition to the inter-frequency phase difference. The RTT measured by the BLE controller 23 is the time from transmitting a predetermined BLE signal requesting a response to receiving a response signal from the mobile device 9. Sending and receiving a signal for measuring the RTT also corresponds to an example of CS ranging communication. Calculating the phase change coefficient or the RTT essentially corresponds to calculating the device distance. Therefore, the process of generating data indicating the device distance, such as the phase change coefficient or the RTT, based on the phase of the signal received from the mobile device 9 or the time of flight, is also included in the concept of CS ranging processing. Calculating the distance also includes generating data that indirectly indicates the distance.

[0176] <Modification of Communication Method> The communication method between the BLE module 2 and the mobile device 9 is not limited to BLE, and may be Bluetooth Classic, etc. Bluetooth-compliant wireless communication includes both BLE communication and communication compliant with Bluetooth Classic.

[0177] <Applicable Targets of the Present Disclosure> The present disclosure is applicable to a variety of vehicles that travel on roads. That is, the present disclosure can be installed in a variety of vehicles that can travel on roads, such as four-wheeled vehicles, two-wheeled vehicles, three-wheeled vehicles, and vehicles with more than four wheels. Furthermore, the present disclosure can be applied to applications other than vehicles that require detection of the position of a user holding a mobile device 9.

[0178] <Supplementary Remark (1)> This specification discloses the following technical ideas and their combinations. The combinations of the following technical ideas apply not only to position detection systems but also to position detection methods and computers that execute the position detection methods. [Technical Idea 1] A position detection system for detecting the position of a portable device (9) relative to an object (Hv), comprising: a communication module (2) that is installed on the object and that performs wireless communication with the portable device using a first communication method; the communication module is configured to be able to perform wireless communication with the portable device also using a second communication method different from the first communication method; a determination unit (S325, S410) that determines whether the portable device supports wireless communication using the second communication method based on wireless communication with the portable device using the first communication method; an acquisition unit (S330, S345, S415, S430, S445, S460) that, when the determination unit determines that the portable device supports wireless communication using the second communication method, causes the communication module to wirelessly communicate with the portable device using the second communication method, and acquires a position-related value associated with a position of the portable device from a wireless communication signal with the portable device using the second communication method; and, when the determination unit determines that the portable device does not support wireless communication using the second communication method, acquires the position-related value associated with the position of the portable device from a wireless communication signal with the portable device using the first communication method; and a determination unit (S340, S350, S420, S435, S450, S465) that determines a position of the portable device relative to the object or an area in which the portable device is located, based on the position-related value acquired by the acquisition unit. [Technical Idea 2] The position detection system according to Technical Idea 1, wherein the first communication method is Bluetooth Low Energy (BLE) communication, and the second communication method is BLE Channel Sounding (BLECS) communication, which transmits and receives continuous wave signals whose frequency is changed periodically.[Technical Idea 3] The position detection system according to Technical Idea 2, wherein the position-related value of the BLE communication is a received signal strength, and the position-related value of the BLECS communication is a received phase difference of continuous wave signals with different frequencies. [Technical Idea 4] The position detection system according to any one of Technical Ideas 1 to 3, wherein the communication module is further configured to be able to perform wireless communication with the portable device also using a third communication method, and the determination unit (S410) determines whether the portable device supports wireless communication using the third communication method based on wireless communication with the portable device using the first communication method. [Technical Idea 5] The position detection system according to Technical Idea 4, wherein the third communication method is ultra-wideband (UWB) communication, and the position-related value of the UWB communication is at least one of a time of flight of a communication signal between the communication module and the portable device, an angle of arrival of the UWB communication signal received by the communication module, and an arrival time difference of the UWB communication signal at different positions. [Technical Idea 6] The location detection system according to Technical Idea 2 or 3, wherein the communication module is further configured to be capable of wireless communication with the portable device using a third communication method, the third communication method being UWB communication, and the communication module includes a first communication module (2) capable of wireless communication with the portable device using the first communication method and the second communication method, and a second communication module (3) capable of wireless communication with the portable device using the third communication method. [Technical Idea 7] The location detection system according to Technical Idea 2 or 3, wherein the communication module has multiple antennas (22A, 22B), and the communication module uses one of the multiple antennas when performing the BLE communication, and uses the multiple antennas while switching between the multiple antennas when performing the BLECS communication. [Technical Idea 8] The location detection system according to Technical Idea 7, wherein the communication module switches between the multiple antennas so that continuous wave signals having the same frequency in the BLECS communication are wirelessly communicated via the multiple antennas.[Technical Idea 9] The position detection system according to any one of Technical Ideas 1 to 8, wherein the determination unit inquires of the portable device via wireless communication using the first communication method whether it supports a communication method other than the first communication method, and determines whether the portable device supports a communication method other than the first communication method based on the presence or absence of a response to the inquiry or a response indicating whether it supports a communication method other than the first communication method. [Technical Idea 10] The position detection system according to Technical Idea 9, further comprising a registration unit (S230, S270) that, when the determination unit determines whether the portable device supports a communication method other than the first communication method, registers compatibility information indicating whether the portable device supports a communication method other than the first communication method, in association with identification information of the portable device. [Technical Idea 11] The position detection system according to Technical Idea 10, wherein, when the compatibility information of the portable device is registered in association with identification information of the portable device acquired through wireless communication using the first communication method with the portable device, the determination unit determines whether the portable device supports a communication method other than the first communication method based on the registered compatibility information. [Technical Idea 12] The position detection system according to any one of Technical Ideas 1 to 8, wherein the portable device transmits, to the communication module, information on a communication method other than the first communication method that the portable device itself supports during wireless communication using the first communication method, and the determination unit determines whether the portable device supports a communication method other than the first communication method based on the information transmitted from the portable device. [Technical Idea 13] The position detection system according to Technical Idea 12, further comprising a registration unit (S230, S270) that, when the determination unit determines whether the portable device supports a communication method other than the first communication method, registers support information indicating whether the portable device supports a communication method other than the first communication method, in association with identification information of the portable device.[Technical Idea 14] The position detection system according to Technical Idea 13, wherein, when the compatibility information of the portable device is registered in association with identification information of the portable device acquired through wireless communication with the portable device using the first communication method, the determination unit determines whether the portable device supports a communication method other than the first communication method based on the registered compatibility information. [Technical Idea 15] The position detection system according to any one of Technical Ideas 1 to 14, further comprising a first selection unit (S520) that, when the determination unit determines that the portable device supports a communication method other than the first communication method, selects a wireless communication method for acquiring the position-related value related to the position of the portable device in accordance with a relative position of the portable device with respect to the object. [Technical Idea 16] The position detection system according to Technical Idea 15, wherein the first selection unit selects multiple communication methods as the wireless communication method for acquiring the position-related value when the relative position of the portable device with respect to the object falls within an area near the object, and selects a fewer number of communication methods when the relative position of the portable device with respect to the object does not fall within an area near the object. [Technical Idea 17] The position detection system according to Technical Idea 15 or 16, wherein the first selection unit selects a wireless communication method for acquiring the position-related value related to the position of the portable device in accordance with the relative position of the portable device with respect to the object when the interval between the previous acquisition time of the position-related value and the current acquisition time of the position-related value is within a predetermined time. [Technical Idea 18] The position detection system according to any one of Technical Ideas 1 to 16, further comprising a second selection unit (S525) that selects a wireless communication method for acquiring the position-related value related to the position of the portable device in accordance with a moving speed of the portable device when the determination unit determines that the portable device supports a communication method other than the first communication method.[Technical Idea 19] The position detection system according to Technical Idea 18, wherein the second selection unit selects a plurality of communication methods as the wireless communication method for acquiring the position-related value when the moving speed of the portable device is equal to or greater than a predetermined threshold, and selects a fewer number of communication methods when the moving speed of the portable device is less than the predetermined threshold. [Technical Idea 20] The position detection system according to Technical Idea 18 or 19, wherein the second selection unit selects a wireless communication method for acquiring the position-related value related to the position of the portable device in accordance with the moving speed of the portable device when the interval between the previous acquisition of the position-related value and the current acquisition of the position-related value is within a predetermined time.

[0179] <Additional Remark (2)> The various flowcharts shown in this disclosure are merely examples, and the number of steps constituting the flowcharts and the order in which the processes are executed can be changed as appropriate. The terms "wireless signal," "BLE signal," "data," "message," "packet," "frame," "package," "data set," "information," and the like used in this disclosure may be read interchangeably.

[0180] The apparatus, system, and method described herein may be implemented by a special-purpose computer including a processor programmed to execute one or more functions embodied in a computer program. The apparatus and method described herein may be implemented using dedicated hardware logic circuits. The apparatus and method described herein may be implemented by one or more special-purpose computers configured by a combination of a processor executing a computer program and one or more hardware logic circuits. For example, some or all of the functions of the BLE controller 23 may be implemented in hardware. Implementations of certain functions in hardware include implementations using one or more integrated circuits (ICs). The processor (computing core) may be a CPU, an MPU, a GPU, a data flow processor (DFP), or the like. Some or all of the functions of the BLE controller 23 may be implemented using a system-on-chip (SoC), an integrated circuit (IC), or a field-programmable gate array (FPGA). The concept of an IC also includes an application-specific integrated circuit (ASIC). Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transient tangible storage medium. Examples of the program storage medium include a hard-disk drive (HDD), a solid-state drive (SSD), and flash memory. The present disclosure also encompasses programs for causing a computer to function as the BLE controller 23 or the main controller 11, and non-transient tangible storage media such as semiconductor memory on which the programs are stored.

Claims

1. A position detection system for detecting the position of a portable device (9) relative to an object (Hv), comprising: a communication module (2) that is installed on the object and that performs wireless communication with the portable device using a first communication method; the communication module is configured to be able to perform wireless communication with the portable device using a second communication method different from the first communication method; and a determination unit (S325, S410) that determines whether or not the portable device supports wireless communication using the second communication method based on the wireless communication with the portable device using the first communication method. an acquisition unit (S330, S345, S415, S430, S445, S460) that, when the determination unit determines that the portable device supports wireless communication using the second communication method, causes the communication module to establish wireless communication with the portable device using the second communication method, and acquires a position-related value associated with a position of the portable device from a wireless communication signal with the portable device using the second communication method, and, when the determination unit determines that the portable device does not support wireless communication using the second communication method, acquires the position-related value associated with the position of the portable device from a wireless communication signal with the portable device using the first communication method; and a determination unit (S340, S350, S420, S435, S450, S465) that determines a position of the portable device relative to the object or an area in which the portable device is located, based on the position-related value acquired by the acquisition unit.

2. The position detection system of claim 1, wherein the first communication method is Bluetooth Low Energy (BLE) communication, and the second communication method is BLE Channel Sounding (BLECS) communication, which transmits and receives continuous wave signals whose frequency is periodically changed.

3. The location detection system of claim 2, wherein the location-related value of the BLE communication is a received signal strength and the location-related value of the BLECS communication is a received phase difference of continuous wave signals of different frequencies.

4. A position detection system as described in any one of claims 1 to 3, wherein the communication module is further configured to be able to perform wireless communication with the portable device using a third communication method, and the determination unit (S410) determines whether or not the portable device supports wireless communication using the third communication method based on the wireless communication with the portable device using the first communication method.

5. The location detection system of claim 4, wherein the third communication method is ultra-wideband (UWB) communication, and the location-related value of the UWB communication is at least one of a time of flight of a communication signal between the communication module and the mobile device, an angle of arrival of the UWB communication signal received at the communication module, and a time difference of arrival of the UWB communication signal at different locations.

6. The position detection system of claim 2 or 3, wherein the communication module is further configured to be capable of wireless communication with the portable device also by a third communication method, the third communication method being UWB communication, and the communication module includes: a first communication module (2) capable of wireless communication with the portable device by the first communication method and the second communication method, and a second communication module (3) capable of wireless communication with the portable device by the third communication method.

7. A location detection system as described in claim 2 or 3, wherein the communication module has a plurality of antennas (22A, 22B), and when performing the BLE communication, the communication module uses one of the plurality of antennas, and when performing the BLECS communication, the communication module uses the plurality of antennas while switching between the plurality of antennas.

8. The position detection system according to claim 7, wherein the communication module switches between the multiple antennas so that continuous wave signals having the same frequency in the BLECS communication are wirelessly transmitted via the multiple antennas.

9. A position detection system as described in any one of claims 1 to 3, wherein the determination unit inquires of the portable device via wireless communication in the first communication method whether or not it supports a communication method other than the first communication method, and determines whether or not the portable device supports a communication method other than the first communication method based on the presence or absence of a response to the inquiry, or a response indicating whether or not it supports the communication method.

10. The position detection system of claim 9, further comprising a registration unit (S230, S270) that, when the determination unit determines whether the portable device supports a communication method other than the first communication method, registers compatibility information indicating whether the portable device supports a communication method other than the first communication method, in association with identification information of the portable device.

11. The position detection system of claim 10, wherein the determination unit determines whether the portable device is compatible with a communication method other than the first communication method based on the registered correspondence information when the correspondence information of the portable device is registered in association with identification information of the portable device obtained through wireless communication between the portable device and the first communication method.

12. A position detection system as described in any one of claims 1 to 3, wherein, in wireless communication using the first communication method, the portable device transmits to the communication module information regarding a communication method other than the first communication method which the portable device itself supports, and the determination unit determines whether or not the portable device supports a communication method other than the first communication method based on the information transmitted from the portable device.

13. The position detection system of claim 12, further comprising a registration unit (S230, S270) that, when the determination unit determines whether the portable device supports a communication method other than the first communication method, registers compatibility information indicating whether the portable device supports a communication method other than the first communication method, in association with identification information of the portable device.

14. The position detection system of claim 13, wherein the determination unit determines whether the portable device is compatible with a communication method other than the first communication method based on the registered correspondence information when the correspondence information of the portable device is registered in association with identification information of the portable device obtained through wireless communication between the portable device and the first communication method.

15. A position detection system as described in any one of claims 1 to 3, further comprising a first selection unit (S520) that, when the determination unit determines that the portable device supports a communication method other than the first communication method, selects a wireless communication method for acquiring the position-related value related to the position of the portable device in accordance with the relative position of the portable device with respect to the target object.

16. The position detection system of claim 15, wherein the first selection unit selects a plurality of communication methods as communication methods for wireless communication to acquire the position-related value when the relative position of the portable device with respect to the object belongs to an area close to the object, and selects a smaller number of communication methods when the relative position of the portable device with respect to the object does not belong to an area close to the object.

17. A position detection system as described in claim 15, wherein when the interval between the previous acquisition of the position-related value and the current acquisition of the position-related value is within a predetermined time, the first selection unit selects a wireless communication method for acquiring the position-related value related to the position of the portable device in accordance with the relative position of the portable device with respect to the target object.

18. A position detection system as described in any one of claims 1 to 3, further comprising a second selection unit (S525) that, when the determination unit determines that the portable device supports a communication method other than the first communication method, selects a wireless communication method for acquiring the position-related value related to the position of the portable device in accordance with the moving speed of the portable device.

19. The position detection system of claim 18, wherein the second selection unit selects a plurality of communication methods as communication methods for wireless communication to acquire the position-related value when the moving speed of the portable device is equal to or greater than a predetermined threshold, and selects a smaller number of communication methods when the moving speed of the portable device is less than the predetermined threshold.

20. A position detection system as described in claim 18, wherein when the interval between the previous acquisition of the position-related value and the current acquisition of the position-related value is within a predetermined time, the second selection unit selects a wireless communication method for acquiring the position-related value related to the position of the portable device in accordance with the moving speed of the portable device.

21. A position detection method for detecting a position of a portable device (9) relative to an object (Hv), executed by a computer (1), comprising: using a communication module (2) installed on the object to perform wireless communication with the portable device in a first communication method (S300, S400); the communication module is configured to be capable of performing wireless communication with the portable device also in a second communication method different from the first communication method; and determining whether or not the portable device supports wireless communication in the second communication method based on the wireless communication with the portable device in the first communication method (S325, S410). if it is determined that the portable device supports wireless communication using the second communication method, causing the communication module to perform wireless communication with the portable device using the second communication method, and acquiring a position related value related to a position of the portable device from a wireless communication signal with the portable device using the second communication method, and if it is determined that the portable device does not support wireless communication using the second communication method, acquiring the position related value related to the position of the portable device from a wireless communication signal with the portable device using the first communication method (S330, S345, S415, S430, S445, S460); and determining a position of the portable device relative to the object or an area in which the portable device is located based on the acquired position related value (S340, S350, S420, S435, S450, S465).

22. A computer (1) that executes a process of detecting a position of a portable device relative to an object (Hv) based on a wireless communication signal when a communication module (2) installed in the object and a portable device (9) perform wireless communication, wherein the communication module is configured to be capable of performing wireless communication with the portable device by a second communication method different from the first communication method in addition to a first communication method, and the computer performs a process (S325, S410) of determining whether or not the portable device supports wireless communication by the second communication method based on the wireless communication with the portable device by the first communication method; a process (S330, S345, S415, S430, S445, S460) for causing the communication module to perform wireless communication with the portable device in the second communication method when it is determined that the portable device supports wireless communication in the second communication method, and acquiring a position-related value related to a position of the portable device from a wireless communication signal with the portable device in the second communication method when it is determined that the portable device does not support wireless communication in the second communication method, and acquiring the position-related value related to the position of the portable device from a wireless communication signal with the portable device in the first communication method; and a process (S340, S350, S420, S435, S450, S465) for determining a position of the portable device relative to the object or an area in which the portable device is located based on the acquired position-related value.