Position detection system, position detection method, and computer

Abstract

The present invention comprises: a plurality of UWB modules (3) that are installed in a vehicle (Hv) and perform UWB communication with a portable device (9); at least one BLE module (2) that is similarly installed in the vehicle (Hv) and performs BLE communication with the portable device (9); and a computer (1) that executes a process for determining the position of the portable device (9) with respect to the vehicle (Hv) on the basis of a UWB communication signal and / or a BLE communication signal. The computer (1) assesses whether UWB communication can be performed, and, if it is assessed that UWB communication cannot be performed, determines the position of the portable device (9) with respect to the vehicle (Hv) using the BLE communication signal.

Description

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

[0001] This application is based on Patent Application No. 2023-206916 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 technique for detecting the position of a mobile device relative to an object by wirelessly communicating with the mobile device.

[0003] Patent Literature 1 discloses a vehicle control device capable of accurately measuring the distance between a vehicle and a mobile terminal while reducing power consumption. In this device, when the mobile terminal enters an exterior communication area for Bluetooth (registered trademark, the same applies hereinafter) Low Energy (LE) communication, Bluetooth LE communication is performed between the vehicle and the mobile terminal. Via this Bluetooth LE communication, the mobile terminal transmits terminal location information, including current location information of the mobile terminal detected by a terminal GPS sensor, to the vehicle. The vehicle control device measures the vehicle-terminal distance with relatively low accuracy based on the received terminal location information and the current location of the vehicle detected by the vehicle GPS sensor.

[0004] The vehicle control device performs ultra-wideband (UWB) communication only when it recognizes from the measured time-series data of the vehicle-to-terminal distance that the mobile terminal is approaching the vehicle, and measures the vehicle-to-terminal distance with relatively high accuracy. In this way, when the mobile terminal is located within the exterior communication area, UWB communication is not performed unconditionally between the vehicle and the mobile terminal, thereby reducing the power consumption required to measure the vehicle-to-terminal distance with relatively high accuracy.

[0005] Japanese Patent Application Laid-Open No. 2021-96143

[0006] However, the device of Patent Document 1 does not take into account situations in which UWB communication, a communication method capable of measuring the vehicle-to-terminal distance with relatively high accuracy, cannot be used normally. For example, in some countries, the use of UWB communication outdoors is restricted. Furthermore, if multiple UWB communication antennas or communication devices installed in the vehicle malfunction, normal UWB communication signals cannot be obtained, and the vehicle-to-terminal distance may not be measured with relatively high accuracy. Therefore, there is a problem in that it becomes difficult to detect the location of the mobile terminal when a situation arises in which UWB communication, which can measure the vehicle-to-terminal distance with relatively high accuracy, cannot be used normally.

[0007] 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 terminal relative to an object even when it is difficult to use a first communication unit that wirelessly communicates with a mobile device using a first communication method that enables highly accurate positioning.

[0008] In order to achieve the above object, the position detection system according to the present disclosure is a position detection system that detects the position of a portable device relative to an object, and includes: a first communication unit that is installed on the object and that performs wireless communication with the portable device using a first communication method; a second communication unit that is installed on the object and that performs wireless communication with the portable device using a second communication method different from the first communication method; and a computer that executes processing to determine the position of the portable device relative to the object based on a first communication signal wirelessly communicated between the first communication unit and the portable device and / or a second communication signal wirelessly communicated between the second communication unit and the portable device, wherein the first communication method is ultra-wideband (UWB) communication, and the computer is configured to have: a determination unit that determines whether wireless communication with the portable device can be performed using the first communication unit; and a determination unit that determines the position of the portable device relative to the object using the second communication signal when the determination unit determines that wireless communication with the portable device cannot be performed using the first communication unit.

[0009] Furthermore, a position detection method according to the present disclosure is a position detection method executed by a computer for detecting the position of a portable device relative to an object, and is configured to include: acquiring at least one of a first communication signal wirelessly communicated using a first communication method between a first communication unit installed on the object and the portable device, and a second communication signal wirelessly communicated using a second communication method different from the first communication method between a second communication unit installed on the object and the portable device, wherein the first communication method is ultra-wideband communication; determining whether wireless communication with the portable device is possible using the first communication unit; and, if it is determined that wireless communication with the portable device is not possible using the first communication unit, determining the position of the portable device relative to the object using the second communication signal.

[0010] Furthermore, a computer according to the present disclosure is a computer that performs processing to detect the position of a portable device relative to an object, wherein the computer is configured to be able to acquire a first communication signal that is wirelessly communicated between a first communication unit installed on the object and the portable device using a first communication method, and a second communication signal that is wirelessly communicated between a second communication unit installed on the object and the portable device using a second communication method different from the first communication method, wherein the first communication method is ultra-wideband communication, and the computer is configured to have: a determination unit that determines whether wireless communication with the portable device is possible using the first communication unit; and a determination unit that determines the position of the portable device relative to the object using the second communication signal when the determination unit determines that wireless communication with the portable device is not possible using the first communication unit.

[0011] According to the position detection system, the position detection method, and the computer disclosed herein, as described above, it is determined whether wireless communication with the portable device is possible using the first communication unit. If it is determined that wireless communication with the portable device is not possible using the first communication unit, the position of the portable device relative to the object is determined using a second communication signal wirelessly transmitted between the second communication unit and the portable device using a second communication method. Therefore, even if the first communication unit, which wirelessly communicates with the portable device using the first communication method, is unable to be used normally, it is possible to detect the position of the portable terminal relative to the object by using the second communication signal.

[0012] 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.

[0013] 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.

[0014] 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 arrangement of a BLE module and a UWB module in a vehicle. FIG. 5 is a block diagram illustrating the configuration of a 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 a communication connection between the portable device and the in-vehicle system has not yet been established. 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 communicate data via BLE communication after a communication connection between the portable device and the in-vehicle system has been established. FIG. 9 is a diagram illustrating the operation of a portable device and an in-vehicle system when CS ranging communication is performed between the portable device and the in-vehicle system. FIG. 10 is a diagram illustrating the operation of a portable device and an in-vehicle system when UWB ranging communication is performed between the portable device and the in-vehicle system. FIG. 10 is a flowchart showing a process executed in an in-vehicle system for detecting the position of a mobile device using either a BLE module or a UWB module. FIG. 11 is a diagram showing examples of areas when the position of a mobile device is detected as belonging to an area using a BLE module. FIG. 12 is a flowchart showing an example of a process for determining a method for measuring the distance to a mobile device. FIG. 13 is a flowchart showing a process executed in an in-vehicle system according to a second embodiment for detecting the position of a mobile device using either a BLE module or a UWB module. FIG. 14 is a diagram showing whether UWB ranging communication with a mobile device is possible when one of the UWB modules has failed. FIG. 15 is a flowchart showing a process executed in an in-vehicle system according to a third embodiment for detecting the position of a mobile device using either or both of a BLE module and a UWB module. FIG. 16 is a flowchart showing a process for periodically performing both CS ranging and UWB ranging. FIG. 17 is a diagram showing the configuration of a modified example.

[0015] 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.

[0016] (First Embodiment) <Overall Configuration> As shown in Fig. 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 an ECU 1. ECU stands for Electronic Control Unit and refers to an electronic control device. The ECU 1 can also be referred to as a computer, microcomputer, processor, etc.

[0017] The ECU 1 is configured to be able to perform wireless communication compliant with Bluetooth LE (hereinafter referred to as BLE communication) with a portable device 9 carried by a user of the vehicle Hv. The following describes a case in which the 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."

[0018] The 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 a master in communication with the ECU 1, and the ECU 1 acts as a slave. The roles of each device are interchangeable. Furthermore, the functions and configurations of the ECU 1 and the portable device 9 may be changed as appropriate in accordance with the role interchange.

[0019] 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.

[0020] The in-vehicle system VS and the portable device 9 are configured to be capable of UWB communication, which is a wireless communication method using the UWB-IR (Ultra Wide Band - Impulse Radio) system. That is, the in-vehicle system VS and the portable device 9 are configured to be capable of transmitting and receiving impulse-shaped radio waves (hereinafter, referred to as impulse signals) used in UWB communication. The impulse signals used in UWB communication are signals having an extremely short pulse width (e.g., 2 ns) and a bandwidth of approximately 500 MHz or more (i.e., ultra-wide bandwidth).

[0021] Note that UWB communication can use multiple channels as specified in IEEE 802.15.4z. Channels (frequency bands) available for UWB communication may be restricted depending on the country. The in-vehicle system VS can communicate with the portable device 9 using, for example, channel 5 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 channel 3 or channel 9. Channel 3 is a channel with a center frequency of 4492 MHz, channel 5 is a channel with a center frequency of 6489.6 MHz, and channel 9 is a channel with a center frequency of 7987.2 MHz. IEEE (registered trademark) is an abbreviation for the Institute of Electrical and Electronics Engineers. Each channel corresponds to a frequency band of ±250 MHz from the center frequency. In UWB communication, frequencies such as 3.1 GHz to 4.8 GHz and 6.0 GHz to 10.6 GHz can be used.

[0022] 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.

[0023] <About the Portable Device 9> The portable device 9 is a portable, general-purpose information processing terminal equipped with a BLE communication function and a UWB 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.

[0024] 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.

[0025] 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 a UWB module 98.

[0026] 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.

[0027] The storage 93 may store a device ID, a key code used in wireless authentication processing with the ECU 1, and the like. The key code may also be called an encryption key. 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 ECU 1 and responding to inquiries / requests from the ECU 1. In this disclosure, the application software may be simply referred to as an app.

[0028] 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 an interface through which the user inputs a password into the portable device 9 for logging in to the digital key app and inputs an operation for pairing the portable device 9 with the ECU 1.

[0029] 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.

[0030] 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.

[0031] The UWB module 98 is a communication module for performing UWB communication. The UWB module 98 outputs received data to the device control unit 90. The UWB module 98 also transmits a UWB signal corresponding to transmission data based on instructions from the device control unit 90. The UWB module 98 can also transmit a UWB signal for distance measurement based on instructions from the device control unit 90. The operation of the UWB module 98 is controlled by the device control unit 90.

[0032] The device control unit 90 causes the BLE module 97 to transmit an advertising signal at a predetermined transmission interval in order to initiate BLE communication with the ECU 1. Furthermore, the device control unit 90 establishes a BLE communication connection with the vehicle Hv (ECU 1) based on the BLE module 97 receiving a connection request transmitted from the ECU 1 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 ECU 1. 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 ECU 1 and return the response code to the ECU 1.

[0033] 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 ECU 1. For example, based on a request from the ECU 1, the device control unit 90 causes the BLE module 97 to transmit a CW signal on a specified channel (or frequency). The interaction between the device control unit 90 and the ECU 1 will be described separately below.

[0034] Furthermore, when the device control unit 90 receives a UWB signal transmitted from the in-vehicle system VS, 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 sender or destination.

[0035] When the device control unit 90 is not connected for communication with the ECU 1, it causes the BLE module 97 to periodically transmit an advertising signal at a predetermined advertising interval. On the other hand, the device control unit 90 stops the operation of the UWB module 98 while the device control unit 90 is not connected for BLE communication with the ECU 1. When the device control unit 90 has established a BLE communication connection with the ECU 1, it activates the UWB module 98, enabling UWB communication. This configuration reduces the power consumption of the UWB module 98.

[0036] 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 ECU 1 via BLE communication after the BLE communication connection with the ECU 1 is established. The UWB ranging start request is a BLE signal requesting the start of UWB ranging processing. The UWB module 98 often consumes more power than the BLE module 97. Therefore, by reducing the time that the UWB module 98 is activated, further power saving effects can be expected.

[0037] <Regarding the In-Vehicle System> As shown in FIG. 3 , the in-vehicle system VS includes an ECU 1, a BLE module 2, multiple UWB modules 3, a body ECU 4, an action sensor 5, an actuator 6, and a telematics control unit (TCU) 7. The ECU 1, the BLE module 2, the multiple UWB modules 3, the body ECU 4, and the TCU 7 are interconnected to be able to communicate with each other via, for example, an in-vehicle network. Various standards, such as Controller Area Network (CAN: registered trademark), Ethernet (registered trademark), and FlexRay (registered trademark), can be adopted as the in-vehicle network standard. 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.

[0038] The ECU 1 executes processing to determine the position of the portable device 9 relative to the vehicle Hv based on the BLE signal communicated between the BLE module 2 of the in-vehicle system VS and the BLE module 97 of the portable device 9 (more specifically, the RSSI of the BLE signal and the CS ranging result) and / or the UWB signal communicated between the UWB module 3 of the in-vehicle system VS and the UWB module 98 of the portable device 9 (more specifically, the UWB ranging result). For example, the 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 an engine start area ESA inside the vehicle based on the UWB signals communicated between the multiple UWB modules 3 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.

[0039] 3, the 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.

[0040] The storage 14 includes a non-volatile storage medium such as a flash memory. The storage 14 stores a device location detection program to be 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 the device ID (e.g., a unique Bluetooth address) of the portable device 9. The storage 14 also stores data indicating the installation positions of the BLE module 2 and each UWB module 3 in the vehicle Hv.

[0041] The CAN controller 15 executes communication processing with other components of the in-vehicle system VS according to the CAN protocol 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, the CAN controller 15 executes reception processing when a data frame is stored in the reception buffer. The reception processing includes determining whether the received data frame is an invalid data frame due to corruption or the like through a form check, a stuff check, a cyclic redundancy check, etc. With regard to the UWB module 3, the CAN controller 15 determines whether, for example, a response signal received in response to a request for transmission of UWB ranging results corresponds to the aforementioned invalid data frame. If the CAN controller 15 determines that the data frame corresponds to an invalid data frame, it assumes that some kind of malfunction has occurred in the UWB module 3 that sent the request signal, and reports this to the main controller 11. Furthermore, for example, if the CAN controller 15 sends a request signal to the UWB module 3 but does not receive a response signal within a predetermined specified time, the CAN controller 15 may assume that some kind of malfunction has occurred in the UWB module 3 that sent the request signal, and may report this to the main controller 11.

[0042] 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.

[0043] The BLE module 2 is a communication module for performing BLE communication. In this embodiment, one BLE module 2 is provided in the vehicle Hv. Multiple BLE modules 2 may be provided in the vehicle Hv. The BLE module 2 is disposed, for example, in the vehicle cabin, as shown in FIG. 4 . The BLE module 2 is configured to be capable of transmitting and receiving a CW signal for each channel (or frequency) as a signal for CS ranging, in addition to a modulated signal for data communication. The BLE module 2 is configured to be capable of scanning for advertising signals using power supplied from an on-board battery, even while the vehicle Hv is parked.

[0044] The UWB module 3 is a communication module for performing UWB communication. As shown in FIG. 4 , a plurality of UWB modules 3, 3A to 3F, are provided in the vehicle Hv. Like the UWB module 98 provided in the portable device 9, each UWB module 3 provided in the vehicle Hv is configured to be able to transmit and receive UWB signals. As will be described in detail later, each UWB module 3 performs UWB communication for ranging with the portable device 9 when the ECU 1 determines that wireless communication with the portable device 9 is possible. This UWB communication measures the distance from each UWB module 3 to the portable device 9 (device distance), and the position of the portable device 9 is detected based on this measured distance. Each UWB module 3 is also referred to as an anchor or a reference station.

[0045] Each UWB module 3 includes 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 module 3 and generates UWB ranging data, which will be described next.

[0046] Each UWB module 3 performs UWB ranging processing based on instructions from the ECU 1. The UWB ranging processing is a process of measuring the device distance based on the propagation time (in other words, the time of flight) of radio waves from the UWB module 3 to the portable device 9. The UWB ranging processing includes a process of transmitting a UWB signal of a predetermined pattern toward the portable device 9 and a process of receiving a UWB signal as a response signal from the portable device 9. The UWB signal exchanged between the UWB module 3 and the portable device 9 in the UWB ranging processing may be a single impulse signal or a pulse sequence signal in which multiple impulse signals are arranged in a predetermined pattern.

[0047] The UWB controller measures the round trip time (RTT), which is the time elapsed between transmitting a UWB signal and receiving a response signal from the portable device 9, and calculates the device distance based on the RTT. 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 times within the UWB module 3. The specific value of the correction value can be designed as appropriate. The UWB module 3 transmits the calculated device distance to the ECU 1 as UWB ranging data. Note that the main controller 11 may perform the process of converting the RTT to distance.

[0048] As shown in FIG. 4 , the in-vehicle system VS includes a plurality of UWB modules 3, for example, an in-vehicle front anchor 3A, an in-vehicle rear anchor 3B, a right-side front anchor 3C, a right-side rear anchor 3D, a left-side rear anchor 3E, and a left-side rear anchor 3F. The in-vehicle front anchor 3A and the in-vehicle rear anchor 3B are UWB modules 3 disposed inside the vehicle cabin. The right-side front anchor 3C, the right-side rear anchor 3D, the left-side rear anchor 3E, and the left-side rear anchor 3F are UWB modules 3 disposed on the exterior of the vehicle Hv. The configuration and performance of each UWB module 3 may be substantially the same regardless of the installation location. Note that the example of the arrangement of the plurality of UWB modules 3 shown in FIG. 4 is merely an example, and the plurality of UWB modules 3 may be installed in different locations.

[0049] Each UWB module 3 operates according to instructions from the ECU 1. Each UWB module 3 starts up based on instructions from the ECU 1 and performs UWB ranging processing. After performing UWB ranging processing, the UWB module 3 stops operating spontaneously or based on instructions from the ECU 1.

[0050] 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 outer door handles, start switches, brake pedal sensors, and seat sensors. The ECU 1 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 on and off the driving power supply.

[0051] 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.

[0052] 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 ECU 1. Based on the event occurrence notification signal input from the body ECU 4, the ECU 1 may execute control and processing related to detection of the device location.

[0053] The TCU 7 is a communication unit that allows the vehicle hybrid vehicle (Hv) to bidirectionally communicate various information with an external network. The TCU 7 may be provided within the housing of the ECU 1, rather than being connected to the ECU 1 via an in-vehicle network. The TCU 7 has a wireless module for wireless communication with the external network. For example, the TCU 7 can report vehicle status and location information to a management center in the event of a vehicle accident or other incident by wirelessly communicating with the external network via the wireless module. Furthermore, the TCU 7 can obtain data for updating software used in various ECUs installed in the vehicle hybrid vehicle (Hv) from a data center or the like.

[0054] The TCU 7 can acquire a mobile country code indicating the operating area and a mobile network code indicating the telecommunications carrier from the communication equipment with which it communicates via the wireless module. The TCU 7 repeatedly transmits the acquired mobile country code to the main controller 11 at a predetermined interval. The TCU 7 also includes a GPS receiver for acquiring position information of the vehicle Hv. The TCU 7 also repeatedly transmits vehicle position information measured by the GPS receiver to the main controller 11 at a predetermined interval. This enables the main controller 11 to identify the country to which the vehicle Hv is located based on the mobile country code and / or vehicle position information transmitted from the TCU 7. The mobile country code and / or vehicle position information correspond to country information.

[0055] <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.

[0056] 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 instructions from the BLE controller.

[0057] The RF core 21 is a circuit module that performs signal processing related to the transmission and reception of radio signals. The RF core 21 may include a modulation circuit, a demodulation circuit, a frequency conversion circuit, an amplifier circuit, a local oscillator, and the like. The RF core 21 also has input / output terminals for outputting signals to the antenna 22 and receiving signals from the antenna 22. 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 signals received by the antenna 22 and provides the demodulated signals to the BLE controller 23. The RF core 21 also modulates transmission data input from the BLE controller 23 and radiates 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).

[0058] 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 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.

[0059] The reception phase detection unit 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 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, for example, 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 shifts the phase of the output signal of the local oscillator by 90°. 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°.

[0060] 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.

[0061] The RF core 21 associates the detected value of the reception phase of the CW signal with information indicating the frequency in use (e.g., a channel number) and provides it to the BLE controller 23. Every time the frequency in use is switched, the RF core 21 detects the reception phase of the CW signal as part of the ranging process. In other words, the BLE controller 23 is provided with data indicating the reception phase for each frequency.

[0062] 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 ECU 1. Specifically, the BLE controller 23 provides the ECU 1 with received data input from the RF core 21 sequentially or based on a request from the ECU 1. The BLE controller 23 also outputs transmission data input from the ECU 1 to the RF core 21.

[0063] 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.

[0064] 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 distance-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 acquire the reception phase, which is a distance-related value. CS ranging can also be referred to as 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.

[0065] 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 signal transmitted by the portable device 9 and the CW 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.

[0066] 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 passive two-way method, an active two-way method, or the like. The passive two-way method and the active two-way method will be described later in a separate supplementary explanation.

[0067] 6 is a flowchart showing an example of CS ranging processing. The CS ranging processing includes a preparation phase for adjusting the conditions for performing ranging, a collection phase for collecting reception phases by actually transmitting and receiving CW signals, and a calculation phase for calculating distance based on the collected reception phases for each frequency. In the present disclosure, wireless communication for acquiring distance-related values ​​(reception phases), such as transmitting and receiving CW signals, is also referred to as CW ranging communication.

[0068] 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.

[0069] 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 is a signal indicating parameters for performing communication for CS ranging. 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 represents 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 during data communication or may be different. If the frequency transition amount is the same value as the hop increment during data communication, the frequency transition amount for CS ranging may be determined by the hop increment. The initial frequency is the frequency of the CW 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.

[0070] 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.

[0071] In step S125, the portable device 9 starts transmitting a CW signal at the initial frequency when a predetermined time has elapsed since returning the Ack. The transmission of the CW 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 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 signal based on receiving a CW transmission request from the BLE module 2 after receiving the ranging setting notification signal.

[0072] When the BLE module 2 receives a CW 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 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 upon frequency transition amount.

[0073] When the mobile device 9 switches the operating frequency, it transmits a CW signal of the new operating frequency in step S145. By switching the operating frequency, the BLE module 2 also transitions 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 switch.

[0074] 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.

[0075] 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 that ranging communication is to be terminated. 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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, but this is not limiting. The portable device 9, instead of 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 main entity (in other words, the master).

[0084] 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 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. Note that communication for communication confirmation can be performed at connection intervals. Communication for communication confirmation may also be performed each time channel hopping is performed.

[0085] 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.

[0086] 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.

[0087] <Interaction between Portable Device and In-Vehicle System> 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] When the pairing start button is operated, an advertising signal is transmitted from the slave (ECU 1 or portable device 9) in the BLE communication to the central (portable device 9 or ECU 1). 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 returns a connection request in response to the advertising signal. 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.

[0092] 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 keys is verified, the exchanged encryption keys are stored in respective storage media such as storages. After pairing, data signals in BLE communication are encrypted using the exchanged encryption key. This ensures the security of BLE communication between the ECU 1 and the portable device 9.

[0093] Next, the ECU 1 or the portable device 9 generates a UWB Ranging Secret Key (URSK), which is a key used in UWB ranging communication, and shares it via BLE communication. The URSK can be used to create information that proves that the communication partner in UWB ranging communication is the correct communication partner. When the ECU 1 and the portable device 9 share the generated URSK, the ECU 1 can perform UWB ranging communication with the portable device 9 as the communication partner. The ECU 1 registers and stores the generated URSK by linking it to the ID (portable device ID) of the portable device 9. Note that the ECU 1 preferably confirms that UWB ranging communication with the portable device 9 is possible by performing UWB ranging using the generated URSK.

[0094] 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 ECU 1 or the portable device 9) starts transmitting an advertising signal. The central in the BLE communication (the portable device 9 or the 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.

[0095] 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 advertising 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.

[0096] 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.

[0097] 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 communication connection between the portable device 9 and the in-vehicle system VS is established, the portable device 9 and the BLE module 2 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.

[0098] After establishing a communication connection between the portable device 9 and the in-vehicle system VS, the ECU 1 determines whether to use a UWB signal or a BLE signal to locate the portable device 9. In this case, the ECU 1 generally determines to use a UWB signal to locate the portable device 9. However, if the vehicle Hv equipped with the vehicle electronic key system according to this embodiment is used in a country where the use of UWB communication outdoors is restricted, or if country information cannot be obtained from the TCU 7, the ECU 1 determines to use a BLE signal to locate the portable device 9. In this embodiment, UWB communication corresponds to a first communication method, and BLE communication corresponds to a second communication method.

[0099] When the ECU 1 determines to use a BLE signal for positioning the portable device 9, the ECU 1 first determines whether the portable device 9 supports CS ranging communication. For example, the ECU 1 can acquire information regarding whether the portable device 9 supports CS ranging communication via BLE communication. The ECU 1 can determine whether the portable device 9 supports CS ranging communication based on the acquired information. Whether the portable device 9 supports CS ranging communication may be confirmed in advance as part of the registration process when registering the portable device 9 as an owner device. When the ECU 1 determines that the portable device 9 supports CS ranging communication, the ECU 1 measures the position of the portable device 9 based on the CS ranging result using the BLE signal and the ranging result using the received signal strength of the BLE signal. Note that the CS ranging communication is preferably started when the received signal strength of the BLE signal is equal to or greater than a predetermined strength threshold or when the distance between the positions measured by the respective GPS receivers is equal to or less than a distance threshold. When any of the above-described conditions for starting CS ranging communication is satisfied, the ECU 1 can transmit a request to start CS ranging to the BLE module 2 .

[0100] 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.

[0101] 9, when the portable device 9 and the in-vehicle system VS perform data communication and CS ranging communication via the respective BLE modules 2 and 97, the ECU 1 performs, for example, received signal strength ranging based on the received signal strength of the signal for data communication, and also performs CS ranging through the CS ranging communication. On the other hand, when the portable device 9 does not support CS ranging communication, for example, as shown in FIG. 8, normal data communication is performed between the BLE module 2 and the portable device 9, and received signal strength ranging is performed using the received signal strength for the data communication.

[0102] 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-mentioned conditions for terminating the CS ranging communication is satisfied, the ECU 1 can transmit a request to stop CS ranging to the BLE module 2.

[0103] 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.

[0104] FIG. 10 illustrates the interaction between the portable device 9 and the in-vehicle system VS when performing UWB ranging communication. As shown in FIG. 10 , the ECU 1 periodically performs BLE data communication and UWB ranging communication with the portable device 9. The UWB ranging interval, which is the interval at which the ECU 1 instructs the UWB module 3 to perform UWB ranging communication, can be set to, for example, three or four times the connection interval. Increasing the UWB ranging interval in this manner is expected to reduce power consumption. However, the UWB ranging interval may be the same as the connection interval. Note that "UWB-Ranging Interval" in FIG. 10 indicates the UWB ranging interval. One UWB ranging communication may include UWB ranging communication with multiple UWB modules 3. The UWB ranging interval can 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, or the UWB ranging interval may be the same as or shorter than the CS ranging interval.

[0105] It is preferable that the detection of the location of the mobile device using the UWB signal be started, for example, when the received signal strength of the BLE signal exceeds a predetermined strength threshold, or when the distance between the locations measured by each GPS receiver is equal to or less than a distance threshold, because this is expected to have the effect of reducing power consumption.

[0106] When any of the above-described conditions for starting UWB ranging communication is satisfied, the ECU 1 can transmit a request to start UWB ranging to the multiple UWB modules 3. In response to this request, the multiple UWB modules 3 transition from a sleep state to an active state, thereby enabling 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.

[0107] 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.

[0108] When any of the above-described conditions for ending UWB ranging communication is satisfied, the ECU 1 can transmit a request to stop UWB ranging to the multiple UWB modules 3. In response to this request, the multiple UWB modules 3 end the UWB ranging communication. Then, for example, if the multiple UWB modules 3 do not receive a new request to start UWB ranging within a predetermined time after ending the UWB ranging communication, they can transition to a sleep state.

[0109] Even when the UWB ranging communication is terminated in response to the user turning on the start switch, the 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 the 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.

[0110] <Functions of the Main Controller> The main controller 11 includes, as functional blocks, a communication control unit G1 and a position determination unit G2, as shown in Fig. 11. The communication control unit G1 is a software / hardware module that controls the operations of the BLE module 2 and the UWB module 3. For example, the communication control unit G1 causes the BLE module 2 to perform CS ranging processing when it is unable to acquire country information, which will be described later, or when it is determined that the UWB module 3 cannot be used based on the acquired country information.

[0111] The communication system control unit G1 also performs a cyclic measurement process, which is a process of causing each of the multiple UWB modules 3 to perform UWB ranging in turn. After a BLE communication connection is established between the vehicle Hv and the portable device 9, the communication system control unit G1 periodically performs the cyclic measurement process when UWB ranging can be performed. The communication system control unit G1 may determine the start timing of the cyclic measurement process or dynamically change the cyclic measurement interval depending on the value of the received signal strength observed within a predetermined time period. Alternatively, the communication system control unit G1 may perform the cyclic measurement process based on the detection of the occurrence of a predetermined event that requires the location of the portable device 9 to be detected.

[0112] 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 device distance for each UWB module 3 obtained as a result of the patrol measurement process, or based on the received signal strength ranging result and / or the CS ranging result. The device position can be expressed by multiple areas / zones that are set in advance in the vehicle Hv, such as an engine start area ESA inside the vehicle, an entry area EA outside the vehicle, an intermediate area and a far area outside the vehicle.

[0113] 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. 12 . 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 and trunk 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.

[0114] 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. 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 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 / initiated, 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.

[0115] 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.

[0116] 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.

[0117] 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. Alternatively, the main controller 11 may perform a patrol measurement process in response to the occurrence of a predetermined event, and generate and update the device position data.

[0118] <Processing for detecting the position of a portable device> Next, the processing for detecting the position of the portable device 9, which is executed by the in-vehicle system VS of the vehicle electronic key system of this embodiment and is implemented using either the BLE module 2 or the UWB module 3, will be described with reference to the flowchart of Figure 13.

[0119] In step S200, the BLE controller 23 or the ECU 1 determines whether or not it has established a communication connection with the portable device 9. If it has established a communication connection with the portable device 9, the ECU 1 proceeds to step S205 and determines whether or not it is possible to acquire country information from the TCU 7. Note that outdoor use of UWB communication may be restricted depending on the country. Even if UWB communication is available, the frequency bands available for outdoor UWB communication may be limited depending on the country. As a result, the frequency bands available for outdoor UWB communication vary depending on the country. If the country information cannot be acquired from the TCU 7, it is impossible to determine whether outdoor use of UWB communication is permitted or the permitted frequency bands for UWB communication. Therefore, it is preferable to avoid using UWB communication when the country information cannot be acquired. For example, if the vehicle Hv is parked in a parking lot within a building, the TCU 7 may be unable to communicate with an external network via the wireless module and may be unable to receive GPS signals from satellites using the GPS receiver. When the ECU 1 determines through communication with the TCU 7 that the TCU 7 is in the above-mentioned situation, it determines that it is not possible to acquire the country information from the TCU 7, and proceeds to the processing of step S240. Note that the ECU 1 may also determine that it is not possible to acquire the country information if it is unable to communicate with the TCU 7 for some reason. On the other hand, when the ECU 1 determines through communication with the TCU 7 that it is possible to acquire the country information, it proceeds to the processing of step S210.

[0120] In step S210, the ECU 1 acquires country information from the TCU 7. Then, in step S215, the ECU 1 determines whether UWB ranging communication is available based on the acquired country information. UWB communication restriction information for each country is pre-stored in the memory 13 of the main controller 11 of the ECU 1. The UWB communication restriction information includes information on whether UWB communication can be used outdoors, as well as information on channels (frequencies) available for UWB communication. If it is determined in step S215 that UWB communication is unavailable, the ECU 1 proceeds to the process of step S240. On the other hand, if it is determined that UWB communication is available, the ECU 1 proceeds to the process of step S220.

[0121] In step S220, the ECU 1 references the UWB communication regulation information stored in the memory 13 and selects a channel (frequency) available for UWB communication based on the acquired country information. Then, in step S225, the ECU 1 shares UWB communication specification information, including the selected channel, with the portable device 9, and then instructs each UWB module 3 to periodically perform a UWB ranging process, i.e., a patrol measurement process. The ECU 1 then acquires the device distance for each UWB module 3 obtained as a result of the patrol measurement process. In step S230, the ECU 1 determines (detects) the position of the portable device 9 relative to the vehicle Hv based on the acquired device distance for each UWB module 3. Although not shown in the flowchart of FIG. 13 , once the ECU 1 determines the position of the portable device 9, it transmits the determined position data of the portable device 9 to the body ECU 4. The body ECU 4 can execute predetermined controls, such as unlocking / locking the vehicle Hv or turning on the power, based on the position data of the portable device 9 provided by the ECU 1.

[0122] In step S240, when the ECU 1 determines the location of the portable device 9 using the BLE signal as any of the predetermined areas, if there are limitations on the determinable areas, the ECU 1 notifies the user of the area limitation information via, for example, BLE communication. This allows the user to recognize in advance which areas the location of the portable device 9 cannot be determined, in other words, which areas the approach of the portable device 9 cannot be detected.

[0123] In this embodiment, one BLE module 2 is mounted on the vehicle Hv. Therefore, whether CS ranging is performed or ranging based on received signal strength is performed, the determined area is an area approximately centered on the BLE module 2, as shown in FIG. 14 . For example, in the example shown in FIG. 14 , a fourth entry area EA4 and an engine start area ESA are defined approximately centered on the BLE module 2. In this case, if the fourth entry area EA4 is expanded to include an entry area where the trunk can be opened and closed, the entry area for the driver's seat and passenger seat would become too large. Therefore, when the location of the portable device 9 is determined as one of the areas using a BLE signal, as in the example shown in FIG. 14 , the determinable area may be more limited than when the location of the portable device 9 is determined as one of the areas using a UWB signal. Note that in the example shown in FIG. 14 , the third entry area EA3 is limited among the areas shown in FIG. 12 , but the restricted entry area may differ depending on the installation location of the BLE module 2 in the vehicle Hv.

[0124] In step S245, the ECU 1 periodically executes a process of measuring the device distance from the BLE module 2 to the portable device 9 using the BLE signal. At this time, before executing the process of measuring the device distance, the ECU 1 executes a process of determining a method of measuring the distance to the portable device 9 using the BLE signal. The flowchart in FIG. 15 shows an example of the process of determining a method of measuring the distance to the portable device 9.

[0125] In step S300, the ECU 1 determines whether the portable device 9 supports CS ranging communication and is capable of CS ranging based on a signal received from the portable device 9 indicating whether the portable device 9 supports CS ranging communication or not, or a response from the portable device 9 to an inquiry about whether the portable device 9 supports CS ranging communication. If the ECU 1 determines that CS ranging is possible, the ECU 1 proceeds to step S305. On the other hand, if the ECU 1 determines that CS ranging is not possible, the ECU 1 proceeds to step S310. Note that when the portable device 9 is the master, the portable device 9 may determine whether the BLE module 2 of the in-vehicle system VS supports CS ranging communication.

[0126] In step S305, the ECU 1 determines to perform both CS ranging using a BLE signal and ranging using the received signal strength of the BLE signal as a method for measuring the distance to the portable device 9, and periodically performs CS ranging and received signal strength ranging. This is because performing ranging using the received signal strength in addition to CS ranging can improve the accuracy of detecting the position of the portable device 9. For example, by periodically performing CS ranging and received signal strength ranging, it is possible to determine that the portable device 9 is inside the vehicle when 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 result of CS ranging indicates that the portable device 9 is inside the vehicle (e.g., within 1 m from the BLE module 2). However, the ECU 1 may perform only CS ranging without performing received signal strength ranging. On the other hand, in step S310, the ECU 1 determines to perform ranging using the received signal strength of a BLE signal as a method for measuring the distance to the portable device 9, and periodically performs received signal strength ranging.

[0127] In step S250 of the flowchart in FIG. 13 , the ECU 1 determines (detects) the position of the portable device 9 relative to the vehicle Hv based on the results of the CS ranging and the received signal strength ranging, or the received signal strength ranging. In this case, as described above, only the distance from one BLE module 2 to the portable device 9 is measured. Therefore, the position of the portable device 9 is detected as whether or not it belongs to each area, such as whether or not it belongs to the fourth entry area EA4 or the engine start area ESA, which are approximately centered on the BLE module 2, as shown in FIG. 14 . Then, after determining the position of the portable device 9, the ECU 1 transmits the determined 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 ECU 1, the body ECU 4 can execute predetermined control, such as unlocking / locking the vehicle Hv or turning on the power.

[0128] 13 , the ECU 1 determines whether or not the positioning of the portable device 9 has been completed. For example, the ECU 1 may determine that the positioning of the portable device 9 has been completed when the vehicle Hv is stopped, the occupant gets out of the vehicle, the vehicle Hv is locked, the portable device 9 is separated from the vehicle, and the position of the portable device 9 cannot be measured. If the positioning of the portable device 9 has not been completed, the ECU 1 returns to step S205 and repeatedly executes the above-described process. As a result, country information is repeatedly (periodically) acquired, and a communication method corresponding to the acquired country information can be selected.

[0129] Second Embodiment Overview of a Vehicle Electronic Key System According to a Second Embodiment Next, a vehicle electronic key system incorporating a location detection system, a location detection method, and a computer according to a second embodiment of the present disclosure will be described. The vehicle electronic key system according to this embodiment is configured similarly to the vehicle electronic key system according to the first embodiment. Therefore, a description of the configuration of the vehicle electronic key system according to this embodiment will be omitted.

[0130] The vehicle electronic key system according to the first embodiment described above determines whether to use the distance measurement results using BLE signals or the distance measurement results using UWB signals to detect the location of the portable device 9, based on the country information acquired from the TCU 7. In contrast, the vehicle electronic key system according to the present embodiment switches between using the distance measurement results using BLE signals or the distance measurement results using UWB signals to detect the location of the portable device 9, depending on whether the failed UWB module is involved in determining whether the device belongs to the required area near the driver's door.

[0131] <Processing for detecting the position of a portable device> Hereinafter, the processing for detecting the position of the portable device 9, which is executed using either the BLE module 2 or the UWB module 3 in the in-vehicle system VS of the vehicle electronic key system according to this embodiment, will be described with reference to the flowchart of FIG. 16 .

[0132] In step S400, the BLE controller 23 or the ECU 1 determines whether or not communication is established with the portable device 9. If communication is established with the portable device 9, the ECU 1 proceeds to step S405, where it determines whether all anchors of the UWB module 3 (e.g., UWB modules 3A to 3F in FIG. 4 ) are operating normally. As described above, when the ECU 1 determines that, for example, a response signal received in response to a request for transmission of a UWB ranging result corresponds to an invalid data frame, the ECU 1 can determine that some kind of malfunction has occurred in the UWB module 3 that transmitted the request signal. Furthermore, for example, when the ECU 1 transmits a request signal to a UWB module 3 but does not receive a response signal within a predetermined time, the ECU 1 may determine that some kind of malfunction has occurred in the UWB module 3 that transmitted the request signal. Furthermore, each UWB module 3 may be provided with an abnormality diagnosis circuit that detects abnormalities such as disconnections and short circuits, and the ECU 1 may determine that the corresponding UWB module 3 is malfunctioning when notified of the occurrence of an abnormality from the UWB module 3.

[0133] If the ECU 1 determines that all of the anchors 3A to 3F of the UWB module 3 are operating normally, the process proceeds to step S410. On the other hand, if the ECU 1 determines that at least one of the anchors 3A to 3F has failed, the process proceeds to step S425. The processes of steps S410, S415, and S420 are similar to steps S225, S230, and S235 in the flowchart of FIG. 13, and therefore description thereof will be omitted.

[0134] In step S425, the ECU 1 identifies the installation location of the faulty anchor. For example, the ECU 1 stores a table indicating the installation locations of the anchors 3A to 3F. The ECU 1 can identify the installation location of the faulty anchor by referring to this table. In the following step S430, the ECU 1 determines whether the faulty anchor is involved in the determination of whether or not the anchor belongs to the required area near the driver's door where the portable device 9 is located.

[0135] Here, for example, assume that anchor 3C of UWB module 3 fails, as shown in FIG. 17 . In this case, ECU 1 cannot obtain the distance measurement result from anchor 3C to the correct portable device 9. Therefore, as shown in FIG. 17 , when portable device 9 approaches vehicle Hv from the side of failed anchor 3C, ECU 1 may obtain distance measurement results only from two anchors 3A and 3D. As a result, ECU 1 may not be able to identify the location of portable device 9 and may not be able to correctly detect the location of portable device 9. In particular, when failed anchor 3C is involved in determining whether or not an entry area near the driver's seat belongs to the vehicle Hv, ECU 1 may not be able to detect that a user holding portable device 9 has approached the driver's seat of the vehicle Hv. In this case, even if the user is located near the driver's door or performs an unlocking operation, the driver's door may not be unlocked, which may significantly impair user convenience.

[0136] Therefore, in the vehicle electronic key system according to this embodiment, the area near the driver's seat door is defined as a required area, and a determination is made as to whether the failed anchor is a required anchor involved in the determination of whether the area near the driver's seat belongs to the vehicle. If the failed anchor is a required anchor involved in the determination of whether the area near the driver's seat belongs to the vehicle, the ECU 1 determines that wireless communication with the portable device 9 using UWB communication is not possible, and proceeds to step S435. On the other hand, if the failed anchor is a non-required anchor not involved in the determination of whether the area near the driver's seat belongs to the vehicle, the ECU 1 determines that wireless communication with the portable device 9 using UWB communication is possible, and proceeds to step S455. The processes in steps S435, S440, S445, and S450 are similar to steps S240, S245, S250, and S255 in the flowchart of FIG. 13 , and therefore will not be described here.

[0137] In step S455, the ECU 1 notifies the user of the area where access to the vehicle Hv is restricted because the location of the portable device 9 cannot be determined by UWB ranging due to the faulty anchor, as area restriction information, for example, via BLE data communication. This allows the user to know in advance that there are areas where approach to the vehicle Hv will not be recognized, and enables the user to take measures such as avoiding the unrecognized areas when accessing the vehicle. Then, in step S460, the ECU 1 instructs each UWB module 3 to periodically perform UWB ranging processing because the faulty anchor is not involved in determining whether the essential area near the driver's seat belongs to the vehicle. Note that the processing in steps S460, S465, and S470 is similar to steps S225, S230, and S235 in the flowchart of FIG. 13 , and therefore further description will be omitted.

[0138] Third Embodiment Overview of a Vehicle Electronic Key System According to a Third Embodiment Next, a vehicle electronic key system incorporating a location detection system, a location detection method, and a computer according to a third embodiment of the present disclosure will be described. The vehicle electronic key system according to this embodiment has the same configuration as the vehicle electronic key system according to the first embodiment. Therefore, a description of the configuration of the vehicle electronic key system according to this embodiment will be omitted.

[0139] In the vehicle electronic key system according to the second embodiment, if at least one of the anchors in the UWB module 3 fails, the system switches between using the distance measurement results based on the BLE signal or the distance measurement results based on the UWB signal to detect the location of the portable device 9, depending on whether the failed anchor is involved in determining whether the portable device 9 belongs to the required area near the driver's door. In contrast, in the vehicle electronic key system according to the present embodiment, if at least one of the anchors in the UWB module 3 fails and there is a possibility that the failed anchor will prevent accurate distance measurement results from being obtained for the portable device 9, the system changes the method for detecting the location of the portable device 9.

[0140] <Processing for detecting the position of a portable device> Hereinafter, the processing for detecting the position of the portable device 9, which is performed using either or both of the BLE module 2 and the UWB module 3, executed in the in-vehicle system VS of the vehicle electronic key system according to this embodiment will be described with reference to the flowchart of FIG. 18 .

[0141] The processes of steps S500, S505, S510, S515, S520, and S525 are similar to steps S400, S405, S410, S415, S420, and S425 in the flowchart of FIG. 16, and therefore description thereof will be omitted.

[0142] In step S530, the ECU 1 determines whether the portable device 9 is located near or within the area in which the faulty anchor is involved in the determination of whether it belongs to the vehicle Hv. For example, the ECU 1 can obtain GPS location information from the portable device 9 and compare it with the GPS location information of the vehicle Hv to determine the approximate location of the portable device 9 relative to the vehicle Hv. Alternatively, for example, as shown in FIG. 17 , even if one of multiple anchors fails, the approximate location of the portable device 9 relative to the vehicle Hv can be determined by UWB ranging communication with two anchors. If the ECU 1 determines that the determined location of the portable device 9 is located near or within the area in which the faulty anchor is involved in the determination of whether it belongs to the vehicle Hv, the ECU 1 proceeds to step S535. On the other hand, if the ECU 1 determines that the determined location of the portable device 9 is not located near or within the area in which the faulty anchor is involved in the determination of whether it belongs to the vehicle Hv, the ECU 1 proceeds to step S550.

[0143] In step S535, the ECU 1 instructs the BLE module 2 and the UWB module 3 to periodically perform both CS ranging and UWB ranging. Specifically, as shown in the flowchart of FIG. 19 , in step S600, the ECU 1 instructs the multiple UWB modules 3 to periodically perform UWB ranging, i.e., to start periodically performing patrol measurement processing. In step S605, the ECU 1 instructs the BLE module 2 to start periodically performing CS ranging when the UWB modules 3 are not performing UWB ranging. The BLE module 2 can acquire the timing when the UWB modules 3 are not performing UWB ranging from the ECU 1. Note that if the portable device 9 does not support CS ranging communication, the ECU 1 instructs the BLE module 2 to periodically perform received signal strength ranging.

[0144] In step S610, the ECU 1 acquires UWB ranging results from multiple UWB modules 3 and also acquires CS ranging results or received signal strength ranging results from the BLE module 2. In this way, the ECU 1 acquires CS ranging results or received signal strength ranging results in addition to UWB ranging results. For example, if one UWB module 3 fails and UWB ranging cannot be obtained, the failure can be compensated for by CS ranging or received signal strength ranging. Therefore, even if a UWB module 3 fails, the ECU 1 can detect the position of the portable device 9 with high accuracy in step S540 of the flowchart in FIG. 18 . Note that the processes of steps S545, S550, S555, and S560 of the flowchart in FIG. 18 are similar to steps S450, S460, S465, and S470 of the flowchart in FIG. 16 , and therefore will not be described here.

[0145] <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.

[0146] <Modification of System Configuration (1)> In the above-described embodiment, the BLE module 2 is disposed outside the housing of the ECU 1. However, this is not limiting. For example, the BLE module 2 may be disposed inside the housing of the ECU 1.

[0147] <Variation (2) of System Configuration> The in-vehicle system VS may include, for example, multiple BLE modules 2A to 2F as BLE modules, as shown in FIG. 20 . In the example shown in FIG. 20 , the multiple BLE modules 2A to 2F are arranged in close proximity to multiple UWB modules 3A to 3F. In this case, if at least one UWB module 3 fails, a BLE module 2 arranged in close proximity to the failed UWB module 3 may be caused to perform CS ranging, and the location of the portable device 9 may be detected based on the UWB ranging results from the normal UWB module 3 and the CS ranging results from the BLE module 2. Alternatively, if at least one UWB module 3 fails, multiple BLE modules 2 may be caused to perform CS ranging, and the location of the portable device 9 may be detected from the CS ranging results. Furthermore, the position of the mobile device 9 may be calculated based on the UWB ranging results by the normal UWB module 3, while the position of the mobile device 9 may be calculated based on the CS ranging results by multiple BLE modules 2, and the final position of the mobile device 9 may be determined from the two calculated positions of the mobile device 9. For example, if the calculated positions of the two mobile devices 9 match, the matched position may be determined as the final position of the mobile device 9. If the calculated positions of the two mobile devices 9 do not match, the position of the mobile device 9 based on the CS ranging results by multiple normally operating BLE modules 2 may be determined as the final position of the mobile device 9. Note that when multiple BLE modules 2 are caused to perform CS ranging, one BLE module 2 may distribute channel information and timing information for performing the CS ranging process to the other BLE modules 2, so that the other BLE modules 2 may also be able to intercept (sniff) the CW signal transmitted from the mobile device 9.

[0148] 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.

[0149] <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.

[0150] <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, 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.

[0151] <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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] <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.

[0157] <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.

[0158] <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.

[0159] <Supplementary Remarks (1)> [Technical Idea 1] A position detection system for detecting a position of a portable device (9) relative to an object (Hv), comprising: a first communication unit (3) installed on the object and performing wireless communication with the portable device using a first communication method; a second communication unit (2) installed on the object and performing wireless communication with the portable device using a second communication method different from the first communication method; and a computer (1) that executes processing to determine the position of the portable device relative to the object, based on a first communication signal wirelessly communicated between the first communication unit and the portable device and / or a second communication signal wirelessly communicated between the second communication unit and the portable device, wherein the first communication method is ultra-wideband (UWB) communication, and the computer comprises: a determination unit (S205, S215, S405, S430, S505) that determines whether wireless communication with the portable device can be performed using the first communication unit; and a determination unit (S250, S445, S465, S540, S555) that determines the position of the portable device relative to the object using the second communication signal when the determination unit determines that wireless communication with the portable device cannot be performed using the first communication unit. [Technical Idea 2] The position detection system according to Technical Idea 1, wherein the second communication method is Bluetooth Low Energy Channel Sounding (BLE-CS) communication. [Technical Idea 3] The position detection system according to Technical Idea 2, wherein the BLE-CS communication transmits and receives continuous wave (CW) signals whose frequency changes periodically, and the determination unit determines the position of the portable device based on a reception phase difference of CW signals with different frequencies. [Technical Idea 4] A position detection system according to any one of Technical Ideas 1 to 3, further comprising a country information acquisition unit (S210) that acquires country information indicating the country to which the location of the object belongs, and the determination unit (S215) determines whether wireless communication with the mobile device can be performed using the first communication unit based on the country information acquired by the country information acquisition unit.[Technical Idea 5] The position detection system according to Technical Idea 4, wherein the determination unit (S205) determines that wireless communication with the portable device cannot be performed using the first communication unit if the country information acquisition unit cannot acquire the country information. [Technical Idea 6] The position detection system according to Technical Idea 4 or 5, further comprising a frequency determination unit (S220) that determines, based on the acquired country information, a frequency band or frequency channel to be used for wireless communication of the first communication method if the determination unit determines that the country information acquisition unit can acquire the country information and that wireless communication with the portable device can be performed using the first communication unit based on the acquired country information. [Technical Idea 7] The position detection system according to any one of Technical Ideas 4 to 6, wherein the country information acquisition unit repeatedly executes the country information acquisition process. [Technical Idea 8] The position detection system according to any one of Technical Ideas 4 to 7, wherein the determination unit determines the position of the portable device relative to the object using only the second communication signal when the determination unit determines, based on the country information or because the country information cannot be acquired, that wireless communication with the portable device cannot be performed using the first communication unit. [Technical Idea 9] The position detection system according to any one of Technical Ideas 1 to 3, wherein the first communication unit includes a plurality of anchors (3A to 3F) that are installed at different positions on the object and are capable of wireless communication with the portable device, and the determination unit (S405, S505) determines that wireless communication with the portable device cannot be performed using the first communication unit when at least one of the plurality of anchors is faulty. [Technical Idea 10] When the determination unit (S505) determines that wireless communication with the portable device using the first communication unit is not possible due to a malfunction of at least one of the multiple anchors, the determination unit (S540) determines the position of the portable device relative to the target object based on the first communication signal and the second communication signal obtained by wireless communication using the anchors that are operating normally. This is the position detection system described in Technical Idea 9.[Technical Idea 11] The position detection system described in Technical Idea 9 or 10, wherein the determination unit (S540, S555) determines the position of the mobile device based on the first communication signal in an area where the position of the mobile device can be determined based on the first communication signal via wireless communication using the anchor that is operating normally, and determines the position of the mobile device using the second communication signal in an area where the position of the mobile device can be determined based on the first communication signal via wireless communication using the anchor that is malfunctioning. [Technical Idea 12] The plurality of anchors are divided into essential anchors that are involved in determining whether the location of the portable device belongs to a required area and non-essential anchors that are not involved according to their installation positions on the object, the determination unit (S430) determines that wireless communication with the portable device is possible using the first communication unit if the failed anchor is the non-essential anchor, and the determination unit (S465) determines the location of the portable device relative to the object based on the first communication signal, and the determination unit determines that wireless communication with the portable device is not possible using the first communication unit if the failed anchor is the essential anchor, and the determination unit (S445) determines the location of the portable device relative to the object based on the second communication signal. [Technical Idea 13] The location detection system according to Technical Idea 12, wherein the object is an automobile, the essential anchor is installed near a driver's seat of the automobile, and the first communication signal via wireless communication using the essential anchor is used to determine the location of the portable device in an area near the driver's seat of the automobile.

[0160] <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.

[0161] 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), A first communication unit (3) is installed on the object and performs wireless communication with the portable device using a first communication method, A second communication unit (2) is installed on the object and performs wireless communication with the portable device using a second communication method different from the first communication method, The system includes a computer (1) that performs processing to determine the position of the mobile device relative to the object based on a first communication signal wirelessly transmitted between the first communication unit and the mobile device and / or a second communication signal wirelessly transmitted between the second communication unit and the mobile device, The first communication method described above is ultra-wideband (UWB) communication, The aforementioned computer, A determination unit (S205, S215, S405, S430, S505) determines whether or not wireless communication with the portable device can be performed using the first communication unit, If the determination unit determines that wireless communication with the mobile device cannot be performed using the first communication unit, the determination unit (S250, S445, S465, S540, S555) determines the position of the mobile device relative to the object using the second communication signal, The system includes a country information acquisition unit (S210) that acquires country information indicating the country to which the location of the object belongs, The determination unit determines, based on the country information acquired by the country information acquisition unit, whether or not wireless communication with the mobile device can be performed using the first communication unit, in this location detection system.

2. The location detection system according to claim 1, wherein the determination unit determines that if the country information acquisition unit cannot acquire the country information, it is not possible to perform wireless communication with the mobile device using the first communication unit.

3. The location detection system according to claim 1, further comprising a frequency determination unit (S220) that determines, based on the acquired country information, whether the country information acquisition unit can acquire the country information and whether wireless communication with the mobile device can be performed using the first communication unit, if the determination unit determines that wireless communication with the mobile device can be performed using the first communication unit, based on the acquired country information, the frequency determination unit (S220) determines the frequency band or frequency channel to be used for wireless communication of the first communication method.

4. The location detection system according to claim 1, wherein the country information acquisition unit iteratively performs the process of acquiring the country information.

5. The position detection system according to claim 1, wherein the determination unit determines, based on the country information or because the country information cannot be obtained, that wireless communication with the mobile device cannot be performed using the first communication unit, and the determination unit determines the position of the mobile device with respect to the object using only the second communication signal.

6. A position detection system for detecting the position of a portable device (9) relative to an object (Hv), A first communication unit (3) is installed on the object and performs wireless communication with the portable device using a first communication method, A second communication unit (2) is installed on the object and performs wireless communication with the portable device using a second communication method different from the first communication method, The system includes a computer (1) that performs processing to determine the position of the mobile device relative to the object based on a first communication signal wirelessly transmitted between the first communication unit and the mobile device and / or a second communication signal wirelessly transmitted between the second communication unit and the mobile device, The first communication method described above is ultra-wideband (UWB) communication, The aforementioned computer, A determination unit (S205, S215, S405, S430, S505) determines whether or not wireless communication with the portable device can be performed using the first communication unit, If the determination unit determines that wireless communication with the portable device cannot be performed using the first communication unit, the determination unit (S250, S445, S465, S540, S555) determines the position of the portable device relative to the object using the second communication signal, The first communication unit includes a plurality of anchors (3A to 3F) installed at different locations on the object and capable of wireless communication with the portable device, A location detection system in which the determination unit determines that it is not possible to communicate wirelessly with the mobile device using the first communication unit if at least one of the plurality of anchors is malfunctioning.

7. If the determination unit (S505) determines that it is not possible to wirelessly communicate with the mobile device using the first communication unit because at least one of the plurality of anchors is malfunctioning, the decision unit (S540) determines the position of the mobile device relative to the object based on the first communication signal and the second communication signal obtained by wireless communication using the normally functioning anchors. This is the position detection system according to claim 6.

8. The position detection system according to claim 6, wherein the determination unit (S540, S555) determines the position of the mobile device based on the first communication signal via wireless communication using the normally functioning anchor in an area where the position of the mobile device can be determined based on the first communication signal, and determines the position of the mobile device using the second communication signal in an area where the position of the mobile device can be determined based on the first communication signal via wireless communication using the malfunctioning anchor.

9. The multiple anchors are classified into essential anchors that are involved in determining whether the location of the mobile device belongs to an essential area, and non-essential anchors that are not involved, depending on their installation position on the object. The determination unit (S430) determines that if the faulty anchor is the non-essential anchor, it can communicate wirelessly with the portable device using the first communication unit, and the decision unit (S465) determines the position of the portable device relative to the object based on the first communication signal. The position detection system according to claim 6, wherein the determination unit determines that if the faulty anchor is the essential anchor, it is not possible to communicate wirelessly with the portable device using the first communication unit, and the decision unit (S445) determines the position of the portable device relative to the object based on the second communication signal.

10. The aforementioned object is an automobile, The position detection system according to claim 9, wherein the essential anchor is installed near the driver's seat of the automobile, and the first communication signal transmitted wirelessly using the essential anchor is used to determine the position of the portable device in the area near the driver's seat of the automobile.

11. A position detection method performed by a computer for detecting the position of a portable device (9) relative to an object (Hv), To acquire at least one of a first communication signal wirelessly transmitted between a first communication unit (3) installed on the object and the mobile device using a first communication method, and a second communication signal wirelessly transmitted between a second communication unit (2) installed on the object and the mobile device using a second communication method different from the first communication method (S225, S245). The first communication method described above is ultra-wideband (UWB) communication, Determine whether wireless communication with the portable device can be performed using the first communication unit (S205, S215, S405, S430, S505), If it is determined that wireless communication with the portable device cannot be performed using the first communication unit, the position of the portable device relative to the object is determined using the second communication signal (S250, S445, S465, S540, S555), and The process includes obtaining country information indicating the country to which the location of the object belongs (S210), A location detection method that determines whether wireless communication with the mobile device can be performed using the first communication unit, based on the acquired country information.

12. A position detection method for detecting the position of a portable device (9) relative to an object (Hv), which is performed by a computer, To acquire at least one of a first communication signal wirelessly transmitted between a first communication unit (3) installed on the object and the mobile device using a first communication method, and a second communication signal wirelessly transmitted between a second communication unit (2) installed on the object and the mobile device using a second communication method different from the first communication method (S225, S245). The first communication method described above is ultra-wideband (UWB) communication, Determining whether wireless communication with the portable device can be performed using the first communication unit (S205, S215, S405, S430, S505), and If it is determined that wireless communication with the portable device cannot be performed using the first communication unit, the position of the portable device relative to the object is determined using the second communication signal (S250, S445, S465, S540, S555), The first communication unit includes a plurality of anchors (3A to 3F) installed at different locations on the object and capable of wireless communication with the portable device, A location detection method that determines whether wireless communication with the mobile device can be performed using the first communication unit, including determining that wireless communication with the mobile device cannot be performed using the first communication unit if at least one of the plurality of anchors is malfunctioning.

13. A computer that performs processing to detect the position of a portable device relative to an object, The computer is configured to acquire a first communication signal wirelessly transmitted between a first communication unit installed on the object and the portable device using a first communication method, and a second communication signal wirelessly transmitted between a second communication unit installed on the object and the portable device using a second communication method different from the first communication method. The first communication method described above is ultra-wideband (UWB) communication, The aforementioned computer, A determination unit (S205, S215, S405, S430, S505) determines whether or not wireless communication with the portable device can be performed using the first communication unit, If the determination unit determines that wireless communication with the mobile device cannot be performed using the first communication unit, the determination unit (S250, S445, S465, S540, S555) determines the position of the mobile device relative to the object using the second communication signal, The system includes a country information acquisition unit (S210) that acquires country information indicating the country to which the location of the object belongs, The determination unit is a computer that determines, based on the country information acquired by the country information acquisition unit, whether or not wireless communication with the mobile device can be performed using the first communication unit.

14. A computer that performs processing for detecting the position of a portable device relative to an object, The computer is configured to acquire a first communication signal wirelessly transmitted between a first communication unit installed on the object and the portable device using a first communication method, and a second communication signal wirelessly transmitted between a second communication unit installed on the object and the portable device using a second communication method different from the first communication method. The first communication method described above is ultra-wideband (UWB) communication, The aforementioned computer, A determination unit (S205, S215, S405, S430, S505) determines whether or not wireless communication with the portable device can be performed using the first communication unit, If the determination unit determines that wireless communication with the portable device cannot be performed using the first communication unit, the determination unit (S250, S445, S465, S540, S555) determines the position of the portable device relative to the object using the second communication signal, The first communication unit includes a plurality of anchors (3A to 3F) installed at different locations on the object and capable of wireless communication with the portable device, The determination unit is a computer that determines that it is not possible to communicate wirelessly with the portable device using the first communication unit if at least one of the plurality of anchors is malfunctioning.