Distance measuring system and distance measuring method

Abstract

To provide a technique capable of reducing a detection delay against an approach of a user.SOLUTION: A position determination device makes an anchor to intermittently perform a distance measuring communication with a portable device after a measuring distance setting is exchanged in a short-range communication in the case where it is connected with the portable device in the short-range communication. In the case where the position determination device is connected for communicating with a plurality of portable devices, the anchor executes the distance measuring communication with each of the plurality of portable devices. The position determination device determines a priority order for each portable device on the basis of a reception strength of a signal from the portable device, a result of the distance measuring communication, or an attribute of an owner. The anchor detects a collision timing when distance measuring timings of the plurality of portable devices overlap on the basis of the distance measuring setting. The anchor executes the distance measuring communication with the portable device of which the priority order is relatively high at the collision timing.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present disclosure relates to a technique for measuring the distance from a predetermined reference point to a mobile device via wireless communication. [Background technology]

[0002] Patent Document 1 describes a system in which a vehicle performs distance measurement communication with a portable device using ultra wide band (UWB) communication, thereby determining the position of the portable device relative to the vehicle. In the configuration disclosed in Patent Document 1, it is described that, prior to distance measurement communication by UWB, setting parameters (e.g., distance measurement interval) for distance measurement communication by UWB are exchanged using Bluetooth (registered trademark) communication. Distance measurement communication between the vehicle and the portable device can be performed periodically according to the agreed setting parameters. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-104962 A Summary of the Invention [Problem to be solved by the invention]

[0004] When multiple registered devices are present near the vehicle at the same time, the in-vehicle UWB module will perform ranging communication with each of the multiple portable devices. Since ranging communication with each of the multiple portable devices is performed periodically, the timing of ranging communication with any two portable devices may overlap. On the other hand, the UWB module can perform ranging communication with only one portable device at exactly the same timing. When the timing of ranging communication with multiple devices overlaps, if the ranging communication with a portable device owned by a user who is less willing to use the vehicle is prioritized, the detection of the approach of a user who is truly intending to use the vehicle will be delayed. As a result, the convenience of the user may be reduced.

[0005] To address this issue, Patent Document 1 does not consider a situation in which a vehicle's UWB module performs distance measurement communication with multiple portable devices in parallel, and does not consider a response policy when the timing of distance measurement communication with multiple devices overlaps.

[0006] The present disclosure has been made based on the above considerations or points of view, and one of its objectives is to provide a technology capable of reducing a detection delay in response to the approach of a user. [Means for solving the problem]

[0007] One ranging system included in the present disclosure comprises a communication unit (2) configured to be able to perform ranging communication with multiple portable devices using a predetermined wireless protocol, and a control device (1) having a memory unit in which information on multiple portable devices to be subject to position determination is stored, wherein the control device is configured to perform prioritization of the multiple portable devices and notify the communication unit of the priority of each portable device, and the communication unit or the control device is configured to perform acquisition of ranging timing, which is the timing for performing ranging communication with the portable device, and determination of whether there is a collision timing at which the ranging timings of the multiple portable devices overlap, and the communication unit is configured to perform ranging communication with a high priority device, which is a portable device with a relatively high priority among the multiple portable devices whose ranging timings overlap at the collision timing.

[0008] In the distance measurement system, distance measurement communication with a portable device having a higher priority is performed preferentially at the time of collision, and thus the distance measurement system can reduce a detection delay in response to the approach of a user of a portable device having a relatively higher priority to a vehicle.

[0009] The ranging method included in the present disclosure includes a control device storing information on multiple portable devices to be subjected to position determination in a memory unit, the control device prioritizing the multiple portable devices whose information is stored in the memory unit, the control device notifying a communication unit configured to perform ranging communication with the portable devices using a predetermined wireless protocol of the priority of each portable device, the communication unit or the control device identifying a ranging timing, which is the timing for executing ranging communication, for each portable device, the communication unit or the control device determining whether there is a collision timing at which the ranging timings of the multiple portable devices overlap, and the communication unit performing ranging communication with a high priority device, which is a portable device with a relatively high priority among the multiple portable devices whose ranging timings overlap at the collision timing.

[0010] In addition, the symbols in parentheses in the claims indicate a correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of the present disclosure. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing an overall view of a vehicle electronic key system. [Diagram 2] FIG. 1 is a block diagram showing a configuration of an in-vehicle system. [Diagram 3] FIG. 2 is a block diagram showing a configuration of a portable device. [Figure 4] FIG. 13 is a diagram showing the mounting position of the anchor. [Diagram 5] FIG. 2 is a block diagram showing a configuration of an anchor. [Figure 6] FIG. 11 is a sequence diagram showing a flow of distance measurement communication between a portable device and a vehicle. [Figure 7] FIG. 11 is a diagram for explaining a method of calculating a distance. [Figure 8] FIG. 11 is a diagram for explaining the timing of performing distance measurement communication. [Figure 9]1 is a sequence diagram showing the operation of the entire system from communication connection to the start of distance measurement communication. [Figure 10] FIG. 13 is a diagram showing a case where distance measurement timings collide. [Figure 11] 1 is a flowchart for explaining the flow of the entire system. [Figure 12] 13 is a flowchart of a priority order determination process. [Figure 13] 13 is a flowchart of a collision determination process. [Figure 14] 11A and 11B are diagrams for explaining the operation of an anchor when a collision occurs in ranging communication. [Figure 15] 10 is a flowchart for explaining another example of the operation of the in-vehicle system when a collision occurs. [Figure 16] 11 is a diagram for explaining a configuration for determining an effective priority order determined from registered priorities and the reception strength of a short-range communication signal. FIG. [Figure 17] 13A and 13B are diagrams illustrating other examples of anchor arrangement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiment, and can be implemented with various modifications within the scope of the gist. Various modified examples may be implemented in appropriate combinations within the scope of no technical contradiction. The present disclosure also includes configurations that combine multiple modified examples and are not explicitly shown. In the following description, components having the same function are given the same reference numerals, and specific descriptions thereof may be omitted. In addition, when only a part of the configuration is mentioned, the description described elsewhere may be applied to the other parts.

[0013] <Overall structure> As shown in Fig. 1, the electronic key system for a vehicle according to this embodiment includes an in-vehicle system 10 and one or more portable devices 9. The in-vehicle system 10 is a system mounted on a vehicle Hv. As shown in Fig. 2, the in-vehicle system 10 includes a position determination device 1 and multiple anchors 2. The in-vehicle system 10 corresponds to a ranging system. Furthermore, a method executed by the ranging system corresponds to a ranging method.

[0014] The portable device 9 is a wireless communication terminal carried by each of a plurality of users. The portable device 9 is linked to the position determination device 1. The device linked to the position determination device 1 refers to a device whose device information is registered in the position determination device 1. The device information includes a device identification number (hereinafter, device ID). The device ID is different for each portable device 9. The device ID may be a device address or a universally unique identifier (UUID), etc. In the following, a case where two portable devices 9a and 9b are linked to the position determination device 1 will be described. When the portable devices 9a and 9b are not distinguished from each other, they will simply be referred to as portable devices 9. The user of the portable device 9a will also be referred to as the first user, and the user of the portable device 9b will also be referred to as the second user. The number of portable devices 9 linked to the position determination device 1 may be three or more.

[0015] The position determination device 1 is a device that determines the position of the portable device 9 relative to the vehicle Hv. The position determination device 1 and the multiple portable devices 9 each include a short-range communication module. The short-range communication module is a wireless communication module for enabling short-range communication. The short-range communication here refers to communication conforming to a predetermined wireless communication standard with a practical communication distance of 5 m to 50 m, and at most about 100 m. The short-range communication may be Bluetooth (registered trademark) Low Energy (hereinafter, Bluetooth LE), Wi-Fi (registered trademark), or the like. In the following and in the drawings, the short-range communication may be referred to as SRC (Short Range Communication) or SRWC (Short Range Wireless Communication). In the following, a signal transmitted and received in the short-range communication may be referred to as a short-range communication signal or an SRC signal.

[0016] In the following, the operation of each part will be described by taking the case where the short-range communication is Bluetooth LE as an example. Furthermore, in the following, the portable device 9 is set to operate as a central (master) in Bluetooth LE, and the position determination device 1 to act as a peripheral (slave). Of course, the roles of the portable device 9 and the position determination device 1 may be interchanged.

[0017] The anchor 2 is a wireless communication module for performing distance measurement communication with the portable device 9, which will be described later. The distance measurement communication may be performed by UWB communication, which is wireless communication of the UWB-IR (Ultra Wide Band - Impulse Radio) system. In this embodiment, the anchors 2 and the portable devices 9 are both configured to be able to perform UWB communication. That is, the anchor 2 and the portable device 9 are configured to be able to transmit and receive impulse-shaped radio waves (hereinafter, impulse signals) used in UWB communication. The impulse signal used in UWB communication may be a signal having a very short pulse width (e.g., 2 ns) and a bandwidth (i.e., ultra-wide bandwidth) of 500 MHz (strictly speaking, 499.2 MHz) or more. In the following, the UWB signal means a signal exchanged in UWB communication.

[0018] <Mobile Device 9> The portable device 9 may be a portable information processing terminal equipped with a short-range communication function. The portable device 9 may be various communication terminals such as a smartphone or a wearable device. The portable device 9 may also be called a user device, a key device, or the like.

[0019] The portable device 9 may be a smart key, which is a dedicated device as an electronic key for the vehicle Hv. The smart key is a device that is transferred to the owner together with the vehicle Hv when the vehicle Hv is purchased. The smart key can be understood as one of the accessories of the vehicle Hv. The smart key can adopt various shapes such as a flat rectangular parallelepiped type, a flat ellipsoid type (so-called fob type), a card type, etc. The smart key can be called a vehicle portable device, a key fob, a key card, an access key, etc. The portable device 9 may be a device that functions as a key for the vehicle Hv by performing wireless authentication using short-range communication with the position determination device 1.

[0020] As shown in FIG. 3, the portable device 9 includes a device control unit 91, a short-range communication module 92, and a UWB module 93. The device control unit 91 is a module that controls the operation of the entire portable device 9. The device control unit 91 may be configured as a computer including a device processor, a memory, a storage, and an input / output circuit. The device processor is configured to perform various arithmetic processing. The device processor may be, for example, a CPU (Central Processing Unit). The memory is a volatile storage medium such as a RAM (Random Access Memory). The storage is a recording device including a non-volatile storage medium such as a flash memory.

[0021] The storage stores the device ID of the portable device 9 and various data for performing wireless communication with the position determination device 1. The data for performing wireless communication with the position determination device 1 includes parameters received from the position determination device 1 by pairing, such as the device ID of the position determination device 1. The data for performing wireless communication with the position determination device 1 may also include an identification number of the vehicle Hv (hereinafter, vehicle ID). The vehicle ID corresponds to identification information of the vehicle / vehicle-mounted system to be communicated with. The vehicle ID may be referred to as a system ID. The vehicle ID may be a vehicle identification number (VIN) or a number of a different type from the VIN. The vehicle ID may be a global identification number assigned according to a predetermined rule.

[0022] The storage may store a key code used for wireless authentication with the position determination device 1. The key code may also be called an encryption key. The storage may have installed therein a digital key app, which is application software for causing the mobile device 9 to function as a key for the vehicle Hv. The digital key app is an app for secure communication with the position determination device 1 and for securely storing data related to the use of the vehicle Hv. App is an abbreviation for application software.

[0023] The short-range communication module 92 is a short-range communication module included in the portable device 9. The configuration and function of the short-range communication module 92 may be similar to that of the short-range communication module 14 included in the position determination device 1 described later. Hereinafter, when there is no need to distinguish between the short-range communication module 92 included in the portable device 9 and the short-range communication module 14 included in the position determination device 1, they will also be referred to (simply) as short-range communication modules without being given reference symbols.

[0024] The UWB module 93 is a communication module for performing UWB communication. The UWB module 93 outputs received data to the device control unit 91. The UWB module 93 also transmits a UWB signal corresponding to transmission data based on an instruction from the device control unit 91. The operation of the UWB module 93 is controlled by the device control unit 91. Hereinafter, when there is no need to distinguish between the UWB module 93 included in the portable device 9 and the UWB module 22 included in the position determination device 1, they are also simply referred to as UWB modules.

[0025] The device control unit 91 periodically scans using the short-range communication module 92 and attempts to connect to the position determination device 1. When the short-range communication module 92 receives an advertisement signal (e.g., ADV_IND) from the position determination device 1, the device control unit 91 transmits a connection request signal (e.g., CONNECT_IND) to the position determination device 1 and establishes a communication connection with the position determination device 1.

[0026] When the communication connection with the position determination device 1 is completed, the device control unit 91 exchanges parameters for distance measurement communication (hereinafter, distance measurement settings) through short-distance communication. Then, the device control unit 91 causes the UWB module 93 to perform distance measurement communication with each anchor 2 in a mode according to the distance measurement settings. A specific procedure for distance measurement communication will be described separately later.

[0027] The device control unit 91 may put the UWB module 93 to sleep when it is not connected to the position determination device 1 via short-range communication. The sleep state of the UWB module 93 may be a state in which some or all of its functions are stopped in order to reduce power consumption. The device control unit 91 may transition the UWB module 93 to an active state based on the connection with the position determination device 1 via short-range communication. The active state is a state in which UWB signals can be transmitted and received. This control may reduce power consumption during standby. Additionally, the device control unit 91 may perform authentication processing by short-range communication (i.e., wireless authentication) based on the establishment of a communication connection with the position determination device 1. The wireless authentication may be performed by a challenge-response method.

[0028] <In-vehicle systems> As shown in FIG. 2, the in-vehicle system 10 may have other devices such as a body ECU 3 in addition to the position determination device 1 and the multiple anchors 2. The position determination device 1 is connected to each of the multiple anchors 2 by a dedicated communication cable. The position determination device 1 is also connected to the body ECU 3 via an in-vehicle network. The in-vehicle network is a communication network built in the vehicle Hv. As a standard for the in-vehicle network, various standards such as Controller Area Network (CAN: registered trademark), Ethernet (registered trademark), and FlexRay (registered trademark) can be adopted. The connection form between the devices disclosed here is one example and may be changed as appropriate. The position determination device 1 and the multiple anchors 2 may be connected via an in-vehicle network.

[0029] The position determination device 1 is an ECU that determines a device position in cooperation with the anchor 2. In this disclosure, the device position means a relative position of the portable device 9 with respect to the vehicle Hv. Since the portable device 9 corresponds to a user, determining the device position is equivalent to determining the user's position. Therefore, the description of the device position may be read as the user position. The position determination device 1 controls the operation of the anchor 2.

[0030] The position determination device 1 includes a processor 11, a memory 12, a storage 13, a short-range communication module 14, and an in-vehicle communication unit 15. The processor 11 may be a CPU. The memory 12 may be a volatile storage medium (e.g., RAM). The storage 13 includes a non-volatile storage medium such as a flash memory. The storage 13 may include multiple types of storage media such as a ROM (Read Only Memory) and a flash memory. The position determination device 1 / processor 11 correspond to a control device.

[0031] A position determination program is stored in the storage 13. The position determination program is a program including instructions for causing a computer to function as the position determination device 1. The position determination program is executed by the processor 11. Execution of the position determination program by the processor 11 corresponds to execution of a position determination method corresponding to the position determination program. The position determination method includes some or all of a distance measurement method. The storage 13 may also store data indicating the device ID of the portable device 9 and the mounting position of each anchor 2 in the vehicle Hv, and data for authenticating the portable device 9 (e.g., a key code).

[0032] The short-range communication module 14 is a short-range communication module built into the position determination device 1. Even while the driving power source is set to be off, the short-range communication module 14 is supplied with power from the vehicle battery. The short-range communication module 14 periodically performs advertising and attempts to connect with the portable device 9 using the power supplied from the vehicle battery. Advertising is a process of transmitting an advertising signal using a predetermined channel. The advertising signal is a wireless signal for notifying (i.e. advertising) the presence of the short-range communication module 14 to other devices. When the short-range communication module 14 receives a connection request signal from the portable device 9, it communicates with the portable device 9.

[0033] The in-vehicle communication unit 15 is a circuit for the processor 11 to communicate with each of the multiple anchors 2. The in-vehicle communication unit 15 may also include a circuit for the processor 11 to communicate with other in-vehicle devices via an in-vehicle network. The in-vehicle communication unit 15 may include a PHY chip and a cable connector that comply with the communication standard of the in-vehicle network.

[0034] Upon receiving communication connection with the portable device 9, the position determination device 1 transitions each anchor 2 to an active state and causes the anchor 2 to perform distance measurement communication with the portable device 9. The position determination device 1 acquires data indicating the result of the distance measurement communication from each of the multiple anchors 2 (hereinafter, distance measurement result data). The distance measurement result data includes the ID of the portable device 9 that performed the distance measurement, and data indicating the distance from the anchor 2 to the portable device 9. In this disclosure, a value indicating the distance from the anchor 2 to the portable device 9, which is determined by the distance measurement communication, may be referred to as a distance measurement value. When the position determination device 1 is communication connected with multiple portable devices 9, each anchor 2 performs distance measurement communication with each of the multiple connected portable devices 9.

[0035] The position determination device 1 specifies the distance from the vehicle Hv to the portable device 9 (hereinafter, also referred to as the device distance) based on the distance measurement result data provided from each anchor 2. The position determination device 1 may determine the device distance by combining / integrating the distance measurement values ​​observed by the multiple anchors 2. The device distance may be the minimum value of the distance measurement values ​​observed by the multiple anchors 2. The position determination device 1 may also determine whether the portable device 9 connected by short-range communication is present inside the vehicle, in a nearby area, or in another area based on the distance measurement result data provided from each anchor 2. The nearby area is an area outside the vehicle that is within a predetermined operating distance from the vehicle Hv. The operating distance may be set to 1.0 m, 1.5 m, 2.0 m, etc. The nearby area can be interpreted as an area in which automatic unlocking / locking of the vehicle Hv can be performed. The nearby area may be rephrased as a passive entry area.

[0036] The position determination device 1 may regard the portable device 9 that is not connected by short-range communication as being present in another area. The position determination device 1 provides the body ECU 3 with the position information of the identified portable device 9.

[0037] The position determination device 1 may be attached to the left C-pillar, the instrument panel, the overhead console, the right C-pillar, or under the driver's seat of the vehicle Hv. The C-pillar refers to the third pillar from the front among the pillars provided in the vehicle Hv. Of course, the position determination device 1 may be attached.

[0038] As described above, the anchor 2 is a device for performing distance measurement communication with the portable device 9. The anchor 2 is configured to be able to perform UWB communication. The in-vehicle system 10 of this embodiment includes anchors 2A, 2B, 2C, 2D, 2P, and 2Q as the anchors 2, as shown in FIG. 4. The anchor 2A is an anchor 2 disposed at the right front corner of the vehicle Hv. The anchor 2A may be disposed near the right front wheel, at the right end of the front bumper, or on the right side mirror. Note that the vicinity of a certain member in the description of the mounting position of the anchor 2 may be interpreted as a range within 0.3 m from the member. The anchor 2A may be rephrased as a right front anchor or a first anchor, etc.

[0039] Anchor 2B is an anchor 2 disposed at the left front corner of the vehicle Hv. Anchor 2B may be disposed near the left front wheel, at the left end of the front bumper, or at the left side mirror, etc. Anchor 2B may be referred to as a left front anchor or a second anchor. Anchor 2C is an anchor 2 disposed at the right rear corner of the vehicle Hv. Anchor 2C may be disposed near the right rear wheel, or at the right end of the rear bumper, etc. Anchor 2C may be referred to as a right rear anchor or a third anchor. Anchor 2D is an anchor 2 disposed at the left rear corner of the vehicle Hv. Anchor 2D may be disposed near the left rear wheel, or at the left end of the rear bumper, etc. Anchor 2D may be referred to as a left rear anchor or a fourth anchor.

[0040] Anchors 2P and 2Q are anchors 2 arranged inside the vehicle. Anchor 2P is arranged forward of anchor 2Q inside the vehicle. Anchor 2P may be arranged on the instrument panel, the upper end of the windshield, the center console, or the like. Anchor 2P may be referred to as an interior front anchor or a fifth anchor. Anchor 2Q is an anchor 2 arranged rearward of anchor 2P inside the vehicle. Anchor 2Q may be arranged in a position closer to the rear, such as the center of the rear seat, the ceiling above the rear seat, or the trunk. Anchor 2Q may be referred to as an interior rear anchor or a sixth anchor.

[0041] The anchors 2A to 2D are all attached to the outer surface of the vehicle Hv, and may be referred to as outdoor units or exterior anchors. The anchors 2P to 2Q are all attached to the interior of the vehicle, and may be referred to as indoor units or interior anchors.

[0042] The configuration and performance of each anchor 2 may be substantially the same. Each anchor 2 includes an in-vehicle communication unit 21 and a UWB module 22, as shown in Fig. 5. The in-vehicle communication unit 21 is a circuit for communicating with the position determination device 1. The in-vehicle communication unit 21 includes a PHY chip or the like corresponding to a communication method (e.g., CAN) with the position determination device 1.

[0043] The UWB module 22 is a module for performing UWB communication. The UWB module 22 includes an antenna for UWB communication, a transmission / reception circuit, and a UWB controller. The transmission / reception circuit is a circuit for performing signal processing related to modulation and demodulation. The UWB controller is a microcomputer. The UWB controller executes processing for ranging communication. The processing for ranging communication includes selecting a communication partner / communication format for each time according to ranging setting data provided from the position determination device 1. The processing for ranging communication also includes analyzing received data, outputting transmitted data, and generating ranging result data. When the UWB controller generates ranging result data by performing ranging communication with the portable device 9, it transmits (reports) the ranging result data to the position determination device 1 through the in-vehicle communication unit 21.

[0044] The body ECU 3 is an ECU (Electronic Control Unit) that controls body-related equipment such as headlights, door lock motors, power window motors, and side mirror motors. The body ECU 3 controls unlocking / locking of doors based on device position information determined by the position determination device 1. Controlling unlocking / locking of doors corresponds to controlling the locking state of the vehicle Hv. The body ECU 3 may be interpreted as an ECU that provides a passive entry function in cooperation with the position determination device 1. The passive entry function is a function that unlocks the vehicle Hv in response to a predetermined user action on the vehicle Hv, such as touching a door handle. The body ECU 3 may be replaced with an integrated ECU, a zone ECU, or a domain ECU. The body ECU 3 and the position determination device 1 may be integrated. The functional arrangement in the in-vehicle system 10 may be changed as appropriate.

[0045] In addition to the above, various in-vehicle devices may be directly or indirectly connected to the position determination device 1. For example, the position determination device 1 is connected to a power supply ECU, a cellular module, an NFC module, etc. via an in-vehicle network / using a dedicated cable so as to be able to communicate with each other. The power supply ECU is an ECU that controls the on / off of the vehicle power supply. The vehicle power supply is a power supply that is turned on when the vehicle Hv runs. The cellular module is a communication module that performs cellular communication such as 4G or 5G. The NFC module is a communication module for performing near field communication (NFC). NFC is a communication in which the communication distance is several centimeters to about 10 cm. In terms of the communication distance, NFC and the short-range communication of the present disclosure may be considered to be different (different) communication methods.

[0046] <Distance communication> Here, distance measurement communication performed between one portable device 9 and a vehicle Hv will be described. Distance measurement communication is communication for measuring distance based on the propagation time (in other words, flight time) of radio waves from an anchor 2 to the portable device 9. Distance measurement communication between the portable device 9 and the vehicle Hv may be interpreted as distance measurement communication between the portable device 9 and multiple anchors 2. As shown in FIG. 6, distance measurement communication generally includes five processes of steps S11 to S15. In distance measurement communication, the portable device 9 operates as an initiator, and each anchor 2 operates as a responder. Note that "Ank" in the figure represents an anchor. Although only anchors 2A to 2C are shown in FIG. 6, anchors 2D, 2P, and 2Q also operate in the same manner as anchors 2A to 2C.

[0047] Step S11 (first process) is a step in which the portable device 9 transmits a pre-poll signal (Pre-Poll) to all anchors 2. The pre-poll signal is a UWB signal that notifies (notifies) the communication party that ranging will start soon. Note that the pre-poll signal may be a signal for switching the anchor 2 in a sleep state to an active state.

[0048] The pre-pole signal may be broadcast. However, the pre-pole signal may include information specifying the device that should respond, such as a vehicle ID. This makes it possible to prevent anchors 2 mounted on vehicles other than the vehicle Hv (i.e., other vehicles) from responding to the pre-pole signal, etc. Not only the pre-pole signal, but any UWB signal to be transmitted or received may include information specifying the communication partner. The information specifying the communication partner may be exchanged by short-range communication between the position determination device 1 and the portable device 9 prior to ranging communication. The UWB signal with the vehicle Hv set as the communication partner is received by each of the multiple anchors 2 mounted on the vehicle Hv.

[0049] Step S12 is a step in which the mobile device 9 transmits a poll signal (Poll) to the anchor 2. The poll signal is a signal requesting the anchor 2 to transmit a response. The transmission of the poll signal may be executed a predetermined time after the transmission of the pre-poll signal. The time difference between the transmission of the pre-poll signal and the transmission of the poll signal may be determined in advance.

[0050] Step S13 is a step in which the anchor 2 transmits a response signal upon receiving the poll signal. Each of the anchors 2 transmits a response signal upon receiving the poll signal. The response signal may be called an answer signal.

[0051] Step S14 is a step in which the mobile device 9 broadcasts a final signal (Final). The final signal may be a response signal to the response signal. The final signal may be transmitted to all anchors 2 (in other words, vehicles Hv).

[0052] Step S15 is a step in which the portable device 9 broadcasts a final data signal. The final data signal may be a signal notifying the end of the current ranging communication. The final data signal may include a device measurement result, which is ranging result distance data generated by the portable device 9. The device measurement result may be data indicating the distance from the portable device 9 to each anchor 2.

[0053] Furthermore, the final data signal may include information indicating a delay time, which is the time from receiving a response signal to transmitting a final signal. The time at which a response signal is received from each anchor 2 is different. Therefore, the final data signal may include delay time information for each anchor 2.

[0054] By performing the above-mentioned distance measurement communication sequence, as shown in FIG. 7, the portable device 9 can obtain a first round trip time (RTT1 in the figure), which is the elapsed time from transmitting a poll signal to receiving a response signal. RTT is an abbreviation for Round Trip Time. RTT1 is a value obtained by combining the time of flight (ToF: Time of Flight) of radio waves corresponding to the distance from the portable device 9 to the anchor 2 and the anchor reaction time (Td1). The relationship is RTT1=ToF+Td+ToF. The anchor reaction time is the delay time from receiving a poll signal to transmitting a response signal. The anchor reaction time is a parameter derived from the hardware constituting the anchor 2. The anchor reaction time can be treated as a fixed value. Therefore, by substituting the set value of the anchor reaction time and the observed value of RTT1 into the above relational expression, the portable device 9 can calculate the one-way flight time (i.e., ToF). The distance from the portable device 9 to the anchor 2 can be easily calculated from the ToF by a person skilled in the art using the propagation speed of radio waves. As explained above, the mobile device 9 can generate device measurement results indicating the distance from the mobile device 9 to each anchor 2 based on the results of the ranging communication.

[0055] Furthermore, according to the above ranging sequence, the anchor 2 can obtain a second round trip time (RTT2 in the figure), which is the elapsed time from transmitting a response signal to receiving a final signal. RTT2 includes a device response time (Td2). The device response time corresponds to the delay time described above. If the final data signal includes delay time information for each anchor 2, the anchor 2 can identify the device response time (Td2) by referring to the final data signal. Therefore, the anchor 2 itself can also generate data indicating the distance from the anchor 2 to the portable device 9 by the above ranging communication (hereinafter, anchor measurement result). The anchor measurement result corresponds to the above ranging result. The anchor measurement result includes a ranging value and information indicating the portable device 9 that performed the measurement. The anchor measurement result may be generated for each anchor 2.

[0056] In addition, when the final data signal includes the device measurement result, the anchor 2 does not have to generate the distance measurement value by itself. When the final data signal includes the device measurement result, the anchor 2 may report the distance value indicated in the final data signal to the position determination device 1.

[0057] In another aspect, step S14 may be a step in which the portable device 9 transmits a final signal individually to each anchor 2. In step S14, upon receiving a response signal from a certain anchor 2, the portable device 9 may unicast a final signal toward the source of the response signal. In this case, the device reaction time (Td2) may be regarded as a design value. Therefore, in a configuration in which the portable device 9 transmits a final signal for each anchor 2, even if the final data signal does not include delay time information or device measurement results for each anchor 2, the anchor 2 can generate a ranging value by the above ranging communication.

[0058] Distance measurement communication between one portable device 9 and a vehicle Hv is performed by dividing time into blocks having a predetermined length, as shown in Fig. 8. Each block includes a plurality of rounds. Fig. 8 shows a case in which one block includes 12 rounds. A round is obtained by dividing a block by a predetermined number. The number of rounds included in one block may be variable.

[0059] Distance measurement communication between the portable device 9 and the vehicle Hv is performed within one round. That is, the communication sequence shown in Fig. 6 is executed within one round. One portable device 9 and a vehicle Hv perform distance measurement communication only once per block.

[0060] The round number in which the portable device 9 performs the distance measurement communication may differ for each block. For example, the distance measurement communication may be performed in the fifth round in the first block, whereas the distance measurement communication may be performed in the eleventh round in the second block. The round number in which the portable device 9 performs the distance measurement communication is determined by a hopping key and interval that are agreed upon in advance between the portable device 9 and the position determination device 1 as distance measurement settings.

[0061] The mobile device 9 and the position determination apparatus 1 exchange ranging configuration data upon establishing a short-range communication connection. The ranging configuration data is a data set including parameters for ranging communication (hereinafter also referred to as ranging parameters). The ranging configuration data may be understood as a parameter set defining rules for performing recurring ranging communication. The position determination apparatus 1 may be configured to transmit a desired ranging configuration to the mobile device 9 in short-range communication and the mobile device 9 may be configured to accept / modify the proposal of the position determination apparatus 1.

[0062] The ranging setting data may include an interval, a number of rounds, a hopping key, a number of anchors, and communication format information. The interval is a parameter that defines the length of a block. The value of the interval (in other words, the block length) included in the ranging setting may be expressed in terms of time, such as 100 milliseconds. The interval may also be expressed as the number of rounds. The interval may be selected from a plurality of candidates (options) that are prepared in advance, such as 8, 12, 16, 20, and 24 rounds. The number of rounds included in the interval may be set to a multiple of 4. Since the portable device 9 and the vehicle Hv are configured to perform ranging communication once per block, the length of the block may be the average interval of ranging communication. The interval may be interpreted as a parameter that defines the average value (in other words, the expected value) of the interval of ranging communication. The setting value of the interval may be different for each portable device 9. The setting value of the number of rounds included in the ranging setting data defines the number of rounds that one block has. The distance measurement setting data may include either an interval setting value or the number of rounds. The data indicating the interval setting value corresponds to interval information.

[0063] The hopping key is a parameter for determining a round number (hereinafter, used round number) for performing ranging communication within a block. The hopping key may be interpreted as a parameter for changing the used round number for each block. The set value of the hopping key may be randomly determined within a selectable range. The value of the hopping key may be fixed for each mobile device 9. Each UWB module is configured to be able to specify the used round number for each block once the hopping key and the number of rounds are determined. The used round number may be determined by inputting the hopping key and the number of rounds into a predetermined function / program. The function / program for determining the used round number may be configured so that the used round number for each block is pseudo-random. The function / program itself for determining the used round number from the hopping key may be common to a plurality of UWB modules. Data indicating the set value of the hopping key corresponds to the hopping information.

[0064] The number of anchors is a parameter indicating the number of anchors 2 provided in the vehicle Hv. By including the number of anchors in the ranging setting data, the portable device 9 can recognize the number of communication partners. Note that in this technical field, the anchors 2 are sometimes simply called antennas. The number of anchors may be rephrased as the number of antennas.

[0065] The communication format information is a code indicating which communication format is to be used among a plurality of communication formats defined in the UWB standard. The communication format information may be a code specifying the data sequence or the length of a preamble, etc. The communication format information may also be information specifying the channel (band) to be used, the modulation method, the pulse width, etc. The communication format may be rephrased as a communication method, a communication protocol, a mode, etc.

[0066] Additionally, the distance measurement setting data may include a setting value for the length of one round (hereinafter, round length). The round length may be configured to be changeable in three stages: standard, short, and long. The round length may also be adjusted so that it is longer as the number of anchors increases.

[0067] <Communication connection ~ Distance measurement communication> Fig. 9 is a sequence diagram showing the operation of the entire system from communication connection to the start of distance measurement communication. The portable device 9 shown in Fig. 9 is sufficiently far away from the vehicle Hv at the time when the sequence shown in Fig. 9 is started, and the position determination device 1 is not connected to the portable device 9 for communication. The position determination device 1 may be in standby at the time when the sequence shown in Fig. 9 is started. "In standby" refers to a state where the portable device 9 is not connected to the portable device 9 for communication.

[0068] 9, the position determination device 1 may already be connected for communication with another mobile device 9. Even if the position determination device 1 is already connected for communication with a certain mobile device 9, the position determination device 1 may be configured to periodically transmit an advertising signal in order to detect the approach of the other mobile device 9.

[0069] In the standby state, the position determination device 1 periodically transmits an advertising signal (S21). When the portable device 9 enters a short-distance communication area of ​​the position determination device 1 as the user moves, the portable device 9 can receive the advertising signal. Upon receiving the advertising signal from the position determination device 1, the portable device 9 transmits a connection request signal (S22) and establishes a connection with the position determination device 1.

[0070] Thereafter, the portable device 9 transmits a ranging setting request signal to the position determination device 1 by short-range communication (S23). The ranging setting request signal is a short-range communication signal requesting transmission of ranging setting data. Upon receiving the ranging setting request signal from the portable device 9, the position determination device 1 transmits the ranging setting data back to the portable device 9 (S24). Note that step S23 is an optional element and may be omitted. The position determination device 1 may be configured to transmit the ranging setting data upon communication connection with the portable device 9.

[0071] Upon receiving the ranging setting data from the position determination apparatus 1, the portable device 9 returns a positive response (so-called Ack) (S25). Based on receiving the Ack from the portable device 9, the position determination apparatus 1 notifies all anchors 2 of the ranging setting data and information on the portable device 9 that will be the communication partner (S26).

[0072] Note that the return of an Ack in response to the reception of the ranging setting data is an optional element and may be omitted. In that case, the position determination device 1 may generate ranging setting data at any timing after communication connection with the portable device 9, and transmit information about the portable device 9 and the ranging setting data to all anchors 2. Before step S26, there may be a step of returning the anchor 2 in the sleep state to the active state.

[0073] In this embodiment, the position determination device 1 determines the values ​​of various ranging parameters, but this is not limiting. Some or all of the ranging parameters may be determined by the portable device 9. Step S24 may be a step in which the portable device 9 transmits ranging setting data to the position determination device 1, in other words, a step in which the portable device 9 proposes ranging settings to the position determination device 1.

[0074] When the exchange of the ranging settings or the agreement on the ranging settings is completed, repetitive ranging communication is started. That is, the mobile device 9 and each anchor 2 transmit and receive UWB signals for ranging (S27). The UWB signals for ranging include the above-mentioned pre-pole signal, poll signal, response signal, final signal, and final data signal.

[0075] Each time one distance measurement communication is completed, each anchor 2 transmits an anchor measurement result determined as a result of the distance measurement communication to the position determination device 1 (S28). Note that the portable device 9 may also transmit data indicating the distance to each anchor 2 (i.e., the distance measurement result) to the position determination device 1 by short-range communication (S29). Step S29 is an optional element and may be omitted.

[0076] After step S28 or S29, steps S27 to S28 (or S27 to S29) are repeated until a predetermined termination condition is satisfied. When the termination condition is satisfied, the distance measurement communication between the portable device 9 and the vehicle Hv is terminated. The termination condition may be disconnection of the communication connection between the position determination device 1 and the portable device 9. When a state in which no signal is received from the portable device 9 continues for a predetermined time (e.g., Super Vision Time), the position determination device 1 may release (i.e., cut) the connection with the portable device 9. Furthermore, when a termination request signal (TERMINATE_IND) is received from the portable device 9 by short-range communication, the position determination device 1 may determine that the termination condition is satisfied. The portable device 9 may be configured to be able to transmit a termination request signal in response to a user operation or a decrease in the remaining battery level.

[0077] <Regarding distance measurement timing conflicts> When multiple portable devices 9 are present around the vehicle Hv, the position determination device 1 connects to each of the multiple portable devices 9 through short-range communication. When the position determination device 1 is connected to the multiple portable devices 9 through short-range communication, the position determination device 1 exchanges ranging setting data with each of the multiple portable devices 9. Then, the position determination device 1 causes each anchor 2 to perform ranging communication with the multiple portable devices 9 in parallel.

[0078] As described above, distance measurement communication between one portable device 9 and the vehicle Hv is performed intermittently (repeatedly). When the vehicle Hv performs distance measurement communication with multiple portable devices 9, the distance measurement timings of two portable devices 9 may accidentally overlap (in other words, collide) as shown in Fig. 10. The distance measurement timing is the timing at which distance measurement communication is performed.

[0079] 10 shows a case where the distance measurement timing of the portable device 9a in the Nth block and the distance measurement timing of the portable device 9b in the Kth block overlap. Specifically, the case where the distance measurement communication between the portable device 9a and the vehicle Hv is scheduled in the 10th round of the Nth block, and the distance measurement communication between the portable device 9b and the vehicle Hv is scheduled in the 4th round of the Kth block is shown. The round surrounded by a thick frame is the round where the distance measurement communication is scheduled. Since the communication connection timing differs for each portable device 9, the round number and the block number corresponding to the same time may differ for each portable device 9. "N" and "K" in this description may be any numbers.

[0080] Basically, the UWB module 22 cannot communicate completely simultaneously with two portable devices 9. Therefore, if the distance measurement timings overlap in a certain block, the distance measurement communication with one of the portable devices 9 becomes impossible (fails) at least in that block.

[0081] Here, it is assumed that the portable device 9a is located very close to the vehicle Hv, and the portable device 9b is located relatively far from the vehicle Hv, and the distance measurement timings of the portable devices 9a and 9b collide. Since the portable device 9a is located very close to the vehicle Hv, the user of the portable device 9a (i.e., the first user) is more likely to use the vehicle Hv than the user of the portable device 9b.

[0082] In the above case, if the distance measurement communication with the portable device 9b is prioritized and the distance measurement communication with the portable device 9a becomes impossible, the distance measurement communication between the portable device 9a and the vehicle Hv is postponed until a predetermined round (e.g., the seventh round) of the N+1th block. As a result, the detection by the position determination device 1 of the approach of the first user to the vehicle Hv is delayed, which may impair the convenience of the first user.

[0083] <Measures to prevent collisions in distance measurement timing> FIG. 11 is a flowchart for explaining the flow of operation of the entire system incorporating the above-mentioned measures against collision of distance measurement timing, and includes steps S101 to S111. Step S101 is a step in which the position determination device 1 communicates with a mobile device 9 present within the short-distance communication area of ​​the position determination device 1. Step S101 may be executed based on reception of a connection request signal from an unconnected mobile device 9. In addition, when the position determination device 1 is set to act as a central, step S101 may be executed based on reception of an advertising signal from an unconnected mobile device 9. Step S101 may include a step of determining whether or not a connection request signal or an advertising signal has been received from an unconnected mobile device 9. Step S101 may be executed at a predetermined cycle even when steps S102 and after are being executed. The position determination device 1 as the executing entity of the following processes may be rephrased as a processor 11.

[0084] Step S102 is a step in which the position determination device 1 exchanges ranging setting data with the portable device 9 newly connected in step S101. Step S102 may be performed after step S101 has been executed. In this step S102, ranging parameters such as the interval, the number of rounds, and the hopping key are determined. Step S102 includes notifying all anchors 2 of the ranging setting agreed upon with the portable device 9.

[0085] Step S103 is a step in which the position determination device 1 acquires the reception strength of a short-range communication signal transmitted from a connected device. The connected device is the portable device 9 with which the position determination device 1 has already been connected by short-range communication. When there are multiple connected devices, the position determination device 1 acquires the reception strength for each of the multiple connected devices. The signal used to measure the reception strength may be any signal, such as a signal for maintaining the connection. In a communication connection state in short-range communication, the position determination device 1 and the portable device 9 are configured to exchange data packets (e.g., empty packets) at a predetermined connection interval in order to maintain the connection.

[0086] Step S104 is a step in which the position determination device 1 executes a priority order determination process. The priority order determination process is a process in which a priority order is determined for connected devices in performing distance measurement communication. As shown in FIG. 12, the priority order determination process includes steps S201 to S203. Step S201 is a step in which it is determined whether or not a distance measurement result is available for each connected device. If a distance measurement result is available for each connected device (S201 YES), the priority order is set in descending order of distance from the vehicle Hv. The position determination device 1 sets the highest priority order for a connected device that is close to the vehicle Hv. The proximity from the vehicle Hv may be evaluated by the magnitude of the measured device distance.

[0087] Furthermore, if no distance measurement results have been obtained for any of the connected devices (NO in S201), the priority is set in descending order of the strength of the short-range communication signal reception. In other words, a connected device with a relatively strong reception strength is set to have a higher priority than a connected device with a weak reception strength.

[0088] If there is only one connected device, the priority of the connected device may be set to 1. Furthermore, among the portable devices 9 registered in the position determination device 1, the priority of a portable device 9 that is not connected to the position determination device 1 may be set to a lower priority than the connected devices, such as the lowest priority. Note that the position determination device 1 does not perform distance measurement communication with a portable device 9 that is not connected to the position determination device 1, so the position determination device 1 does not need to set a priority of an unconnected portable device 9.

[0089] Furthermore, in a case where a connected device that has performed distance measurement communication and a connected device that has not performed distance measurement communication are mixed, the position determination device 1 may set the priority of the connected device that has performed distance measurement communication higher than that of the connected device that has not performed distance measurement communication. In a case where there are multiple connected devices that have performed distance measurement communication, the position determination device 1 may set a higher priority for the connected device that is closer to the vehicle Hv than that of the connected device that is farther from the vehicle Hv. In a case where there are multiple connected devices that have not performed distance measurement communication, the position determination device 1 may set a higher priority for the connected device that has a stronger reception strength than that of the connected device that has a weaker reception strength.

[0090] However, there may be a case where the user activates the short-distance communication function of the portable device 9 after approaching the vehicle Hv. In such a case, the distance measurement result has not been obtained, but the reception strength is high. Assuming the above-mentioned case, the priority of a connected device for which distance measurement communication has not been performed and whose reception strength is equal to or greater than a predetermined value may be exceptionally set to a high priority. The position determination device 1 may be configured to set the priority of a connected device for which distance measurement communication has not been performed and whose reception strength is equal to or greater than a predetermined value to the first priority. With this configuration, it may be possible to quickly perform the first distance measurement communication with the portable device 9 that may be near the vehicle Hv. The priority determination process may also be performed periodically.

[0091] When the prioritization of each connected device is completed, in step S105, the position determination device 1 notifies all anchors 2 of the priorities of each connected device determined in step S104. This enables each anchor 2 to determine the portable device 9 with which to communicate preferentially when the ranging timings overlap.

[0092] Step S106 is a step in which the anchor 2 creates a communication schedule based on the communication settings for each connected device notified by the position determination device 1. Creating a communication schedule includes determining a communication partner for each time. Creating a communication schedule may include determining a channel number or a communication format to be used for each time within a certain period of time. Note that step S106 may be a step of specifying the next distance measurement timing for each connected device. Step S106 may also be executed periodically.

[0093] Step S107 is a step in which each anchor 2 executes a collision determination process. The collision determination process includes steps S211 to S212 as shown in FIG. 13. Steps S211 to S212 may be performed by each of the multiple anchors 2. Step S211 is a step in which, based on the communication settings for each connected device, a collision of distance measurement timing will occur within a fixed time period. In step S211, the anchor 2 verifies, based on the communication schedule generated in step S106, whether communication with multiple connected devices is scheduled at the same time. In other words, in step S211, the anchor 2 determines whether the distance measurement timings of the multiple connected devices overlap. Note that, when there is only one connected device, each anchor 2 may determine that there is no collision of distance measurement timing.

[0094] When the anchor 2 determines that there is an overlap (collision) in the ranging timing (S211 YES), in step S212, the anchor 2 sets the communication partner at the collision timing to a high priority device, and ends this flow. The collision timing means the time / period when the ranging timing overlaps. Step S212 corresponds to a step in which the anchor 2 adjusts the communication schedule. The high priority device here is a connected device with a relatively high priority among two connected devices whose ranging timings overlap. In contrast, in the present disclosure, a connected device with a relatively low priority among two connected devices whose ranging timings overlap is also referred to as a low priority device.

[0095] On the other hand, if the anchor 2 determines that there is no collision in the distance measurement timing (NO in S211), the anchor 2 may switch the communication settings according to the schedule generated in step S106. Therefore, the collision determination process ends without performing any special process. Steps S211 to S212 may be incorporated into step S106.

[0096] Each anchor 2 changes the communication settings as step S108 from time to time based on the communication schedule determined in the above process. Step S108 is a step of switching communication settings such as the channel to be used and the communication format to settings appropriate for the communication partner. Step S108 may be executed periodically at intervals shorter than a round. Alternatively, step S108 may be executed a predetermined time before the time when the next ranging communication is scheduled.

[0097] Step S109 is a step in which each anchor 2 and the portable device 9 perform distance measurement communication. Step S110 is a step in which each anchor 2 reports a distance measurement result (i.e., an anchor measurement result) to the position determination device 1. A series of processes in steps S108 to S110 may be executed at any time in parallel with other steps.

[0098] Step S111 is a step in which the position determination device 1 determines whether or not a complete end condition is satisfied. The complete end condition may be that there is no connected device. The position determination device 1 may also determine that the complete end condition is satisfied when a certain time (e.g., five minutes) has elapsed since the vehicle Hv was locked.

[0099] When the position determination device 1 determines that the complete termination condition is satisfied (YES in step S111), a predetermined closing process is performed, and the in-vehicle system 10 transitions to a standby state. The closing process may include outputting a predetermined control signal to each anchor 2 to transition to a sleep state. The closing process may also include saving, in the storage 13, information on the portable device 9 that was connected until the end and information on the portable device 9 that has been detected as having entered the vehicle. The standby state of the in-vehicle system 10 may be a state in which each anchor 2 is in a sleep state and the position determination device 1 is waiting for connection to the portable device 9. The sleep state of the anchor 2 may be a state in which the UWB module 22 is in sleep.

[0100] <Operation and Effects> FIG. 14 is a time chart showing the operation of the anchor when the timings of distance measurement with multiple portable devices 9 overlap. (A) in FIG. 14 shows a communication schedule with high priority devices, and (B) shows a communication schedule with low priority devices. (C) shows a communication schedule with all connected devices for the anchor 2. (C) corresponds to a diagram integrating (A) and (B). Time T3 is the timing when the timings of distance measurement with multiple portable devices 9 overlap. In the diagram, "INT1" shows the design value of the interval with high priority devices, and "INT2" shows the design value of the interval with low priority devices.

[0101] In the above-mentioned in-vehicle system 10, when the distance measurement timings of multiple portable devices 9 overlap, the anchor 2 executes the distance measurement communication of the high-priority device as scheduled, as shown in Fig. 14, and postpones the distance measurement communication of the low-priority device until the next distance measurement timing determined by the interval setting value. The next distance measurement timing for the low-priority device is T5 shown in Fig. 14.

[0102] According to this configuration, when the distance measurement timings with multiple portable devices 9 overlap, it is possible to reduce the possibility that distance measurement communication with a device that is likely to be near the vehicle Hv will be postponed until the next time. As a result, it is possible to reduce the possibility that the timing at which the position determination device 1 detects that the user is approaching the vehicle Hv will be delayed. In turn, it is possible to reduce the delay in the system's response to the user's approach to the vehicle Hv.

[0103] <Modification> The position determination device 1 may be configured to change the distance measurement setting of the low priority device when a collision of distance measurement timing occurs. Specifically, as shown in FIG. 15, when the communication partner at the collision timing is set to the high priority device in step S212, the anchor 2 may transmit information of the mobile device 9 (i.e., the low priority device) for which the implementation of distance measurement communication has been postponed to the position determination device 1 in step S213. In step S214, the position determination device 1 may exchange distance measurement setting data with the low priority device through short-range communication and lengthen the interval. If the current interval value of the low priority device is 100 milliseconds, the new interval value may be set to 125 milliseconds or 150 milliseconds. The interval may be extended by 4 rounds or 8 rounds.

[0104] When the change of the distance measurement setting with the low priority device is completed, the position determination device 1 transmits the updated distance measurement setting to each anchor 2 in step S215. This reduces the possibility that the distance measurement timing between the low priority device and the high priority device will collide again. Note that making the interval value longer corresponds to making the block size larger.

[0105] In the above, a configuration has been described in which the priority of each portable device 9 is dynamically determined by using the reception strength of the short-range communication signal and the distance information (i.e., the distance measurement value) obtained as a result of the ranging communication in a complementary manner. However, the position determination device 1 does not necessarily need to use the distance measurement value. The position determination device 1 may determine the priority by using the reception strength of the short-range communication signal even after the ranging communication is started. In another embodiment, the position determination device 1 may be configured to determine the priority by using the distance measurement value without using the reception strength of the short-range communication signal. The position determination device 1 may set the priority of the portable device 9 that has already performed the ranging communication higher than the priority of the portable device 9 that has not yet performed the ranging communication. Alternatively, conversely, the position determination device 1 may set the priority of the portable device 9 that has not yet performed the ranging communication higher than the priority of the portable device 9 that has already performed the ranging communication.

[0106] Data indicating the priority of each portable device 9 may be preregistered in the storage 13 of the position determination device 1. The priority of a portable device 9 owned by an owner (hereinafter, an owner device) may be set to be the highest. Furthermore, the priority of a guest device, which is a portable device 9 other than the owner, may be set in the order in which the device information is registered in the position determination device 1, in other words, in the order in which they are paired. A guest device may be referred to as a family device or a friend device.

[0107] Hereinafter, the priority registered in the storage 13 will be referred to as the registered priority. The registered priority may be changed according to the frequency of use of the vehicle Hv for each user. The higher the frequency of use of the vehicle Hv of a user, the higher the registered priority of the portable device 9 of that user may be set.

[0108] Furthermore, the registered priority for each portable device 9 may be changed according to the time that has elapsed since the user of each portable device 9 last used the vehicle Hv. The more recent the last usage date and time, the higher the priority may be set. Specifically, the registered priority of the portable device 9 with the most recent last usage date and time may be set higher than the other portable devices 9. The usage date and time of the vehicle Hv for each portable device 9 may be the date and time when the portable device 9 entered the vehicle or the date and time when it was used to unlock the vehicle Hv, etc.

[0109] The registered priority order may be updated at a predetermined interval, such as every day or every week. The priority order of the owner device may be fixed at number 1. Furthermore, the location determination device 1 may update the priority order of all portable devices 9 based on the frequency of use, the last date and time of use, etc., without distinguishing between the owner device and the guest device.

[0110] The position determination device 1 may perform priority control when there is a collision of distance measurement timings based on the registered priorities as described above, without performing real-time prioritization using the reception strength and / or distance measurement results.

[0111] Furthermore, the position determination device 1 may dynamically determine the priority order using both the registered priority order and the reception strength in the short-distance communication. As shown in FIG. 16, the position determination device 1 calculates the sum of the score according to the registered priority order and the score according to the reception strength of the short-distance communication signal from the mobile device 9 (i.e., RSSI: Received Signal Strength Indicator / Indication) for each mobile device 9. Then, the position determination device 1 may determine the final priority order (hereinafter, effective priority order) in descending order of the sum value. A function / rule / program for converting the registered priority order and the reception strength into a score may be appropriately designed. The score according to the registered priority order may be interpreted as a base point. The score according to the registered priority order may be interpreted as an additional point component that roughly indicates the device distance. The RP score in FIG. 16 means the score according to the registered priority order, and the RSSI score means a score based on the RSSI. According to this configuration, it is possible to apply a priority order according to both the user attribute / usage frequency / last use date and time behind the registered priority order and the current device distance.

[0112] Similarly, the position determination device 1 may comprehensively determine the priority order using both the registered priority order and the measured device distance. Furthermore, the position determination device 1 may comprehensively determine the priority order using three items: the registered priority order, the reception strength, and the distance measurement result. The position determination device 1 calculates a score according to the registered priority order, a score according to the reception strength, and a score according to the distance measurement result for each portable device 9. Then, the total score may be calculated for each portable device 9, and the effective priority order may be determined in descending order of the total value. The function that converts the device distance into a score may be designed as appropriate.

[0113] Although the above describes the manner in which each anchor 2 determines whether or not there is a collision in the distance measurement timing, the position determination device 1 may determine whether or not there is a collision in the distance measurement timing. The position determination device 1 may calculate the next distance measurement timing for each connected device based on the distance measurement setting for each connected device and determine whether or not there is a collision in the distance measurement timing. When the position determination device 1 detects a collision in the distance measurement timing, it may notify each anchor 2 of the connected device that should communicate at the collision timing based on the priority of each connected device. At the collision timing, each anchor 2 may apply a setting for communicating with the connected device notified (instructed) by the position determination device 1. Also, in a configuration in which the position determination device 1 determines whether or not there is a collision in the distance measurement timing by itself, even if there is no notification from the anchor 2, a process of changing the distance measurement setting with a low priority device (S214) may be performed.

[0114] Furthermore, the position determination device 1 may change the interval (i.e., the interval) at which distance measurement communication is performed depending on whether the vehicle Hv is moving or not. The position determination device 1 / portable device 9 may set the interval longer when the vehicle Hv is moving than when the vehicle is stopped. The interval when the vehicle Hv is moving may be set to be two, three, four, or ten times longer than the interval when the vehicle is stopped. The position determination device 1 / portable device 9 may be configured not to perform distance measurement communication when the vehicle Hv is moving. The above control may be mainly executed by the portable device 9. The portable device 9 may determine whether the vehicle Hv is moving or not based on the output of an acceleration sensor built into the device or the moving speed of the position information based on the GNSS.

[0115] In the above, the case where the ranging timings of two mobile devices 9 collide has been described. However, it is also possible that three or more mobile devices 9 overlap. When three or more mobile devices 9 are involved in a collision timing, the position determination device 1 performs ranging communication with the mobile device 9 having the highest priority among the plurality of mobile devices 9 whose ranging timings overlap, and the ranging communication with other mobile devices 9 may be postponed to the next time. When the ranging timings of three or more mobile devices 9 overlap, the device with the highest priority among those mobile devices 9 corresponds to the high-priority device, and the remaining devices correspond to the low-priority devices. The expression "a plurality of mobile devices whose ranging timings overlap" may be interpreted as two or three or more mobile devices whose ranging timings overlap.

[0116] <UWB communication> In UWB communication, multiple channels may be used as specified by IEEE802.15.4z. IEEE (registered trademark) is an abbreviation of Institute of Electrical and Electronics Engineers, and means the Institute of Electrical and Electronics Engineers. The anchor 2 and the mobile device 9 may be configured to be able to communicate using the third, fifth, ninth, or other channels of UWB communication. The anchor 2 and the mobile device 9 may be configured to be able to communicate selectively using multiple channels. The third channel is a channel with a center frequency of 4492 MHz, and the fifth channel is a channel with a center frequency of 6489.6 MHz. The ninth channel is a channel with a center frequency of 7987.2 MHz. Each channel corresponds to a frequency band of ±250 MHz from the center frequency. In UWB communication, 3.1 GHz to 4.8 GHz, 6.0 GHz to 10.6 GHz, etc. may be used. The modulation method for UWB communication may be On Off Keying (OOK), Pulse Position Modulation (PPM), Pulse Width Modulation (PWM), etc. The On Off Modulation method is a method of expressing information (e.g., 0 and 1) by the presence / absence of an impulse signal. The Pulse Position Modulation method is a method of modulating the position at which a pulse occurs. The Pulse Width Modulation method is a method of expressing information by the pulse width. UWB communication between the anchor 2 and the mobile device 9 may be performed by the OOK method. Data transmission by UWB communication is realized using multiple impulse signals. Since a UWB signal includes multiple impulses, it may be referred to as a pulse sequence signal.

[0117] The mounting position of the anchor 2 is not limited to the arrangement pattern shown in FIG. 3. For example, the in-vehicle system 10 may include anchors 2E, 2F, 2G, and 2P as shown in FIG. 17. The anchor 2E is an anchor 2 built into an outer door handle for the right front seat. The anchor 2E may be arranged on a right B-pillar, a right side mirror, a right side sill, or the right edge of the roof. The anchor 2E may be rephrased as a right anchor. The anchor 2F is an anchor 2 built into an outer door handle for the left front seat. The anchor 2F may be arranged on a left B-pillar, a left side mirror, a left side sill, or the left edge of the roof. The anchor 2F may be rephrased as a left anchor. The anchor 2G is an anchor 2 arranged in the center of the rear bumper or the trunk door handle, or the upper end or lower end of the rear window. The anchor 2G may be rephrased as a rear anchor. The anchor 2P is an anchor 2 arranged inside the vehicle as described above. Even in the configuration including the anchors 2E to 2G, the in-vehicle system 10 may include the anchor 2Q in addition to the anchor 2P. The in-vehicle system 10 may also include a front anchor arranged in the center of the front end of the vehicle Hv.

[0118] UWB-IR is a first wireless protocol, and Bluetooth LE is a second wireless protocol. The communication method between the anchor 2 and the mobile device 9 (in other words, the first wireless protocol) is not limited to UWB-IR, and may be Bluetooth LE, Bluetooth Classic, Wi-Fi, EnOcean (registered trademark), Zigbee (registered trademark), or the like. The communication method between the position determination apparatus 1 and the mobile device 9 (i.e., the second wireless protocol) may also be Wi-Fi, or the like. In this disclosure, the terms wireless protocol, communication standard, and communication method may be interchangeable.

[0119] <Additional remarks (1)> The present disclosure also includes the following technical ideas. In addition, a distance measuring method, a control device, and a program corresponding to the following technical ideas are also included in the scope of the present disclosure.

[0120] [Technical thought 1] A communication unit (2) configured to be able to carry out distance measurement communication with a plurality of portable devices using a predetermined wireless protocol; A control device (1) having a storage unit in which information on a plurality of portable devices to be subjected to position determination is stored, The control device includes: prioritizing the plurality of mobile devices; notifying the communication unit of a priority order for each of the portable devices; The communication unit or the control device is Specifying a distance measurement timing, which is a timing for performing distance measurement communication, for each of the portable devices; and determining whether there is a collision timing at which distance measurement timings of the plurality of portable devices overlap; A ranging system in which the communication unit is configured to perform the ranging communication with a high priority device, which is the portable device having the relatively higher priority among two portable devices whose ranging timings overlap at the collision timing.

[0121] [Technical thought 2] The communication unit is repeatedly executing the distance measurement communication with each of the plurality of portable devices in accordance with a distance measurement interval set for each of the portable devices; applying a setting for performing the distance measurement communication with the high priority device at the collision timing; The ranging system described in Technical Idea 1 is configured to postpone the ranging communication with a low-priority device, which is the mobile device with a lower priority among the two mobile devices whose ranging timings overlap, until the next time determined by the ranging interval.

[0122] [Technical thought 3] The communication unit is repeatedly executing the distance measurement communication with each of the plurality of portable devices in accordance with a distance measurement interval set for each of the portable devices; determining whether or not there is a collision timing; When it is determined that there is a collision timing, information of a low-priority device, which is a portable device with a low priority among the portable devices with which the distance measurement timing overlaps, is notified to the control device; The distance measurement system according to Technical Idea 1 or 2, wherein the control device is configured to perform communication with the low priority device to change the distance measurement interval with the low priority device.

[0123] [Technical thought 4] The distance measuring system according to Technical Idea 1, wherein the storage unit registers data indicating the priority order for each of the portable devices.

[0124] [Technical thought 5] The distance measurement system according to any one of technical ideas 1 to 3, wherein the control device is configured to determine the priority order for each mobile device based on the result of the distance measurement communication.

[0125] [Technical Thought 6] the communication unit is a first communication unit, a second communication unit (14) configured to be capable of wireless communication with the portable device using a wireless protocol different from the wireless protocol supported by the communication unit; The control device includes: acquiring data indicating a reception strength of a signal transmitted by the portable device from the second communication unit; The ranging system described in any one of technical ideas 1 to 3 is configured to carry out the steps of: determining the priority order for each portable device based on the reception strength for each portable device.

[0126] [Technical Thought 7] The control device includes: A ranging system described in any one of technical ideas 1 to 6, configured so that the priority of the portable device that has not yet performed the ranging communication is set lower than that of the portable device that has already performed the ranging communication.

[0127] [Technical Thought 8] A ranging system described in any one of Technical Ideas 1 to 7, wherein the communication unit or the control device is configured to determine whether the ranging timing overlaps based on setting data for the ranging communication with the portable device.

[0128] [Technical Thought 9] A ranging system according to technical idea 8, wherein the setting data includes interval information defining a ranging interval and hopping information for determining the timing of execution of the ranging communication within a period corresponding to the ranging interval.

[0129] [Technical Thought 10] The distance measuring system according to any one of Technical Ideas 1 to 9, wherein the communication unit is configured to perform the distance measuring communication using UWB (Ultra Wide Band) communication.

[0130] [Technical Thought 11] the first wireless protocol supported by the first communication unit is UWB (Ultra Wide Band) communication; The ranging system according to Technical Idea 6, wherein the second wireless protocol supported by the second communication unit is Bluetooth (registered trademark) Low Energy.

[0131] [Technical Thought 12] the communication unit is a first communication unit, a second communication unit (14) configured to be capable of wireless communication with the portable device using a wireless protocol different from the wireless protocol supported by the communication unit; The control device includes: acquiring data indicating a reception strength of a signal transmitted by the portable device from the second communication unit; A ranging system described in any one of Technical Ideas 1 to 11, wherein the priority of the portable device that has performed the ranging communication at least once after the second communication unit has established a communication connection with the portable device is set higher than the priority of the portable device that has not yet performed the ranging communication even once.

[0132] [Technical Thought 13] the communication unit is a first communication unit, a second communication unit (14) configured to be capable of wireless communication with the portable device using a wireless protocol different from the wireless protocol supported by the communication unit; The control device includes: acquiring data indicating a reception strength of a signal transmitted by the portable device from the second communication unit; A ranging system described in any one of technical ideas 1 to 12, in which if the receiving strength of a signal from a portable device that has not yet performed ranging communication even once since the second communication unit has established a communication connection with the portable device is greater than or equal to a predetermined value, the priority of the portable device is set to the highest.

[0133] [Technical Thought 14] A control device (1) having a storage unit in which information on a plurality of portable devices to be subjected to position determination is stored, The control device includes: prioritizing the plurality of mobile devices; notifying a communication unit configured to be capable of performing distance measurement communication with a plurality of portable devices using a predetermined wireless protocol of the priority order for each portable device; acquiring data indicating a distance measurement timing for each of the portable devices; Obtaining data on collision timings at which the distance measurement timings of a plurality of the portable devices overlap; A control device configured to, at the collision timing, cause the communication unit to perform the ranging communication with a high priority device, which is the portable device having the relatively higher priority among the two portable devices whose ranging timings overlap.

[0134] [Technical Thought 15] A processor for controlling an operation of a communication unit configured to be able to perform distance measurement communication with a plurality of mobile devices using a predetermined wireless protocol, Referencing a storage unit in which information on a plurality of portable devices to be subjected to position determination is stored; Prioritizing the plurality of portable devices for which the information is stored in the storage unit; notifying the communication unit of a priority order for each of the portable devices; acquiring data indicating a distance measurement timing for each of the portable devices; Obtaining data on collision timings at which the distance measurement timings of a plurality of the portable devices overlap; A control device configured to, at the collision timing, cause the communication unit to perform the ranging communication with a high priority device, which is the portable device having the relatively higher priority among the two portable devices whose ranging timings overlap.

[0135] <Additional remarks (2)> The various flowcharts shown in this disclosure are all examples, and the number of steps constituting the flowcharts and the order of execution of the processes can be changed as appropriate. The controls shown in each flowchart may be combined / executed in parallel to the extent that there is no contradiction. Expressions such as acquisition, determination, detection, generation, and calculation may be interchangeable. An apparatus acquiring certain data also includes the apparatus generating the data based on a signal input from another apparatus / sensor. A communication module may be interchangeable with a communication chip. In this disclosure, descriptions such as a wireless signal, data, message, packet, frame, package, data set, and information may be interchangeable with each other.

[0136] The apparatus, system, and methods described herein may be implemented by a dedicated computer having a processor programmed to execute one or more functions embodied in a computer program. The apparatus and methods described herein may be implemented by a dedicated hardware logic circuit. The apparatus and methods described herein may be implemented by one or more dedicated computers configured by a combination of a processor that executes a computer program and one or more hardware logic circuits. The processor may be any computing core such as a CPU, MPU, GPU, or DFP (Data Flow Processor). Some or all of the functions of the position determination device 1 and the anchor 2 may be implemented by any of a system-on-chip (SoC), an integrated circuit (IC), and a field-programmable gate array (FPGA).

[0137] The computer program includes instructions to be executed by a computer. The computer program may be stored in a computer-readable non-transitive tangible storage medium. The storage medium for the computer program may be a variety of media, such as a hard-disk drive (HDD), a solid-state drive (SSD), or a flash memory. [Explanation of symbols]

[0138] 1 Position determination device (control device), 2 anchor (communication unit, first communication unit), 9 portable device, 10 in-vehicle system (ranging system), 11 processor, 12 memory, 13 storage (storage unit), 14 short-range communication module (second communication unit), 15 in-vehicle communication unit

Claims

1. A communication unit (2) configured to perform ranging communication with a plurality of mobile devices using a predetermined wireless protocol, A control device (1) including a storage unit storing information of the plurality of mobile devices to be subjected to position determination, The control device, Performing prioritization for the plurality of mobile devices, Configured to execute notifying the communication unit of the priority for each of the mobile devices, The communication unit or the control device acquires a ranging timing which is a timing for executing the ranging communication with the mobile device, The communication unit, Repeatedly executing the ranging communication with each of the plurality of mobile devices according to a ranging interval set for each of the mobile devices, Determining whether there is a collision timing at which the ranging timings of the plurality of mobile devices overlap, At the collision timing, performing the ranging communication with a high-priority device which is a mobile device having a relatively high priority among the plurality of mobile devices whose ranging timings overlap, When it is determined that there is a collision timing, executing notifying the control device of information of a low-priority device which is a mobile device having a low priority among the mobile devices whose ranging timings overlap, The control device is a ranging system configured to execute communication for changing the ranging interval with the low-priority device with the low-priority device.

2. The communication unit, At the collision timing, applying settings for performing the ranging communication with the high-priority device, Among the plurality of mobile devices whose ranging timings overlap, the ranging communication with a low-priority device which is a mobile device having a low priority is configured to be postponed to the next time determined by the ranging interval. The ranging system according to claim 1.

3. The ranging system according to claim 1, wherein data indicating the priority for each of the mobile devices is registered in the storage unit.

4. The ranging system according to claim 1, wherein the control device is configured to determine the priority for each of the mobile devices based on the result of the ranging communication.

5. The communication unit is a first communication unit, Further provided is a second communication unit (14) configured to be capable of wireless communication with the mobile device using a wireless protocol different from the wireless protocol supported by the communication unit. The control device obtains data indicating the reception intensity of the signal transmitted by the mobile device from the second communication unit, and determines the priority for each mobile device based on the reception intensity for each mobile device. The ranging system according to claim 1 is configured to perform the above operations.

6. The control device is configured to set the priority of the mobile device for which the ranging communication has not been performed to be lower than that of the mobile device for which the ranging communication has been performed. The ranging system according to claim 1 is configured to perform the above operations.

7. The communication unit or the control device is configured to determine whether the ranging timings overlap based on the setting data for the ranging communication with the mobile device. The ranging system according to claim 1 is configured to perform the above operations.

8. The setting data includes interval information defining a ranging interval and hopping information for determining the execution timing of the ranging communication within the period corresponding to the ranging interval. The ranging system according to claim 7 is configured to perform the above operations.

9. The communication unit is configured to perform the ranging communication using UWB (Ultra Wide Band) communication. The ranging system according to any one of claims 1 to 8 is configured to perform the above operations.

10. A first communication unit (2) configured to be capable of performing ranging communication with a plurality of mobile devices using a predetermined wireless protocol, a second communication unit (14) configured to be capable of wireless communication with the mobile device using a wireless protocol different from the wireless protocol supported by the first communication unit, and a control device (1) including a storage unit in which information on a plurality of the mobile devices to be subjected to position determination is stored. The control device obtains data indicating the reception intensity of the signal transmitted by the mobile device from the second communication unit, performs prioritization for the plurality of mobile devices based on the reception intensity for each mobile device obtained from the second communication unit, and notifies the first communication unit of the priority for each mobile device. The first communication unit or the control device Obtaining ranging timing which is the timing for executing the ranging communication with the portable device Determining whether there is a collision timing where the ranging timings of a plurality of the portable devices overlap The first communication unit is configured to perform the ranging communication with a high-priority device which is a portable device having a relatively high priority among the plurality of portable devices whose ranging timings overlap at the collision timing. A ranging system

11. The control device stores information of a plurality of portable devices to be subjected to position determination in a storage unit The control device assigns priorities to the plurality of portable devices in which the information is stored in the storage unit The control device notifies the priority of each portable device to a communication unit configured to be able to perform ranging communication with the portable device using a predetermined wireless protocol The communication unit or the control device specifies, for each portable device, ranging timing which is the execution timing of the ranging communication The communication unit repeatedly executes the ranging communication with each of the plurality of portable devices according to the ranging interval set for each portable device The communication unit determines whether there is a collision timing where the ranging timings of the plurality of portable devices overlap At the collision timing, the communication unit performs the ranging communication with a high-priority device which is a portable device having a relatively high priority among the plurality of portable devices whose ranging timings overlap When it is determined that there is the collision timing, the communication unit notifies the control device of information of a low-priority device which is a portable device having a lower priority among the portable devices whose ranging timings overlap A ranging method including: the control device executing communication for changing the ranging interval with the low-priority device with the low-priority device

12. The control device stores information of a plurality of portable devices to be subjected to position determination in a storage unit The first communication unit performs ranging communication with the portable device using a first wireless protocol The control device obtains data indicating the reception intensity of a signal transmitted by the mobile device from a second communication unit configured to be capable of wireless communication with the mobile device in accordance with a second wireless protocol different from the first wireless protocol. The control device ranks a plurality of the mobile devices in which the information is stored in the storage unit based on the reception intensity for each of the mobile devices obtained from the second communication unit. The control device notifies the first communication unit configured to be capable of performing ranging communication with the mobile device using a predetermined wireless protocol of the priority order for each of the mobile devices. The first communication unit or the control device specifies, for each of the mobile devices, a ranging timing which is an execution timing of the ranging communication. The first communication unit or the control device determines whether there is a collision timing at which the ranging timings of a plurality of the mobile devices overlap. The ranging method includes: at the collision timing, the first communication unit performs the ranging communication with a high-priority device which is a mobile device having a relatively high priority among the plurality of mobile devices whose ranging timings overlap.

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