Position determination device, position determination system, wireless communication module, and computer program

Abstract

The invention relates to a position determination device, a position determination system, a wireless communication module, and a computer program. A DK-ECU as a position determination device includes a main controller (11) and a BLE module (12). On the basis of the situation that the vehicle is stopped, the main controller (11) is in a power-saving mode (power-off / sleep). On the other hand, the BLE module (12) maintains a state in which the BLE module (12) can be communicatively connected to the portable device (9) even when the vehicle is parked. If the BLE module (12) is in communication connection with the portable device (9), CS ranging processing is executed regularly. The CS distance measurement process is a process for calculating a distance on the basis of reception phase data for each frequency acquired by sequentially transmitting and receiving continuous wave signals of respective different frequencies to and from the portable device (9). The BLE module (12) activates the main controller (11) when the first distance calculated in the CS distance measurement process is less than a predetermined value.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on Japanese Patent Application No. 2022-197267 filed in Japan on December 9, 2022, and the contents of the basic application are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to a technique for determining a position of a portable device relative to a vehicle by wirelessly communicating with the portable device. Background Art

[0004] Patent Document 1 discloses a structure in which, in an in-vehicle system comprising a master unit and multiple slave units, the master unit detects the presence of a portable device near the vehicle based on the reception strength of the signal transmitted from the portable device and activates the slave units. The master unit and slave units are communication devices that wirelessly communicate with mobile terminals.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-171401

[0006] According to the structure disclosed in Patent Document 1, the communication module equivalent to the extension will not be started and will remain in a stopped state until the communication module as the host detects the portable device. Therefore, it is expected that the power consumption during standby (for example, when the car is parked) can be suppressed. Based on the above structure, the developers of the present disclosure have studied a structure in which the host restores (i.e., starts) the target device from the power saving mode to the normal mode when the reception strength of the signal from the portable device is above a specified value. The target device is not limited to the extension and can be any device.

[0007] However, after verifying the operation of a configuration using a communication module that performs communications based on Bluetooth (registered trademark) Low Energy (hereinafter referred to as BLE) as the host, the developers discovered the following problem. Specifically, in the aforementioned configuration, the host detected the portable device and activated the target device even when the portable device was more than 10 meters away from the vehicle. This is believed to be because the radio waves used in BLE have a frequency of more than 1 GHz, resulting in strong linearity. Furthermore, multipath and other factors can easily cause variations in reception strength.

[0008] In this configuration, where activation of the target device is conditional on the signal reception strength from the portable device being at or above a predetermined value, the target device may be activated unnecessarily even if it is not actually near the vehicle. Furthermore, unnecessary activation of the target device increases power consumption during standby mode. Furthermore, the target device may be a variety of devices / modules, such as a computer, a communication module, or a circuit module. Summary of the Invention

[0009] The present disclosure has been made based on the above-mentioned research and ideas, and one of its objects is to provide a position determination device, a position determination system, a wireless communication module, and a computer program that can reduce power consumption during standby.

[0010] The position determination device disclosed herein is a position determination device for determining the position of a portable device relative to a vehicle, comprising: a first communication unit for performing wireless communication based on Bluetooth with the portable device; and a computer for performing processing related to the position determination of the portable device, wherein the computer has a normal mode and a power saving mode as states, and the first communication unit is configured to maintain a state in which it can communicate with the portable device even when the computer is in the power saving mode. The first communication unit performs a first distance measurement process in which a first distance is calculated using data related to a reception phase, flight time, or arrival time of a wireless signal transmitted from the portable device, wherein the first distance is the distance from the first communication unit to the portable device. The first communication unit compares the first distance obtained as a result of the first distance measurement process with a specified value and, based on the comparison result, causes the computer to transition from the power saving mode to the normal mode.

[0011] In the above configuration, the condition for returning the computer to normal mode is that a first distance, determined based on parameters corresponding to the propagation time of the wireless signal transmitted from the portable device, such as the reception phase or arrival time, is less than a predetermined value. This first distance reduces the ranging error caused by the communication environment compared to the reception strength. Therefore, the above configuration can reduce the likelihood of the computer being activated when the portable device is far from the vehicle, for example, when activation is not necessary. This also reduces power consumption during standby mode.

[0012] The position determination system included in the present disclosure includes: a first communication unit that implements wireless communication based on Bluetooth with a portable device; and a computer that implements processing related to position determination of the portable device, wherein the computer has a normal mode and a power saving mode as states. When the computer is in the power saving mode, the first communication unit performs a first ranging process, in which a first distance is calculated using a reception phase, flight time, or arrival time of a wireless signal sent from the portable device, wherein the first distance is the distance from the first communication unit to the portable device, and the first communication unit compares the first distance obtained as a result of the first ranging process with a specified value, and based on the comparison result, restores the computer from the power saving mode to the normal mode.

[0013] The position determination system described above also has the same structure as the position determination device described above, and therefore, the power consumption during standby mode can also be reduced by the system described above.

[0014] The wireless communication module included in the present disclosure is a wireless communication module that implements Bluetooth-based wireless communication with a portable device, and includes: an antenna for communicating with the portable device; and a communication controller that obtains data related to the reception phase, flight time, or arrival time of a wireless signal transmitted from the portable device based on a signal received by the antenna. The communication controller implements the following processing: maintaining a state in which communication with the portable device is possible even when the vehicle is parked, based on power from a battery mounted on the vehicle; performing a first ranging process when the vehicle is parked, in which the data related to the reception phase, flight time, or arrival time of the wireless signal is used to calculate a first distance from the communication controller itself to the portable device; and comparing the first distance obtained as a result of the first ranging process with a specified value, and outputting a signal for causing a specified target device mounted on the vehicle to shift from a power saving mode to a normal mode based on the comparison result.

[0015] The wireless communication module can also reduce power consumption during standby mode for the same reason as the position determination device.

[0016] The computer program included in the present disclosure includes instructions for causing a processor of a portable device to execute processing, wherein the portable device includes: a Bluetooth communication unit for performing wireless communication based on Bluetooth and an ultra-wideband (UWB) communication unit for performing UWB communication. The processing includes: establishing a Bluetooth communication connection with a vehicle upon receipt of a signal transmitted from a previously associated vehicle; returning a signal for a ranging process upon receipt of a request to start a first ranging process from the vehicle, wherein the first ranging process is a ranging process based on Bluetooth communication; sequentially transmitting continuous wave signals of different frequencies after returning the signal for the ranging process; activating the UWB communication unit upon receipt of a request to start a second ranging process from the vehicle, wherein the second ranging process is a ranging process based on UWB communication; and returning a UWB signal of a predetermined pattern upon receipt of a UWB signal for ranging from the vehicle.

[0017] The computer program is a computer program for causing a conventional device to function as a portable device that responds to a position determination apparatus / position determination system. Furthermore, the computer program allows the UWB communication unit to be stopped even when the portable device does not receive a request to start the second ranging process from the vehicle, thereby reducing power consumption during standby mode.

[0018] In addition, the reference numerals in parentheses described in the claims indicate a correspondence relationship with specific elements described in an embodiment described later as one aspect, and do not limit the technical scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram showing an overall image of a vehicle electronic key system.

[0020] Figure 2 This is a block diagram showing the structure of a portable device.

[0021] Figure 3 This is a block diagram showing the structure of DK-ECU.

[0022] Figure 4 This is a block diagram showing the structure of a BLE module.

[0023] Figure 5 Schematically shows the flow of CS ranging processing.

[0024] Figure 6 This is the functional block diagram of the main controller.

[0025] Figure 7 This is a flowchart for explaining the operation of the DK-ECU when the main controller is in the power saving mode.

[0026] Figure 8 This is a flowchart for explaining the operation of the DK-ECU when the main controller is in the normal mode.

[0027] Figure 9 This is a flowchart for explaining the operation of the DK-ECU in response to the user approaching the vehicle.

[0028] Figure 10 This is a flowchart showing another operation example of the DK-ECU after the main controller is activated.

[0029] Figure 11 This is a flowchart showing the operation of the main controller when selecting a UWB module to be used for the next position determination based on the device position determination result.

[0030] Figure 12 This figure is used to explain an example in which an anchor point is not required to correspond to the device position.

[0031] Figure 13 This is a flowchart showing another operation example of the BLE controller when the main controller is in the power saving mode.

[0032] Figure 14This is a flowchart showing another operation example of the BLE controller when the main controller is in the power saving mode.

[0033] Figure 15 This is a flowchart showing another operation example of the BLE controller when the main controller is in the power saving mode.

[0034] Figure 16 This is a diagram for explaining the operation of the in-vehicle system and the portable device in the first waiting state.

[0035] Figure 17 This is a diagram for explaining the operation of the in-vehicle system and the portable device in the second waiting state.

[0036] Figure 18 This is a diagram for explaining the operations of the in-vehicle system and the portable device in the third waiting state.

[0037] Figure 19 This is a diagram for explaining the operation of the in-vehicle system and the portable device in the position determination state.

[0038] Figure 20 This is a block diagram showing another configuration example of the in-vehicle system.

[0039] Figure 21 This is a block diagram showing another configuration example of the in-vehicle system. DETAILED DESCRIPTION

[0040] Below, an embodiment of the electronic key system for a vehicle to which the present disclosure is applied is described using figures. The present disclosure is not limited to the following embodiments, and the various modifications described later are also included in the technical scope of the present disclosure. Moreover, in addition to the following, various changes can be made and implemented without departing from the main purpose. Various supplements, modifications, etc. can be appropriately combined and implemented within the scope that does not cause technical contradictions. Components with the same function are marked with the same figure numerals, and their descriptions are sometimes omitted. In addition, when only a part of the structure is mentioned, the description recorded in other places can be applied to the other parts.

[0041] Overall Structure

[0042] like Figure 1 As shown, the vehicle electronic key system of this embodiment includes an onboard system VS and a portable device 9. The onboard system VS includes a digital key ECU (hereinafter referred to as DK-ECU) 1. ECU is the abbreviation for Electronic Control Unit, which refers to an electronic control device. DK is the abbreviation for Digital Key.

[0043] The DK-ECU 1 is configured to perform wireless communication (hereinafter referred to as BLE communication) based on Bluetooth (registered trademark) Low Energy with a portable device 9 carried by a user of the vehicle Hv. The following describes a scenario in which the DK-ECU 1 functions as the master device in data communication with the portable device 9, and the portable device 9 functions as the slave device. The term "master device" can be replaced by a central device or scanner. The term "slave device" can be replaced by a peripheral device or a public device.

[0044] DK-ECU1 establishes a communication connection with the portable device 9 by receiving an advertising signal from the portable device 9. The advertising signal is a BLE signal used to notify (i.e., advertise) the existence of itself to other devices. The BLE signal is a wireless signal based on BLE. The BLE signal can contain a code indicating the source or destination. The source and destination can be represented by a device ID, etc. Of course, as another method, the electronic key system for a vehicle can also be set so that the portable device 9 serves as the master device in the communication with the DK-ECU1, and the DK-ECU1 acts as a slave device. The role of each device can be replaced. In addition, the functions and structures of the DK-ECU1 and the portable device 9 can be appropriately changed as the roles are replaced.

[0045] In the present disclosure, wireless signals based on the BLE standard are recorded as BLE signals. In addition, the signal of the advertising channel in the BLE signal is sometimes recorded as an advertising signal, and the signal of the data channel is recorded as a data signal. Channels numbered 37 to 39 among the 40 channels are equivalent to advertising channels. In addition, channels numbered 0 to 36 are equivalent to data channels. The definitions of advertising channels and data channels and the specific frequency values are determined according to the BLE standard. In addition, according to changes in the BLE standard, the structure of the present disclosure can also be appropriately changed to be based on the changed standard and implemented.

[0046] Furthermore, the in-vehicle system VS and the portable device 9 are configured to be capable of wireless communication using the UWB-IR (Ultra Wide Band-Impulse Radio) method, or UWB communication. Specifically, the in-vehicle system VS and the portable device 9 are configured to be capable of transmitting and receiving pulsed radio waves (hereinafter referred to as pulse signals) used in UWB communication. The pulse signals used in UWB communication have an extremely short pulse width (e.g., 2 nanoseconds) and a bandwidth (i.e., an ultra-wide bandwidth) of at least 500 MHz (strictly, 499.2 MHz).

[0047] In addition, in UWB communication, multiple channels can be used as specified in IEEE802.15.4z. Below, as an example, the vehicle-mounted system VS is configured to communicate with the portable device 9 using the fifth channel of UWB communication. Of course, the vehicle-mounted system VS can also be configured to be able to communicate with the portable device 9 using other channels such as the third channel and the ninth channel. 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. In addition, IEEE (registered trademark) is the abbreviation of Institute of Electrical and Electronics Engineers, which refers to the American Institute of Electrical and Electronics Engineers. Each channel is equivalent to a frequency band of ±250 MHz of the center frequency. In UWB communication, frequencies such as 3.1 GHz to 4.8 GHz and 6.0 GHz to 10.6 GHz can be used.

[0048] The modulation method of UWB communication may be an on-off keying (OOK) method, a pulse position modulation (PPM) method, a pulse width modulation (PWM) method, etc. The modulation method may also be MB-OFDM or DS-UWB. In addition, the on-off keying method is a method of expressing information by the presence / absence of a pulse signal. The pulse position modulation method is a method of modulating at the position where the pulse is generated. The pulse width modulation method is a method of expressing information by the width of the pulse. Here, as an example, the UWB communication between the vehicle-mounted system VS and the portable device 9 is implemented by the OOK method. Data transmission based on UWB communication is achieved using multiple pulse signals. Hereafter, the data signal exchanged through UWB communication will be referred to as a UWB signal. The UWB signal contains multiple pulses, so it can also be called a pulse train signal.

[0049] Portable Devices 9

[0050] Portable device 9 is a portable, universal information processing terminal equipped with BLE communication capabilities. Portable device 9 can be any communication terminal, such as a smartphone or a wearable device. A wearable device is a device worn on the user's body. Wearable devices can take various forms, including wristbands, watches, rings, glasses, and headphones. Portable device 9 can also be referred to as a user device, a key device, or the like.

[0051] Alternatively, the portable device 9 may be a dedicated device serving as an electronic key for the vehicle HV, namely a smart key. A smart key is a device that is transferred to the owner of the vehicle HV along with the vehicle HV when the vehicle HV is purchased. A smart key can be understood as one of the accessories of the vehicle HV. Smart keys can come in a variety of shapes, such as a flat rectangular parallelepiped, a flat oval (so-called watchband-style), or a card. Smart keys can be referred to as vehicle portable devices, key fobs, key cards, access keys, and the like.

[0052] like Figure 2 As shown, the portable device 9 includes a device control unit 90 , a display 91 , a touch panel 92 , a BLE module 93 , and a UWB module 94 .

[0053] The device control unit 90 is a module that controls the overall operation of the portable device 9. The device control unit 90 is configured as a computer including a device processor 901, memory 902, storage 903, and input / output circuits 904. The device processor 901 can be a CPU (Central Processing Unit). The memory 902 is a volatile storage medium such as RAM (Random Access Memory). The storage 903 is a non-volatile storage medium such as flash memory.

[0054] The memory 903 may also store a key code used in wireless authentication between the device ID and the DK-ECU 1. This key code may also be referred to as an encryption key. The memory 903 may also store a digital key application, which is application software for enabling the portable device 9 to function as a vehicle key. The digital key application is used to securely communicate with the DK-ECU 1 and respond to inquiries / requests from the DK-ECU 1. In this disclosure, application software may sometimes be referred to simply as "application."

[0055] The display 91 may be a liquid crystal display or an organic EL display. The display 91 displays images corresponding to input signals from the device control unit 90. The touch panel 92 is a capacitive touch panel and is laminated on the display 91. The touch panel 92 is an input device included in the portable device 9. The touch panel 92 and the display 91 serve as an interface for the user to enter a password for logging into the digital key application into the portable device 9 or for pairing the portable device 9 with the DK-ECU 1.

[0056] The BLE module 93 is a communication module for implementing BLE communication. It includes a strength detection unit, which measures the strength of received signals. The measured strength value itself is called the RSSI (Received Signal Strength Indicator). In addition to receiving data, the BLE module 93 also transmits data indicating the measured strength, along with information about the source, to the device control unit 90.

[0057] In addition, the BLE module 93 is configured to transmit and receive a continuous wave (CW) signal of a specified waveform as a signal for CS (Channel Sounding) ranging, described later, in addition to the modulated signal used for data communication. The CW signal can be either a sine wave or a triangular wave. The BLE module 93 can have the same structure as the BLE module 12 included in the vehicle-mounted system VS. The BLE module 93 can refer to part or all of the description of the BLE module 12. The BLE module 93 is equivalent to the Bluetooth communication unit.

[0058] The UWB module 94 is a communication module for implementing UWB communication. The UWB module 94 outputs received data to the device control unit 90. Furthermore, based on instructions from the device control unit 90, the UWB module 94 transmits a UWB signal corresponding to the transmitted data. Based on instructions from the device control unit 90, the UWB module 94 can also transmit a single pulse signal as a UWB signal for ranging. The operation of the UWB module 94 is controlled by the device control unit 90. The UWB module 94 functions as a UWB communication unit.

[0059] The device control unit 90 causes the BLE module 93 to send an advertising signal at a specified sending interval. In addition, based on the fact that the BLE module 93 receives a connection request from the DK-ECU1, a communication connection process with the DK-ECU1 is implemented. When the device control unit 90 receives a BLE signal sent from the vehicle Hv, it returns a response signal corresponding to the received signal. The device control unit 90 may also implement an authentication process based on wireless communication (hereinafter referred to as wireless authentication process) based on the fact that a communication connection with the DK-ECU1 has been established. The wireless authentication process may be implemented in a challenge-response manner. When the device control unit 90 receives a challenge code from the DK-ECU1, it may also use the key code to generate a response code and return it to the DK-ECU1.

[0060] The device control unit 90 performs distance measurement communications based on a request from the DK-ECU 1. Based on the request from the DK-ECU 1, the portable device 9 causes the BLE module 93 to transmit a CW signal on a specified channel. The interaction between the portable device 9 and the DK-ECU 1 (actually, the DK-ECU 1) will be described later.

[0061] Furthermore, when the portable device 9 receives a UWB signal from the in-vehicle system VS, it returns a response signal corresponding to the received signal. Upon receiving a UWB signal serving as a search signal, the portable device 9 returns a UWB signal modulated with a code containing its own device ID to the in-vehicle system VS as a response signal. The search signal is a signal used by the in-vehicle system VS to search for the portable device 9 and request the portable device 9 to return a response signal. UWB signals transmitted by the portable device 9 and the in-vehicle system VS may include a code indicating the source or destination.

[0062] The device control unit 90 maintains the BLE module 93 in a standby state even when not communicating with the DK-ECU 1. The standby state is a state in which advertising signals are periodically transmitted at predetermined advertising intervals. The standby state is a state in which advertising signals are transmitted, i.e., a state in which advertising signals are transmitted, and a state in which advertising signals are not transmitted are repeated.

[0063] On the other hand, the device control unit 90 stops the UWB module 94 when a BLE link is not established with the DK-ECU 1. The device control unit 90 activates the UWB module 94 when a BLE link is established with the DK-ECU 1. This configuration reduces power consumption during standby mode.

[0064] The device control unit 90 can also be configured to activate the UWB module 94 upon receiving a UWB ranging start request from the DK-ECU 1 via BLE after establishing a BLE communication connection with the DK-ECU 1. The UWB ranging start request is a BLE signal requesting the start of the UWB ranging process. In many cases, the power consumption of the UWB module 94 is greater than that of the BLE module 93. Therefore, by reducing the time it takes for the UWB module 94 to activate, further power savings can be expected.

[0065] <In-vehicle system>

[0066] like Figure 3As shown, the vehicle-mounted system VS includes a DK-ECU1, a plurality of UWB modules 2, a body ECU3, a motion sensor 4, and an actuator 5. The DK-ECU1 is individually connected to the plurality of UWB modules 2 via cables. In addition, the DK-ECU1 is also connected to the body ECU3 in a manner that allows mutual communication via a dedicated communication cable or an in-vehicle network. The in-vehicle network is a communication network constructed within the vehicle Hv. The standard of the in-vehicle network can be any standard such as Controller Area Network (CAN: registered trademark), Ethernet (registered trademark), or FlexRay (registered trademark). The body ECU3 is connected to the motion sensor 4 and the actuator 5. Of course, the connection method between the devices disclosed here is an example and can be changed appropriately.

[0067] The DK-ECU 1 is an ECU that determines the device's location by collaborating with the UWB module 2. In this disclosure, device location refers to the relative position of the portable device 9 relative to the vehicle Hv. The DK-ECU 1 determines whether the portable device 9 is present within the vehicle based on the communication status between the multiple UWB modules 2 and the portable device 9. The DK-ECU 1 functions as a location determination device. Since the portable device 9 corresponds to the user, determining the device's location is equivalent to determining the user's location.

[0068] The DK-ECU 1 may be placed in the vehicle's instrument panel. The DK-ECU 1 may also be installed in an overhead console, the right or left C-pillar, or under the driver's seat. The C-pillar is the third pillar from the front of a vehicle.

[0069] like Figure 3 As shown, the DK-ECU 1 includes a main controller 11, a BLE module 12, an input / output circuit 13, and a power supply circuit 14. The main controller 11 is a computer that performs various processes related to determining the device's location. The main controller 11 includes a main processor 111, memory 112, and storage 113. The main processor 111 can be a CPU. The main processor 111 can also be referred to as an ECU processor, etc. The memory 112 is a volatile storage medium such as RAM.

[0070] The memory 113 includes a non-volatile storage medium such as flash memory. A device location determination program, executed by the main processor 111, is stored in the memory 113. Execution of the device location determination program by the main processor 111 is equivalent to executing the location determination method corresponding to the device location determination program. The device ID of the portable device 9 is registered in the memory 113. Furthermore, the memory 113 stores data indicating the installation location of each UWB module 2 in the vehicle Hv.

[0071] The main controller 11 has a normal mode and a power-saving mode as power supply states, or in other words, operating modes (or states). The normal mode is a state in which power is supplied to the main controller 11 and various processes such as position determination can be executed. The power-saving mode is a so-called power-off state in which the power supply to the main controller 11 is completely cut off.

[0072] The power saving mode can also be a sleep mode or a pause mode. Sleep mode refers to a state in which the power supply to the main processor 111 is stopped while the data in operation, in other words, the program execution state, is saved in a volatile memory such as RAM. The pause mode refers to a state in which the power supply to the main processor 111 and the memory 112 is stopped while the program execution state is saved in a writable non-volatile memory such as flash memory. Since the power saving mode stops operation in a certain mode, it can also be referred to as a pause mode.

[0073] In addition, the power saving mode can also be an action mode in which the system is started intermittently at a low frequency such as once every 10 seconds, once every 10 minutes, etc., and communicates with the vehicle body ECU 3 and an external server. Furthermore, the power saving mode can also be an action mode in which the functions are limited compared to the normal mode, in other words, an action mode in which only a part of the functions can be executed. The power saving mode can also be a state in which the position determination function is stopped and the authentication function based on the backup means is maintained. The backup means refers to transponder communication or NFC (Near Field Communication) and the like. The main controller 11 is equivalent to a computer. Details of the main controller 11 will be described later.

[0074] The BLE module 12 is a communication module for implementing BLE communication. Similar to the BLE module 93 included in the portable device 9, the BLE module 12 is configured to transmit and receive CW signals for each channel as signals for CS ranging, in addition to modulated signals for data communication. Even when the driving power supply is set to off, power from the vehicle's battery is supplied to the BLE module 12. Using power from the vehicle's battery, the BLE module 12 remains in a standby state, either constantly or intermittently, even when the vehicle Hv is parked.

[0075] The BLE module 12 also performs periodic scanning during the period when the main controller 11 is in power saving mode, and attempts to connect with the portable device 9. In addition, the BLE module 12 performs the CS ranging process described later based on the fact that it has been connected to the portable device 9 for communication. In this way, in the present disclosure, the BLE module that maintains a state of being able to receive signals from the portable device 9 even when the main controller 11 is in power saving mode is called a gateway module. The gateway module can also be understood as a BLE module that plays the role of activating the main controller 11 based on the communication status with the portable device 9. The communication status here mainly includes the device distance and / or reception strength obtained as a result of CS ranging. The device distance refers to the distance from a communication module such as the BLE module 12 or the UWB module 2 mounted on the vehicle Hv to the portable device 9. In addition, the gateway module can also be understood as a BLE module that is connected to the portable device 9 for communication. The details of the BLE module 12 will be explained separately later. The BLE module 12 is equivalent to the wireless communication module and the first communication unit.

[0076] The input / output circuit 13 is a circuit module used by the DK-ECU 1 to communicate with other devices, such as the body ECU 3. This circuit may include analog circuit components, integrated circuits, or physical physical layer (PHY) chips that conform to the communication standards of the vehicle's internal network. Alternatively, the circuit may include a chipset that converts logical signals into actual electrical signals within interfaces such as CAN, Ethernet (registered trademark), and UART.

[0077] The power supply circuit 14 is a circuit module that supplies power to the main controller 11, the BLE module 12, and the input / output circuit 13. The power supply circuit 14 converts the voltage input from the power cable (e.g., battery voltage) into a voltage suitable for the operation of the main controller 11, the BLE module 12, and the input / output circuit 13, and outputs the voltage to each component.

[0078] The power supply circuit 14 may also have a function of switching the power supply of the DK-ECU 1 from the off state to the on state in response to a predetermined activation signal input from the BLE module 12. The off state of the DK-ECU 1 corresponds to a state in which power supply to components other than the power supply circuit 14 and the BLE module 12 is stopped. The on state of the DK-ECU 1 corresponds to a state in which the main controller 11 operates in normal mode. When the driving power supply is switched from on to off, the main controller 11 cooperates with the power supply circuit 14 to transition to the power saving mode.

[0079] UWB module 2 is a communication module for implementing UWB communication. Similar to UWB module 94 included in portable device 9, UWB module 2 is configured to transmit and receive UWB signals. UWB module 2 is a communication device used to determine the location of portable device 9, also known as an anchor point or base station. UWB module 2 serves as the second communication unit.

[0080] The UWB module 2 includes a UWB communication antenna, a transceiver circuit, and a UWB controller. The transceiver circuit performs signal processing related to modulation and demodulation. The UWB controller is a microcomputer that controls the operation of the UWB module 2 and generates the UWB distance measurement data described below.

[0081] The UWB module 2 implements the UWB ranging process based on the instruction from the DK-ECU 1. The UWB ranging process is a process of measuring the device distance based on the propagation time (in other words, the flight time) of the radio wave from the UWB module 2 to the portable device 9. The UWB ranging process includes the process of sending a UWB signal of a prescribed pattern toward the portable device 9 and the process of receiving a UWB signal as a response signal from the portable device 9. The UWB signal exchanged between the UWB module 2 and the portable device 9 in the UWB ranging process can also be a single pulse signal or a pulse sequence signal in which multiple pulse signals are configured in a prescribed pattern. The UWB ranging process is equivalent to the second ranging process.

[0082] The UWB controller measures the round trip time (RTT), which is the time elapsed from the start of sending the UWB signal to the receipt of the response signal from the portable device 9, and calculates the device distance based on the RTT. RTT is equivalent to the round-trip flight time of the UWB signal. RTT obtains a value corresponding to the distance from the UWB module 2 to the portable device 9. The UWB controller of this embodiment calculates the device distance by multiplying half of the value obtained by subtracting a specified correction value from the RTT by the propagation time of the radio wave. The correction value here is a parameter used to offset the response processing time in the portable device 9 and the delay time in the UWB module 2. The specific value of the correction value can be appropriately designed. The correction value can also be 0.

[0083] In the present disclosure, the device distance calculated in the UWB ranging process is referred to as the second distance. The second distance can also be referred to as the UWB ranging value. The data representing the second distance is UWB ranging data. In the case where no response is obtained from the portable device 9 in the UWB ranging process, the UWB module 2 adopts a value indicating that it cannot be measured or a specified value that is sufficiently large as the second distance. The UWB module 2 sends the generated UWB ranging data to the DK-ECU1. In addition, since the flight time corresponds to the distance, the case of calculating the above-mentioned RTT essentially corresponds to the case of calculating the distance from the UWB module 2 to the portable device 9. Therefore, the process of calculating the RTT and providing it to the DK-ECU1 is also included in the concept of UWB ranging processing (second ranging processing). The process of converting the RTT into a distance can also be implemented by the main controller 11.

[0084] Furthermore, the UWB module 2 may generate position-related data indicating the possible location / area of the portable device 9 based on the second distance and its own location. The UWB module 2 may also transmit the position-related data to the DK-ECU 1 instead of or in addition to the UWB distance measurement data.

[0085] The in-vehicle system VS includes an interior anchor point 2A, a right anchor point 2B, a left anchor point 2C, and a rear anchor point 2D as UWB modules 2. The interior anchor point 2A is a UWB module 2 located within the vehicle cabin. It can be located at any location within the vehicle, such as the instrument panel, the upper end of the windshield, or the center of the interior ceiling. The interior anchor point 2A can also be housed within the DK-ECU 1 housing. The right anchor point 2B, the left anchor point 2C, and the rear anchor point 2D are all UWB modules 2 located on the exterior of the vehicle Hv. The right anchor point 2B is built into the outside door handle for the right front seat. The right front seat is the front seat located to the right of the center console. When the steering wheel is located to the right of the instrument panel, the right front seat corresponds to the driver's seat. Alternatively, the right anchor point 2B can be located at the right B-pillar, the right rearview mirror, or the right side sill. The right anchor point 2B can be referred to as the right outdoor unit. The right anchor point 2B corresponds to the right communication unit.

[0086] The left anchor point 2C is built into the outside door handle for the left front seat. The left anchor point 2C can also be located on the left B-pillar, the left rearview mirror, or the left lower side sill. The left anchor point 2C can be referred to as the left outdoor unit. The left anchor point 2C is equivalent to the left communication unit. The rear anchor point 2D is located near the rear bumper or the trunk door. The rear anchor point 2D can be referred to as the rear outdoor unit. The right anchor point 2B, the left anchor point 2C, and the rear anchor point 2D can be referred to as outdoor units or outside anchor points. The structure and performance of each UWB module 2 can be substantially identical.

[0087] Each UWB module 2 operates according to the instructions of DK-ECU1. Each UWB module 2 is started based on the instructions from DK-ECU1 and performs UWB ranging processing. The state in which the UWB module 2 is able to communicate can be in other words an active state (activated state) or an awake state, etc. The UWB module 2 that performs UWB ranging processing stops operating spontaneously or based on the instructions from DK-ECU1. The state in which the operation is stopped can also be a power-off state or a state in which only part of the functions are activated. The state in which the operation is stopped can be in other words a sleep state, an invalid state, etc. In addition, each UWB module 2 can also be configured to spontaneously attempt UWB ranging processing at specified intervals. The structure including DK-ECU1 and UWB module 2 is equivalent to a position determination system.

[0088] The body ECU 3 is an ECU that detects the user's operation (action) on the vehicle Hv based on the input signal from the motion sensor 4, and causes the actuator 5 to act according to the detected user's operation. The motion sensor 4 here refers to a sensor for detecting the user's action on the vehicle Hv. Action can also be said to be an operation or an instruction. As actions for the vehicle Hv, locking operation, unlocking operation, sitting, pressing the start switch, stepping on the brake pedal, etc. are listed. The motion sensor 4 includes a door sensor, a start switch, a brake pedal sensor, and a part or all of the seating sensor provided on the outer door handle. The unlocking operation refers to the user operation for unlocking the vehicle Hv. The locking operation refers to the operation for locking the vehicle Hv. The DK-ECU1 can detect the touch operation on the door sensor as an unlocking operation / locking operation.

[0089] Furthermore, the door sensor is a sensor used to detect user operations for unlocking and locking the doors of the vehicle Hv. The door sensor can be a touch sensor or a push-button switch. The starter switch is a pushbutton switch used by the user to toggle the power supply for driving on and off. The starter switch can also be referred to as a power switch.

[0090] Actuator 5 is part or all of the locking motor, headlights, and welcome lights. The locking motor switches the doors between lock and unlock. The welcome lights illuminate the road surface near the doors. They are located on the side mirrors, rocker panels, and lower ends of the door panels.

[0091] When the body ECU 3 detects a predetermined event requiring the location determination of the portable device 9, such as an unlocking operation, it transmits an event generation notification signal to the DK-ECU 1. Upon receiving the event generation notification signal from the body ECU 3, the DK-ECU 1 may also return (i.e., start up) from power saving mode to normal mode and execute control and processing related to device location determination. Furthermore, the DK-ECU 1 may also possess the function of detecting the event.

[0092] In addition to the above-mentioned body ECU3 and UWB module 2, a variety of vehicle-mounted devices can be directly or indirectly connected to the DK-ECU1. The DK-ECU1 can also be connected to the power supply ECU, cellular module, NFC module, etc. via the vehicle's internal network / using a dedicated cable to enable mutual communication. The power supply ECU is an ECU that controls the on / off of the driving power supply mounted on the vehicle Hv. In addition, the driving power supply is the power supply used to supply the vehicle Hv with power. In the case where the vehicle Hv is an engine vehicle, the ignition power supply is equivalent to the driving power supply. In the case where the vehicle Hv is an electric vehicle, the system main relay can be understood as the driving power supply.

[0093] The cellular module is a communication module that implements cellular communications such as 4G and 5G. The NFC module is a communication module that implements near-field communication (NFC). NFC refers to communication with a communication distance of several centimeters to approximately 10 centimeters. Multiple NFC modules may be installed in the vehicle HV. The NFC module can also be used as a tool for pairing the portable device 9 with the DK-ECU 1. Pairing here also includes so-called binding, which stores the keys exchanged between devices.

[0094] <Structure and functions of the BLE module>

[0095] Here we will explain the structure and function of the BLE module 12. Figure 3 as well as Figure 4 As shown, the BLE module 12 includes an antenna 121 , an RF core 122 and a BLE controller 123 .

[0096] Antenna 121 is an antenna element for sending and receiving radio waves in the frequency band used for BLE communication, that is, the 2.4 GHz band. The 2.4 GHz band can be understood as a frequency band containing multiple channels (0 to 39 Ch) used for BLE communication. Antenna 121 is electrically connected to the RF core 122. The channel can also be said to be a frequency. Among the multiple channels allocated to BLE, the channel used for actual communication (in other words, the used frequency / used channel) changes over time through frequency hopping or according to instructions from the BLE controller.

[0097] The RF core 122 is a circuit module for signal processing involved in sending and receiving wireless signals. The RF core 122 can include a modulation circuit, a demodulation circuit, a frequency conversion circuit, an amplification circuit, a local oscillator, etc. In addition, the RF core 122 has input and output terminals for outputting signals toward the antenna 121 or receiving signals from the antenna 121. The RF core 122 is connected to the BLE controller so that they can communicate with each other. The RF core 122 demodulates the signal received by the antenna 121 and provides it to the BLE controller 123. In addition, the RF core 122 modulates the transmission data input from the BLE controller 123 and radiates it as radio waves from the antenna 121. The RF core 122 can also be implemented as an IC chip (i.e., a transmitting and receiving IC). The BLE controller 123 is equivalent to a communication controller.

[0098] In addition to modulated signals for data communication, the RF core 122 also functions as a CS ranging device, capable of transmitting and receiving CW signals for each channel. Furthermore, the RF core 122 includes an intensity detector E1 and a phase detector E2. The intensity detector E1 measures the strength of the received signal. The intensity detector E1 outputs data indicating the detected strength to the BLE controller 123.

[0099] The phase detector E2 is a circuit that detects the phase angle of the received signal relative to the local oscillator's output signal, or the received phase, when receiving a CW signal. The phase angle of the received signal relative to the local oscillator's output signal corresponds to the received phase. Specifically, the received phase can be understood as the output value of the inverse tangent of the ratio of the Q (quadrature-phase) component to the I (in-phase) component of the received signal as the input value. The magnitude of the I component corresponds to the strength of the received signal's in-phase component. The magnitude of the Q component corresponds to the strength of the received signal's quadrature component. The I component is obtained by multiplying the received signal by the carrier wave output by the local oscillator. The Q component is obtained by multiplying the received signal by a phase-shifted signal obtained by shifting the phase of the local oscillator's output signal by 90°. The phase-shifted signal can be obtained by passing the local oscillator's output signal through a circuit that shifts its phase by 90°, namely, a phase shift circuit.

[0100] Furthermore, a local oscillator (LO) is a circuit that generates a sine or cosine wave at the transmission frequency. This LO can be implemented using a voltage-controlled oscillator (VCO). The receive phase can also be determined based on the IQ signal, which has been frequency-downgraded to baseband. The detected receive phase information is used to calculate the device distance.

[0101] The RF core 122 associates the detected value of the CW signal's reception phase with information indicating the frequency in use (e.g., the channel number) and provides it to the BLE controller 123. Whenever the frequency in use switches, the RF core 122 transmits the CW signal and detects the reception phase as part of the ranging process. In other words, it provides the BLE controller 123 with data indicating the reception phase for each frequency.

[0102] The BLE controller 123 is a microcomputer that controls the RF core 122 . The BLE controller 123 includes a processor 124 , a memory 125 , a storage 126 , and an input / output circuit 127 . Figure 4 "I / O" in this context refers to input / output circuits. The BLE controller 123 controls data exchange with the DK-ECU 1. Specifically, the BLE controller 123 provides receive data from the RF core 122 to the DK-ECU 1 sequentially or upon request from the DK-ECU 1. Furthermore, the BLE controller 123 outputs transmit data from the DK-ECU 1 to the RF core 122.

[0103] The BLE controller 123 includes a CS ranging unit F1, a reception strength acquisition unit F2, an activation unit F3, and a report processing unit F4. Each of the CS ranging unit F1, the reception strength acquisition unit F2, the activation unit F3, and the report processing unit F4 can be a software module or a hardware module. The following description of the CS ranging unit F1, the reception strength acquisition unit F2, the activation unit F3, and the report processing unit F4 can be appropriately replaced with the BLE module 12 or the BLE controller 123.

[0104] The CS ranging unit F1 is a functional unit that performs CS ranging. CS ranging here refers to the process of generating distance data representing the device distance based on a distance-related value, a parameter representing the length of the wireless signal propagation path to the portable device 9. CS ranging includes the process of performing bidirectional or unidirectional communication with the portable device 9 to obtain the distance-related value. CS ranging can also be referred to as High Accuracy Distance Measurement (HADM) or phase difference ranging. In this disclosure, the series of processes including the communication used for CS ranging are sometimes also described as CS ranging processing. The CS ranging processing is equivalent to the first ranging processing.

[0105] The distance-related value can be any parameter that takes a value corresponding to the propagation time of the wireless signal, in other words, the flight time. The reception phase of the signal sent from the portable device 9 is equivalent to the distance-related value. The distance-related value can also be the arrival time of the wireless signal sent by the portable device 9. The arrival time of the wireless signal can be RTT instead. These distance-related values are parameters different from the reception strength. As a CS ranging process, the CS ranging unit F1 of this embodiment obtains the reception phase of each frequency and calculates the device distance based on the reception phase. The reception phase is the phase difference between the CW signal sent by the portable device 9 and the CW signal received by the BLE module 12. The reception phase can be called the transmission and reception phase difference, the single-frequency phase difference, or the primary phase difference.

[0106] The CS ranging unit F1 acquires the reception phase for each frequency using a unidirectional method. The unidirectional method assumes that the initial phase of the CW signal for each frequency transmitted from the portable device 9 is constant, and uses the reception phase of the CW signal transmitted from the portable device 9 as the basis for calculating the inter-frequency phase difference. Furthermore, the reception phase used as the basis for calculating the inter-frequency phase difference (in other words, the single-frequency phase difference) can also be acquired using other methods, such as a passive bidirectional method or an active bidirectional method. Passive and active bidirectional methods will be discussed in detail later.

[0107] Figure 5 This flowchart shows an example of CS ranging processing, including steps S101 to S111. The CS ranging process includes a preparation phase for adjusting ranging conditions, a collection phase for collecting reception phases by actually transmitting and receiving CW signals, and a calculation phase for calculating distance based on the collected reception phases for each frequency. In this disclosure, wireless communications used to obtain distance-related values, such as the transmission and reception of CW signals, are also referred to as ranging communications.

[0108] Step S101 is a step in which the BLE module 12 transmits a CS ranging start request to the portable device 9. The CS ranging start request is a BLE signal requesting the start of CS ranging. The CS ranging start request can be transmitted using a data channel. Upon receipt of the CS ranging start request, the portable device 9 returns a positive response signal (so-called Ack) to the BLE module 12 (S102).

[0109] The BLE controller 123 sends a ranging setting notification signal (S103) based on the Ack of the start request for CS ranging received from the portable device 9. The ranging setting notification signal is a BLE signal that indicates various factors involved in the implementation of the communication for CS ranging. The various factors involved in the implementation of the ranging communication may include the setting value of the initial phase, the hopping interval, the channel shift amount, and part or all of the initial frequency. The setting value of the initial phase is basically set to 0. The hopping interval indicates the time for switching frequencies, in other words, the time for maintaining one frequency. The hopping interval can also be the same as the connection interval used for data communication. The channel shift amount is a parameter that indicates the amount of change in the channel when switching channels. The channel shift amount can also be the same value as the hopping increment (hopIncrement) during data communication. In other words, the channel shift amount in CS ranging can also be determined by the hopping increment. The initial frequency is the frequency of the CW signal initially sent in a series of ranging communications. The initial frequency can be determined randomly. The frequency information can be represented by the channel number.

[0110] Upon receiving the ranging setup notification signal, the portable device 9 returns an Ack to the BLE module 12 (S104). Upon receiving the Ack from the portable device 9, the BLE module 12 transitions to a state capable of receiving signals of the initial frequency (S105). The state capable of receiving wireless signals can also be referred to as a receiving state or a scanning state.

[0111] After returning the Ack, the portable device 9 starts sending the CW signal at the initial frequency at a predetermined time (S106). The transmission of the CW signal can be stopped at a predetermined time after the start of the transmission. The time for continuously sending the CW signal, i.e., the CW transmission time, can be set to be shorter than the frequency hopping interval. In addition, the portable device 9 can also start sending the CW signal based on the situation that a CW transmission request is received from the BLE module 12 after receiving the ranging setting notification signal. The CW transmission request is a BLE signal requesting the transmission of the CW signal.

[0112] Upon receiving a CW signal from the portable device 9, the BLE module 12 detects the received phase and stores the received phase data along with the frequency information (e.g., channel number) in the memory 125 (S107). In step S103, the BLE module 12 and the portable device 9 automatically switch the frequency to be used at the pre-agreed frequency hopping interval (S108). The changed frequency can be uniquely determined based on the pre-agreed frequency and the pre-agreed channel shift amount. The changed channel can be a channel numbered by adding the pre-agreed channel number to the frequency hopping increment setting.

[0113] When the portable device 9 switches the channel, it transmits a CW signal of the new channel (S109). When the channel is switched, the BLE module 12 also transitions to a state where it can receive signals from the new channel. Furthermore, the BLE module 12 observes the reception phase at the switched frequency (S110).

[0114] The BLE module 12 and the portable device 9 repeatedly perform steps S108 to S110 until the receiving phases of all channels (0 to 36 Ch) that can be used for data communication are collected. In addition, the BLE module 12 and the portable device 9 may also end the repetitive processing at the timing when the receiving phases of each channel of the predetermined required number can be collected. The required number here may be the same as the number of data channels or smaller. The structure in which the required number is set to 37 is equivalent to the structure in which the receiving phases of all channels are collected. The more channels the receiving phases are collected, the higher the ranging accuracy described later. On the other hand, the time and power consumption required for ranging communication may increase. The required number may also be 3, 4, 5, 8, 10, 16, etc. The required number can be set to any value from 2 to 37. Of course, if the number of data channels is 37 or more, the required number can take a value greater than 37.

[0115] The BLE module 12 sends a ranging end notification signal (S111) toward the portable device 9 at a timing when the required number of reception phases of each frequency can be collected. The ranging end notification signal is a data signal used to notify the end of ranging communication. The portable device 9 switches to the normal data communication mode based on the receipt of the ranging end notification signal. The normal data communication mode is equivalent to a state in which specified data such as voice data can be sent and received. The sending and receiving of the ranging end notification signal is an optional element and can also be omitted. The portable device 9 can also return an Ack to the BLE module 12 based on the receipt of the ranging end notification signal.

[0116] Once the reception phase for each frequency has been collected, the CS ranging unit F1 calculates the phase variation coefficient (α) in step S111. The phase variation coefficient is a parameter that indicates the degree to which the reception phase changes with frequency. The phase variation coefficient can also be referred to as the phase change degree, phase shift amount, or phase-frequency correlation coefficient.

[0117] The phase variation coefficient can be calculated based on the received phases observed at any two frequencies, namely the first frequency and the second frequency. Assume that the difference between the first frequency and the second frequency, namely the differential frequency, is Δf, and the difference between the received phases observed at the first frequency and the second frequency, namely the inter-frequency phase difference, is If the phase change coefficient is set to α, then we have In addition, the phase difference between frequencies The difference between the received phases observed at two different frequencies. The inter-frequency phase difference can be called a dual-frequency phase difference or a quadratic phase difference. The inter-frequency phase difference corresponds to the amount of phase angle shift caused by a change in the operating frequency.

[0118] The CS ranging unit F1 of this embodiment calculates a regression line representing the relationship between frequency and reception phase based on the reception phase of each frequency, and adopts the slope of the regression line as the phase change coefficient. This is because the slope of the regression line represents the change in the displacement of the reception phase relative to the frequency. The regression line and its slope can be calculated by any method such as the least squares method. Assuming that the regression line is represented by y=a·x+b, the coefficient a of x is equivalent to the slope of the regression line. That is, the CS ranging unit F1 can calculate the coefficient (a) as the phase change coefficient (α). According to this structure, the phase change coefficient can be calculated based on the inter-frequency phase difference and differential frequency of each combination of multiple frequencies. In addition, "x" in the above formula is a variable corresponding to the frequency, and "y" is a variable corresponding to the reception phase. The regression line can also be said to be an approximate straight line.

[0119] The CS ranging unit F1 can also temporarily calculate a first regression line based on all the observed received phase data, and after excluding values (so-called outliers) that are at a distance greater than a specified value from the temporarily calculated first regression line, recalculate a second regression line. In this case, the CS ranging unit F1 can also use the slope of the second regression line as the phase variation coefficient. In this way, the phase variation coefficient used for distance calculation can also be determined based on the overall regression line using the data after excluding the outliers. According to this structure, the accuracy of the inter-frequency phase difference can be improved, thereby improving the ranging accuracy.

[0120] In addition, the CS ranging unit F1 may calculate the inter-frequency phase difference for each combination of frequencies where the reception phase can be observed. Differential frequency (Δf) and phase variation coefficient: The CS distance measuring unit F1 may use the average value or median value of the phase difference variation coefficient for each frequency combination as the phase difference variation coefficient for distance calculation.

[0121] Step S112 is a step in which the CS ranging unit F1 calculates the device distance (D) using the phase difference variation coefficient generated based on the received phase information at multiple frequencies. If the device distance is D, then the phase difference between the differential frequency Δf and the frequency is Between, there is The parameter "C" in the above formula represents the propagation speed of radio waves (3×10^8m / sec). The CS ranging unit F1 calculates the device distance based on this relationship. The CS ranging unit F1 uses Formula 1: D=k·C·α / 2π to calculate the device distance. The parameter k that constitutes Formula 1 is a design value and is set to 1.0 and 0.5. The value of k can be determined based on whether the transmit and receive phase difference is calculated as a one-way phase change coefficient or as a round-trip phase change coefficient. The CS ranging unit F1 saves the calculated device distance data in the memory 125. In the present disclosure, the communication distance calculated by the BLE module 12 in the CS ranging process is referred to as the first distance. The first distance can also be referred to as the CS ranging value.

[0122] As another method, the CS distance measuring unit F1 may use Δf, The temporary value (d) of the device distance is calculated, and the average value or the median value is used as the device distance in the antenna. The temporary value (d) of the device distance in a certain frequency combination can be used Wait to calculate.

[0123] In addition, Figure 5 The steps executed by the BLE module 12 in the series of processes shown are performed through the collaboration of the CS ranging unit F1 and the RF core 122. The above example shows that the BLE module 12 determines and notifies the implementation conditions involved in CS ranging, but is not limited to this. Alternatively, the portable device 9 may determine the various factors involved in implementing ranging communication and transmit the ranging setting notification signal, rather than the BLE module 12. Furthermore, the execution entity of each step can be interchangeable. The above steps can also be performed using the portable device 9 as the main body (in other words, as the master device).

[0124] The reception strength acquisition unit F2 is a structure that obtains data indicating the reception strength of signals from the portable device 9 at each frequency from the RF core 122. While the BLE module 12 is in communication with the portable device 9, it periodically transmits and receives data signals for communication confirmation. The reception strength acquisition unit F2 obtains reception strength data when the data signals for communication confirmation are received. Furthermore, communication for communication confirmation can be performed at connection intervals. Communication for communication confirmation can also be performed each time a channel hop is performed. The connection interval corresponds to the first interval.

[0125] Furthermore, the signal used to detect reception strength is not limited to a data signal used for communication confirmation. It can be a normal data signal or an advertising signal. Unless otherwise specified, the reception strength hereafter can be understood as the reception strength of the signal transmitted from the portable device 9.

[0126] The activation unit F3 is a software / hardware module that activates the main controller 11 when the first distance calculated during the CS ranging process is less than a specified value (hereinafter referred to as the activation distance). If the first distance remains less than the activation distance for a specified time or a specified number of times, the activation unit F3 sends an activation signal to the main controller 11. The activation signal is used to activate the main controller 11.

[0127] The term "startup" here refers to switching from power-saving mode to normal mode. Startup can be translated as recovery, validation, activation, or awakening. The main controller 11 can also be started in cooperation with the power supply circuit 14. The starter F3 can also output a control signal to the power supply circuit 14 for starting the main controller 11, which then receives the control signal and starts the main controller 11. Furthermore, switching from normal mode to power-saving mode can be translated as sleep mode, shutdown mode, or the like. The power-saving mode state can also be referred to as a sleep state.

[0128] The activation distance can be set to any value, such as 2.5m, 3.0m, 5.0m, or 6.0m. The smaller the activation distance, the less frequently the main controller 11 is activated, and the more power consumption can be suppressed. On the other hand, the smaller the activation distance, the later the system activation occurs relative to the user's approach. Therefore, if the user runs, the system may not activate in time, potentially impairing user convenience.

[0129] The report processing unit F4 transmits the reception intensity data indicating the reception intensity acquired by the reception intensity acquisition unit F2 and the first distance data indicating the first distance calculated by the CS ranging unit F1 to the main controller 11. While the main controller 11 is operating in normal mode, the various data may be transmitted periodically. The report processing unit F4 may also transmit various data based on a request from the main controller 11.

[0130] Furthermore, while the main controller 11 is in power-saving mode and communicating with the portable device 9, the BLE module 12 periodically performs CS ranging processing. On the other hand, after the main controller 11 returns to normal mode, the BLE module 12 stops performing periodic CS ranging processing. Of course, the BLE module 12 may also continue performing periodic CS ranging processing after the main controller 11 returns to normal mode. The BLE module 12 may also be configured to perform CS ranging processing only when a determination event occurs while the main controller 11 is in normal mode.

[0131] <Functions of the main controller>

[0132] like Figure 6As shown, the main controller 11 includes a communication system control unit G1 and a position determination unit G2 as functional modules. Each functional module is activated in normal mode. The communication system control unit G1 is a software / hardware module that controls the respective operations of the BLE module 12 and the UWB module 2. When the communication system control unit G1 detects the occurrence of a determination event, in other words, a specified user action, it causes the BLE module 12 to perform CS ranging processing. As described above, the occurrence of a determination event can also be detected by the body ECU 3, or it can be detected by the main controller 11 based on signals input from various sensors and ECUs.

[0133] Furthermore, the communication system control unit G1 performs a roving measurement process, which causes each of the multiple UWB modules 2 to sequentially perform UWB ranging. In normal mode, the communication system control unit G1 periodically performs the roving measurement process. The communication system control unit G1 may also dynamically change the roving measurement interval, or the roving measurement interval, based on the device distance values and vehicle Hv status observed within a recent predetermined period. The communication system control unit G1 may also perform the roving measurement process upon detecting the occurrence of a determination event.

[0134] The position determination unit G2 determines the device location based on the second distance of each UWB module 2 obtained as a result of the round-trip measurement process. The device location is the position of the portable device 9 relative to the vehicle Hv. The device location can be represented by multiple predefined areas / divisions for the vehicle Hv, such as the vehicle interior, nearby area, intermediate area, and distant area. The vehicle interior refers to the interior of the vehicle cabin. The vehicle interior can also include the interior of the trunk. The vehicle interior can also be divided into the interior of the vehicle cabin and the interior of the trunk.

[0135] The proximity zone is an area outside the vehicle Hv whose distance from the vehicle Hv is less than a predetermined proximity determination value. The proximity determination value is a parameter defining the proximity zone outside the vehicle. The proximity determination value is set to values such as 1.0m, 1.5m, and 2m. The proximity zone can be understood as an area where automatic unlocking / locking of the vehicle Hv can be performed. The proximity zone can also be referred to as a passive entry zone.

[0136] The distant area is an area whose distance from the vehicle Hv is greater than a prescribed distant judgment value. The distant judgment value is a parameter used to determine that there is no portable device 9 around the vehicle Hv. The distant judgment value is set to a value such as 5.0m, 6.0m, 10m, 12m, etc. The intermediate area is an area between the distant area and the nearby area. The intermediate area can also be a so-called welcome area that receives the entry of the portable device 9 into the area and performs prescribed welcome controls such as lighting of the exterior lighting. The intermediate area can also be an area that executes / starts prescribed controls that are not executed when the portable device 9 is far outside the vehicle, such as authentication based on wireless communication with the portable device 9, tracking of the device location, shortening of the location judgment cycle, etc. The intermediate area can also be called a waiting area, a peripheral area, etc. In addition, the intermediate area can also be an area where the user can use the function of parking / unparking the vehicle Hv through remote operation.

[0137] The aforementioned nearby area, middle area, and distant area are areas that subdivide the area outside the vehicle. The position determination unit G2 may also only determine whether the portable device 9 is present in the vehicle. In addition, the position determination unit G2 not only determines the distance from the vehicle Hv to the portable device 9, but also determines the direction in which the device exists. The direction in which the device exists refers to the direction in which the portable device 9 is located when viewed from the vehicle Hv / anchor point inside the vehicle. The direction in which the device exists can be represented by right, left, rear, front, etc. The nearby area may also be divided into the right area, the left area, and the rear area. The right area is the range outside the vehicle that is smaller than the nearby determination value from the right door handle or the right B-pillar. The left area and the rear area may also be defined based on a specific part of the vehicle Hv. The middle area may also be subdivided into front, back, left, and right in the same way as the nearby area.

[0138] As described above, the position determination unit G2 of this embodiment determines the area where the portable device 9 is located, i.e., the stay area. Alternatively, the position determination unit G2 may calculate the device location coordinates instead of determining the stay area or in conjunction with it. The device location coordinates refer to the location coordinates of the portable device 9 in a two-dimensional or three-dimensional coordinate system based on the predetermined position of the vehicle Hv. The device location coordinates can be calculated using the same methods as three-point positioning or multi-point positioning in the field of GPS and position estimation.

[0139] The main controller 11 transmits device position data, representing the determination result of the device position, to a predetermined ECU, such as the body ECU 3. The main controller 11 may also periodically generate device position data during normal mode. Furthermore, the main controller 11 may generate device position data by performing a roving measurement process in response to the occurrence of a determination event.

[0140] <DK-ECU Operation Example>

[0141] During the period when the main controller 11 is in the power saving mode, Figure 7 As shown, the BLE module 12 periodically implements the startup determination process (S11). The startup determination process is a process for determining whether the startup conditions of the main controller 11 are met. The startup conditions include the case where the first distance is less than the startup distance. Therefore, the startup determination process includes the CS ranging process. The startup conditions may also include the case where the reception intensity from the portable device 9 observed by the BLE module 12 is above a specified intensity threshold. In this case, the startup determination process may include a process for measuring the reception intensity of the advertising signal or data signal from the portable device 9. The startup conditions may include a variety of items related to the communication status of the portable device 9. Items related to the communication status refer to the reception intensity, device distance, degree of deviation of the reception intensity within a certain time, feasibility of the communication connection, and SN ratio, etc. The startup determination process can be appropriately designed to include a process for collecting the value / data of each item constituting the startup condition.

[0142] If the startup conditions are met (S12 is yes), the BLE module 12 returns to normal mode (S13) by sending a startup signal to the main controller 11. If the various data related to the communication status of the portable device 9 collected during the startup determination process do not meet the startup conditions (S12 is no), the BLE module 12 performs the startup determination process again after a specified standby time. In addition, the startup determination process can also be implemented each time an advertisement / data signal is received from the portable device 9. The startup determination process can also be implemented in parallel with processes such as communication connection and data communication.

[0143] In addition, during the normal mode, Figure 8 As shown, the main controller 11 regularly performs the stop determination process (S21). In addition, the stop determination process may be performed by a user operation of turning off the power supply for driving, a locking operation of the vehicle door, or the like as a trigger.

[0144] The stop determination process is a process for determining whether the stop condition of the main controller 11 is satisfied. The stop condition includes a case where the vehicle Hv is locked while the driving power source is disconnected. The stop condition may also include a case where the minimum value of a plurality of second distances collected in the patrol measurement process is greater than a prescribed stop distance. The stop distance can be set to 10m, 15m, etc. In addition, the stop condition may also include a case where the state where the reception intensity is less than the prescribed stop intensity continues for a prescribed time. The stop condition may also include a plurality of items related to the communication status of the portable device 9. The stop determination process can be appropriately designed to include a step for collecting the value / data of each item constituting the start condition.

[0145] If the stop condition is met (S22: Yes), the main controller 11 performs a predetermined stop preparation process and then transitions to the power saving mode (S23). The stop preparation process may include saving the current vehicle state in the memory 113, notifying the BLE module 12 of the subsequent transition to the power saving mode, etc. If the various data related to the communication status of the portable device 9 collected during the stop determination process does not meet the stop condition (S22: No), the main controller 11 performs the stop determination process after a predetermined standby time has passed.

[0146] Figure 9 This is a flowchart showing a more specific example of the operation of the DK-ECU 1 in a scenario where a user approaches the parked vehicle Hv. Figure 9 The flowchart shown in FIG. 1 shows the process until the main controller 11 returns to the normal mode from the power saving mode and performs the position determination process. For the sake of convenience, the series of processes involved in the startup of the main controller 11 and the position determination are referred to as user approach response processing. Figure 9 As shown, the user approach response process can include steps S201 to S210. When step S201 is executed, the main controller 11 is in the power saving mode. In addition, the portable device 9 is sufficiently far away from the vehicle Hv, and the portable device 9 and the BLE module 12 are not connected.

[0147] Step S201 is a step in which the BLE controller 123 determines whether a communication connection with the portable device 9 has been established. If a communication connection with the portable device 9 has been established (Yes in S201), the BLE controller 123 begins periodic execution of CS ranging (S202). Periodic execution of CS ranging can continue until the communication connection with the portable device 9 is severed or the main controller 11 is activated.

[0148] Step S203 is a step of determining whether the device distance (ie, the first distance) obtained by CS ranging is less than the activation distance. Step S203 is performed each time CS ranging is performed. Figure 9 "D1" in the figure represents the first distance. "ThD1" represents the activation distance. The first distance used for comparison with the activation distance, in other words, for determining whether to activate the main controller 11, may be the latest calculated value.

[0149] If the first distance is less than the activation distance (Yes in S203), the BLE controller 123, acting as the activation unit F3, activates the main controller 11 (S204). Based on the activation of the main controller 11, the BLE controller 123 stops executing the periodic CS ranging process (S205). Steps S201 to S203 correspond to the activation determination process described above.

[0150] Furthermore, the first distance used to determine whether to activate the main controller 11 may be an average value or median value of the first distances observed within a recent predetermined period, i.e., a moving average value or a moving median value. By activating the main controller 11 based on the moving average or median value of the first distance being above the activation threshold, the possibility of unnecessary activation of the main controller 11 can be further reduced.

[0151] Once the main controller 11 is activated, it transitions each UWB module 2 to a communication-capable state (S206). Furthermore, the main controller 11 begins periodic execution of the itinerant measurement process (S207). This periodic execution of the itinerant measurement process may continue until the vehicle Hv is powered on or the communication connection with the portable device 9 is terminated.

[0152] Furthermore, before executing the patrol measurement process, the main controller 11 may also transmit a UWB ranging start request to the portable device 9 via BLE. This allows the portable device 9 to activate the UWB module 94 and respond to the UWB signal from the vehicle Hv. The transmission of the UWB ranging start request may be omitted for any reason. In a configuration where the portable device 9 always activates the UWB module 94, the transmission of the UWB ranging start request may be omitted. The content of the preparatory processing for various ranging processes can be modified depending on the configuration of the portable device 9.

[0153] Step S208 is a step in which the main controller 11 collects second distance data as a result of the round-trip measurement process from each of the plurality of UWB modules 2. If the collection of the second distance data is completed, the main controller 11 executes step S209.

[0154] Step S209 is where the main controller 11 determines the device location based on the second distances observed by the multiple UWB modules 2. The device location can be determined using a variety of algorithms. For example, if the second distance observed by the in-vehicle anchor point 2A is less than a predetermined indoor threshold, the main controller 11 determines that the device location is inside the vehicle. The indoor threshold can be set to 1 meter, for example. Alternatively, if the second distance observed by the in-vehicle anchor point 2A is greater than a predetermined value, the main controller 11 determines that the device location is outside the vehicle.

[0155] The main controller 11 may also determine that the portable device 9 is located outside the vehicle if there is an outdoor unit that observes a second distance less than the proximity determination value, and the device is located in the nearby area. Alternatively, the main controller 11 may determine that the device is located in the intermediate area if there is no outdoor unit that observes a second distance less than the proximity determination value, and there is an outdoor unit that observes a second distance less than the distance determination value. Alternatively, the main controller 11 may determine that the device is located in the distant area if there is no outdoor unit that observes a second distance less than the distance determination value. Alternatively, the main controller 11 may determine that the portable device 9 is located on the left side of the vehicle if the UWB module 2 that observes the smallest second distance is the left anchor point 2C.

[0156] As described above, the main controller 11 may also calculate the device location coordinates by combining the second distances of multiple UWB modules 2. In a configuration in which the UWB module 2 reports location-related data to the DK-ECU 1, the main controller 11 may also determine the device location by combining the location-related data reported from each UWB module 2. Furthermore, the main controller 11 may also determine the device location using the reception intensity of the signal from the portable device 9 observed by the BLE module 12 and the UWB module 2. The main controller 11 may also determine that the device location is inside the vehicle when the reception intensity at the in-vehicle anchor point 2A is greater than the maximum value of the reception intensity observed by the outdoor unit by a specified value or more, and when the second distance observed at the in-vehicle anchor point 2A is within a specified value (e.g., 2 meters).

[0157] Once the device position determination is complete, the main controller 11 transmits device position data indicating the determination result to the body ECU 3. The body ECU 3 can execute predetermined controls such as unlocking / locking and powering on the vehicle Hv based on the device position data provided by the DK-ECU 1.

[0158] In addition, the above description describes a control mode in which the BLE module 12 stops performing periodic CS ranging after the main controller 11 is activated. However, the operation of the DK-ECU 1 is not limited thereto. The DK-ECU 1 may also continue performing periodic CS ranging after the main controller 11 is activated. Figure 10 This is a flowchart for explaining the operation of the DK-ECU 1 in this control mode. Figure 9 Step S204. Figure 10 Step S301 shown is a process after the main controller 11 is activated, and is a step in which the main controller 11 activates each UWB module 2. Step S302 is a step in which the main controller 11 starts regular execution of the patrol measurement process.

[0159] Step S303 is a step in which the BLE module 12 performs CS ranging at a timing when UWB ranging by the UWB module 2 is not being performed. The BLE module 12 can obtain the timing when UWB ranging by the UWB module 2 is not being performed from the host controller 11. Furthermore, after the host controller 11 is activated, the BLE module 12 can be configured to perform CS ranging based on an instruction from the host controller 11. Step S303 can be performed at predetermined intervals.

[0160] In step S304, the main controller 11 obtains the second distances from the multiple UWB modules 2 and the first distance from the BLE module 12. In step S305, the main controller 11, acting as the position determination unit G2, determines the device's position based on the first distance data and the multiple second distance data. In step S306, similar to step S210, the main controller 11 transmits the device's position determination result to the body ECU 3.

[0161] As described above, according to the configuration in which not only the second distance but also the first distance is used in determining the position of the device, an effect of improving the accuracy of position determination can be expected.

[0162] <Supplementation of UWB module for patrol measurement processing>

[0163] The above describes a configuration in which all UWB modules 2 are used for patrol measurement processing. However, it is not necessary to use all UWB modules 2. The main controller 11 may also be configured to divide multiple UWB modules 2 into unnecessary anchor points and useful anchor points based on the previous device position determination results, with unnecessary anchor points not being used for patrol measurement processing. Unnecessary anchor points are UWB modules 2 that do not perform UWB ranging processing during patrol measurement processing, in other words, UWB modules 2 that are inactive. Unnecessary anchor points can be referred to as invalid anchor points. Useful anchor points are UWB modules 2 that perform UWB ranging processing during patrol measurement processing. UWB modules 2 other than unnecessary anchor points are equivalent to useful anchor points. Useful anchor points can be referred to as valid anchor points.

[0164] Figure 11 This is a flowchart showing an example of the operation of the main controller 11 corresponding to the technical concept, including steps S401 to S403. Figure 11 The flowchart shown.

[0165] Step S401 is a step in which the main controller 11 refers to the previous device position determination result. Step S402 is a step in which the main controller 11 classifies each UWB module 2 as an unnecessary anchor point or a useful anchor point based on the device position information read in step S401.

[0166] like Figure 12As shown, if the main controller 11 determines that the portable device 9 is present in the left area of the vehicle Hv, it sets the right anchor point 2B as an unnecessary anchor point. Furthermore, if the main controller 11 determines that the portable device 9 is present on the right side of the vehicle Hv, it sets the left anchor point 2C as an unnecessary anchor point. In this way, the main controller 11 can set the outer anchor point on the side opposite to the device's presence direction as an unnecessary anchor point.

[0167] Furthermore, if the main controller 11 determines that the portable device 9 is outside the vehicle, the main controller 11 may set the vehicle interior anchor point 2A, which is the vehicle interior anchor point, as an unnecessary anchor point until the vehicle door / window is opened. Furthermore, if the main controller 11 determines that the portable device 9 is inside the vehicle, the main controller 11 may set the right side anchor point 2B, the left side anchor point 2C, and the rear side anchor point 2D, which are the exterior side anchor points, as unnecessary anchor points until the vehicle door / window is opened.

[0168] Data indicating the correspondence between device positions / device directions and unnecessary anchor points may be stored in advance in the memory 113 in the form of a data table or program. The main controller 11 can dynamically change the setting of unnecessary anchor points according to the device position / device direction based on the pre-registered data / program.

[0169] In one embodiment, the main controller 11 can be understood as a computer that deactivates the UWB module 2 located in a zone that is not required to be partitioned, as determined by the device's location. The exterior of the vehicle, opposite the direction in which the device is located, corresponds to the zone that is not required to be partitioned. If the portable device 9 is inside the vehicle, the exterior of the vehicle can correspond to the zone that is not required to be partitioned. If the portable device 9 is outside the vehicle, the interior of the vehicle can correspond to the zone that is not required to be partitioned.

[0170] If there is a UWB module 2 for which no anchor point setting is required, the main controller 11 stops the operation of the UWB module 2 (S403). The setting of no anchor point can also be updated after each round-trip search process. Alternatively, the setting of no anchor point can be reset after each round-trip search process is performed a predetermined number of times (e.g., three times). By resetting the setting of no anchor point after a predetermined number of times, the possibility of misjudging the device location due to the continued deactivation of some UWB modules 2 can be reduced.

[0171] <Startup determination processing>

[0172] like Figure 13 As shown, the BLE controller 123 may also be configured to initiate periodic CS ranging when the reception strength is above a predetermined value after establishing a communication connection with the portable device 9. In other words, the BLE controller 123 may also be configured to perform CS ranging processing based on the conditions that the communication connection with the portable device 9 is established and the reception strength is above a predetermined value.

[0173] Figure 13 This is a flowchart showing a control example corresponding to the technical concept, and includes steps S501 to S506. Figure 13 The flowchart shown can be used as Figure 9 That is, while the main controller 11 is in the power saving mode, step S501 can be executed periodically.

[0174] also, Figure 13 Step S501 shown is a step in which the BLE controller 123 determines whether a communication connection has been established with the portable device 9. If a communication connection has been established (Yes in S501), regular data communication with the portable device 9 and measurement of reception strength are started (S502). While the communication connection is maintained, regular data communication with the portable device 9 can continue. In addition, if the communication connection with the portable device 9 ends, the process restarts from step S501. As another embodiment, regular communication can also be the transmission and reception of advertising signals.

[0175] Step S503 is a step of determining whether the reception intensity of the data signal transmitted as regular data communication from the portable device 9 is a predetermined intensity threshold. Step S503 is executed each time regular communication is performed. Figure 13 "RSSI" in the figure represents the observed value of the received signal strength from the portable device 9. "ThRSSI" represents the strength threshold. The strength threshold is set to a value corresponding to the received signal strength observed when the device is at a specified distance (e.g., 10 meters). An ideal environment refers to a condition where there are no obstacles between the portable device 9 and the BLE module 12. The above strength threshold can be set through experiments or simulations.

[0176] The comparison with the intensity threshold in step S503, in other words, the reception intensity used to determine whether to perform CS ranging, can be the most recently observed value. Alternatively, the reception intensity used to determine whether to perform CS ranging can be the average or median value of the reception intensities observed within a recent specified period, i.e., a moving average or moving median value. This configuration reduces the possibility of unnecessary execution of CS ranging processing.

[0177] If the reception strength is above the strength threshold (Yes in S503), the BLE controller 123 begins periodic CS ranging (S504). Step S505 determines whether the most recent first distance obtained through the CS ranging process is less than the startup distance. This determination in step S505 is performed each time the CS ranging process is executed.

[0178] If the first distance is less than the start-up distance (Yes at S505), the BLE controller 123 starts the main controller 11 (S506). Figure 9 Steps S205 to S210 or Figure 10 Steps S301 to S306 are the same as those in Steps S501 to S505. Steps S501 to S505 also correspond to an example of the above-mentioned start determination process.

[0179] The above configuration reduces the likelihood of executing CS ranging processing in situations where reception strength is low, i.e., when the portable device 9 is likely to be far from the vehicle Hv. Naturally, reducing the frequency of executing CS ranging processing leads to reduced power consumption. The above configuration further reduces power consumption. Furthermore, in one embodiment, the strength threshold can also be understood as a parameter for initiating CS ranging.

[0180] And, as Figure 14 As shown, the BLE controller 123 may be configured to perform the CS ranging process under the condition that the communication connection with the portable device 9 is completed and the deviation of the reception intensity is smaller than a predetermined value. Figure 14 The “δ” in represents the degree of deviation of the received strength. Figure 14 The "Thδ" in represents a threshold value for the degree of deviation of the received strength. The degree of deviation of the received strength can be represented by the variance in statistics. Of course, the degree of deviation of the received strength can also be represented by the standard deviation or the difference between the maximum and minimum values.

[0181] also, Figure 14 Steps S601 to S602 and steps S604 to S606 shown are the same as steps S501 to S502 and steps S504 to S506 described above, so detailed descriptions are omitted. Step S603 is a step of determining whether the degree of deviation of the reception intensity observed within the most recent specified time is less than a specified threshold. When the degree of deviation of the reception intensity is less than the specified threshold (S603 is), the BLE controller 123 starts to perform periodic CS ranging processing. In other words, the BLE controller 123 can also be configured to not start the periodic execution of the CS ranging processing when the degree of deviation of the reception intensity is above the threshold.

[0182] Generally, when there is a wall or other object that blocks radio waves between the portable device 9 and the vehicle Hv, the deviation of the received signal strength becomes larger than when there is no wall or other object. In other words, a large deviation of the received signal indicates that the portable device 9 is likely to be inside a building such as a home or office. Of course, when the portable device 9, which is the key of the vehicle Hv, is inside a building, the possibility that the vehicle Hv is used by the user is also low. Therefore, the necessity of performing the CS ranging process itself is also low. Figure 14The control flow structure shown can reduce the likelihood of executing CS ranging processing when the portable device 9 is inside a building. This can further reduce power consumption during standby mode. Standby mode, as used herein, corresponds to a state where the vehicle Hv is parked. Furthermore, by reducing the frequency of unnecessary CS ranging processing, the possibility of unnecessary activation of the main controller 11 and the UWB module 2 can be reduced.

[0183] Of course, use Figure 13 as well as Figure 14 The technical concepts described above can be implemented in combination. The BLE controller 123 can also be configured to perform CS ranging processing based on the conditions that the communication connection with the portable device 9 is completed, the reception strength is above a specified value, and the deviation of the reception strength is less than a specified value. With this configuration, system malfunctions and power consumption can be further reduced.

[0184] In addition, the above description is based on the working example that the BLE module 12 is connected to the portable device 9 for communication. The communication connection between the BLE module 12 and the portable device 9 is not necessary. Figure 15 As shown, the BLE module 12 may sequentially detect the reception strength of a BLE signal such as an advertising signal periodically transmitted from the portable device 9 and execute the CS ranging process when the reception strength is equal to or greater than a strength threshold. Figure 15 Steps S701 to S704 shown are equivalent to steps S503 to S506 described above. Figure 15 The flowchart shown can be started when the main controller 11 changes from the normal mode to the power saving mode. In addition, while the main controller 11 is in the power saving mode, step S701 is executed at predetermined intervals. The first interval may also be an advertising interval.

[0185] Interaction between portable devices and in-vehicle systems

[0186] Here, the interaction between the portable device 9 and the in-vehicle system VS is described for each state. When the BLE module 12 begins CS ranging processing with the reception strength exceeding a specified value, the in-vehicle system VS can enter the first waiting state, the second waiting state, the third waiting state, and the position determination state as states corresponding to the device's location.

[0187] The first waiting state is a state in which no communication connection is established with the portable device 9. The first waiting state corresponds to a situation in which the portable device 9 is outside the communication range of the BLE module 12, in other words, a situation in which the portable device 9 is sufficiently far from the vehicle Hv. The first waiting state can be referred to as a connection waiting state.

[0188] In the first waiting state, if Figure 16As shown, the portable device 9 transmits advertising signals at intervals equal to the specified advertising interval plus a random time (the so-called advertising delay). Furthermore, the BLE module 12 enters a reception standby state at specified scanning intervals, searching for signals from the portable device 9. The size of the scanning window can be appropriately designed to correspond to the length of time the reception standby state is maintained.

[0189] The lengths of the scanning interval and advertising interval can also be set to a variety of values. It is preferable that the values of each interval be set to a value that allows for a quick connection as the user approaches the vehicle Hv. The advertising interval can be set to a value between 20 milliseconds and 400 milliseconds, such as 37.5 milliseconds, 50 milliseconds, 80 milliseconds, and 100 milliseconds. Of course, the advertising interval can also be set to a value exceeding 400 milliseconds within the range of the BLE standard. The advertising interval can also be set shorter than the scanning interval.

[0190] The second waiting state is a state where the portable device 9 and the BLE module 12 are in a communication connection state and the receiving strength is less than the strength threshold. The second waiting state can be said to be a strength determination state. In the second waiting state, the BLE module 12 does not implement CS ranging communication. In the second waiting state, Figure 17 As shown, the portable device 9 and the BLE module 12 periodically communicate data at a specified connection interval. The communication content can include various communication options, such as communication confirmation. The connection interval can be set to a value between 7.5 milliseconds and 200 milliseconds, such as 30 milliseconds and 40 milliseconds. The connection interval can also be set to a value exceeding 200 milliseconds within the range specified in the BLE standard.

[0191] The third waiting state corresponds to a state where the portable device 9 and the BLE module 12 are in a communication connection, the reception strength is less than the strength threshold, and the device distance is greater than the activation distance. In the third waiting state, the portable device 9 and the BLE module 12 regularly communicate data at a predetermined connection interval and also regularly communicate for CS ranging. The third waiting state can be referred to as a distance determination state.

[0192] The interval at which the BLE module 12 performs CS ranging communication, i.e., the CS ranging interval, can be set to 2 or 3 times the connection interval. Figure 18 As shown, it is preferable that the CS ranging interval is set longer than the connection interval. By making the CS ranging interval longer than the execution interval of regular data communication, it is possible to expect the effect of further suppressing power consumption. The CS ranging interval is equivalent to the second interval. In addition, Figure 18The "CS-Ranging Interval" in the figure represents the CS ranging interval. A single CS ranging communication can transmit and receive CW signals at multiple frequencies. A single CS ranging communication can also transmit and receive CW signals at a single frequency. The duration of a single CS ranging communication can be adjusted based on the length of the CW signal (tone).

[0193] In the first, second and third waiting states, the main controller 11 and the UWB module 2 maintain a dormant state. Figure 9 As described above, in a configuration in which reception intensity information is not used in activation determination by the main controller 11 or the like, the second waiting state can be omitted, and the first waiting state (connection waiting state) can be shifted to the third waiting state (distance determination state).

[0194] The position determination state is when the main controller 11 regularly performs patrol measurement processing. This state corresponds to the presence of the portable device 9 within the activation distance from the vehicle Hv (actually, the BLE module 12). In this state, the main controller 11 and the UWB module 2 are activated. In this state, the in-vehicle system VS and the portable device 9 regularly perform data communication using BLE and ranging communication using UWB, respectively. This state can be considered the system's operating state.

[0195] The interval at which the main controller 11 causes the UWB module 2 to perform UWB ranging communication, that is, the UWB ranging interval, can be set to 3 times, 4 times, etc., of the connection interval. Figure 19 As shown, it is preferable that the UWB ranging interval is set longer than the connection interval. By extending the UWB ranging interval, it is possible to further suppress the power consumption. Figure 19 The "UWB-Ranging Interval" in the figure represents the UWB ranging interval. One UWB ranging communication can include UWB ranging communications in multiple UWB modules 2. In other words, Figure 19 The UWB ranging communication shown may be a communication equivalent to a roving measurement process. The UWB ranging interval can also be referred to as the roving measurement interval. The UWB ranging interval can be set to a value between 150 and 400 milliseconds, such as 180 milliseconds or 280 milliseconds. The UWB ranging interval may also be longer than the CS ranging interval. Furthermore, the UWB ranging interval may be the same as or shorter than the CS ranging interval.

[0196] Summary of implementation methods

[0197] The signal of the 2.4GHz frequency band used in BLE is easily affected by reflective objects and the human body. Therefore, even if the distance is constant, the reception intensity is likely to deviate due to the way the user holds the portable device 9 and the surrounding environment. As a comparative structure, the developers of the present disclosure studied a structure that starts the main controller 11, etc. when the first distance is not used and the reception intensity is above a specified value. The threshold value for the reception intensity in the comparative structure is set to a value corresponding to the reception intensity observed when the device distance is 5.5m in an ideal environment. In addition, the description of the main controller 11, etc. refers to the main controller 11 and the UWB module 2.

[0198] When the system operation test was carried out in the above-mentioned comparative structure, when the user was holding the portable device 9, the main controller 11 and the like were sometimes activated when the device distance was 10m. In addition, when the user put the portable device 9 in the back pocket, the main controller 11 and the like were sometimes not activated until the device distance became 2.4m. Thus, in the comparative structure, there is a deviation in the area where the main controller 11 and the like are activated. When the main controller 11 is activated when the portable device 9 is far away from the vehicle, it will also lead to an increase in dark current. In addition, in the structure in which the main controller 11 is activated for the first time after the portable device 9 approaches the vicinity of the vehicle Hv, the user's convenience may be impaired.

[0199] Compared with such a comparative structure, in the above structure, whether to start the main controller 11 is determined not based on the reception strength, but based on the first distance determined based on the propagation time of the signal from the portable device 9. The first distance determined based on the propagation time of the signal has a smaller ranging error caused by the communication environment than the reception strength. In other words, the deviation in the distance measurement from the vehicle Hv to the portable device 9 is reduced. According to the structure of this embodiment, the possibility of unnecessarily starting the main controller 11 even though the portable device 9 is not actually present near the vehicle Hv can be reduced. Furthermore, the current consumption in standby mode can be reduced. In addition, according to the structure of this embodiment, the deviation of the area where the main controller 11 is started can be reduced, so the system operation can also be stabilized. Furthermore, the possibility of confusing the user due to malfunction of the system or delay in the operation of the system can also be reduced.

[0200] Furthermore, in the above configuration, after the main controller 11 is activated, the UWB module 2 is also activated. In other words, while the main controller 11 is in power-saving mode, the UWB module 2 is also inactive. The UWB module 2 can also remain inactive until the first distance falls below the activation distance. This reduces the activation frequency of the UWB module 2, further reducing power consumption. The above configuration can also be understood as a configuration in which the UWB module 2 transitions to a communication-capable state based on the first distance observed by the BLE module 12 falling below a specified value.

[0201] In addition, the above describes a structure in which the BLE module 12 indirectly activates the UWB module 2, but the present invention is not limited to this. The BLE module 12 may also send an activation signal to the UWB module 2 based on the CS ranging result being less than the activation distance. The activation order of the main controller 11 and the UWB module 2 may also be reversed. The BLE module 12 may also activate some or all of the UWB modules 2 based on the CS ranging result being less than the activation distance. Furthermore, the UWB module 2 or the BLE module 12 may also activate the main controller 11 based on the ranging result of at least one UWB module 2 being less than a specified value.

[0202] In addition, after startup, the main controller 11 can also cooperate with the body ECU 3 to perform welcome control such as lighting the welcome light and operating the air conditioning device. This structure is equivalent to a system in which the main controller 11 performs welcome control based on the situation that the first distance measured by the BLE module 12 in CS ranging is less than the startup distance. As mentioned above, the first distance determined by CS ranging represents the device distance with high precision compared to the receiving intensity. Therefore, the structure that performs welcome control based on the situation that the first distance is less than the specified value can reduce the possibility of unnecessary execution of well control compared to the structure that performs welcome control based on the situation that the receiving intensity is greater than the specified value. The main controller 11 and various devices such as the UWB module can become the target device. The target device can also be the body ECU 3, etc.

[0203] <Modification of system structure (1)>

[0204] In the above embodiment, the BLE module 12 is configured inside the housing of the DK-ECU 1, but the present invention is not limited thereto. Figure 20 As shown, the BLE module 12 can also be configured outside the housing of the DK-ECU 1. The BLE module 12 configured outside the housing works in a manner of starting the DK-ECU 1 based on the CS ranging result being less than the starting distance. Figure 20 The body ECU 3 and the like are omitted from the illustration.

[0205] <Modification of system structure (2)>

[0206] The in-vehicle system VS may also include a ranging module 12β as a BLE module in addition to the gateway module 12α. As described above, the gateway module 12α communicates with the portable device 9 even when the main controller 11 is in power-saving mode, and is responsible for activating the main controller 11 based on the CS ranging results. The gateway module 12α is equivalent to the BLE module 12 described so far. Figure 21The "BLE-GW" in the text represents a module in the vehicle-mounted module that performs BLE communication and functions as a gateway module 12α. "GW" is the abbreviation of Gateway. The expression "gateway module" can be replaced by "representative module" or "BLE-GW module". Figure 21 The body ECU 3 and the like are omitted from the illustration.

[0207] The distance measurement module 12β is a BLE module that functions as an anchor point and performs CS distance measurement processing based on an instruction from the main controller 11 . Figure 21 The "BLE-CS" in the figure represents the module used for CS ranging among the vehicle-mounted BLE modules. The term "ranging module" can be replaced with "BLE-CS module," "BLE anchor point," "CS anchor point," and so on. Ranging module 12β can be a BLE module dedicated to ranging. Ranging module 12β can also be a BLE module used only for ranging and receiving strength measurement. Furthermore, ranging module 12β can also perform a primary function of ranging and temporarily communicate data with portable device 9.

[0208] While the main controller 11 is in power-saving mode, the ranging module 12β stops operating. Alternatively, the ranging module 12β can be configured to intermittently activate and perform CS ranging processing even when the main controller 11 is in power-saving mode. The ranging module 12β can also be activated at the timing when the gateway module 12α performs CS ranging processing, eavesdropping on (sniffing / eavesdropping on) the CW signal transmitted from the portable device 9 and detecting the reception phase for each frequency.

[0209] Sniffing / eavesdropping is a technology in which a BLE module other than the gateway module 12α uses the channel information provided from the gateway module 12α to eavesdrop on the communication between the portable device 9 and the gateway module 12α. Channel information is information indicating the channel used for data communication between the gateway module 12α and the portable device 9 (hereinafter referred to as channel information). The channel information can also be a specific channel number or a parameter indicating the transfer rule of the used channel (the so-called frequency hopping increment). Preferably, the channel information includes the current used channel number and the frequency hopping increment. The channel information can also be expanded in each ranging module 12β via the main controller 11. In addition, the channel information can also be expanded in each ranging module 12β directly from the gateway module 12α, in other words, not via the main controller 11. In addition, the BLE module other than the gateway module 12α refers to the ranging module 12β.

[0210] In BLE, frequency hopping is performed after a communication connection is established, and usually only the gateway module 12α that is in communication connection can capture the data signal from the portable device 9. In contrast, according to the detection technology, since the channel information is expanded to each ranging module 12β, the ranging module 12β can also capture the data signal from the portable device 9. This is because the ranging module 12β can identify which channel among the multiple channels that can be used in BLE can receive the signal from the portable device 9 by referring to the channel information. In addition, as a result, the ranging module 12β can detect the reception strength, reception phase, reception time, etc. of the signal from the portable device 9 even if a communication connection is not established. Therefore, according to the structure that applies the detection technology, there is an advantage that multiple BLE modules can implement CS ranging processing in parallel.

[0211] In this disclosure, the BLE module disposed inside the housing of the DK-ECU 1 is referred to as a built-in module, and the BLE module disposed outside the housing is also referred to as an external module. Figure 21 In the embodiment, the case where the built-in module functions as the gateway module 12α is illustrated, but the present invention is not limited thereto. As described above, the gateway module 12α may also be an external module.

[0212] exist Figure 21 , a structure in which multiple external modules serving as distance measuring modules 12β are connected to the DK-ECU1 is shown. Multiple distance measuring modules 12β can be dispersedly arranged on the right side face, left side face, rear end, and part or all of the front end of the vehicle Hv. The BLE module can be arranged at the side of the vehicle at the B-pillar, C-pillar, side mirror, door handle, lower side sill, roof edge, etc. The BLE module can be arranged at the rear end of the vehicle at the inside of the rear bumper, near the license plate, at the top / bottom of the rear window glass, trunk door handle, etc. The BLE module can be arranged at the front end of the vehicle at the inside of the front bumper, front grille, at the top / bottom of the windshield, etc. Of course, the vehicle-mounted system VS can also have only one distance measuring module 12β.

[0213] If the in-vehicle system VS includes multiple ranging modules 12β, the position determination unit G2 may determine the device's location using the CS ranging results from the multiple ranging modules 12β. That is, the multiple UWB modules 2 may be omitted. The second communication unit may also be a ranging module 12β. Furthermore, the position determination unit G2 may determine the device's location using both the CS ranging results from the multiple ranging modules 12β and the UWB ranging results from the multiple UWB modules.

[0214] Furthermore, the position determination unit G2 may use the CS ranging results of the multiple ranging modules 12β to determine the approximate device location or device presence direction, and set no unnecessary anchor points based on the determination results. This configuration can reduce the number of UWB modules 2 that are activated after the main controller 11 is activated.

[0215] Supplementary information on the method for obtaining single-frequency phase difference

[0216] The BLE module 12 can also obtain the single-frequency phase difference of each frequency through an active two-way method or a passive two-way method, and use them to calculate the inter-frequency phase difference. Here, the overview of the active two-way method and the passive two-way method is described.

[0217] The active bidirectional method involves an initiator and a reflector transmitting and receiving CW signals to and from each other. Each device detects the phase difference between the transmitted and received signals and uses these differences to determine the single-frequency phase difference. The active bidirectional method involves the initiator and reflector transmitting and receiving CW signals to and from each other, and then transmitting the received phase (θr) observed by the reflector to the initiator.

[0218] The initiator is the device that starts communication, in other words, the device that requests a response. Furthermore, the reflector is the device that returns a response. In the above embodiment, the BLE module 12 is equivalent to the initiator, and the portable device 9 is equivalent to the reflector.

[0219] If the initial phase of the initiator is δi, the initial phase of the reflector is δr, and the single-frequency phase difference that should be observed corresponding to the one-way distance between the initiator and the reflector is Let the object frequency be f, then we have Based on this relationship, the average value of θi and θr becomes the single-frequency phase difference in which the initial phase components of the initiator and reflector are canceled. The active two-way method calculates the average of the received phase at the initiator and the received phase at the reflector as the single-frequency phase difference. Here, the phase difference due to one-way propagation is assumed, so the average of θi and θr is used as the single-frequency phase difference. Alternatively, if the phase difference due to round-trip propagation is assumed as the single-frequency phase difference, the single-frequency phase difference can be calculated as θi + θr.

[0220] The passive two-way method also involves an initiator and a reflector transmitting and receiving CW signals. Unlike the active two-way method, the reflector reflects the received phase of the CW signal sent from the initiator onto the initial phase of the transmitted signal before transmitting. When the received phase at the reflector is θr, a CW signal represented by z(t) = A·exp{-i(ωt+θr+2πn)} is transmitted. A represents the amplitude. Ω is the angular frequency corresponding to the target frequency (f), with the relationship ω = 2πf. N is a natural number corresponding to the interval between receiving the CW signal from the reflector and transmitting the CW signal. With this method, the received phase observed by the initiator does not include the initial phase component of the reflector. The received phase observed by the initiator is the same as when receiving a CW signal reflected from a reflective object such as a wall. As a result, the initiator can calculate the single-frequency phase difference without obtaining the received phase from the reflector. Compared to the active two-way method, the passive two-way method has the advantage that the reflector does not need to transmit receive phase information. As described above, single-frequency phase difference and inter-frequency phase difference can be performed in a variety of ways.

[0221] Modification of CS ranging

[0222] The BLE controller 123 can also use RTT instead of / in conjunction with the phase difference between frequencies to calculate the first distance. The RTT measured by the BLE controller 123 is the time from sending a specified BLE signal requesting a response to receiving a response signal from the portable device 9. RTT is also equivalent to a distance-related value. Sending and receiving a signal for measuring RTT is also equivalent to an example of CS ranging communication. Calculating the phase variation coefficient or RTT is equivalent to essentially calculating the device distance. Therefore, the process of generating data representing the device distance such as the phase variation coefficient or RTT based on the phase, flight time, or arrival time of the signal received from the portable device 9 is also included in the concept of the first ranging process. Calculating the distance also includes generating data that indirectly represents the distance.

[0223] <Targets of application of the present disclosure>

[0224] The above-described embodiments can be applied to a variety of vehicles traveling on roads. That is, the present disclosure can be applied to a variety of vehicles traveling on roads, including two-wheeled vehicles, three-wheeled vehicles, and other vehicles in addition to four-wheeled vehicles. Light motorcycles can also be included in two-wheeled vehicles.

[0225] The in-vehicle system VS may be configured such that, using multipoint technology, multiple in-vehicle BLE modules operate as hosts (master devices) of the portable device 9. Alternatively, multiple in-vehicle BLE modules may operate as slave devices (slave devices) of the portable device 9.

[0226] The communication method between the BLE module 12 and the portable device 9 is not limited to BLE, and may be Bluetooth Classic, etc. Wireless communication based on Bluetooth includes both communication based on Bluetooth Low Energy and communication based on Bluetooth Classic.

[0227] The communication standard used for distance measurement communication after the main controller 11 is activated is not limited to BLE and UWB, and may also be Wi-Fi (registered trademark), EnOcean (registered trademark), Zigbee (registered trademark), etc. In other words, the second communication unit may also be a communication module based on Wi-Fi or the like.

[0228] <Postscript (1)>

[0229] The present disclosure also includes the following technical ideas.

[0230] [Technical Thought 1]

[0231] A position determination device is a position determination device for determining the position of a portable device relative to a vehicle, comprising:

[0232] a first communication unit (12) for performing wireless communication with the portable device based on Bluetooth (registered trademark); and

[0233] A computer (11) performs processing related to determining the position of the portable device.

[0234] The computer has a normal mode and a power saving mode as states.

[0235] The first communication unit is configured to maintain a state in which communication with the portable device is possible even when the computer is in the power saving mode.

[0236] The first communication unit performs a first ranging process, wherein the first distance is calculated using data related to a reception phase, a flight time, or an arrival time of a wireless signal transmitted from the portable device, wherein the first distance is the distance from the first communication unit to the portable device.

[0237] The first communication unit compares the first distance obtained as a result of the first distance measurement process with a predetermined value, and causes the computer to shift from the power saving mode to the normal mode based on the comparison result.

[0238] [Technical Thought 2]

[0239] According to the position determination device described in technical idea 1,

[0240] The position determination device is used in connection with a second communication unit (2), wherein the second communication unit is arranged in the vehicle and is capable of wireless communication with the portable device.

[0241] The computer performs the following processing:

[0242] activating the second communication unit based on a return from the power saving mode to the normal mode;

[0243] causing the second communication unit to perform a second ranging process for calculating a second distance using data related to a reception phase, a flight time, or an arrival time of a wireless signal transmitted from the portable device, wherein the second distance is the distance from the second communication unit to the portable device; and

[0244] The position of the portable device is determined based on the second distance determined based on the result of the second distance measurement process.

[0245] [Technical Thought 3]

[0246] According to the position determination device described in technical idea 2,

[0247] The second communication unit is a communication module that implements ultra-wideband (UWB) communication.

[0248] The second distance measurement process includes: measuring the flight time of the wireless signal by transmitting and receiving a pulse signal used in UWB communication with the portable device; and calculating the second distance based on the measured flight time.

[0249] The second communication unit performs the second distance measurement process based on an instruction from the computer.

[0250] [Technical Thought 4]

[0251] The position determination device according to technical idea 2 or 3, wherein:

[0252] After the computer shifts to the normal mode, the computer causes the first communication unit to perform the first distance measurement process.

[0253] The position of the portable device is determined based on the first distance and the second distance.

[0254] [Technical Thought 5]

[0255] According to any one of technical ideas 2 to 4, the position determination device,

[0256] The position determination device is used in connection with a plurality of the second communication units.

[0257] The computer performs the following processing:

[0258] respectively obtaining the second distances from the plurality of second communication units;

[0259] determining a position of the portable device based on the second distance of each of the second communication units; and

[0260] The operation of some of the plurality of second communication units is stopped according to the determined position of the portable device.

[0261] [Technical Thought 6]

[0262] According to the position determination device described in technical idea 5,

[0263] The plurality of second communication units include a right communication unit (2B) disposed on the right side of the vehicle and a left communication unit (2C) disposed on the left side.

[0264] The computer stops the operation of the left communication unit when determining that the portable device is located on the right side of the vehicle, and stops the operation of the right communication unit when determining that the portable device is located on the left side of the vehicle.

[0265] [Technical Thought 7]

[0266] According to any one of technical ideas 1 to 6, the position determination device,

[0267] The first communication unit periodically receives a signal from the portable device at a first interval and obtains a reception strength of the received signal.

[0268] The first communication unit executes the first ranging process when the observed value of the reception intensity is equal to or greater than a predetermined intensity threshold.

[0269] [Technical Thought 8]

[0270] According to the position determination device described in technical idea 7,

[0271] The first communication unit compares the observed value of the reception intensity with a predetermined threshold value, and based on the comparison result, periodically performs the first ranging process at a second interval.

[0272] The second interval is set to be longer than the first interval.

[0273] [Technical Thought 9]

[0274] According to the position determination device described in technical idea 7 or 8,

[0275] When the computer is in the power saving mode and the communication connection with the portable device is not established, the first communication unit intermittently sends or scans a signal for establishing a communication connection with the portable device.

[0276] The first communication unit starts periodically receiving or transmitting a data signal based on the establishment of a communication connection with the portable device.

[0277] [Technical Thought 10]

[0278] According to any one of technical ideas 7 to 9, the position determination device,

[0279] The first communication unit stores the observed value of the reception intensity in a memory.

[0280] The first communication unit performs the first ranging process on the condition that a degree of variation in the reception intensity within a certain period of time is smaller than a predetermined value.

[0281] [Technical Thought 11]

[0282] According to any one of technical ideas 2 to 10, the position determination device,

[0283] The computer stops the first distance measurement process of the first communication unit based on the fact that the second communication unit has been activated.

[0284] <Postscript (2)>

[0285] The various flowcharts shown in this disclosure are examples, and the number of steps constituting the flowcharts and the order in which the processes are executed can be changed as appropriate. The descriptions of wireless signal / BLE signal / data / message / packet / frame / encapsulation / data set / information in this disclosure are interchangeable.

[0286] The devices, systems, and methods described in the present disclosure may also be implemented by a dedicated computer, which constitutes a processor programmed to execute one or more functions embodied by a computer program. The devices and methods described in the present disclosure may also be implemented using dedicated hardware logic circuits. The devices and methods described in the present disclosure may also be implemented by one or more dedicated computers, which are composed of a combination of a processor that executes a computer program and one or more hardware logic circuits. Part or all of the functions possessed by the BLE controller 123 may also be implemented as hardware. The method of implementing a function as hardware includes the method of using one or more ICs, etc. In addition to the CPU, the processor (computing core) may also be an MPU, GPU, DFP (Data Flow Processor), etc. Part or all of the functions possessed by the BLE controller 123 may also be implemented using any one of a system-on-chip (SoC), an IC (Integrated Circuit), and an FPGA (Field-Programmable Gate Array). The concept of IC also includes ASIC (Application Specific Integrated Circuit). Furthermore, a computer program may be stored as instructions executed by a computer on a non-transitory tangible storage medium that is readable by the computer. The recording medium for the program may be an HDD (Hard Disk Drive), an SSD (Solid State Drive), a flash memory, or the like. In the present disclosure, a program for causing a computer to function as the BLE controller 123 or the host controller 11, and a non-transitory physical recording medium such as a semiconductor memory storing the program, are also included within the scope of the present disclosure.

Claims

1. A position determination device for determining a position of a portable device relative to a vehicle, comprising: a first communication unit (12) for performing wireless communication with the portable device based on Bluetooth (registered trademark); and A computer (11) performs processing related to determining the position of the portable device. The computer has a normal mode and a power saving mode as states. The first communication unit is configured to maintain a state in which communication with the portable device is possible even when the computer is in the power saving mode. The first communication unit performs a first distance measurement process, wherein the first distance is calculated using data related to a reception phase, flight time, or arrival time of a wireless signal transmitted from the portable device. The first distance is the distance from the first communication unit to the portable device. The first communication unit compares the first distance obtained as a result of the first distance measurement process with a predetermined value, and causes the computer to shift from the power saving mode to the normal mode based on the comparison result.

2. The position determination device according to claim 1, wherein: The position determination device is used in connection with a second communication unit (2), wherein the second communication unit is arranged in the vehicle and is capable of wireless communication with the portable device. The computer performs the following processing: activating the second communication unit based on a return from the power saving mode to the normal mode; causing the second communication unit to perform a second ranging process for calculating a second distance using data related to a reception phase, a flight time, or an arrival time of a wireless signal transmitted from the portable device, wherein the second distance is the distance from the second communication unit to the portable device; and The position of the portable device is determined based on the second distance determined based on the result of the second distance measurement process.

3. The position determination device according to claim 2, wherein: The second communication unit is a communication module that implements ultra-wideband (UWB) communication. The second distance measurement process includes: measuring the flight time of the wireless signal by transmitting and receiving a pulse signal used in UWB communication with the portable device; and calculating the second distance based on the measured flight time. The second communication unit performs the second distance measurement process based on an instruction from the computer.

4. The position determination device according to claim 2 or 3, wherein: After the computer shifts to the normal mode, the computer causes the first communication unit to perform the first distance measurement process. The position of the portable device is determined based on the first distance and the second distance.

5. The position determination device according to claim 2, wherein: The position determination device is used in connection with a plurality of the second communication units. The computer performs the following processing: respectively obtaining the second distances from the plurality of second communication units; determining a position of the portable device based on the second distance of each of the second communication units; and The operation of some of the plurality of second communication units is stopped according to the determined position of the portable device.

6. The position determination device according to claim 5, wherein: The plurality of second communication units include a right communication unit (2B) disposed on the right side of the vehicle and a left communication unit (2C) disposed on the left side. The computer stops the operation of the left communication unit when determining that the portable device is located on the right side of the vehicle, and stops the operation of the right communication unit when determining that the portable device is located on the left side of the vehicle.

7. The position determination device according to claim 1, wherein: The first communication unit periodically receives a signal from the portable device at a first interval and obtains a reception strength of the received signal. The first communication unit executes the first ranging process when the observed value of the reception intensity is equal to or greater than a predetermined intensity threshold.

8. The position determination device according to claim 7, wherein: The first communication unit compares the observed value of the reception intensity with a predetermined threshold value, and periodically performs the first ranging process at a second interval based on the comparison result. The second interval is set to be longer than the first interval.

9. The position determination device according to claim 7, wherein: When the computer is in the power saving mode and the communication connection with the portable device is not established, the first communication unit intermittently sends or scans a signal for establishing a communication connection with the portable device. The first communication unit starts periodically receiving or transmitting a data signal based on the establishment of a communication connection with the portable device.

10. The position determination device according to claim 7, wherein: The first communication unit stores the observed value of the reception intensity in a memory. The first communication unit performs the first ranging process on the condition that a degree of variation in the reception intensity within a certain period of time is smaller than a predetermined value.

11. The position determination device according to claim 2, wherein: The computer stops the first distance measurement process of the first communication unit based on the fact that the second communication unit has been activated.

12. A position determination system comprising: a first communication unit (12) for performing wireless communication with a portable device based on Bluetooth; and a computer (11) for performing processing related to position determination of the portable device. The above-mentioned computer has a normal mode and a power saving mode as states. When the computer is in the power saving mode, the first communication unit performs a first distance measurement process, wherein the first distance is calculated using a reception phase, a flight time, or an arrival time of a wireless signal transmitted from the portable device. The first distance is the distance from the first communication unit to the portable device. The first communication unit compares the first distance obtained as a result of the first distance measurement process with a predetermined value, and restores the computer from the power saving mode to the normal mode based on the comparison result.

13. The position determination system according to claim 12, wherein: It also includes a plurality of second communication units (2), which are arranged at different positions of the vehicle and can communicate wirelessly with the portable device. The computer executes the following processing: activating the second communication unit based on a return from the power saving mode to the normal mode; and instructing the second communication unit to perform a second ranging process for calculating a second distance using data related to a reception phase, flight time, or arrival time of a wireless signal transmitted from the portable device, wherein the second distance is the distance from the second communication unit to the portable device; The second communication unit performs the following processing: performing the second ranging process based on an instruction from the computer; generating position-related data indicating the position of the portable device based on the second distance determined based on the result of the second distance measurement process; and Sending the generated location-related data to the computer, The computer determines the position of the portable device by integrating the position-related data received from the plurality of second communication units.

14. A wireless communication module for implementing wireless communication with a portable device based on Bluetooth, comprising: an antenna (121) for communicating with the portable device; and The communication controller (123) acquires data related to the reception phase, flight time, or arrival time of the wireless signal transmitted from the portable device based on the signal received by the antenna. The communication controller performs the following processing: maintaining a state of being able to communicate with the portable device even while the vehicle is parked, based on power from a battery mounted on the vehicle; A first distance measurement process is performed when the vehicle is parked, wherein the first distance is calculated using data related to the reception phase, the flight time, or the arrival time of the wireless signal, wherein: The first distance is the distance from the communication controller itself to the portable device; and The first distance obtained as a result of the first distance measurement process is compared with a predetermined value, and based on the comparison result, a signal for causing a predetermined target device mounted on the vehicle to shift from a power saving mode to a normal mode is output.

15. A computer program comprising instructions, The above command is used to cause the processor (901) of the portable device (9) to execute a process, wherein: The portable device comprises: a Bluetooth communication unit (93) for implementing wireless communication based on Bluetooth, and a UWB communication unit (94) for implementing ultra-wideband (UWB) communication. The above processing includes: establishing a Bluetooth-based communication connection with a vehicle based on receipt of a signal transmitted from a previously associated vehicle; returning a signal for the distance measurement process based on a request to start the first distance measurement process received from the vehicle, wherein the first distance measurement process is a distance measurement process based on Bluetooth communication; After returning the signal used for the above-mentioned ranging process, continuous wave signals of different frequencies are sequentially sent; activating the UWB communication unit when a request to start a second distance measurement process is received from the vehicle, the second distance measurement process being a distance measurement process based on UWB communication; and When a UWB signal for distance measurement is received from the vehicle, a UWB signal of a predetermined pattern is returned.

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