Position determination system and position determination method

Abstract

In the present invention, a smart ECU (2), in a situation in which a user device is disposed at a prescribed inner set position, generates a measured value by averaging the reception strengths of device signals observed by a plurality of inner anchors. The smart ECU (2) determines a correction value on the basis of the difference between the measured value and a reference value, which indicates the communication characteristics of a reference device registered in advance, and stores the correction value in a characteristic data storage unit. The smart ECU (2) uses the stored correction value to correct the reception strength observed in an actual communication and determines whether there is a portable device in a vehicle.

Description

Position determination system and position determination method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-144710 filed in Japan on September 6, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] TECHNICAL FIELD The present disclosure relates to techniques for determining the location of a mobile device relative to a vehicle.

[0003] Patent document 1 discloses a configuration for determining whether a portable device is inside a vehicle based on whether the received power (in other words, the received strength) of a signal transmitted from the portable device at an in-vehicle antenna is greater than a predetermined value.

[0004] Japanese Patent Application Laid-Open No. 2015-214316

[0005] In recent years, in-vehicle systems have been developed that allow general-purpose mobile devices such as smartphones to be used as vehicle keys. The in-vehicle systems communicate with the mobile devices via short-range wireless communication (hereinafter, referred to as SRWC). Here, SWRC refers to Bluetooth (registered trademark) Low Energy, Wi-Fi (registered trademark), or the like. The in-vehicle systems can determine the location of the mobile device based on the reception strength of the SWRC signal transmitted from the mobile device.

[0006] However, the transmission power and antenna configuration (i.e., directivity) of smartphones may differ depending on the model or type. The mobile device used by a user (hereinafter referred to as a user device) may differ from the reference device. The reference device here refers to a mobile device used by a manufacturer to set a reception strength threshold. A configuration that determines the location of a user device by comparing the reception strength of a signal from the user device with a threshold designed using the reference device may result in an erroneous determination of the location due to the communication characteristics of each mobile device.

[0007] The present disclosure has been made in light of the above circumstances, and one of its objectives is to provide a technology that can reduce the risk of erroneously determining the location of a mobile device.

[0008] The location determination system disclosed herein is an in-vehicle system comprising a communication device configured to be capable of wireless communication with a portable device used by a vehicle user using a predetermined communication method, and a control unit that determines the location of the portable device relative to the vehicle based on the reception strength of a signal received by the communication device from the portable device. The control unit comprises a threshold memory unit in which a threshold for reception strength for determining the location of the portable device, which threshold is registered and is designed based on the communication characteristics of a predetermined reference device, and a characteristic data memory unit for storing data indicating the communication characteristics of the portable device. The control unit is configured to acquire the reception strength from the communication device, generate characteristic data indicating the difference in communication characteristics between the portable device and the reference device based on the reception strength detected when the portable device is placed in a predetermined position, and store the generated characteristic data in the characteristic data memory unit, and determine the location of the portable device based on the characteristic data stored in the characteristic data memory unit, the reception strength detected by the communication device, and the threshold.

[0009] According to the above configuration, the location of the portable device is determined using characteristic data indicating the difference in communication characteristics between the portable device used by the user and the reference device, thereby reducing the risk of erroneous location determination due to differences in communication characteristics between the portable devices.

[0010] In addition, a location determination method included in the present disclosure includes acquiring the reception strength of a signal from a mobile device from a communication device configured to be able to perform wireless communication with the mobile device using a predetermined communication method, accessing a threshold memory unit in which a threshold for reception strength for determining the location of the mobile device, the threshold designed based on the communication characteristics of a predetermined reference device, is registered, and reading the threshold from the threshold memory unit, generating characteristic data indicating the communication characteristics of the mobile device based on the reception strength detected when the mobile device is placed at a predetermined location, storing the generated characteristic data in a characteristic data memory unit, and determining the location of the mobile device based on the characteristic data stored in the characteristic data memory unit, the reception strength detected by the communication device, and the threshold.

[0011] Note that the symbols in parentheses in the claims indicate a correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of the present disclosure.

[0012] FIG. 1 is a diagram showing an overall view of a vehicle electronic key system; FIG. 2 is a diagram showing an example of an anchor mounting position; FIG. 3 is a flowchart for explaining an outline of the operation of a smart ECU; FIG. 4 is a flowchart for explaining an outline of a position determination process; FIG. 5 is a functional block diagram of a smart ECU;

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments. The configurations disclosed below may be implemented with various modifications within the scope of the gist. Various modified examples may be implemented in appropriate combinations within the scope of no technical contradiction. The present disclosure also includes configurations that are not explicitly stated and are formed by combining multiple modified examples. In the following description, components having the same function may be assigned the same reference numerals, and specific descriptions thereof may be omitted. When only a portion of a configuration is mentioned, descriptions given elsewhere may apply to other parts.

[0014] <Overall Configuration> As shown in FIG. 1, the electronic key system for a vehicle according to this embodiment includes an in-vehicle system 1 and a user device 9. The in-vehicle system 1 is a system mounted on the vehicle Hv. The in-vehicle system 1 includes a smart ECU 2. ECU stands for Electronic Control Unit and refers to an electronic control device. In the following description, the in-vehicle system 1 and the vehicle Hv may be interpreted as interchangeable. The in-vehicle system 1 is a system that determines the position of the user device 9 and controls the locking state of the doors of the vehicle Hv based on the determination result. The in-vehicle system 1 corresponds to a position determination system.

[0015] The user device 9 is a wireless communication terminal (in other words, a portable device) carried by a user. The user device 9 is linked to the smart ECU 2. That is, device information of the user device 9 is registered in the smart ECU 2. The device information includes a device identification number (hereinafter, referred to as a device ID). The device ID may be a device address or a universally unique identifier (UUID), etc. The device information of multiple user devices 9 may be registered in the smart ECU 2.

[0016] Both the smart ECU 2 and the user device 9 include a short-range communication module. The short-range communication module is a communication module for enabling short-range communication. Here, short-range communication refers to communication conforming to a predetermined wireless communication standard with an actual communication distance of 5 m to 50 m, and at most 100 m. The short-range communication may be Bluetooth (registered trademark) Low Energy (hereinafter, Bluetooth LE) or Wi-Fi (registered trademark), etc. In the following description and drawings, short-range communication may be referred to as SRWC (Short Range Wireless Communication). Furthermore, in this disclosure, a signal transmitted and received via short-range communication may be referred to as a short-range communication signal or an SRWC signal. In particular, the SRWC signal transmitted from the user device 9 is also referred to as a device signal.

[0017] The following describes the operation of each part using an example in which short-range communication (i.e., SRWC) is Bluetooth LE. Furthermore, the user device 9 is configured to operate as a peripheral in Bluetooth LE, and the smart ECU 2 is configured to act as a central. The roles of the user device 9 and the smart ECU 2 may be interchanged. SRWC may be a communication method that can use multiple frequencies (in other words, channels). SRWC may be a communication method that incorporates channel hopping technology.

[0018] <In-Vehicle System> In addition to the smart ECU 2, the in-vehicle system 1 has other devices such as multiple anchors 3, an in-vehicle display 4, an input device 5, and a device detection unit 6. The smart ECU 2 is connected to each of the multiple anchors 3 via a dedicated communication cable. The smart ECU 2 is connected to the in-vehicle display 4, the input device 5, and the device detection unit 6 via an in-vehicle network. The in-vehicle network is a communication network established within the vehicle Hv. The standard of the in-vehicle network may be any standard, such as Controller Area Network (CAN is a registered trademark), Ethernet (registered trademark), or FlexRay (registered trademark). The connection configuration between devices may be changed as appropriate.

[0019] The smart ECU 2 is an ECU that determines the device position in cooperation with the anchor 3. As will be described later, the anchor 3 is a wireless communication module for performing ranging communication with the user device 9. Ranging communication in this disclosure refers to wireless communication for measuring the distance between communication devices based on the time of flight of a signal or phase information of a received signal.

[0020] The smart ECU 2 may have a function to execute vehicle control according to the determined device position. In the present disclosure, the device position means the relative position of the user device 9 with respect to the vehicle Hv. Determining the device position is equivalent to determining the user's position. The term "device position" may be read as "user position." The smart ECU 2 controls the operation of the anchor 3. Here, the vehicle control may be switching the locking state of the door (e.g., unlocking) or switching the vehicle power on / off.

[0021] The smart ECU 2 includes a processor 21, a memory 22, a storage 23, a wireless communication module 24, and an in-vehicle communication unit 25. The processor 21 may be a central processing unit (CPU) or a micro processing unit (MPU). The processor 21 corresponds to a control unit. The memory 22 may be a volatile storage medium such as a random access memory (RAM). The memory 22 may be a component for temporarily storing data received from other in-vehicle devices, calculation results by the processor 21, programs, etc. The storage 23 is a rewritable non-volatile memory. The storage 23 is realized by at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium. The storage 23 may include multiple types of storage media, such as a read-only memory (ROM) and a flash memory.

[0022] The storage 23 may store the device ID, anchor data, and authentication data of the user device 9. The anchor data is data indicating the mounting positions of multiple anchors 3 in the vehicle Hv. The authentication data may be data (e.g., a key code) for authenticating the user device 9.

[0023] The storage 23 stores a device response program executed by the processor 21. The device response program may be a program for realizing at least some of the functions of the smart ECU 2. Execution of the device response program by the processor 21 corresponds to execution of a location determination method.

[0024] The wireless communication module 24 is a short-range communication module built into the smart ECU 2. The wireless communication module 24 includes an antenna for the SRWC, a transmitting / receiving circuit, and an SRWC controller. The transmitting / receiving circuit is a circuit that performs signal processing related to modulation and demodulation. The SRWC controller is a microcomputer that executes data processing related to the SRWC.

[0025] The wireless communication module 24 receives power from the vehicle battery even when the running power supply is set to off. The wireless communication module 24 periodically scans using power supplied from the vehicle battery and attempts to connect with the user device 9. Scanning means becoming ready to receive an SRWC signal. Upon receiving an advertising signal from the user device 9, the wireless communication module 24 transmits a connection request to the user device 9 and establishes a communication connection with the user device 9. The wireless communication module 24 may be considered an SRWC module that functions as a gateway for the user device 9 to communicate and connect to the vehicle Hv. In the present disclosure, the wireless communication module 24 is also referred to as a gateway module. The wireless communication module 24 may be disposed outside the smart ECU 2.

[0026] The in-vehicle communication unit 25 is a circuit that allows the processor 21 to communicate with each of the multiple anchors 3. The in-vehicle communication unit 25 may also include a circuit that allows the processor 21 to communicate with other in-vehicle devices via an in-vehicle network. The in-vehicle communication unit 25 may include a PHY chip or the like that complies with the communication standard of the in-vehicle network.

[0027] The smart ECU 2 performs wireless authentication processing in the SRWC based on the establishment of a communication connection with the user device 9 using the wireless communication module 24. The wireless authentication processing is a process for authenticating (in other words, verifying) the user device 9 via wireless communication. The authentication may be performed by any method, such as a challenge-response method.

[0028] Upon establishing a communication connection with the user device 9, the smart ECU 2 causes each anchor 3 to perform ranging communication with the user device 9. The smart ECU 2 acquires data indicating the results of the ranging communication (hereinafter, ranging result data) from each of the multiple anchors 3. The ranging result data includes the ID of the user device 9 that performed the ranging, data indicating the distance from the anchor 3 to the user device 9, and the reception strength of the device signal. In this disclosure, the value indicating the distance from the anchor 3 to the user device 9, determined by ranging communication, may be referred to as a ranging value.

[0029] The smart ECU 2 determines whether the user device 9 is located inside the vehicle, in a nearby area, or in a far area based on the distance measurement values ​​and reception strength provided by each anchor 3. The nearby area is an area outside the vehicle that is within a predetermined distance (e.g., 1.5 m) from the vehicle Hv. The far area is an area outside the vehicle that is outside the nearby area. Details of the method for determining the device location will be described separately later.

[0030] The smart ECU 2 may be configured to calculate device position coordinates by combining distance measurements provided from multiple anchors 3. The device position coordinates refer to the position coordinates of the user device 9 in a two-dimensional / three-dimensional coordinate system based on a predetermined position of the vehicle Hv. The calculation of the device position coordinates can be performed using a method similar to three-point positioning or multi-point positioning in the technical fields of GPS and position estimation.

[0031] As described above, each anchor 3 is a device for performing ranging communication with the user device 9. The configuration and function of the anchor 3 may be similar to those of the wireless communication module 24. The anchor 3 is configured to be able to perform SWRC (i.e., Bluetooth LE). The anchor 3 includes an antenna, a transmitting / receiving circuit, and an SRWC controller for SWRC. Based on instructions from the smart ECU 2, the SRWC controller of the anchor 3 performs ranging communication with the user device 9, generates ranging result data, and transmits (reports) the ranging result data to the smart ECU 2.

[0032] The ranging method using Bluetooth LE may be CS (Channel Sounding) ranging. CS ranging is a method of measuring distance based on the difference in reception phase between channels, obtained by transmitting and receiving CW (Continuous Wave) signals over multiple channels. CS ranging is sometimes called High Accuracy Distance Measurement (HADM) or phase difference ranging. The anchor 3 may be configured to transmit and receive a continuous wave (CW) signal with a predetermined waveform as a ranging signal, in addition to a modulated signal for data communication. The waveform of the CW signal may be a sine wave or a triangular wave. Specific methods of CS ranging will be described later.

[0033] The ranging method may also be an RTT method, which calculates the distance based on the round trip time. In the RTT method, the user device 9 measures the elapsed time from transmitting a poll signal to the anchor 3 until receiving a response signal from the anchor 3 as the RTT. The user device 9 may calculate a distance measurement value from the RTT measured by performing ranging communication and transmit the calculated distance value to the smart ECU 2 using the SRWC. The poll signal is a signal that requests the responder to return a response. The response signal may be referred to as an answer signal.

[0034] In the ranging communication of this embodiment, the user device 9 operates as an initiator, and the anchor 3 operates as a responder. The initiator is a device that takes the lead in the ranging communication. The division of roles in the ranging communication may be changed as appropriate. Multiple anchors 3 may individually act as initiators and perform ranging communication with the user device 9.

[0035] The in-vehicle system 1 may include multiple anchors 3. As shown in FIG. 2 , the in-vehicle system 1 of this embodiment includes anchors 3a, 3b, 3c, 3p, and 3q. Anchor 3a is an anchor 3 built into the outer door handle for the right front seat. Anchor 3a may be arranged on the right B-pillar, right side mirror, right side sill, or the right edge of the roof. Anchor 3a may be referred to as a right anchor or a first anchor. Anchor 3b is an anchor 3 built into the outer door handle for the left front seat. Anchor 3b may be arranged on the left B-pillar, left side mirror, left side sill, or the left edge of the roof. Anchor 3b may be referred to as a left anchor or a second anchor. Anchor 3c is an anchor 3 arranged in the center of the rear bumper, the trunk door handle, or the upper or lower edge of the rear window. Anchor 3c may be referred to as a rear anchor or a third anchor.

[0036] Anchors 3p and 3q are anchors 3 arranged inside the vehicle. Anchor 3p is arranged forward of anchor 3q inside the vehicle cabin. Anchor 3p may be arranged on the instrument panel, the upper edge of the windshield, the center console, or the like. Anchor 3p may be referred to as a front interior anchor or a fourth anchor. Anchor 3q is an anchor 3 arranged rearward of anchor 3p inside the vehicle. Anchor 3q may be arranged in a rearward position, such as the center of the rear seat, the ceiling above the rear seat, or the trunk. Anchor 3q may be referred to as a rear interior anchor or a fifth anchor. The mounting locations of the anchors 3 disclosed herein are merely examples and may be changed as appropriate.

[0037] Anchors 3a to 3c are all attached to the exterior of the vehicle Hv, and therefore may be referred to as outdoor units or outer anchors. Anchors 3a to 3c correspond to outer communication devices. Anchors 3p and 3q are attached inside the vehicle, and therefore may be referred to as indoor units or inner anchors. Anchors 3p and 3q correspond to inner communication devices. The anchor 3 is activated in response to an instruction from the smart ECU 2 and performs ranging communication. The anchor 3 transitions to a power-saving state based on an instruction from the smart ECU 2. The power-saving state may be a state in which some or all functions are stopped to reduce power consumption. The wireless communication module 24 may also be used as the anchor 3. The wireless communication module 24 may be considered to be one of multiple inner anchors.

[0038] The in-vehicle display 4 is a display installed inside the vehicle. The in-vehicle display 4 displays an image in response to an instruction signal input from the smart ECU 2. The in-vehicle display 4 may be a liquid crystal display or an organic EL display. The in-vehicle display 4 may be configured to be able to display multiple colors.

[0039] The input device 5 is a device for receiving user instructions and operations for the in-vehicle system 1 (mainly the smart ECU 2). The input device 5 may be a touch panel stacked on the in-vehicle display 4. The user device 9 and the in-vehicle system 1 may be configured so that the user device 9 functions as the input device 5. The in-vehicle system 1 may include multiple types of devices as the input device 5.

[0040] The input device 5 outputs an operation signal, which is an electrical signal corresponding to a user operation, to the smart ECU 2. The operation signal includes information indicating the user's operation. The smart ECU 2 receives an instruction to register the communication characteristics of the user device 9 via the input device 5. In the present disclosure, a signal indicating that a registration operation for the communication characteristics of the user device 9 has been performed is also referred to as a registration instruction signal. Upon receiving the registration instruction signal, the smart ECU 2 may display a characteristic registration guide image (described below) on the in-vehicle display 4.

[0041] The device detector 6 is a device that detects whether the user device 9 is placed in a predetermined position (hereinafter referred to as an inner set position) inside the vehicle. The inner set position may be a holder for the user device 9 provided on the center console SC or on the instrument panel.

[0042] The device detection unit 6 may be a device that detects the user device 9 based on a communication connection with the user device 9 using a communication method with a communication distance of 0.1 m or less. The device detection unit 6 may be an NFC (Near Field Communication) module located at the inner set position. NFC here refers to communication with a communication distance of several centimeters to several tens of centimeters. Specific NFC standards may be ISO / IEC 18092 (NFCIP-1), ISO / IEC 21481 (NFCIP-2), ISO / IEC 14443, or ISO / IEC 18092. When the device detection unit 6 connects with the user device 9 via NFC, the smart ECU 2 may recognize that the user device 9 has been placed at the inner set position.

[0043] In another embodiment, the device detection unit 6 may be a wireless charger placed in the inner set position. When the wireless charger starts supplying power to the user device 9, the smart ECU 2 may recognize that the user device 9 has been placed in a predetermined position in the vehicle. The wireless charging method may be any method, such as Qi or AirFuel Inductive / Resonant. Conversely, the location in the vehicle where the wireless charger or NFC module is located may be set to the inner set position.

[0044] Alternatively, the device detection unit 6 may be a device that detects that the user device 9 has been placed in a predetermined position inside the vehicle by analyzing video from a camera capturing the interior of the vehicle. Such a device detection unit 6 outputs a signal indicating whether the user device 9 has been placed in the predetermined position inside the vehicle to the smart ECU 2. Note that the device detection unit 6 is an optional element and may be omitted. The device detection unit 6 may be considered a type of in-vehicle sensor.

[0045] In addition to the above, various other in-vehicle devices may be directly or indirectly connected to the smart ECU 2. For example, the smart ECU 2 is connected to a power supply ECU, a cellular module, and body-related equipment so that they can communicate with each other via an in-vehicle network or using dedicated cables. The power supply ECU is an ECU that controls the on / off of the vehicle power supply. The vehicle power supply is a power source that is turned on when the vehicle HV is running. The cellular module is a communication module that implements cellular communication such as 4G or 5G. The body-related equipment includes headlights, door lock motors, and power window motors.

[0046] The smart ECU 2 controls the unlocking / locking of the doors based on (i) the presence of the user device 9 in the vicinity area, (ii) the user device 9 has been authenticated, and (iii) a predetermined user action. The user action for locking / unlocking the doors may be touching the exterior door handle or waving a foot over a detection area formed below the door. The smart ECU 2 may be understood as an ECU that provides a passive entry function. The passive entry function is a function that locks / unlocks the vehicle Hv in response to a predetermined user action on the vehicle Hv.

[0047] The smart ECU 2 may be divided into multiple ECUs. For example, the smart ECU 2 may be divided into an ECU that determines the device location and an ECU that executes vehicle control such as unlocking. The functional layout within the in-vehicle system 1 may be changed as appropriate.

[0048] <User Device 9> The user device 9 may be a general-purpose information processing terminal equipped with an SRWC function. The user device 9 may be a smartphone or a wearable device. The user device 9 functions as a key for the vehicle Hv by performing wireless authentication using the smart ECU 2 and the SRWC. The user device 9 may also be referred to as a portable device, a key device, or the like. The user device 9 may also be a dedicated device that functions as a wireless key for the vehicle Hv. The dedicated device may be called a smart key, a key fob, a key card, an access key, or the like.

[0049] The user device 9 of this embodiment has a rectangular shape and is defined in left, right, top, and bottom directions. The user device 9 has edges corresponding to the four sides of the rectangle: an upper edge, a lower edge, a left edge, and a right edge.

[0050] The user device 9 includes a device display 91, an input device 92, an antenna 93, an RF (radio frequency) core 94, and a controller 95. The antenna 93 and the RF core 94 are electrically connected by a communication line or a conductor pattern. The device display 91, the input device 92, and the RF core 94 are connected to the controller 95 so as to be able to communicate with each other. The user device 9 may also include a battery, a power receiving circuit for receiving power from a wireless charger, an NFC communication module, etc.

[0051] The device display 91 is a device that displays an image according to a video signal input from the controller 95. The device display 91 may be a liquid crystal display or an organic EL display. The input device 92 is a device that receives user instructions and operations on the user device 9. The input device 92 may be a touch panel that is stacked on the device display 91. The input device 92 outputs an operation signal, which is an electrical signal corresponding to the user's operation, to the controller 95. The operation signal includes information indicating the content of the user's operation on the user device 9.

[0052] The controller 95 may be configured to receive an instruction to register the communication characteristics of the user device 9 in the smart ECU 2 via the input device 92. The controller 95 may be configured to start a process of registering the communication characteristics of the user device 9 (hereinafter, characteristic learning process) in cooperation with the in-vehicle system 1 based on receiving the registration instruction via the input device 92. The controller 95 may transmit an SRWC signal corresponding to a registration instruction signal to the smart ECU 2 based on receiving the registration instruction via the input device 92. The smart ECU 2 may be configured to be able to receive the registration instruction using the input device 92 (user device 9).

[0053] The characteristic learning process may include displaying a characteristic registration guide image on the device display 91 or the in-vehicle display 4, or both. The characteristic registration guide image is an image that shows the user the procedure for registering the communication characteristics of the user device 9 in the smart ECU 2. The characteristic registration guide image includes an image that shows the location where the user device 9 should be placed and the posture of the user device 9 when registering the communication characteristics. The characteristic registration guide image may include multiple patterns / images. Hereinafter, the in-vehicle display 4 and the device display 91 will also be collectively referred to as the display. Hereinafter, the display may be interpreted as the in-vehicle display 4, the device display 91, or both.

[0054] The antenna 93, RF core 94, and controller 95 correspond to a configuration for implementing SRWC. The antenna 93, RF core 94, and controller 95 may be mounted on a single circuit board. The antenna 93 is an antenna element for transmitting and receiving radio waves in a frequency band (e.g., 2.4 GHz band) used for SRWC.

[0055] The RF core 94 is a circuit module that performs processing related to the transmission and reception of radio signals. The RF core 94 may include a modulation circuit, a demodulation circuit, a frequency conversion circuit, an amplifier circuit, a local oscillator, etc. The RF core 94 is connected to the antenna 93 and a controller 95. The RF core 94 demodulates a signal received by the antenna 93 and provides the demodulated signal to the controller 95. The RF core 94 also modulates transmission data input from the controller 95 and radiates it as radio waves from the antenna 93. The RF core 94 may be realized as an IC chip (i.e., a transmission and reception IC).

[0056] Like the anchor 3, the RF core 94 is configured to be able to transmit and receive CW signals for each channel as ranging signals. The RF core 94 provides the controller 95 with reception phase information and reception strength for each channel. In this embodiment, the controller 95 generates a ranging value based on the reception phase information for each channel, but the functional arrangement within the user device 9 is not limited to this. The RF core 94 may be configured to calculate a ranging value based on the reception phase information for each channel.

[0057] The controller 95 is a microcomputer that controls the overall operation of the user device 9. The controller 95 includes a processor E1, a memory E2, a storage E3, and a communication interface E4. The processor E1 may be a CPU. The memory E2 is a volatile storage medium such as RAM. The storage E3 is a recording device including a non-volatile storage medium such as flash memory. The storage E3 may include multiple types of storage media, such as ROM (Read Only Memory) and flash memory. The communication interface E4 is a circuit module that allows the processor E1 to communicate with other components, such as the device display 91, input device 92, and RF core 94.

[0058] Storage E3 stores a device control program. The device control program is a program including instructions related to device characteristic learning processing. Storage E3 also stores communication data. The communication data is data for wireless communication with the vehicle Hv. The communication data may include parameters received from the smart ECU 2 through pairing, such as the device ID of the smart ECU 2. The communication data may also include an identification number of the vehicle Hv (hereinafter referred to as vehicle ID). The vehicle ID corresponds to identification information for the vehicle / on-board system to be communicated with. The vehicle ID may be referred to as a system ID. The vehicle ID may be a VIN (Vehicle Identification Number). The communication data may also include a key code used for wireless authentication with the vehicle Hv.

[0059] The controller 95 is configured to periodically perform advertising using the RF core 94 and the antenna 93. Advertising is a process of transmitting an advertising signal using a predetermined channel. The advertising signal is a radio signal for notifying other devices of the presence of the controller 95. When the controller 95 receives a connection request from the vehicle Hv in response to the advertising, the controller 95 establishes a communication connection with the vehicle Hv. Based on the establishment of a communication connection with the vehicle Hv, the controller 95 can perform an authentication process (i.e., wireless authentication) using the SRWC.

[0060] <Outline of location determination> If the user device 9 is located far from the vehicle Hv (i.e., outside the SRWC area), the smart ECU 2 cannot connect to the user device 9 via SRWC. If the smart ECU 2 is not connected to the user device 9 via SWRC, it sets the anchor 3 to a dormant state and does not perform location determination. If the smart ECU 2 is not connected to the user device 9, it periodically scans to search for the user device 9. If the user device 9 is not connected to the smart ECU 2, it periodically transmits an advertising signal.

[0061] When the user device 9 enters the SRWC area of ​​the vehicle Hv as the user moves, the smart ECU 2 may receive an advertising signal from the user device 9. Upon receiving the advertising signal from the user device 9, the smart ECU 2 transmits a connection request signal to the user device 9. This causes the user device 9 and the smart ECU 2 to transition to a communication connection state (FIG. 3, S11). The communication connection state may be interpreted as a state in which an SRWC link is established. The connection request signal is a signal requesting a communication connection.

[0062] In the communication connection state, the smart ECU 2 and the user device 9 transmit and receive wireless signals to check communication or perform encrypted data communication at predetermined intervals (e.g., connection intervals). Accordingly, the smart ECU 2 periodically obtains the reception strength of the device signal from the wireless communication module 24.

[0063] The smart ECU 2 keeps the anchor 3 in the dormant state until the reception strength of the device signal exceeds the predetermined activation strength (NO in S12). Also, if the communication connection between the user device 9 and the smart ECU 2 is cut off without the reception strength exceeding the activation strength, this flow may be ended.

[0064] If the reception strength of the device signal exceeds a predetermined activation strength (YES in S12), the smart ECU 2 activates all anchors 3 and causes the anchors 3 to perform distance measurement communication with the user device 9 (S13). Thereafter, the smart ECU 2 periodically executes a location determination process until a termination condition is met (S14). The location determination process includes the anchors 3 performing distance measurement communication with the user device 9.

[0065] The activation strength used in step S12 is a threshold value related to the reception strength for starting ranging communication. The activation strength may be determined, for example, based on the reception strength of an SRWC signal transmitted from a predetermined reference device placed at a predetermined position outside the vehicle. For example, the activation strength may be set based on the reception strength observed by the wireless communication module 24 when the reference device is placed at a point 10 m away from the vehicle Hv.

[0066] The reference device refers to a device used to determine the threshold for the reception strength for determining the device location. The reference device may be any model of iPhone (registered trademark) or Android (registered trademark) terminal. The reference device may be any model of various user devices 9 generally available on the market. The user device 9 used as the reference device may be selected by the designer. The activation strength may be set based on the reception strength observed when the reference device and the smart ECU 2 actually communicate with each other as a test.

[0067] The termination condition may be the disconnection of communication between the smart ECU 2 and the user device 9. Alternatively, the smart ECU 2 may determine that the termination condition is met when the traveling speed of the vehicle Hv becomes equal to or greater than a predetermined value. If the termination condition is met (YES in S15), the smart ECU 2 transitions all anchors 3 to a sleep state and terminates the periodic position determination.

[0068] The device location may be determined using both the distance measurement value and the reception strength, as shown in FIG. 4 . Note that the reception strength used in the following description may be interpreted as a strength value corrected using characteristic data, which will be described later. The location determination process includes determining whether the minimum observed distance obtained as a result of the distance measurement communication exceeds a predetermined proximity determination distance (S21). If the minimum observed distance obtained as a result of the distance measurement communication exceeds the predetermined proximity determination distance (YES in S21), the smart ECU 2 may determine that the user device 9 is located in a distant area (S22).

[0069] The minimum observed distance value means the minimum value of the distance measurement values ​​observed by multiple anchors 3. "Dmin" in FIG. 4 represents the minimum observed distance value. Also, "Dn" represents the proximity determination distance. The proximity determination distance is a parameter that defines the proximity area outside the vehicle. The proximity determination distance may be set to, for example, 1.0 m, 1.5 m, 2 m, etc. The proximity area can be interpreted as an area where automatic unlocking / locking of the vehicle Hv can be performed. The proximity area may also be referred to as a passive entry area.

[0070] On the other hand, if the minimum distance measurement value (Dmin) is equal to or less than the proximity determination distance (Dn), the smart ECU 2 determines whether the maximum inner intensity value exceeds a predetermined indoor determination value (S23). The maximum inner intensity value here means the maximum value of the reception intensity observed at the inner anchor. "PinMax" in the figure represents the maximum inner intensity value. Also, "Pin" in the figure represents the indoor determination intensity.

[0071] If the minimum observation distance is equal to or less than the proximity determination distance and the maximum inner intensity value does not exceed the predetermined interior determination intensity (S23 NO), the smart ECU 2 may determine that the device location is in the proximity area (S24).On the other hand, if the minimum observation distance is equal to or less than the proximity determination distance and the maximum inner intensity value exceeds the predetermined interior determination intensity (S23 YES), the smart ECU 2 may determine that the device location is inside the vehicle (S24).

[0072] The interior determination strength is a threshold value related to the reception strength for determining that the user device 9 is inside the vehicle. The interior determination strength may be determined based on the reception strength at the inner anchor of the SRWC signal transmitted from a reference device arranged at an inner set position inside the vehicle. The interior determination strength may be set in advance by testing using the reference device.

[0073] Of course, the device position determination method shown in FIG. 4 , in other words, the determination method described above, is merely an example and is not limited thereto. The conditions for determining that the user device 9 is inside the vehicle (hereinafter, referred to as the inside-vehicle determination conditions) may include the condition that the inside / outside intensity, which is the value obtained by subtracting the outside intensity maximum from the inside intensity maximum, is equal to or greater than a predetermined intensity difference threshold (e.g., 10 dB). The outside intensity maximum here refers to the maximum value of the reception intensity observed at multiple outside anchors. Furthermore, the inside-vehicle determination conditions may include the condition that the inside distance minimum, which is the minimum value of the distance measurements at the inside-vehicle anchors, is less than a predetermined interior determination distance (e.g., 1.0 m).

[0074] The conditions for determining whether a device is located within the vicinity area (hereinafter, "proximity determination conditions") may also be changed as appropriate. The proximity determination conditions may include the outer maximum strength being equal to or greater than a predetermined proximity determination strength. The proximity determination strength may be set based on the results of a reception strength observation test using a reference device.

[0075] The above-described various parameters for determining the device position (hereinafter, referred to as position determination parameters) may be registered in the storage 23 of the smart ECU 2. The position determination parameters include some or all of the activation intensity, the interior determination intensity, the intensity difference threshold, the proximity determination intensity, the proximity determination distance, and the interior determination distance.

[0076] <Issues Related to Position Determination Accuracy> Portable devices that can serve as user devices 9, such as smartphones, tablets, and wearable devices, can be manufactured by multiple manufacturers. The strength and directivity of the SRWC signal transmitted by the user device 9 can vary depending on the manufacturer and model. This is because the antenna configuration, transmission power settings, and the like vary depending on the manufacturer and model.

[0077] Furthermore, even for user devices 9 of the same model, communication characteristics may differ due to manufacturing errors. Here, communication characteristics may be interpreted as directivity or transmission characteristics. Furthermore, the communication characteristics of the user device 9 may be affected by attachments to the user device 9, such as a cover. Thus, communication characteristics may differ for each user device 9. In a configuration in which the device location is determined by comparing the actual reception strength of a signal from the user device 9 with a threshold value designed based on a reference device, the device location may be erroneously determined. For this reason, the smart ECU 2 of this embodiment incorporates a mechanism that learns the difference in communication characteristics between the user device 9 and the reference device and uses the learning results in determining the location.

[0078] <Functions of the Smart ECU> As shown in FIG. 5 , the smart ECU 2 includes functional blocks, such as an intensity acquisition unit F1, a characteristic learning unit F2, a correction unit F3, a position determination unit F4, and a distance measurement unit F5. Some or all of these functional blocks may be implemented by the processor 21 executing a device control program. The smart ECU 2 also includes a reference value storage unit M1, a threshold value storage unit M2, and a characteristic data storage unit M3. These storage units may be implemented using storage areas provided in the storage E3. The reference value storage unit M1, the threshold value storage unit M2, and the characteristic data storage unit M3 may be implemented in the same storage medium, or some of these units may be implemented in separate storage media. The smart ECU 2 may be configured to access the reference value storage unit M1, the threshold value storage unit M2, and the characteristic data storage unit M3 and perform data read, write, or deletion. The smart ECU 2 corresponds to a control unit.

[0079] The reference value storage unit M1 is a storage medium / area that stores data indicating the communication characteristics of the reference device. The data indicating the communication characteristics of the reference device includes data on the reception strength observed at the inner anchor when the reference device is present inside the vehicle. The data indicating the communication characteristics of the reference device includes data on the reception strength observed at the outer anchor when the reference device is in the vicinity area.

[0080] In this embodiment, the data indicating the communication characteristics of the reference device includes an inner reference value and an outer reference value. The inner reference value may be the average value of the reception strength of the SRWC signal from the reference device observed by multiple inner anchors when the reference device is placed at the inner set position. In another example, the inner reference value may be the reception strength of the SRWC signal from the reference device detected by a specific anchor 3 when the reference device is placed at the inner set position. The specific anchor 3 may be, for example, anchor 3p or the wireless communication module 24.

[0081] The outer reference value may be the maximum value of the reception strength of the SRWC signal from the reference device observed by multiple outer anchors when the reference device is placed at a predetermined outer set position. The outer set position is a predetermined measurement position outside the vehicle. The outer set position may be a point 1.5 m to the right of the outer door handle for the right front seat. In another embodiment, the outer set position may be a point 0.1 m from the outer door handle for the right front seat or the bottom edge of the side window. The reception strength used to determine the outer reference value may be the reception strength of a direct wave (hereinafter referred to as direct wave strength). A direct wave refers to an SRWC signal transmitted from a mobile device and reaching the anchor 3 without being reflected by other objects. Generally, a reflected wave has a longer propagation path than a direct wave. Therefore, the direct wave is received by the anchor 3 earlier than the reflected wave. The anchor 3 may report the strength of the device signal received first in one ranging communication to the processor 21 as the strength of the direct wave. Note that the anchor 3 may receive a signal in which a reflected wave is superimposed on a direct wave over time. The anchor 3 may extract a direct wave from the received signal and acquire its reception strength by digital signal processing such as the MUSIC method or the ESPRIT method. The direct wave may be referred to as a first path.

[0082] In another example, the outer reference value may be the received strength of the SRWC signal from the reference device detected by a predetermined outer anchor when the reference device is positioned at the outer set position. The predetermined outer anchor may be anchor 3 (i.e., anchor 3a) that is located closest to the outer set position.

[0083] In addition to the inner reference value and the outer reference value, the reference value storage unit M1 may also store a gateway reference value. The gateway reference value is the reception strength of a signal from a reference device detected by the wireless communication module 24 when the reference device is placed in the outer set position. The gateway reference value may be understood as a parameter that serves as the basis for the activation strength. The various reference values ​​correspond to assumed values ​​of the reception strength of a signal transmitted from the reference device.

[0084] The threshold memory unit M2 is a storage medium / area that stores parameters for determining the location, such as the activation strength, the indoor determination strength, etc. The parameters for determining the location related to the reception strength may be set based on an inner reference value or an outer reference value.

[0085] The characteristic data storage unit M3 is a storage medium / area in which data indicating the difference in communication characteristics between the user device 9 and the reference device is stored. The difference in communication characteristics may be interpreted as a difference in signal strength (in other words, reception strength). The data indicating the difference in communication characteristics may be a correction value γ. When the reception strength of the SRWC signal from the reference device observed under the same conditions (hereinafter referred to as the reference value) is α and the reception strength of the device signal (observed value) is β, the correction value γ may be β-α.

[0086] The characteristic data storage unit M3 stores, for example, an inner correction value γ1, which is a value for correcting the reception strength observed at the inner anchor. The inner correction value γ1 may be a value obtained by subtracting a reference value α1 from the measured value β1. The reference value α1 may be an inner reference value. The measured value β1 may be the average value of the reception strength detected at multiple inner anchors when the user device 9 is placed at the inner set position. The measured value β1 may be the reception strength of a device signal detected by a specific anchor 3. The inner correction value γ1 corresponds to a correction value assuming that the user device 9 is inside a vehicle.

[0087] In addition to the inner correction value γ1, an outer correction value γ2 may be registered in the characteristic data storage unit M3. This is a value for correcting the reception strength observed at the outer anchor. The outer correction value γ2 is a correction value assuming that the user device 9 is outside the vehicle. The outer correction value γ2 may be a value obtained by subtracting a reference value α2 from the measured value β2. The reference value α2 may be an outer reference value. The measured value β2 may be the maximum value of the direct wave strength detected at multiple outer anchors when the user device 9 is placed at the outer set position. The reference value α2 and the measured value β2 may be the direct wave strength observed at a specific outer anchor when the reference device and the user device 9 are placed at the outer set position. The specific outer anchor may be the anchor 3 (i.e., anchor 3a) closest to the outer set position.

[0088] A gateway correction value may be registered in the characteristic data storage unit M3. The gateway correction value may be a value obtained by subtracting a gateway reference value from the device signal detected by the wireless communication module 24 when the user device 9 is positioned in the outer set position. The gateway correction value may be used to correct the reception strength or activation strength used in the determination of step S12. The data stored in the characteristic data storage unit M3 is updated by the characteristic learning unit F2. A data set indicating the communication characteristics of one user device 9 will hereinafter also be referred to as characteristic data. The characteristic data may be understood as data including various correction values ​​such as an inner correction value. The characteristic data may also be referred to as correction data or difference data. The various correction values ​​and their calculation methods described above are merely examples. The types of correction values ​​generated by the smart ECU 2 and their calculation methods may be changed as appropriate.

[0089] The strength acquisition unit F1 is configured to acquire data indicating the reception strength of the device signal from the wireless communication module 24 and the anchor 3. The reception strength data acquired by the strength acquisition unit F1 is temporarily stored in the memory E2. The reception strength data stored in the memory E2 is referenced by the characteristic learning unit F2, the correction unit F3, and the position determination unit F4.

[0090] The characteristic learning unit F2 is configured to generate characteristic data for the user device 9 and store it in the characteristic data storage unit M3. The characteristic learning unit F2 acquires characteristic data such as an inner correction value by executing a characteristic learning process described below. The characteristic data may be stored in association with the device ID of the user device 9. The characteristic learning unit F2 may be configured to be able to store characteristic data for multiple user devices 9 in the characteristic data storage unit M3. The device characteristic data for each user device 9 may be distinguished using a device ID or the like.

[0091] The correction unit F3 is configured to correct the reception strength acquired by the strength acquisition unit F1 using characteristic data stored in the characteristic data storage unit M3. The correction unit F3 corrects the reception strength observed at the inner anchor with an inner correction value. For example, when the reception strength detected at the inner anchor is ρ1, the correction unit F3 corrects the reception strength by ρ1-γ1. For convenience, the reception strength after correction is also referred to as the corrected strength. ρ1 may be the maximum inner strength value. The correction unit F3 may be configured to correct each of the reception strengths observed at multiple inner anchors.

[0092] The correction unit F3 may correct the reception strength observed at the outer anchor with an outer correction value. For example, when the reception strength detected at the outer anchor is ρ2, the correction unit F3 corrects the reception strength by ρ2-γ2. ρ2 may be the maximum outer strength value. The correction unit F3 may be configured to correct each of the reception strengths observed at multiple outer anchors.

[0093] The correction unit F3 may use the gateway correction value to correct the reception strength used to determine activation of the anchor 3. The reception strength used to determine activation of the anchor 3 is the reception strength at the wireless communication module 24. In the present disclosure, the reception strength of the device signal detected by the wireless communication module 24 is also referred to as the gateway strength. The corrected gateway strength may be a value obtained by subtracting the gateway correction value from the gateway strength.

[0094] The location determination unit F4 is configured to determine the device location based on the corrected reception strength and the distance measurement value. The distance measurement unit F5 is configured to control distance measurement communication between the anchor 3 and the user device 9. The distance measurement unit F5 activates the anchor 3 and performs distance measurement communication with the user device 9 based on the fact that the uncorrected gateway strength exceeds the activation strength.

[0095] <Example of Operation of Portable Device> Here, the operation of the smart ECU 2 will be described using the flowcharts shown in Figures 6 and 7. The flow shown in Figure 6 corresponds to a flow that incorporates a characteristic learning process and a reception strength correction process into the position determination process described using Figures 3 and 4. The series of processes shown in Figure 6 can be called a position determination-related process. The position determination-related process may include steps S101 to S111 as shown in Figure 6. In the following description of the flow, the term "processor 21" may be replaced with the smart ECU 2, the strength acquisition unit F1, the characteristic learning unit F2, the correction unit F3, the position determination unit F4, or the distance measurement unit F5.

[0096] The flow shown in FIG. 6 may be started when the wireless communication module 24 receives an advertising signal from the user device 9. Step S101 is a step of transmitting a connection request signal to the user device 9 and establishing a communication connection with the user device 9. Step S102 is a step of the processor 21 determining whether characteristic data of the user device 9 with which the smart ECU 2 is connected is stored in the characteristic data storage unit M3. A case in which the characteristic data of the user device 9 is not stored in the characteristic data storage unit M3 may occur, for example, when the location determination process is performed for the first time after pairing the smart ECU 2 and the user device 9. A case in which the characteristic data is not stored may also occur when a user uses a vehicle that the user has never used before in a car sharing service or the like for the first time.

[0097] If the characteristic data of the user device 9 is not stored in the characteristic data storage unit M3, a negative judgment is made in step S102 and the process proceeds to step S103. On the other hand, if the characteristic data of the user device 9 is stored in the characteristic data storage unit M3, a positive judgment is made in step S102 and the process proceeds to step S106. Note that even if a certain period of time has passed since the previous characteristic learning process was performed, a positive judgment is made in step S102 and steps S103 to S105 may be performed.

[0098] Step S103 is a step in which the processor 21 executes an intention confirmation process. The intention confirmation process is a process of inquiring of the user as to whether or not to register the characteristic data of the user device 9 in the smart ECU 2 (i.e., the vehicle Hv). The intention confirmation process may include displaying on the display an image (hereinafter, an intention confirmation screen) including a message inquiring as to whether or not to register the characteristic data in the vehicle Hv. The processor 21 acquires the result of the intention confirmation process, i.e., the user's response indicating whether or not to register the characteristic data in the vehicle, via the input device 5, 92. The input device 5, 92 transmits a response signal indicating that the characteristic data will be registered in the vehicle to the processor 21 based on the user's operation. The response signal corresponds to a registration instruction signal.

[0099] If the processor 21 receives a registration instruction signal (YES in S103), the processor 21 executes step S104. On the other hand, if the processor 21 does not receive a registration instruction signal as a result of the intention confirmation process (NO in S103), the processor 21 proceeds to step S106.

[0100] Step S105 is a step of executing a characteristic learning process. The characteristic learning process includes steps S201 to S208 as shown in FIG. 7. In the present disclosure, steps S201 to S206 are also referred to as a strength measurement process. The strength measurement process may include multiple in-vehicle anchors simultaneously / sequentially measuring the reception strength of device signals for each frequency. The strength measurement process may include an inner strength measurement process and an outer strength measurement process. The inner strength measurement process is a process of measuring the reception strength of device signals when the user device 9 is located in an inner set position. The outer strength measurement process is a process of measuring the reception strength of device signals when the user device 9 is located outside the vehicle (e.g., in an outer set position).

[0101] Step S201 is a step of displaying a characteristic registration guide image on the display. The characteristic registration guide image may include an image indicating that the user device 9 is placed in an initial set position. The initial set position refers to a position to which the user device 9 should be initially set among a plurality of set positions preset in the smart ECU 2. In this embodiment, the initial set position is the inner set position. In another embodiment, the initial set position may be the outer set position.

[0102] The characteristic registration guide image may include a set completion button. The set completion button is a button for inputting to the smart ECU 2 that the user device 9 has been placed in the designated set position. Step S201 may include outputting a voice message guiding the user to place the user device 9 in the inner set position. After step S201 is executed, the process proceeds to step S202. The set position where the processor 21 requests the user to place the user device 9 using a voice or image is also referred to as a designated position in the present disclosure.

[0103] Step S202 is a step in which the processor 21 confirms that the user device 9 has been placed at the designated position. The designated position here may be interpreted as the inner set position. The placement of the user device 9 at the designated position may be confirmed based on a user operation on the input devices 92 and 5. The processor 21 may determine that the user device 9 has been placed at the designated position based on the user pressing the set completion button. The processor 21 may determine whether the user device 9 has been placed at the designated set position based on distance measurements observed by multiple anchors 3. If the position of the user device 9 estimated from the distance measurements deviates from the designated set position, the processor 21 may display an image on the display requesting the user to adjust the position of the user device 9. Alternatively, the processor 21 may confirm that the user device 9 has been placed at the inner set position based on a signal from the device detection unit 6.

[0104] If the processor 21 confirms that the user device 9 has been placed at the designated position (YES in S203), the process proceeds to step S204. If the processor 21 cannot confirm that the user device 9 has been placed at the designated position (NO in S203), the processor 21 may re-display the characteristic registration guide image. If the processor 21 cannot confirm that the user device 9 has been placed at the designated position even after a certain time has elapsed since displaying the characteristic registration guide image, the processor 21 may interrupt the characteristic learning process and execute step S106.

[0105] Step S204 is a step of conducting test communication. The test communication may be communication in which each anchor 3 observes the reception strength of a device signal. The test communication may be communication in which each anchor 3 eavesdrops (sniffers) on communication between the wireless communication module 24 and the user device 9. The test communication may be a step in which multiple anchors 3 individually perform SRWC with the user device 9. The test communication may include the anchor 3 detecting the reception strength of each channel by switching channels in sequence. The test communication may also be ranging communication between the user device 9 and the anchor 3. When the test communication is completed, the process proceeds to step S205.

[0106] Step S205 is a step in which the processor 21 collects communication results from the anchors 3. For example, the processor 21 may receive the reception strength for each channel as the communication result from each anchor 3. The communication result may include a distance measurement value. The communication result is linked to data indicating the measurement conditions and stored in the memory 22. The measurement conditions indicate the position of the user device 9 when the test communication was performed. The measurement conditions may include the attitude of the user device 9 when the test communication was performed. Hereinafter, the attitude of the user device 9 may also be referred to as the device attitude. Once step S205 is completed, the process proceeds to step S206.

[0107] Step S206 is a step of determining whether the strength measurement process has been completed under all planned measurement conditions. The characteristic learning process may include a step of causing multiple anchors 3 to detect the reception strength of the device signal under multiple measurement conditions each with a different position or orientation of the user device 9.

[0108] If the intensity measurement process has not been completed under all measurement conditions (NO in S206), the process returns to step S201, and the processor 21 may display a characteristic registration guide image for executing the intensity measurement process under unmeasured conditions. For example, if the inner intensity measurement process has been completed but the outer intensity measurement process has not been completed, the processor 21 may change the designated position to the outer set position and then perform steps S201 to S205.

[0109] The intensity measurement process at the outer set position may include observing the reception intensity when the user device 9 is placed at the outer set position in different orientations. For example, the characteristic learning process may include collecting reception intensity when the user device 9 is placed at the outer set position in first to fifth orientations. The first orientation may be an orientation in which the screen of the user device 9 is horizontal and the upper end is facing the vehicle vehicle Hv. The second orientation may be an orientation in which the screen of the user device 9 is horizontal and the lower end is facing the vehicle vehicle Hv. The third orientation may be an orientation in which the screen of the user device 9 is horizontal and the left edge is facing the vehicle vehicle Hv. The fourth orientation may be an orientation in which the screen of the user device 9 is horizontal and the right edge is facing the vehicle vehicle Hv. The fifth orientation may be an orientation in which the screen or the back of the user device 9 is facing the vehicle vehicle Hv. The first to fifth orientations applied in the outer intensity measurement process may be referred to as outer first to fifth orientations. Each orientation may be different from the others. Note that the combination of device postures in which test communication should be performed in the outer strength measurement process may be only postures 1 to 4, or may be only postures 1 and 5. The combination of device postures in which test communication should be performed may be designed as appropriate.

[0110] Furthermore, the number of outer set positions is not limited to one. A first outer set position and a second outer set position may be set in the smart ECU 2. The first outer set position may be within 0.1 m from the center of the driver's side window. The second outer set position may be 1.5 m to the side of the driver's outer door handle. The processor 21 may perform the strength measurement process in the order of the inner set position, the first outer set position, and the second outer set position.

[0111] The orientation of the user device 9 at the first outer setting position may be an orientation in which the screen faces the interior of the vehicle. The measurement orientation at the first outer setting position may be one pattern or multiple patterns. The measurement orientation at the second outer setting position may be one of the five patterns of the first to fifth orientations described above, or may be four patterns of the first to fourth orientations.

[0112] If the intensity measurement process has been completed under all conditions (YES in S206), the process proceeds to step S207. In step S207, the processor 21 generates characteristic data based on the received intensity data collected in the above process. As described above, the processor 21 generates various correction values ​​based on the difference between the reference value α and the measured value β observed under the same conditions.

[0113] The measured value β1 used to calculate the inner correction value may be the average value of the reception strength for each channel detected by multiple inner anchors when the user device 9 is placed in the inner set position. In this disclosure, the average value of the reception strength for each channel is also referred to as the average strength value at multiple frequencies or the average frequency value. If there are three inner anchors and reception strength is observed for 10 channels, β1 may be the average value of 30 reception strength samples. The reference value α2 and measured value β2 used to calculate the outer correction value may be the maximum value of the direct wave strength for each channel and for each outer anchor.

[0114] The above steps S201 to S205 may be designed to collect data for generating a desired correction value. Step S206 may be a step of performing predetermined arithmetic processing on the reception intensity data collected in steps S201 to S205 to generate a correction value according to the device position determination method. The arithmetic processing may include excluding outliers, calculating an average value, subtracting, etc.

[0115] When the generation of the characteristic data is completed, the process proceeds to step S207, in which the characteristic data generated in step S206 is stored in the characteristic data storage unit M3.

[0116] When the above characteristic learning process is completed, the process proceeds to step S106 in FIG. 6. Note that the set positions for which the intensity measurement process is performed in the characteristic learning process may be only the inner set position or the outer set position. The combination of locations for placing the user device 9 may be changed as appropriate depending on the correction value to be generated. The correction value to be generated in the characteristic learning process may be configured to be selectable by the user in the intention confirmation process.

[0117] Step S106 is a step in which the processor 21 monitors the gateway strength. Step S106 corresponds to step S12 described above. If the characteristic data is stored in the characteristic data storage unit M3, step S106 may include the processor 21 correcting the reception strength (gateway strength) detected by the wireless communication module 24 with a gateway correction value. The gateway strength compared with the activation strength may be the corrected gateway strength. The processor 21 executes step S107 based on the corrected gateway strength being equal to or greater than the activation strength. Note that if the characteristic data is stored in the characteristic data storage unit M3, the gateway strength compared with the activation strength may be an uncorrected value.

[0118] Step S107 is a step of executing communication for position determination. The communication for position determination may be distance measurement communication between each anchor 3 and the user device 9. Step S107 may include activating the anchor 3. Step S107 may include the smart ECU 2 exchanging distance measurement communication settings with the user device 9 via the SRWC. The distance measurement communication settings include the execution interval of distance measurement communication, etc. As described below, step S107 is executed periodically until a predetermined termination condition is satisfied. The processor 21 executes step S108 each time step S107 is executed.

[0119] Step S108 is a step in which the processor 21 acquires the results of the ranging communication, such as the reception strength and the distance measurement value, from each anchor 3. When step S108 is completed, the process proceeds to step S109. Step S109 is a step in which the collected reception strength is corrected using characteristic data. Step S109 may include correcting the reception strength observed at the outer anchor using an outer correction value. Step S109 may also include correcting the reception strength observed at the inner anchor using an inner correction value. Step S109 may include correcting the outer maximum strength value and the inner maximum strength value.

[0120] When step S109 is completed, the process proceeds to step S110. Step S110 is a step for determining the device position using the corrected inner intensity maximum value and the corrected outer intensity maximum value. The explanation for FIG. 4 may be applied to the outline of step S110. When step S110 is completed, the process proceeds to step S111. Note that if no characteristic data is registered at the time step S110 is executed, the processor 21 may perform position determination using the uncorrected reception intensity. Examples of cases where no characteristic data is registered at the time step S110 is executed include when the characteristic registration process fails and when a registration instruction signal is not received as a result of the intention confirmation process (S103 NO).

[0121] Step S111 is a step for determining whether or not the termination condition is met. Step S111 corresponds to S15. If the termination condition is met, the processor 21 puts the anchor 3 to sleep. The processor 21 repeatedly executes steps S107 to S111 until the termination condition is met.

[0122] The processor 21 may execute processing according to a user action based on the latest device location determination result. For example, when the processor 21 determines that the device location is in the nearby area and detects a user unlocking operation, the processor 21 unlocks the door. If the vehicle control execution function is provided in an ECU other than the smart ECU 2, the smart ECU 2 may periodically transmit data including the device location determination result and device ID / user information to the other ECU.

[0123] <Effects> The smart ECU 2 generates characteristic data indicating the difference in communication characteristics between the user device 9 used by the user and the reference device by communicating with the actual user device 9. The smart ECU 2 also determines the device location using the reception strength of the device signal corrected using the characteristic data. This reduces the risk of erroneous determination of the device location due to the difference in communication characteristics between the user device 9 and the reference device.

[0124] The inner correction value is calculated based on the average value of the reception strength observed at multiple in-vehicle anchors. Based on test results, the developers of the present disclosure have found that because the inside of a vehicle is a multipath environment, the orientation of the user device 9 is unlikely to affect the average value of the reception strength at multiple anchors 3. A configuration that determines the correction value based on the average value of the reception strength observed at multiple in-vehicle anchors can reduce the effect of the device orientation on the correction value.

[0125] Furthermore, different frequencies may have different propagation paths, and the degree of influence of reflected waves may vary depending on the frequency. By generating a correction value based on the received signal strength at multiple frequencies, it is possible to set a more appropriate correction value.

[0126] Additionally, when the user uses the vehicle hybrid vehicle for the first time, or when the characteristic data of the user device 9 is not registered in the smart ECU 2, the smart ECU 2 automatically executes an intention confirmation process. Furthermore, when the smart ECU 2 receives a response instructing the user to start the characteristic learning process as a result of the intention confirmation process, the smart ECU 2 instructs the user on the operation procedure by displaying a characteristic registration guide image, etc. This configuration allows the user to easily register communication characteristics without any confusion.

[0127] <Modifications> The processor 21 may be configured to execute an intention confirmation process when a certain period of time (e.g., six months or one year) has elapsed since the characteristic data was registered. An expiration date may be set for the characteristic data. The processor 21 may be configured to automatically delete expired characteristic data. The processor 21 may be configured to execute an intention confirmation process when the inside / outside determination has failed a certain number of times (e.g., once or twice). The failure of the inside / outside determination may be input by the user via the input device 5, 92. Furthermore, the processor 21 may determine that the inside / outside determination has failed if a start operation is performed a certain number of times within a certain period of time while the device position is determined to be outside the vehicle (e.g., in the vicinity area). The start operation is an operation to turn on the vehicle power. The start operation may be an operation of pressing a start switch (in other words, a power switch) while depressing the brake pedal.

[0128] The measured value β1 used to calculate the inner correction value may be a value obtained by subtracting a nearby measured value from the inner measured value. The inner measured value here may be the average value of the reception strength observed at the in-vehicle anchor when the user device 9 is placed at the inner set position. The nearby measured value may be the average value of the reception strength observed at the in-vehicle anchor when the user device 9 is placed at the first outer set position. The average value may be the average value of the strength at multiple frequencies. When the measured value β1 is a value obtained by subtracting the nearby measured value from the inner measured value, the reference value α1 may also be a value calculated under similar conditions. In other words, the reference value α1 may also be a value obtained by subtracting the nearby measured value from the inner measured value observed using a reference device.

[0129] The above describes a pattern in which the reception strength is corrected using characteristic data, but the object of correction may not be the reception strength but may be thresholds such as the activation strength, the indoor determination strength, the intensity difference threshold, and the proximity determination strength. The processor 21 may determine the device location by comparing the thresholds corrected using the characteristic data with the actual reception strength.

[0130] The processor 21 may have a function of receiving attitude-related data indicating the device attitude from the user device 9 and determining whether the user device 9 is in a designated attitude. The attitude-related data may be data including some or all of the detection results of the magnetic sensor, acceleration sensor, and gyro sensor. When the processor 21 detects that the user device 9 is not in a designated attitude based on the received attitude-related data, the processor 21 may execute processing to display an image on the display requesting that the device attitude be adjusted.

[0131] The processor 21 may execute the intensity measurement process for determining the inside correction value when there are no occupants in the vehicle and all doors are closed. Closing the doors creates a multipath environment inside the vehicle, which is expected to mitigate the effects of device posture. Furthermore, device signals may be attenuated by human bodies. By leaving the vehicle empty, the effects of human bodies on the inside correction value can be reduced. Given the above circumstances, the processor 21 may request the user to exit the vehicle and close all doors after placing the user device 9 in the inside set position. The user may be notified of this request using a screen display or a voice message.

[0132] The processor 21 may determine whether all doors are closed from an output signal of an in-vehicle sensor (e.g., a courtesy switch). When the processor 21 detects that some doors are open from the output signal of the in-vehicle sensor during the inside strength measurement process, the processor 21 may display an image on the in-vehicle display 4 requesting that all doors be closed.

[0133] The processor 21 may detect whether or not there is an occupant inside the vehicle based on the output signal of an in-vehicle sensor such as a seating sensor or an in-vehicle camera. When the processor 21 detects that there is an occupant inside the vehicle based on the output signal of the in-vehicle sensor in the inside intensity measurement process, the processor 21 may perform a process of outputting an image / audio requesting the occupant to exit the vehicle.

[0134] In the outer intensity measurement process, the processor 21 may request the user to hold the user device 9 in their hand so that the user device 9 is positioned between the vehicle Hv and the user. This positional relationship reduces the risk of the device signal being attenuated by the human body. In addition, the user's body can play a role in blocking reflected waves from walls and the like. In the outer intensity measurement process, the processor 21 may instruct the user to stand facing the vehicle Hv and hold the user device 9 in a predetermined posture. In the outer intensity measurement process, requesting the user to stand facing the vehicle Hv is expected to increase the intensity of direct waves while suppressing reflected waves. Instructions / requests to the user may be given by image display or audio output.

[0135] The strength measurement process at the inner set position may include observing the reception strength when the user device 9 is placed at the inner set position in different orientations. For example, the strength measurement process at the inner set position may be performed in a pattern in which the user device 9 is placed in a first inner orientation and a pattern in which the user device 9 is placed in a second inner orientation. The first inner orientation may be a position in which the screen of the user device 9 is facing upward. The second inner orientation may be a position in which the screen of the user device 9 is facing downward.

[0136] Furthermore, the number of inner set positions is not limited to one. A first inner set position and a second inner set position may be set in the smart ECU 2. If the first inner set position is on the center console, the second inner set position may be in the center of the rear seat, or may be in the trunk.

[0137] As described above, the processor 21 may calculate the correction value by averaging the reception strength measured under multiple measurement conditions that differ in physical state (position / posture) of the user device 9. This configuration can improve the accuracy of the correction value.

[0138] The above describes a mode in which the outer correction value is determined based on the reception strength observed at the outer anchor when the user device 9 is placed at a predetermined position outside the vehicle (e.g., the second outer set position), but this is not limiting. The outer correction value may also be determined based on the reception strength observed when the user device 9 is located at any location outside the vehicle. However, the reception strength may attenuate depending on the distance between the communication devices. If the device position is not specified in the outer strength measurement process due to such circumstances, the processor 21 may correct the reception strength based on the distance measurement value. The processor 21 may determine the outer correction value based on the reception strength at the outer anchor corrected based on the distance measurement value.

[0139] Although the above describes a case where the inner correction value is determined based on the reception strength observed at the inner anchor when the user device 9 is placed in a predetermined position (e.g., the inner set position) in the vehicle, the present invention is not limited to this. The inner correction value may also be determined based on the reception strength observed when the user device 9 is located anywhere in the vehicle.

[0140] The smart ECU 2 (i.e., the processor 21) may be configured to transmit a characteristic report to a predetermined server via cellular communication based on the execution of the characteristic learning process. The characteristic report is a data set including characteristic data of the user device 9. The characteristic report may include, in addition to the characteristic data, vehicle model information of the vehicle Hv and model information of the user device 9. The server may be a server managed by a vehicle manufacturer or an entity providing a car sharing service. The server may also be referred to as a center. Note that the user device 9 may send the characteristic report instead of the processor 21. The user device 9 may be configured to acquire the characteristic data from the smart ECU 2 via the SRWC.

[0141] The server may statistically generate correction values ​​corresponding to a combination of vehicle model and model based on characteristic reports received from multiple smart ECUs 2 or user devices 9, and distribute the correction values ​​to the user devices 9. For example, the server may generate various correction values ​​for the same vehicle model and model combination by averaging characteristic data indicated in multiple characteristic reports for the combination. This configuration can improve the accuracy of the correction values. Furthermore, the above-described configuration in which the server generates and distributes correction values ​​may enable characteristic data to be registered even in user devices 9 / smart ECUs 2 that have not yet undergone characteristic learning processing. Furthermore, if the server is a server for a car sharing service, the server may pre-distribute correction values ​​appropriate for the combination of the user device 9 and the service car to vehicles reserved by the user. This system can improve the accuracy of location determination even in vehicles used by a user for the first time. As a result, user convenience may be improved.

[0142] <CS Ranging> Here, we will provide additional information about CS ranging. The CS ranging process includes a step of collecting the reception phase for each channel, a step of calculating a phase change coefficient from the reception phase for each channel, and a step of calculating data indicating distance (i.e., a measured distance value) from the phase change coefficient.

[0143] The reception phase for each channel may be collected by transmitting and receiving a CW signal between the anchor 3 and the user device 9 while switching channels in sequence. The anchor 3 and the user device 9 may collect the reception phase for all channels available in the SRWC, or may collect the reception phase for a predetermined number of channels (for example, 10).

[0144] The phase change coefficient is a parameter indicating the degree to which the received phase changes in response to a change in frequency. The phase change coefficient can also be called the phase change degree, the phase shift amount, or the phase-frequency correlation coefficient. The anchor 3 may calculate a regression line indicating the relationship between frequency and received phase based on the received phase for each channel, and use the slope of the regression line as the phase change coefficient. This is because the slope of the regression line indicates the amount of change in the received phase relative to the amount of frequency shift. The regression line and its slope can be calculated using various methods, such as the least squares method. The anchor 3 may also calculate the phase difference, differential frequency, and phase change degree for each combination of frequencies for which the received phase can be observed. The anchor 3 may also use the average or median of the phase change degree for each frequency combination as the phase difference change coefficient. The phase difference is the difference between the received phases observed at two frequencies. The differential frequency is the difference between the two frequencies, and the phase change degree is the value obtained by dividing the phase difference by the differential phase difference. The phase change coefficient corresponds to a parameter obtained by averaging the phase change degrees for multiple frequency combinations. The phase change degree and the phase change coefficient correspond to the amount of phase angle displacement caused by a change in the frequency used.

[0145] Calculating the distance measurement value from the phase change coefficient may be performed using the following relational expression. There is a relationship of D∝C·Δφ / (2π·Δf) between the device distance (D), the differential frequency (Δf), and the phase difference (Δφ). There is a relationship of α=Δφ / Δf between the phase change coefficient (α), the differential frequency (Δf), and the phase difference (Δφ). From the above relationship, the anchor 3 can calculate the device distance using D=k·C·α / 2π. The parameter "C" in the expression represents the propagation speed of radio waves (3×10^8 m / sec). The parameter "k" is a design value and is set to 1.0 or 0.5. If D is the one-way distance, k may be set to 0.5. Also, if D is the round-trip distance, k may be set to 1.

[0146] The anchors 3 may individually detect the reception phase for each channel by transmitting and receiving CW signals to and from the user device 9, or may collect the reception phase for each channel using sniffer (sniffing) technology. Sniffing / sniffing is a technology in which the anchors 3 eavesdrop on communications between the user device 9 and the gateway module using channel information provided by the gateway module. The gateway module is one of the SRWC modules installed in the vehicle Hv that is responsible for bidirectional communication with the user device 9. The gateway module may be the wireless communication module 24. The channel information indicates the channel used for data communication between the gateway module and the user device 9. The channel information may be a specific channel number or a parameter (so-called hop increment) indicating a transition rule for the channel in use. The channel information preferably includes the currently used channel number and the hop increment.

[0147] In short-range communications such as Bluetooth LE, frequency hopping occurs after a communication connection is established. Therefore, typically, only the connected gateway module can capture data signals from the user device 9. In contrast, with sniffer technology, channel information is deployed to each anchor 3, allowing the anchor 3 to also capture data signals from the user device 9. By referencing the channel information, the anchor 3 can determine which of the many channels available in short distances can be used to receive a signal from the user device 9. As a result, the anchor 3 can detect the reception strength, reception phase, reception time, and other characteristics of the signal from the user device 9 without a communication connection. Therefore, a configuration employing sniffer technology has the advantage of enabling multiple SRWC modules to calculate distance measurements and detect reception strength in parallel. While this supplementary note describes a configuration in which the anchor 3 calculates distance measurements, the processor 21 may instead collect reception phase information for each channel from the anchor 3 and calculate the distance measurements.

[0148] <Communication Method> The method of data communication between the user device 9 and the smart ECU 2 is not limited to Bluetooth LE, and may be Bluetooth Classic, Wi-Fi (registered trademark), EnOcean (registered trademark), Zigbee (registered trademark), etc. The wireless protocol used for data communication (communication connection) may be referred to as the first wireless protocol, and the wireless protocol used for ranging communication may be referred to as the second wireless protocol.

[0149] Ranging communication may be performed using a communication method other than Bluetooth LE. For example, the anchor 3 may be configured to perform ranging communication using UWB communication. UWB communication is wireless communication using the UWB-IR (Ultra-Wide Band - Impulse Radio) method. The anchor 3 and the user device 9 may be configured to transmit and receive impulse radio waves (hereinafter, referred to as impulse signals) used in UWB communication. The impulse signal used in UWB communication may be a signal with an extremely short pulse width (e.g., 2 nsec) and a bandwidth (i.e., ultra-wide bandwidth) of 500 MHz (strictly speaking, 499.2 MHz) or more. Hereinafter, the term "UWB signal" may be interpreted as a signal exchanged in UWB communication.

[0150] <Supplementary Remark (1)> The present disclosure also includes the following technical ideas. In addition, methods, programs, and computer-readable recording media on which programs are stored that correspond to the following technical ideas are also included in the scope of the present disclosure.

[0151] [Technical Idea 1] An in-vehicle system comprising: a communication device (3) configured to be able to perform wireless communication with a portable device used by a vehicle user using a predetermined communication method; and a control unit (2) that determines the position of the portable device relative to the vehicle based on the reception strength of a signal from the portable device received by the communication device, wherein the control unit comprises: a threshold memory unit (M2) in which a threshold for the reception strength used to determine the position of the portable device is registered, the threshold being designed based on communication characteristics of a predetermined reference device; and a characteristic data memory unit (M3) for storing data indicating the communication characteristics of the portable device, wherein the control unit is configured to: acquire the reception strength from the communication device; generate characteristic data indicating a difference in communication characteristics between the portable device and the reference device based on the reception strength detected when the portable device is placed in a predetermined position, and store the generated characteristic data in the characteristic data memory unit; and determine the position of the portable device based on the characteristic data stored in the characteristic data memory unit, the reception strength detected by the communication device, and the threshold. The predetermined position does not refer to a specific location, but may be interpreted as a predetermined area having a diameter of about 0.5 m. The predetermined position may be inside or outside the vehicle. The threshold value may be the activation intensity or a threshold value used for determining whether the vehicle is inside or outside, such as an interior determination intensity.

[0152] [Technical Idea 2] The position determination system according to Technical Idea 1, wherein the communication device is an inner communication device (3p, 3q) that is a communication device arranged inside the vehicle, the predetermined position is a predetermined position inside the vehicle, the communication method is a communication method that can use a plurality of frequencies, and the control unit is configured to: acquire the reception strength at the plurality of frequencies from the inner communication device, calculate an average value of the reception strength for each of the frequencies, and generate the characteristic data based on the average value.

[0153] [Technical Idea 3] The control unit is configured to: acquire the reception strength for each frequency when the portable device is placed at the predetermined position in a first attitude; acquire the reception strength for each frequency when the portable device is placed at the predetermined position in a second attitude different from the first attitude; and generate the characteristic data based on an average of the reception strength for each frequency acquired when the portable device is placed at the predetermined position in the first attitude and the reception strength for each frequency acquired when the portable device is placed at the predetermined position in the second attitude.

[0154] [Technical Idea 4] The position determination system described in Technical Idea 2 or 3, wherein the communication device includes a plurality of inner communication devices (3p, 3q) arranged inside the vehicle, and the control unit is configured to: acquire the reception strength for each of the frequencies detected by each of the plurality of inner communication devices when the portable device is arranged at the predetermined position; and generate the characteristic data based on an average value of the reception strength for each of the frequencies detected by each of the plurality of inner communication devices.

[0155] [Technical Idea 5] A position determination system described in any one of Technical Ideas 1 to 4, wherein the communication device is an inner communication device (3p, 3q) that is a communication device arranged inside the vehicle, the predetermined position is a predetermined position inside the vehicle, and the control unit is configured to determine whether or not there is an occupant inside the vehicle based on a signal from an on-board sensor, and if it is determined that there is no occupant inside the vehicle, to cause the communication device to perform wireless communication to generate the characteristic data.

[0156] [Technical Idea 6] The position determination system according to any one of Technical Ideas 1 to 5, wherein the communication device is an inner communication device (3p, 3q) that is a communication device arranged inside the vehicle, the predetermined position is a predetermined position inside the vehicle, and the control unit is configured to: determine whether all doors of the vehicle are closed based on signals from an on-board sensor; determine whether the portable device is arranged at the predetermined position based on signals from an on-board sensor, an input device installed in the vehicle, the portable device, or the communication device; and cause the communication device to perform wireless communication to generate the characteristic data when it is determined that all the doors are closed and the portable device is arranged at the predetermined position.

[0157] [Technical Idea 7] A position determination system according to any one of Technical Ideas 1 to 6, wherein the characteristic data is data indicating the difference between an expected value of the reception strength of the signal transmitted from the reference device and the reception strength of the signal transmitted from the mobile device.

[0158] [Technical Idea 8] A position determination system described in any one of Technical Ideas 1 to 7, wherein the communication device includes an outer communication device (3a) that is a communication device arranged on the outer surface of the vehicle, the predetermined position is a predetermined position outside the vehicle, and the control unit is configured to generate the characteristic data based on the reception strength of a signal corresponding to a direct wave, among the reception strengths detected when the control unit is arranged at the predetermined position.

[0159] [Technical Idea 9] The position determination system according to Technical Idea 8, wherein the control unit is configured to acquire the reception strength of the direct wave in a situation where the portable device is placed at the predetermined position in different postures, and generate the characteristic data based on the maximum value of the reception strength for each posture.

[0160] [Technical Idea 10] The position determination system described in Technical Idea 8 or 9, wherein the communication device includes a plurality of outer communication devices arranged on an outer surface of the vehicle, and the control unit is configured to: acquire the reception strength of the direct wave detected by each of the plurality of outer communication devices when the portable device is arranged at the predetermined position; and generate the characteristic data based on the maximum value of the reception strength of the direct wave detected by each of the plurality of outer communication devices.

[0161] [Technical Idea 11] The control unit is configured to perform the following: cause the outer communication device to perform ranging communication, which is wireless communication for measuring the distance to the portable device; obtain from the outer communication device or the portable device a ranging value indicating the distance from the outer communication device to the portable device as a result of the ranging communication; correct the reception strength based on the ranging value and the characteristic data; and generate the characteristic data using the corrected reception strength.

[0162] <Supplementary Note (2)> The various flowcharts shown in this disclosure are all examples, and the number of steps constituting the flowcharts and the execution order of the processes can be changed as appropriate. The controls shown in each flowchart may be combined / executed in parallel to the extent that there is no contradiction. Expressions such as acquisition, determination, detection, generation, and calculation may be interchangeable. When a device acquires certain data, it also includes the device generating the data based on a signal input from another device / sensor.

[0163] The devices, systems, and methods described herein may be implemented by a special-purpose computer comprising a processor programmed to execute one or more functions embodied in a computer program. The devices and methods described herein may be implemented using dedicated hardware logic circuits. The devices and methods described herein may be implemented by one or more special-purpose computers configured by combining a processor executing a computer program with one or more hardware logic circuits. The processor may be any computing core, such as a CPU, MPU, GPU, or DFP (Data Flow Processor). The processor of the present disclosure may be understood as a device that performs predetermined processing based on an input signal and generates and outputs a signal / data different from the input signal. Some or all of the functions of the smart ECU may be implemented using a system-on-chip (SoC), an integrated circuit (IC), or a field-programmable gate array (FPGA).

[0164] The computer program includes instructions that are executed by a computer. The computer program may be stored in a computer-readable non-transitory tangible storage medium. The storage medium for the computer program may be a variety of media, such as a hard-disk drive (HDD), a solid-state drive (SSD), or a flash memory.

Claims

1. A vehicle-mounted system comprising: a communication device (3) configured to be capable of wireless communication with a portable device used by a vehicle user using a predetermined communication method; and a control unit (2) that determines a position of the portable device relative to the vehicle based on a reception strength of a signal from the portable device received by the communication device, wherein the control unit comprises: a threshold memory unit (M2) in which a threshold for the reception strength used to determine the position of the portable device, the threshold being designed based on communication characteristics of a predetermined reference device, is registered; and a characteristic data memory unit (M3) for storing data indicating the communication characteristics of the portable device, wherein the control unit is configured to: acquire the reception strength from the communication device; generate characteristic data indicating a difference in communication characteristics between the portable device and the reference device based on the reception strength detected when the portable device is placed in a predetermined position, and store the generated characteristic data in the characteristic data memory unit; and determine the position of the portable device based on the characteristic data stored in the characteristic data memory unit, the reception strength detected by the communication device, and the threshold.

2. The position determination system of claim 1, wherein the communication device is an inner communication device (3p, 3q) that is a communication device arranged inside the vehicle, the specified position is a specified position inside the vehicle, the communication method is a communication method that can use a plurality of frequencies, and the control unit is configured to: acquire the reception strength at the plurality of frequencies from the inner communication device, calculate an average value of the reception strength for each of the frequencies, and generate the characteristic data based on the average value.

3. The location determination system of claim 2, wherein the control unit is configured to: acquire the reception strength for each frequency when the portable device is placed at the specified position in a first attitude; acquire the reception strength for each frequency when the portable device is placed at the specified position in a second attitude different from the first attitude; and generate the characteristic data based on an average of the reception strength for each frequency acquired when the portable device is placed at the specified position in the first attitude and the reception strength for each frequency acquired when the portable device is placed at the specified position in the second attitude.

4. The position determination system of claim 2, wherein the communication device includes a plurality of inner communication devices (3p, 3q) arranged in the vehicle, and the control unit is configured to: acquire the reception strength for each of the frequencies detected by each of the plurality of inner communication devices when the portable device is arranged in the specified position; and generate the characteristic data based on an average value of the reception strength for each of the frequencies detected by each of the plurality of inner communication devices.

5. The position determination system of claim 1, wherein the communication device is an inner communication device (3p, 3q) that is a communication device arranged inside the vehicle, the predetermined position is a predetermined position inside the vehicle, and the control unit is configured to determine whether or not there is an occupant in the vehicle based on a signal from an on-board sensor, and when it is determined that there is no occupant in the vehicle, to cause the communication device to perform wireless communication to generate the characteristic data.

6. The position determination system of claim 1, wherein the communication device is an inner communication device (3p, 3q) that is a communication device arranged inside the vehicle, the predetermined position is a predetermined position inside the vehicle, and the control unit is configured to: determine whether all doors of the vehicle are closed based on a signal from an on-board sensor; determine whether the portable device is arranged at the predetermined position based on a signal from an on-board sensor, an input device installed in the vehicle, the portable device, or the communication device; and, when it is determined that all the doors are closed and the portable device is arranged at the predetermined position, cause the communication device to perform wireless communication to generate the characteristic data.

7. The position determination system according to claim 1, wherein the characteristic data is data indicating a difference between an expected value of a reception strength of a signal transmitted from the reference device and the reception strength of a signal transmitted from the mobile device.

8. The position determination system of claim 1, wherein the communication device includes an outer communication device (3a) that is a communication device arranged on the outer surface of the vehicle, the specified position is a specified position outside the vehicle, and the control unit is configured to generate the characteristic data based on the reception strength of a signal corresponding to a direct wave, among the reception strengths detected when the communication device is arranged at the specified position.

9. The position determination system of claim 8, wherein the control unit is configured to: acquire the reception strength of the direct wave in a situation where the portable device is placed at the specified position in different postures; and generate the characteristic data based on the maximum value of the reception strength for each posture.

10. The position determination system of claim 8, wherein the communication device includes a plurality of outer communication devices arranged on an outer surface of the vehicle, and the control unit is configured to: acquire the reception strength of the direct wave detected by each of the plurality of outer communication devices when the portable device is arranged at the specified position; and generate the characteristic data based on the maximum value of the reception strength of the direct wave detected by each of the plurality of outer communication devices.

11. The position determination system of claim 8, wherein the control unit is configured to: cause the outer communication device to perform ranging communication, which is wireless communication for measuring the distance to the portable device; obtain from the outer communication device or the portable device a ranging value indicating the distance from the outer communication device to the portable device as a result of the ranging communication; correct the reception strength based on the ranging value and the characteristic data; and generate the characteristic data using the corrected reception strength.

12. A method for determining a location comprising: acquiring a reception strength of a signal from a portable device from a communication device configured to be capable of wireless communication with the portable device using a specified communication method; accessing a threshold memory unit (M2) in which a threshold for the reception strength for determining the location of the portable device, the threshold designed based on the communication characteristics of a specified reference device, is registered, and reading out the threshold from the threshold memory unit; generating characteristic data indicating the communication characteristics of the portable device based on the reception strength detected when the portable device is placed in a specified location; storing the generated characteristic data in a characteristic data memory unit (M3); and determining the location of the portable device based on the characteristic data stored in the characteristic data memory unit, the reception strength detected by the communication device, and the threshold.

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