Location determination system, location determination method

Abstract

To provide a position determination system and position determination method each of which enables a position of a mobile device to be highly accurately determined based on a signal to be emitted from the mobile device.SOLUTION: A communication control unit F2 acquires reception strength of a signal from a mobile device in each of a plurality of outdoor equipment and a plurality of indoor equipment. The communication control unit F2 causes each outdoor equipment to perform transmission / reception for distance measurement signal with the mobile device in order, thereby acquiring a two-frequency phase difference or RTT (a round trip time) as a ToF related value for each outdoor equipment. A position estimation unit F3 determines whether the mobile device is present in a vehicle compartment on the basis of the reception strength observed by the indoor equipment and reception strength observed by the outdoor equipment. The communication control unit F2 determines whether the mobile device is present within a locking and unlocking area by use of distance information to be determined by the two-frequency phase difference or RTT.SELECTED DRAWING: Figure 5

Description

Technical Field

[0005] ,

[0004] ,

[0001] The present disclosure relates to a position determination system and a position determination method for estimating the relative position of a mobile device with respect to a vehicle based on the reception status of a wireless signal transmitted from the mobile device carried by a user and used in a system mounted on the vehicle.

Background Art

[0002] As a subsystem for realizing a vehicle electronic key system that performs unlocking of a door or the like according to the position of a mobile device carried by a user, there is a position determination system that estimates the position of the mobile device by performing wireless communication between an in-vehicle device and the mobile device. For example, Patent Document 1 discloses a configuration for determining that the mobile device exists in an unlocking area based on the fact that the in-vehicle device can perform wireless communication with the mobile device using radio waves in the LF (Low Frequency) band. The unlocking area is an area that allows automatic unlocking of the door by wireless communication between the mobile device, and is an area within a predetermined distance from the door among the areas outside the vehicle compartment.

[0003] Generally, in a vehicle electronic key system, from the viewpoint of preventing theft or the like, when the user is separated from the vehicle by a certain distance (for example, 2 m) or more, it may be a system requirement not to perform automatic unlocking of the door by wireless communication with the mobile device. The above-mentioned unlocking area is often set in an area within 2 m from the vehicle, such as within 1 m from the door, from the above-mentioned security viewpoint.

[0004] In many vehicle electronic key systems / position determination systems, the reason why radio waves in the LF band are used for signal transmission from the vehicle to the mobile device is that it is easy to limit the reach of the wireless signal to the vicinity of the vehicle. The antenna for transmitting radio waves in the LF band in the vehicle is adjusted in terms of transmission power and the like so that the wireless signal reaches only the unlocking area.

[0005] Incidentally, in recent years there has been a growing demand to use portable information processing devices such as smartphones and wearable devices as vehicle keys. Accordingly, there is a need for a configuration that can determine the location of a portable device relative to a vehicle using the received strength of high-frequency radio waves used in short-range communications such as Bluetooth®, instead of LF band radio waves.

[0006] Patent Document 2 discloses a configuration in which an authentication device determines whether a mobile device, such as a smartphone, is located near an outdoor door, i.e., in the locking / unlocking area, based on the received strength of a signal compliant with a predetermined short-range wireless communication standard emitted from the mobile device. Here, short-range communication refers to communication compliant with a predetermined wireless communication standard, such as Bluetooth or Wi-Fi (registered trademark), which has a communication range of, for example, several tens of meters.

[0007] Furthermore, Patent Documents 3-7 disclose various configurations for accurately estimating the position of a mobile device. The contents of these prior art documents can be incorporated by reference as explanations of the technical elements in this specification. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Patent No. 5438048 [Patent Document 2] Japanese Patent Publication No. 2020-85487 [Patent Document 3] Japanese Patent Publication No. 2020-26996 [Patent Document 4] Japanese Patent Publication No. 2020-26998 [Patent Document 5] Japanese Patent Publication No. 2019-158765 [Patent Document 6] Japanese Patent Publication No. 2019-73960 [Patent Document 7] Japanese Patent Publication No. 2018-141771 [Overview of the project] [Problems that the invention aims to solve]

[0009] Short-range communications such as BLE (Bluetooth Low Energy) use radio waves above 900MHz (hereinafter referred to as high-frequency radio waves), such as 2.4GHz or 920MHz. Compared to LF band radio waves, these high-frequency radio waves have stronger directivity and are easily reflected by metal objects such as vehicle bodies. In addition, high-frequency radio waves experience less signal attenuation with propagation distance compared to LF band radio waves. Furthermore, high-frequency radio waves are easily attenuated by the human body. Therefore, it is practically difficult to accurately determine whether a mobile device is in the outdoor operating area based on the received strength of the high-frequency signal emitted from the mobile device. The outdoor operating area here refers to areas outside the vehicle where some vehicle controls can be performed, such as the locking / unlocking area. The non-operating area refers to the area located outside the outdoor operating area.

[0010] Furthermore, because elements that obstruct radio wave propagation, such as the vehicle body, exist between the inside and outside of the vehicle, there can be a significant difference in the received signal strength of the signal transmitted from the mobile device to the in-vehicle communication device depending on whether the mobile device is inside or outside the vehicle. Therefore, it is possible to determine with a certain degree of accuracy whether or not a mobile device is inside the vehicle based on the received signal strength.

[0011] However, there is no structure such as the vehicle body between the outdoor operating area and the non-operating area. Therefore, in the configuration disclosed in Patent Document 2, it is practically difficult to determine whether the portable device is located in the outdoor operating area or the non-operating area of ​​the vehicle's exterior.

[0012] This disclosure was made in response to the above-mentioned problems, and one of its objectives is to provide a location determination system and method that can more accurately determine the location of a mobile device based on signals emitted from the mobile device. [Means for solving the problem]

[0013] The location determination system disclosed herein is a vehicle location determination system that determines the location of a portable device carried by a vehicle user by wirelessly communicating with the portable device, comprising: a plurality of outdoor units (7a to 7e) configured to be able to wirelessly communicate with the portable device and installed at different locations on the exterior surface of the vehicle; at least one indoor unit (7p to 7r) which is a communication device installed inside the vehicle's cabin; a communication control unit (F2) that controls the operation of the plurality of outdoor units and at least one indoor unit; and a location estimation unit (F3) that determines whether the portable device is inside the vehicle cabin and whether the portable device is in an outdoor operating area (Lx, Rm) which is an area outside the vehicle cabin that is within a predetermined distance from the vehicle, wherein the communication control unit performs the following: obtaining the received signal strength from the portable device at each of the plurality of communication units and obtaining a ToF-related value which is a parameter separate from the received signal strength that directly or indirectly indicates the time of flight of radio waves from at least one outdoor unit to the portable device, and the location estimation unit , mobile Whether or not a band device is present inside the vehicle. 、 The determination is based on the signal strength observed by the outdoor unit and the signal strength observed by the indoor unit. And if the mobile device is determined to be outside the vehicle Whether or not a portable device is present in the outdoor operating area of The determination is made based on ToF-related values.

[0014] Furthermore, the location determination method of the present disclosure is a location determination method performed by at least one processor for determining the location of a portable device carried by a vehicle user, comprising: acquiring data indicating the received signal strength from a portable device from a plurality of outdoor units, each located at different positions on the exterior surface of the vehicle, and acquiring data indicating the received signal strength from a portable device from at least one indoor unit, which is a communication device located inside the vehicle cabin. , roomBased on the received signal strength observed by the outdoor unit and the received signal strength observed by the indoor unit, determining whether a mobile device is present in the vehicle interior, and obtaining a ToF-related value, which is a parameter different from the received signal strength, that directly or indirectly indicates the propagation time of radio waves from at least one outdoor unit to the mobile device. If the mobile device is determined to be outside the vehicle based on the signal strength, Based on the ToF-related value, determining whether the mobile device is present within an outdoor operation area (Lx, Rm), which is an area within a predetermined distance from the vehicle outside the vehicle.

[0015] In the above position determination system / position determination method, the physical parameters used in the determination process are changed between determining whether the mobile device is present indoors and determining whether the mobile device is present in the outdoor unlocking area. That is, the received signal strength is used for determining whether it is present indoors, while a ToF-related value that directly or indirectly indicates the propagation time of the wireless signal from the communication device to the mobile device is used for determining whether it is present in the outdoor unlocking area. Since the propagation time of the wireless signal is proportional to the distance from the communication device to the mobile device, the ToF-related value directly or indirectly indicates the distance from the communication device to the mobile device. And the ToF-related value is less affected by the human body, and it can be expected to take a value corresponding to the distance to the device compared to the received signal strength. Therefore, according to the above configuration, the determination accuracy of whether the mobile device is present in the outdoor operation area can be improved compared to the configuration that determines based on the strength of the received signal strength. That is, the position of the mobile device can be determined more accurately based on the signal emitted from the mobile device.

[0016] The reference signs in parentheses described in the claims indicate the correspondence with the specific means described in the embodiments to be described later as one aspect, and do not limit the technical scope of the present disclosure.

Brief Description of the Drawings

[0017] [Figure 1] It is a block diagram showing an overall view of an electronic key system for a vehicle. [Figure 2]It is a block diagram showing the configuration of a BLE communication device. [Figure 3] It is a diagram showing an example of the mounting position of a BLE communication device. [Figure 4] It is a block diagram showing the configuration of a mobile device. [Figure 5] It is a functional block diagram of a smart ECU. [Figure 6] It is a flowchart regarding connection-related processing. [Figure 7] It is a flowchart regarding standby processing. [Figure 8] It is a flowchart regarding in-vehicle / out-of-vehicle determination processing. [Figure 9] It is a diagram for explaining the outline of the sniffing method. [Figure 10] It is a flowchart regarding locked / unlocked area determination processing. [Figure 11] It is a flowchart regarding intensity adjustment processing. [Figure 12] It is a diagram showing an example of the adjustment mode of transmission power according to the device position. [Figure 13] It is a diagram showing a modified example of the mounting pattern of a BLE communication device. [Figure 14] It is a diagram showing a modified example of the mounting pattern of a BLE communication device. [Figure 15] It is a diagram showing a modified example of the mounting pattern of a BLE communication device. [Figure 16] It is a diagram showing a modified example of the mounting pattern of a BLE communication device. [Figure 17] It is a diagram showing a modified example of the mounting pattern of a BLE communication device. [Figure 18] It is a flowchart regarding a modified example of locked / unlocked area determination processing. [Figure 19] It is a diagram showing variations of estimation materials of device position and an example of the observation subject. [Figure 20] It is a diagram for explaining the calculation principle of the transmission / reception phase difference by the passive two-way method. [Figure 21]This diagram illustrates the principle of calculating the transmission / reception phase difference using an active two-way system. [Figure 22] This diagram illustrates the principle of calculating the transmission / reception phase difference using a one-way system. [Figure 23] This figure shows an example configuration of an in-vehicle system 1 capable of transmitting a wake signal. [Figure 24] This figure shows an example of a system configuration that uses a UWB communication device to estimate the location of a mobile device. [Modes for carrying out the invention]

[0018] Hereinafter, an example of an embodiment of the vehicle electronic key system according to this disclosure will be described with reference to the figures. Figure 1 is a diagram showing an example of a schematic configuration of the vehicle electronic key system. As shown in Figure 1, the vehicle electronic key system includes an in-vehicle system 1 and a portable device 2. The in-vehicle system 1 is a system installed in the vehicle Hv. The portable device 2 is a device carried by the user of the vehicle Hv. There may be multiple portable devices 2. The vehicle electronic key system corresponds to the location determination system.

[0019] <Introduction> In the following explanation, "vehicle Hv" refers, for example, to a vehicle owned by an individual. Therefore, the user of vehicle Hv refers to the owner or their family. Of course, vehicle Hv may also be a company car owned by a company or an official vehicle owned by a public institution. If vehicle Hv is a company car or official vehicle, a person belonging to the organization that manages the vehicle Hv may be the user. Furthermore, vehicle Hv may be a vehicle used for rental services (so-called rental cars) or a vehicle used for car-sharing services (so-called shared cars). Vehicle Hv may also be a vehicle used for passenger transport services, such as a robot taxi. If vehicle Hv is a vehicle used for the above services (hereinafter referred to as a service vehicle), a person who has entered into a service usage contract and has the authority to temporarily use the vehicle Hv based on a service reservation, etc., may be the user.

[0020] In this embodiment, vehicle Hv is assumed to be an engine-powered vehicle. However, vehicle Hv may also be an electric vehicle such as a hybrid vehicle or an electric vehicle. Here, engine-powered vehicle refers to a vehicle equipped with only an engine as a power source, while hybrid vehicle refers to a vehicle equipped with both an engine and a motor as power sources. Engine-powered vehicles also include diesel vehicles. Electric vehicles refer to vehicles equipped with only a motor as a drive source. Also, as an example, vehicle Hv is assumed to be a vehicle with the driver's seat on the right side, but vehicle Hv may also be a vehicle with the driver's seat on the left side. In the following description, the front-rear, left-right, and up-down directions are defined relative to vehicle Hv. The front-rear direction corresponds to the longitudinal direction of vehicle Hv. The left-right direction corresponds to the width direction of vehicle Hv. The up-down direction corresponds to the height direction of vehicle Hv. Furthermore, this disclosure is not limited to four-wheeled vehicles, but can be mounted on a variety of vehicles that can travel on roads, such as trailers, two-wheeled vehicles, and three-wheeled vehicles. Motorized bicycles can also be included in the category of two-wheeled vehicles.

[0021] <Overview> Both the in-vehicle system 1 and the portable device 2 are configured to enable short-range communication. Here, short-range communication refers to communication compliant with a predetermined short-range wireless communication standard, where the actual communication range is, for example, 5m to 30m, and at most about 100m. Examples of short-range communication standards that can be used here include BLE (Bluetooth Low Energy, Bluetooth is a registered trademark), Wi-Fi (registered trademark), and ZigBee (registered trademark). UWB-IR (Ultra Wide Band - Impulse Radio) can also be used as a short-range communication method.

[0022] In this embodiment, the operation of each part will be explained using the example where the in-vehicle system 1 and the portable device 2 are each configured to perform wireless communication compliant with the BLE standard (hereinafter referred to as BLE communication). Details of the communication method, such as communication connection and encrypted communication, are carried out by the sequence specified in the BLE standard.

[0023] In the following description, we will explain the case where the BLE communication device 7 installed in the vehicle Hv acts as the master in communication with the mobile device 2, and the mobile device 2 acts as the slave. In BLE communication, a slave is a device that intermittently transmits advertisement signals and performs data transmission and reception based on requests from the master. A slave is also called a peripheral. A master is a device that controls the communication connection state and communication timing with the slave. A master is also called a central. In another embodiment, the mobile device 2 may be configured to operate as the master in communication with the in-vehicle system 1.

[0024] An advertisement signal is a signal used to notify other devices of its own presence (i.e., to advertise). An advertisement signal can also be called an advertisement frame or an advertisement packet. Signals transmitted and received via BLE, such as advertisement signals, contain source information. Source information is, for example, unique identification information assigned to mobile device 2 (hereinafter referred to as the device ID). For the device ID, for example, a device address or a UUID (Universally Unique Identifier) ​​can be used. In Bluetooth, the device address can be represented by 48 bits. Also, the UUID can be represented by 128 bits. The device address may be a fixed public address or a random address. A public address is equivalent to a MAC (Media Access Control) address in Ethernet®.

[0025] Mobile device 2 holds key information for using the vehicle Hv and functions as an electronic key for the vehicle Hv using this key information. Here, key information refers to data used in the authentication process described later. Key information is data that proves that the person attempting to access the vehicle Hv is a user, that is, the legitimacy of the person attempting to access the vehicle Hv. Key information can also be called an authentication key, encryption key, or key code. Key information can be, for example, a string (value) obtained by encrypting a password set by the user using a predetermined hash function. Key information may also be generated based on the device ID.

[0026] Key information may differ for each mobile device 2. The in-vehicle system 1 stores and registers the key information for each mobile device 2, associating it with a device ID. Multiple mobile devices 2 may be distinguished by a key ID assigned in the order of registration, instead of a device ID. The device ID is represented by a length of approximately 48 bits (6 bytes) / 128 bits (16 bytes), while the key ID can be represented by a few bytes, such as 1 byte. The key information itself can be represented by a bit sequence with a length of 8 bits or more. Longer key information is preferable as it provides stronger security. Key information can be represented by, for example, 16 bytes or 27 bytes. A configuration with key information of 27 bytes or less allows all key information to be transmitted in a single packet during encrypted communication.

[0027] The in-vehicle system 1 performs automatic authentication via wireless communication with the mobile device 2. If authentication is successful, it then implements a passive entry / passive start system that controls the vehicle according to the user's position relative to the vehicle Hv. Vehicle control in this context includes actions such as locking / unlocking doors, turning the power on / off, and starting the engine.

[0028] For example, if the in-vehicle system 1 can confirm that the mobile device 2 is within a pre-set lock / unlock area Lx for the vehicle Hv, it will perform control such as locking or unlocking the doors based on user operation on the door button 5, which will be described later. Also, if the in-vehicle system 1 can confirm that the mobile device 2 is inside the vehicle via wireless communication with the mobile device 2, it will perform engine start control based on user operation on the start button 6, which will be described later.

[0029] The locking / unlocking area Lx is an area in which the in-vehicle system 1 performs predetermined vehicle controls, such as locking or unlocking the doors, based on the presence of a portable device 2 within that area. The locking / unlocking area Lx is a type of exterior operating area and can also be called a passive entry area. For example, the area near the driver's side door, the passenger side door, and the trunk door are set as the locking / unlocking area Lx. The area near the door refers to the range within a predetermined operating distance from the exterior door handle. The exterior door handle refers to the gripping member provided on the outer surface of the door for opening and closing the door.

[0030] The operating distance that defines the size of the locking / unlocking area Lx is, for example, 1.5m. Of course, the operating distance may be 1m or 0.7m. The operating distance is set to be less than 2m for security reasons. Hereafter, the area outside the vehicle interior that is further outside the locking / unlocking area Lx will be referred to as the non-operating area. The non-operating area may include an unlocking prohibited area that is more than 2m away from the vehicle.

[0031] Authentication of the mobile device 2 by the in-vehicle system 1 can be performed, for example, by a challenge-response method. The authentication process involves comparing the response code generated by the mobile device 2 based on key information with a verification code held or dynamically generated by the vehicle Hv, and can therefore also be called a matching process. Details of the authentication process will be described separately. Successful authentication of the mobile device 2 corresponds to determining that the person attempting to access the vehicle Hv is a legitimate user.

[0032] <About the configuration of in-vehicle system 1> This section describes the configuration and operation of the in-vehicle system 1. As shown in Figure 1, the in-vehicle system 1 includes a smart ECU 4, multiple door buttons 5, a start button 6, multiple BLE communication devices 7, a power supply ECU 11, a body ECU 12, a body system actuator 13, and a body system sensor 14. In the component names, ECU is an abbreviation for Electronic Control Unit, meaning an electronic control unit.

[0033] The smart ECU 4 is connected to the door button 5, the start button 6, and the BLE communication device 7 via dedicated signal lines. The smart ECU 4 is also connected to the power ECU 11 and body ECU 12, etc., via the in-vehicle network Nw, enabling mutual communication. The in-vehicle network Nw is a communication network built within the vehicle Hv. Various standards can be adopted for the in-vehicle network Nw, such as Controller Area Network (CAN: registered trademark) and Ethernet. Note that some components, such as the body ECU 12, may be connected to the smart ECU 4 via dedicated lines without going through the in-vehicle network Nw. The connection configuration between devices can be changed as appropriate.

[0034] The smart ECU 4 estimates the location of the mobile device 2 in cooperation with the BLE communication device 7 and other components. Furthermore, the smart ECU 4, in cooperation with other ECUs, implements vehicle control based on the estimated location of the mobile device 2. The smart ECU 4 is implemented using a computer. Specifically, the smart ECU 4 includes a processor 41, RAM 42, storage 43, I / O 44, and bus lines connecting these components. In this embodiment, the smart ECU 4 incorporates one BLE communication device 7. The smart ECU 4 corresponds to the vehicle authentication device.

[0035] The processor 41 is hardware for arithmetic processing (in other words, an arithmetic core) coupled with RAM (Random Access Memory) 42. The processor 41 is, for example, a CPU (Central Processing Unit). The processor 41 performs various processes to realize the functions of each functional unit described later by accessing RAM 42. RAM 42 is a volatile storage medium. The storage 43 is configured to include a non-volatile storage medium such as flash memory. The storage 43 stores various programs executed by the processor 41. When the processor 41 executes a program, it is equivalent to executing a method corresponding to that program, for example, a device location estimation method. The I / O 44 is a circuit module for communicating with other devices. The I / O 44 is implemented using analog circuit elements or ICs.

[0036] The storage 43 contains the device ID for each mobile device 2. The storage 43 also stores communication device setting data indicating the mounting position of each BLE communication device 7 on the vehicle Hv. The storage 43 corresponds to the memory device where the communication device setting data is stored. The mounting position of each BLE communication device 7 can be represented, for example, as a point on the vehicle coordinate system, which is a two-dimensional coordinate system centered at an arbitrary position on the vehicle Hv and parallel to both the width and longitudinal directions of the vehicle Hv. The X-axis forming the vehicle coordinate system can be set parallel to the vehicle width direction, and the Y-axis can be set parallel to the longitudinal direction of the vehicle. The center of the coordinate system can be, for example, the center of the vehicle body or the center of the rear axle.

[0037] Each BLE communication device 7 in the in-vehicle system 1 is assigned a unique communication device number. This communication device number functions as information for identifying multiple BLE communication devices 7. The storage 43 stores the installation location of each BLE communication device 7, associated with its communication device number, as communication device configuration data. Detailed information on the functions of the smart ECU 4 will be described separately.

[0038] The door button 5 is a button used by the user to unlock and lock the doors of the vehicle Hv. The door button 5 is located on or near the outer door handle provided on each door. When the door button 5 is pressed by the user, it outputs an electrical signal to the smart ECU 4 indicating that the button has been pressed. In addition, a touch sensor can be used to receive at least one of the user's unlock and lock commands. The touch sensor is a device that detects when the user is touching the door handle. The touch sensor can be provided on the outer door handle instead of the door button 5, or together with the door button 5.

[0039] The start button 6 is a push switch for the user to switch the driving power on / off. The driving power is the power supply for the vehicle Hv to run, and if the vehicle is an engine-powered vehicle, it refers to the ignition power. If the vehicle Hv is an electric vehicle or a hybrid vehicle, the driving power refers to the system main relay. The start button 6 can also be understood as a switch for starting the drive source (e.g., engine). When the start button 6 is pushed by the user, it outputs an electrical signal to the smart ECU 4 indicating that the push has been performed.

[0040] The BLE communication device 7 is a communication module for performing wireless communication with the mobile device 2 in accordance with the BLE standard. Each BLE communication device 7 comprises a circuit board 71, an antenna 72, a transceiver 73, and a communication microcontroller 74, as shown in Figure 2. The circuit board 71 is, for example, a printed circuit board. Electronic components constituting the BLE communication device 7, such as the antenna 72, are mounted on the circuit board 71. The antenna 72 is an antenna for transmitting and receiving radio waves in the frequency band used for BLE communication, i.e., the 2.4 GHz band. The 2.4 GHz band is an example of a predetermined frequency band. The frequency band used for BLE communication is from 2400 MHz to 2483.5 MHz. The antenna 72 is electrically connected to the transceiver 73. The antenna 72 may be configured as an array antenna made up of multiple antenna elements arranged in a row.

[0041] The transmitting / receiving unit 73 demodulates the signal received by the antenna 72 and provides it to the communication microcontroller 74. It also modulates the signal input from the smart ECU 4 via the communication microcontroller 74, outputs it to the antenna 72, and radiates it as radio waves. The transmitting / receiving unit 73 is connected to the communication microcontroller 74 so as to be able to communicate with it. The transmitting / receiving unit 73 includes a received signal strength detection unit 731 and a received phase detection unit 732. The received signal strength detection unit 731 is configured to sequentially detect the signal strength received by the antenna 72. The signal indicating the received signal strength detected by the received signal strength detection unit 731, or the measured value itself, may also be called RSSI (Received Signal Strength Indicator / Indication). The received signal strength detected by the received signal strength detection unit 731 is associated with a device ID indicating the source of the received signal and is sequentially provided to the communication microcontroller 74.

[0042] Furthermore, when a continuous wave (CW) signal for distance measurement is received, the receiving phase, which is the phase angle of the received signal with respect to the output signal of the local oscillator, is detected by the receiving phase detection unit 732. The receiving phase corresponds to the output value of an arctangent that takes the ratio of the Q (Quadrature-Phase) component to the I (In-Phase) component of the received signal as its input value. The magnitude of the I component corresponds to the intensity of the in-phase component of the received signal. The magnitude of the Q component corresponds to the intensity of the quadrature component of the received signal. The I component is obtained by multiplying the received signal by the carrier wave output by the local oscillator. The Q component is obtained by multiplying the received signal by a phase-shift signal obtained by shifting the phase of the output signal of the local oscillator by 90°. The phase-shift signal can be obtained by passing the output signal of the local oscillator through a phase-shift circuit, which is a circuit that shifts the phase by 90°. The local oscillator is a circuit that generates a sine wave or cosine wave of the carrier frequency and is implemented using, for example, a voltage-controlled oscillator (VCO). The phase detected by the receiver phase detection unit 732 is output to the communication microcontroller 74 in correspondence with the frequency of the received signal. The received phase may also be determined based on the IQ signal, which has been reduced in frequency to the baseband.

[0043] The communication microcontroller 74 is a microcomputer that controls the exchange of data with the smart ECU 4. The communication microcontroller 74 is implemented using a CPU, RAM, ROM (Read Only Memory), etc. The communication microcontroller 74 provides the received data input from the transmitting / receiving unit 73 to the smart ECU 4 sequentially or based on a request from the smart ECU 4. In addition, the communication microcontroller 74 has the function of authenticating the device ID of the mobile device 2 and performing encrypted communication with the mobile device 2 based on a request from the smart ECU 4. Various encryption methods can be used.

[0044] The communication microcontroller 74 outputs data indicating the received signal strength detected by the received signal strength detection unit 731 to the smart ECU 4 based on a request from the smart ECU 4. The communication microcontroller 74 may also be configured to output received signal strength data sequentially to the smart ECU 4 regardless of whether a request has been made from the smart ECU 4. Similar to the received signal strength, the communication microcontroller 74 outputs phase information for each frequency of the received signal to the smart ECU 4 either spontaneously or based on instructions from the smart ECU 4.

[0045] At least one BLE communication device 7 is provided in the vehicle Hv. In this embodiment, as an example, one BLE communication device 7 is built into the smart ECU 4. In addition, multiple BLE communication devices 7 are distributed at multiple locations on the vehicle outside the smart ECU 4. In this embodiment, as an example, the vehicle is equipped with BLE communication devices 7a to 7c, 7p to 7r, and 7x as shown in Figure 3.

[0046] BLE communication device 7a is located on the outer surface of the B-pillar on the right door. BLE communication device 7b is located on the outer surface of the B-pillar on the left door. For example, BLE communication devices 7a and 7b are positioned within 30 cm above the beltline on the B-pillars of the left and right doors. The beltline is the line that follows the lower edge of the side window and can also be called the waistline. BLE communication device 7c is located in the center of the rear bumper in the left-right direction.

[0047] BLE communication devices 7a to 7c correspond to the outdoor unit, which is the BLE communication device 7, installed on the outer surface of the vehicle. The BLE communication devices 7a to 7c as outdoor units correspond to a configuration that primarily receives signals from a portable device 2 located outside the vehicle. The outdoor units are preferably positioned near the B-pillar or outer door handle so that they can receive signals well from a portable device 2 carried by a user about to board the vehicle Hv. In this embodiment, as an example, each outdoor unit forms an individual locking / unlocking area Lx. For example, BLE communication device 7a forms the right-side area LxR, which is the locking / unlocking area Lx on the right side of the vehicle. Also, BLE communication device 7b forms the left-side area LxL, which is the locking / unlocking area Lx on the left side. BLE communication device 7c forms the rear-side area LxB, which is the locking / unlocking area Lx near the rear end.

[0048] The B-pillar can refer to two types: the door-side B-pillar, which is part of the door module, and the body-side B-pillar, which is a support / frame for the roof of the vehicle. The door-side B-pillar corresponds to the part of the front or rear passenger door that contacts the body-side pillar. In the following, "B-pillar" mainly refers to the door-side B-pillar. Unless otherwise specified, the door-side B-pillar as the mounting location for the outdoor unit refers to the part adjacent to the side window, i.e., the part above the lower edge of the side window. In other configurations, the outdoor unit may be located below the window frame of the door-side B-pillar or on the body-side B-pillar. The B-pillar refers to the second pillar from the front among the pillars of a vehicle hybrid. The B-pillar can also be called the center pillar. The third pillar from the front, or the pillar located behind the rear seats, is called the C-pillar. The A-pillar is the foremost pillar, which corresponds to the pillar located in front of the front seats.

[0049] The BLE communication device 7p is positioned on the interior side of the metal panel that makes up the right front door, at a position at least 0.1m below the window. For example, the BLE communication device 7p is positioned on the interior side of the right front door, within 20cm of the floor. The right front door refers to the door for the front passenger on the right side. The BLE communication device 7q is positioned on the left side of the vehicle, in a position corresponding to the BLE communication device 7p. That is, the BLE communication device 7q is positioned on the interior side of the metal panel that makes up the left front door, at a position at least 0.1m below the window. The left front door refers to the door for the front passenger located on the left side of the vehicle. The BLE communication device 7r is located in the trunk or on the back of the rear seat backrest.

[0050] BLE communication devices 7p to 7r correspond to the indoor unit BLE communication device 7 installed inside the vehicle. The indoor unit BLE communication devices 7p to 7r are configured primarily to receive signals from the portable device 2 located inside the vehicle.

[0051] It is preferable that the indoor unit be installed in a location where the outside of the vehicle is beyond the line of sight. A "beyond line of sight" for a given BLE communication device 7 refers to an area where signals transmitted from the BLE communication device 7 do not directly reach. However, signals transmitted from the BLE communication device 7 can reach areas beyond the line of sight through reflection by various structures. In other words, even if the portable device 2 is located outside the line of sight of the BLE communication device 7, wireless communication can still be performed between the two devices through reflection and diffraction by structures.

[0052] The indoor unit is positioned away from the position where it is paired with the outdoor unit, separated by a metal plate such as a door. The paired position refers to a position where the units are on opposite sides of a metal body. More specifically, the range where the distance from the outdoor unit is less than 20% of the target wavelength can be considered the position paired with the outdoor unit. Therefore, the indoor unit is positioned at a distance of 20% or more, more preferably 40% or more, of the target wavelength from the outdoor unit. The target wavelength here is the wavelength of the signal used for BLE communication, which is approximately 122 mm. Therefore, 20% of the target wavelength is approximately 2.5 cm, and 40% is approximately 5 cm. The above arrangement corresponds to a configuration where the indoor unit is positioned at least 10 cm or more away from the outdoor unit in the vertical or horizontal direction.

[0053] The BLE communication device 7x is built into the smart ECU 4. Figure 3 shows an example where the smart ECU 4 is mounted on the right C-pillar. The smart ECU 4 may be housed inside the instrument panel. Possible locations for housing the smart ECU 4 include the inside of the upper surface of the instrument panel or the inside of the center garnish. It is preferable that the BLE communication device 7x is positioned to communicate not only with the vehicle interior but also with the portable device 2 located outside the vehicle. The smart ECU 4, including the BLE communication device 7x, may be positioned in a location that allows a view to the outside of the vehicle through a window, such as on the ceiling of the vehicle interior. Alternatively, the BLE communication device 7x may be positioned separately from the smart ECU 4.

[0054] The mounting locations of the BLE communication device 7 described above are examples and can be changed as appropriate. For example, the BLE communication devices 7a and 7b, which are outdoor units, may be built into the outer door handles for the front seats, or they may be placed in the locker area below the door. The locker area also includes the inside of the side sill cover. The mounting location of the BLE communication device 7c may be near the rear license plate, near the rear window, near the trunk door handle, etc. In the description of the mounting locations of the BLE communication device 7, "near" a certain component refers to an area within, for example, 30 cm from that component. For example, "near the license plate" refers to an area within 30 cm from the license plate. "Near the door handle" also includes the inside of the door handle.

[0055] The BLE communication devices 7p and 7q, which function as indoor units, may be located at the base of the B-pillar on the vehicle side, or near the footwells of the driver and passenger seats. The base of the B-pillar on the vehicle side refers to the part within 20 cm of the floor. The BLE communication devices 7p and 7q may also be located near the inner door handle, on the door switch panel, door pocket, or armrest. The BLE communication device 7r may be embedded in the center of the rear seat, etc. Furthermore, the number of BLE communication devices 7 in the in-vehicle system 1 may be six or fewer, or eight or more. The in-vehicle system 1 may also have a BLE communication device 7 located near the front bumper / emblem.

[0056] In this disclosure, the BLE communication device 7 provided in the in-vehicle system 1 that is used for data communication with the mobile device 2 is referred to as the representative device or gateway communication device. In this disclosure, the BLE communication device 7x basically operates as the representative device. The setting of the representative device can be dynamically changed by the processor 41.

[0057] The smart ECU 4 uses one of the multiple BLE communicators 7 to perform a key exchange protocol (so-called pairing) with the mobile device 2. The device information, which is information about the mobile device 2 obtained through pairing, is stored in the storage 43 and also in the non-volatile memory of the communication microcontroller 74 of each BLE communicator 7. Device information includes, for example, the key exchanged through pairing and the device ID. If the vehicle Hv is shared by multiple users, device information for each mobile device 2 owned by each user is stored. Furthermore, if the vehicle Hv is a service car, the smart ECU 4 may obtain in advance the device information corresponding to the user who has made a reservation from the digital key server that issues key information and temporarily store it in a predetermined storage medium.

[0058] The BLE communication device 7x, and by extension the in-vehicle system 1, detects that the mobile device 2 is within short-range communication range of the in-vehicle system 1 by receiving signals transmitted from the mobile device 2, such as advertisement signals and scan response signals. The scan response signal corresponds to the response signal issued by the slave to a scan request signal issued by the master. Here, as an example, the mobile device 2 present around the vehicle is detected using a passive scan method in which the BLE communication device 7x acts as the master. The in-vehicle system 1 may also search for the mobile device 2 using an active scan method that involves sending a scan request. The two types of scan methods may be used interchangeably depending on the scene.

[0059] When the BLE communicator 7x receives an advertisement signal or scan response signal from the mobile device 2, it automatically establishes a communication connection with the mobile device 2 using stored device information. The smart ECU 4 then starts encrypted data communication with the mobile device 2. Once the BLE communicator 7x has established a communication connection with the mobile device 2, it provides the smart ECU 4 with the device ID of the connected mobile device 2 as connected device information.

[0060] In BLE communication, when a communication connection is established between devices, data is transmitted and received by sequentially changing between 37 channels. The representative BLE communication device 7x sequentially provides the communication control unit F2 with information indicating the channel to be used for communication with the mobile device 2 (hereinafter referred to as channel information). The channel information may be a specific channel number, or it may be a parameter indicating the channel transition rule (so-called hopIncrement). HopIncrement is a number between 5 and 16 that is randomly determined when the communication connection is established. Preferably, the channel information includes the current channel number and HopIncrement.

[0061] Each BLE communication device 7, located outside the smart ECU4, is connected to the smart ECU4 via a dedicated communication line or the in-vehicle network Nw, enabling mutual communication. Each BLE communication device 7 operates based on control signals from the communication control unit F2 of the smart ECU4. Each BLE communication device 7 also provides the smart ECU4 with received data and information regarding the reception status of signals from the mobile device 2. Information regarding the reception status of signals from the mobile device 2 will be described separately later.

[0062] The Power ECU 11 is an ECU that controls the on / off state of the driving power supply installed in the vehicle hybrid. For example, the Power ECU 11 sets the driving power supply to ON based on instruction signals from other ECUs, such as the Smart ECU 4 or the Body ECU 12. If the vehicle hybrid is a gasoline-powered vehicle, the Power ECU 11 starts the engine based on the above instruction signals.

[0063] The body ECU 12 is an ECU that controls the body system actuators 13 based on requests from the smart ECU 4 or the user. The body ECU 12 is communicatively connected to various body system actuators 13 and various body system sensors 14. Here, the body system actuators 13 refer to, for example, the door lock motors that constitute the locking mechanism of each door. The body system sensors 14 include courtesy switches located on each door. The courtesy switch is a sensor that detects the opening and closing of the door. The body ECU 12 locks or unlocks each door by outputting a predetermined control signal to the door lock motors provided on each door of the vehicle Hv, for example, based on a request from the smart ECU 4.

[0064] <Regarding Mobile Device 2> Mobile device 2 is a portable, general-purpose information processing terminal equipped with BLE communication capabilities. It has a digital key application 204 installed, which functions as an electronic key for a vehicle hybrid. Mobile device 2 can be, for example, a smartphone, tablet, or wearable device. Wearable devices are devices worn on the user's body and can take various forms, such as wristbands, watches, rings, glasses, or earphones.

[0065] The portable device 2 may be a smart key, which is a dedicated device that serves as the electronic key for the hybrid vehicle (HV). The smart key is a device that is transferred to the owner along with the HV when it is purchased. The smart key can be understood as one of the accessories of the HV. The smart key can take on a variety of shapes, such as a flat rectangular prism, a flat ellipsoid (so-called fob type), or a card type. The smart key may also be called a vehicle portable device, key fob, key card, or access key.

[0066] As shown in Figure 4, the portable device 2 comprises a device control unit 20, a display 21, a touch panel 22, a battery 23, a BLE communication unit 24, and a cellular communication unit 25.

[0067] The display 21 is, for example, a liquid crystal display or an organic EL display. The display 21 displays an image corresponding to the input signal from the device control unit 20. The touch panel 22 is a capacitive touch panel and is stacked on the display 21. The touch panel 22 and the display 21 constitute an interface for the user to register key information on the portable device 2 or to pair the portable device 2 with the in-vehicle system 1. The battery 23 is a secondary battery such as a lithium-ion battery.

[0068] The BLE communication unit 24 is a communication module for performing BLE communication. The general configuration of the BLE communication unit 24 can be the same as that of the BLE communication device 7. The BLE communication unit 24 is connected to the device control unit 20 in a way that allows for mutual communication. The BLE communication unit 24 receives data transmitted from the vehicle Hv and provides it to the device control unit 20, and also modulates data input from the device control unit 20 and transmits it to the vehicle Hv.

[0069] The cellular communication unit 25 is a communication module for connecting to the internet via a wireless base station and is configured to perform wireless communication compliant with standards such as 4G or 5G. The cellular communication unit 25 can receive, for example, a data package for installing the digital key application 204 from a predetermined application distribution server. Note that the cellular communication unit 25 is an optional element and may be omitted. Also, the mobile device 2 may be configured to access the internet via a Wi-Fi connection instead of a cellular connection such as 4G or 5G.

[0070] The device control unit 20 is configured as a computer, for example, equipped with a processor 201, RAM 202, storage 203, etc. The digital key application 204 is installed on the storage 203, etc. Key information is also stored on the storage 203. The digital key application 204 is an application for securely performing key information acquisition, storage, authentication processing, etc. The digital key application 204 is an optional element and may be omitted.

[0071] The device control unit 20 causes the BLE communication unit 24 to transmit an advertisement signal at a predetermined transmission interval. In another configuration, the portable device 2 may transmit a scan response based on a request from the in-vehicle system 1, such as a scan request.

[0072] Furthermore, when the device control unit 20 receives data from the BLE communication unit 24, it generates a baseband signal corresponding to the response signal of the received data and outputs it to the BLE communication unit 24. For example, when the BLE communication unit 24 receives a challenge code, it generates a response code using a predetermined procedure / function based on the challenge code and key information. It then outputs a baseband signal including the response code to the BLE communication unit 24. The baseband signal output by the device control unit 20 to the BLE communication unit 24 is modulated by the BLE communication unit 24 and transmitted as a wireless signal.

[0073] The device control unit 20 may be configured not to return a response code during user-defined downtime periods. This configuration reduces the risk of authentication succeeding when the user does not intend to use the vehicle Hv. Downtime periods can be manually set by the user to correspond to times when the vehicle Hv is unlikely to be used. For example, downtime periods may include times when the user is sleeping or at school or work. Downtime periods may also be automatically registered based on the user's activity history information. The user's activity history can be identified based on location information from a mobile device 2, such as GPS.

[0074] Furthermore, the device control unit 20 may be configured not to return a response code if the mobile device 2 remains stationary for a certain period of time or longer. Whether or not the mobile device 2 is stationary can be determined, for example, based on the output of an accelerometer or gyroscope sensor installed in the mobile device 2.

[0075] Furthermore, if the operation of the BLE communication unit 24 can be controlled on an application-by-application basis, the device control unit 20 may stop transmitting advertisements for vehicle Hv during downtime. Such a configuration can suppress power consumption due to unnecessary advertisements. Also, if the operation of the BLE communication unit 24 can be controlled on an application-by-application basis, the device control unit 20 may stop transmitting advertisements for vehicle Hv based on the fact that the mobile device 2 has been stationary for a certain period of time or longer. In addition, the device control unit 20 may be configured to prohibit communication connection with the in-vehicle system 1 based on the fact that it is a downtime period or that it has been stopped for a certain period of time or longer.

[0076] <About the functions of Smart ECU4> Here, the functions and operation of the smart ECU4 will be explained using Figure 5. The smart ECU4 provides functions corresponding to the various functional blocks shown in Figure 5 by executing programs stored in the storage 43. Specifically, the smart ECU4 comprises a vehicle information acquisition unit F1, a communication control unit F2, a position estimation unit F3, an authentication processing unit F4, and a vehicle control unit F5 as functional blocks. The communication control unit F2 comprises a strength collection unit F21, a representative unit selection unit F22, and a ToF-related value acquisition unit F23 as sub-functional units. The position estimation unit F3 comprises an in-vehicle / out-of-vehicle determination unit F31 and an out-of-vehicle position determination unit F32 as sub-functional units. The smart ECU4 also comprises a key information storage unit M1.

[0077] The key information storage unit M1 is a storage medium for storing information about a portable device 2 used as an electronic key for a vehicle hybrid (Hv). The key information storage unit M1 stores information for at least one portable device 2. The key information storage unit M1 stores key information for each portable device 2, associated with a key ID, device ID, user ID, etc. The user ID is an identifier used to identify multiple users and is set for each user. The key information may also be associated with and stored information such as expiration date, authority, and seat position.

[0078] The key information storage unit M1 is implemented using a portion of the storage area provided by the storage 43. Alternatively, the key information storage unit M1 may be implemented using a non-volatile storage medium physically independent of the storage 43. The key information storage unit M1 is configured to allow data writing, reading, and deletion by the processor 41.

[0079] The vehicle information acquisition unit F1 acquires various vehicle information indicating the status of the vehicle Hv from sensors, ECUs, switches, etc., mounted on the vehicle Hv. For example, the status of the vehicle power supply, the open / closed status of each door, the locked / unlocked status of each door, whether the door button 5 is pressed or not, whether the start button 6 is pressed or not, and the shift position are all considered vehicle information. The status of the vehicle power supply includes whether the driving power supply is on or not. The types of vehicle information are not limited to those described above. The output value of the brake sensor that detects the amount / force of the brake pedal depression and the signal indicating the operation status of the parking brake can also be included in the vehicle information.

[0080] The vehicle information acquisition unit F1 identifies the current state of the vehicle Hv based on the various information described above. For example, the vehicle information acquisition unit F1 determines that the vehicle Hv is parked when the engine is off and all doors are locked. The conditions for determining that the vehicle Hv is parked can be designed as appropriate, and a variety of determination conditions can be applied. In addition, acquiring electrical signals from the door buttons 5 and start button 6 is equivalent to detecting user operations on these buttons. The vehicle information acquisition unit F1 detects user operations on the vehicle Hv, such as opening and closing the doors, pressing the door buttons 5 and 6, and opening and closing the doors.

[0081] The communication control unit F2 controls the operation of the BLE communicator 7. The communication control unit F2 performs data communication with the mobile device 2 using the BLE communicator 7x. For example, the communication control unit F2 generates data addressed to the mobile device 2 with which it is connected and outputs it to the BLE communicator 7x. This causes the BLE communicator 7x to transmit a signal corresponding to the desired data as radio waves. The communication control unit F2 also receives data from the mobile device 2 that the BLE communicator 7x has received. In this embodiment, in a more preferred configuration, wireless communication between the smart ECU 4 and the mobile device 2 is performed using encryption.

[0082] The communication control unit F2 recognizes that a user is present in the vicinity of the vehicle Hv based on the reception of a BLE signal transmitted from the mobile device 2. The communication control unit F2 also obtains the device ID of the mobile device 2 with which it is communicating from the BLE communicator 7x. Even if the vehicle Hv is a vehicle shared by multiple users, the smart ECU 4 identifies the user present in the vicinity of the vehicle Hv based on the device ID of the mobile device 2 with which the BLE communicator 7 is communicating.

[0083] The communication control unit F2 acquires the received signal strength for each frequency from each BLE communication device 7 and from the mobile device 2. The strength collection unit F21 is configured to acquire the received signal strength for each frequency and for each communication device.

[0084] The communication control unit F2 can temporarily change the representative device for determining the location of the mobile device 2. For convenience, the state in which BLE communication device 7x is set as the representative device is referred to as the basic state. The state in which any BLE communication device 7 other than BLE communication device 7x is set as the representative device is referred to as the temporary change state. The sub-function unit that changes the representative device corresponds to the representative device selection unit F22.

[0085] The communication control unit F2 obtains ToF-related values, at least relative to the representative BLE communication device 7, by having the representative BLE communication device 7 communicate with the mobile device 2 for distance measurement. ToF-related values ​​are parameters that directly or indirectly indicate the time of flight of radio waves from the BLE communication device 7 to the mobile device. Distance measurement communication is communication to measure the distance from the representative BLE communication device 7 to the mobile device 2. The distance from the BLE communication device 7 to the mobile device 2 corresponds to the time of flight (ToF) of the signal. Identifying the distance to the mobile device 2 is equivalent to identifying the ToF.

[0086] Time of Flight (ToF) is determined based on the two-frequency phase difference and the round-trip time (RTT). The two-frequency phase difference and RTT correspond to ToF-related values. These ToF-related values ​​can also be called distance-related values. These ToF-related values ​​are parameters different from received signal strength. The two-frequency phase difference here is the difference between the transmitted and received phase differences observed at two different frequencies. The two-frequency phase difference corresponds to the amount of phase angle displacement due to the change in frequency. The transmitted and received phase difference corresponds to the phase difference between the transmitted CW signal and the received CW signal. The transmitted and received phase difference can also be simply called the phase angle. Conceptually, the two-frequency phase difference and the transmitted and received phase difference are the same as what is known as the two-frequency CW system in the technical field of radio wave ranging systems.

[0087] In this embodiment, as an example, the two-frequency phase difference for each frequency combination is used as the ToF-related value. In BLE communication, there are two or more frequencies used for communication, so two or more two-frequency phase differences with different frequency combinations, i.e., multi-frequency phase differences, can be obtained. The smart ECU4 of this embodiment estimates the device distance based on the multi-frequency phase differences.

[0088] In a configuration that uses multi-frequency phase difference as a ToF-related value, distance measurement communication can be understood as communication for identifying the transmission and reception phase difference for two or more frequencies. Transmitting and receiving CW signals on multiple frequencies can constitute distance measurement communication. The representative unit's communication microcontroller 74 observes the received phase at the operating frequency each time frequency hopping occurs. The communication microcontroller 74 also identifies the transmission and reception phase difference based on the observed received phase. The processor 41 obtains the transmission and reception phase difference for each frequency from the representative unit's communication microcontroller 74.

[0089] The calculation of the transmission / reception phase difference may also be performed by the processor 41 based on the received phase information provided by the communication microcontroller 74. Data acquisition in this disclosure is not limited to data input from an external source, but also includes data generation / detection through internal calculations. Furthermore, the processor 41 obtains multiple sets of dual-frequency phase differences for each frequency combination by combining the transmission / reception phase differences for each frequency. The sub-function unit that acquires the transmission / reception phase difference and thus the dual-frequency phase difference corresponds to the ToF-related value acquisition unit F23.

[0090] In addition, the communication control unit F2 can acquire data indicating the reception phase of the CW signal for each frequency from devices other than the representative device. The communication control unit F2 also provides data indicating the reception status of the signal from the mobile device 2 at each BLE communication device 7 to other function / circuit modules, such as the position estimation unit F3. The communication control unit F2 may also acquire the direction of arrival of the signal as information indicating the reception status of the signal from the mobile device 2. The direction of arrival of the signal can be estimated using various methods, such as the MUSIC method or the ESPRIT method. Received strength, phase, and direction of arrival can be called characteristics of the received signal.

[0091] The position estimation unit F3 estimates the position of the mobile device 2 based on the signal reception status from the mobile device 2 at each BLE communication device 7. In this disclosure, the position of the mobile device 2 may also be expressed as the device position. Since the mobile device 2 corresponds to the user, estimating the position of the mobile device 2 is equivalent to estimating the user's position.

[0092] The position estimation unit F3 sequentially performs device position estimation processing at predetermined estimation intervals while the BLE communication device 7x is in communication connection with at least one mobile device 2. The estimation interval can be 100 milliseconds. The estimation interval may also be 200 milliseconds or 150 milliseconds, etc. The position estimation processing by the position estimation unit F3 will be described separately later. Note that the position estimation unit F3 may be configured to estimate the position of the source based on the received signal if it is receiving a signal from the mobile device 2, even if there is no communication connection. If the position estimation unit F3 is receiving signals from multiple mobile devices 2, it may perform position estimation processing for each of the multiple mobile devices 2 in parallel. The position estimation unit F3 may be configured to determine the position of unregistered terminals as well as terminals that are not registered as mobile devices 2.

[0093] The vehicle interior / exterior determination unit F31, acting as a sub-function unit of the position estimation unit F3, is configured to determine whether or not the mobile device 2 is inside the vehicle based on the signal strength received from the mobile device 2 observed by the BLE communication device 7. The vehicle exterior position determination unit F32 is configured to determine whether or not the mobile device 2 is within the lock / unlock area Lx based on distance information from the outdoor unit to the mobile device 2, which is determined based on ToF-related values ​​described later. In this disclosure, determining whether or not the mobile device 2 is inside the vehicle is also referred to as vehicle interior / exterior determination. In this disclosure, determining whether or not the mobile device 2 is within the lock / unlock area Lx is also referred to as lock / unlock area determination. Details of the operation of the vehicle interior / exterior determination unit F31 and the vehicle exterior position determination unit F32, as well as the position estimation unit F3 / processor 41, will be described separately later.

[0094] The authentication processing unit F4 works in conjunction with the BLE communication device 7x to verify (in other words, authenticate) that the communication partner is the mobile device 2. The communication for authentication is encrypted. The authentication process itself can be carried out using various methods, such as a challenge-response method. For example, the authentication processing unit F4 sends a predetermined / randomly generated challenge code to the mobile device 2. It also generates a verification code using the challenge code and key information corresponding to the communication partner's device ID / key ID according to a predetermined procedure. Then, it compares the response code returned from the communication partner with the verification code and determines that authentication is successful based on whether the two match.

[0095] The timing at which the authentication processing unit F4 performs the authentication process can be, for example, when a communication connection is established between the BLE communication device 7 and the mobile device 2. The authentication processing unit F4 may also be configured to perform the authentication process at predetermined intervals while the BLE communication device 7 and the mobile device 2 are in communication. Alternatively, it may be configured to perform communication for authentication in response to a predetermined user operation on the vehicle Hv, such as when the start button 6 is pressed by the user or when a door is opened or closed.

[0096] The vehicle control unit F5 is configured to perform vehicle control in cooperation with the body ECU 12, etc., according to the location of the mobile device 2 (in other words, the user) and the state of the vehicle Hv, provided that authentication of the mobile device 2 by the authentication processing unit F4 is successful. The state of the vehicle Hv is determined by the vehicle information acquisition unit F1. The device location is determined by the location estimation unit F3. For example, if the vehicle control unit F5 determines that the mobile device 2 is inside the vehicle cabin and detects that the start button 6 has been pressed by the user, it will start the engine in cooperation with the power supply ECU 11. The inside of the vehicle cabin can be called the passive start area.

[0097] <Connection-related processing> Here, the connection-related processing will be explained using the flowchart shown in Figure 6. The connection-related processing is the process for establishing a communication connection with the mobile device 2 that approaches the vehicle Hv together with the user. The connection-related processing is mainly performed at predetermined scan intervals when the vehicle Hv is parked. The scan interval can be set to 100 milliseconds, 200 milliseconds, etc. The connection-related processing includes steps S11 to S15. The connection-related processing is performed by the processor 41 in cooperation with the BLE communication device 7x. Note that the various flowcharts in this disclosure are all examples, and the number of steps and processing order of each flowchart can be changed as appropriate.

[0098] First, in step S11, the communication control unit F2 sets the BLE communication device 7x to standby mode and performs a search for mobile devices 2 (so-called scanning). Standby mode here refers to a state in which advertised signals can be received. If no mobile devices 2 are detected as a result of scanning in step S11, the processing from step S12 onwards is omitted and this flow is terminated.

[0099] In step S12, the BLE communicator 7x is made to establish a communication connection with the mobile device 2 detected by scanning in step S11. The communication connection can be achieved by exchanging connection requests and responses. The processor 41 identifies the communication partner based on source information included in the advertisement signal, etc. The detailed sequence from scanning to communication connection and the start of encrypted communication should be carried out in accordance with the BLE standard.

[0100] In step S12, authentication of the communication partner is performed using, for example, a challenge code and the key information of the communication partner stored in the key information storage unit M1. The challenge code can be a random number of a predetermined length generated using a random number table or the like. If authentication of the communication partner is successful, the process moves to step S15 and enters standby mode. Standby mode corresponds to a state in which unlocking / locking, switching the driving power on / off, etc., can be performed based on user operations on the door button 5, etc. In one aspect, standby mode corresponds to a state in which the processor 41 recognizes that a legitimate portable device 2 is present in the vicinity of the vehicle. The vicinity of the vehicle includes the locking / unlocking area Lx and the interior of the vehicle.

[0101] In this embodiment, as an example, an expiration date is set for the authentication success result. Re-authentication is performed when the expiration date expires. Since the authentication process can be omitted within the expiration date, power consumption in the mobile device 2 and smart ECU 4 can be reduced. In addition, since the authentication process is performed for each expiration date, the risk of the vehicle Hv being misused can be reduced. The expiration date may be changed depending on the scene, such as whether the vehicle is in motion or not. Since the possibility of the mobile device 2 moving outside the vehicle compartment while driving is small, the expiration date while driving may be set to be a predetermined amount longer than when the vehicle is stopped. For example, the expiration date while stopped may be set to 1 second, 2 seconds, or 5 seconds, while the expiration date while driving may be set to 10 seconds or 20 seconds. Furthermore, the authentication processing unit F4 may be configured to re-execute the authentication process even if there is still time remaining in the expiration date if a predetermined event, such as the opening or closing of a door, is detected.

[0102] If the Smart ECU 4 fails to authenticate the mobile device 2, it may re-execute the authentication process, or it may operate the in-vehicle equipment so that the user can recognize that authentication has not been successful. For example, if authentication is unsuccessful, it may display a predetermined authentication failure image on the in-vehicle display / display 21, or it may illuminate lighting devices provided on the side mirrors, etc., in a predetermined pattern. When authentication fails, the Smart ECU 4 may display an authentication failure screen on the display 21 by transmitting a predetermined control signal. The fact that authentication has not been successful may also be expressed by the color of the light emitted from the welcome lights around the doors toward the road surface.

[0103] <Regarding operation in standby mode> The operation of the smart ECU 4 in standby mode will be explained using the flowchart shown in Figure 7. In standby mode, the processor 41 sequentially executes steps S21 to S28 shown in Figure 7 as an example.

[0104] In standby mode, as step S21, the processor 41 sequentially acquires position estimation information from each BLE communicator 7, which is information for determining the location of the mobile device 2. Position estimation information includes, for example, received signal strength. Received phase can also be included in the position estimation information. ToF-related values ​​also correspond to a type of position estimation information. If the processor 41 determines that the mobile device 2 is outside the vehicle, it may acquire the transmission / reception phase difference for each frequency, or the two-frequency phase difference for each combination of frequencies, as position estimation information from each outdoor unit. Furthermore, in a system configuration that employs RTT as the ToF-related value, the processor 41 may acquire RTT from each outdoor unit. ToF-related values ​​for each BLE communicator 7 can be acquired by sequentially having multiple BLE communicators 7 perform distance measurement communication. Note that, as will be described separately, by using a sniffing method, it is possible to acquire ToF-related values ​​originating from each BLE communicator 7 without each BLE communicator 7 individually performing bidirectional communication with the mobile device 2.

[0105] Step S22 is a step in which the processor 41 (position estimation unit F3) determines the device position based on the position estimation information obtained from each BLE communication device 7 in step S21. Specifically, the processor 41 determines whether the device is inside or outside the vehicle, and if it is determined to be outside the vehicle, whether it is inside the locking / unlocking area Lx. If it is determined that the portable device 2 is inside the locking / unlocking area Lx, the processor 41 identifies whether it is located in the right area LxR, the left area LxL, or the rear area LxB, according to the ID of the nearest communication device. The method for determining the device position will be described separately.

[0106] Step S22 is a step in which the processor 41 determines whether a predetermined user operation has been performed on the vehicle based on signals from the door button 5, start button 6, courtesy switch, etc. If a signal corresponding to a user operation is input to the processor 41, step S24 is performed, and the processor 41 performs vehicle control according to the member operated by the user, the device position, and the state of the vehicle Hv. For example, if the vehicle Hv is locked, the processor 41 (vehicle control unit F5) will unlock the door if the operating member is the door button 5 and the device position is determined to be within the lock / unlock area Lx. Also, if the processor 41 determines that the operating member is the start button 6 and the device position is inside the vehicle, it will set the driving power supply to ON. In addition, the processor 41 will lock the door if the door button 5 is pressed while predetermined locking conditions are met. Locking conditions can include the vehicle Hv being unlocked, the driving power supply being off, the shift position being set to parking or neutral, and the device position being determined to be within the lock / unlock area Lx.

[0107] The vehicle control unit F5 may cancel the execution of vehicle control if the device position determined by the position estimation unit F3 does not match the position of the operation button. The operation button position refers to the position of the button pressed by the user. A case where the device position and the operation button position do not match is, for example, when the driver's door button 5 is pressed while the mobile device 2 is located far from the driver's seat, such as near the passenger seat or trunk. Also, when the start button 6 is pressed while the mobile device 2 is determined to be outside the vehicle, this may also be considered a case where the position of the mobile device 2 and the operation button position do not match. If a touch sensor is used instead of a button, the operation button position can be read as the touch position. The operation button position and touch position are included in the concept of the position of the operating member.

[0108] Step S25 determines whether the authentication result has expired, that is, whether the elapsed time since the authentication success was determined in step S14 or step S26 (described later) has exceeded a predetermined time. If the predetermined time has not elapsed since the last authentication success determination, i.e., if it is within the validity period, the process returns to step S21. On the other hand, if the predetermined time has elapsed since the last authentication success determination, the processor 41 performs the communication to authenticate the mobile device 2 again as step S26.

[0109] If the re-authentication process in step S26 is determined to be successful, the standby mode is continued. In other words, the processes from step S21 onwards are executed sequentially. On the other hand, if authentication fails, the processor 41 exits the standby mode in step S28. The standby mode may also be exited based on a predetermined number of consecutive authentication failures. Furthermore, the processor 41 may terminate the standby mode not only when authentication fails, but also when it detects that the mobile device 2 has left a predetermined authentication state maintenance area. Terminating the standby mode corresponds to discarding the authentication result. The authentication state maintenance area is, for example, an area that integrates the vehicle interior and the locking / unlocking area Lx.

[0110] <Regarding the method for determining the device location> This section describes how to determine the location of the mobile device 2. The device location determination can be divided into, for example, an in / outside determination process to determine whether or not the device is inside the vehicle, and a lock / unlock area determination process to determine whether or not the device is inside the lock / unlock area Lx.

[0111] First, the vehicle interior / exterior determination process will be explained using Figure 8. The vehicle interior / exterior determination process includes steps S31 to S36 as an example. The vehicle interior / exterior area determination process may be executed when the start button 6 is pressed. Alternatively, as a process toward locking, the vehicle interior / exterior determination process may be executed when the door button 5 is pressed while the vehicle Hv is unlocked. The vehicle interior / exterior determination process may also be executed periodically at estimated intervals when the vehicle Hv is unlocked or when the driving power supply is set to ON.

[0112] Step S31 is the step of collecting the received signal strength from the mobile device 2 from each BLE communicator 7. The collection of received signal strength can be performed at any time. Note that not all BLE communicators 7 need to be in communication with the mobile device 2 in order to determine the received signal strength from the mobile device 2. As shown in Figure 9, BLE communicators 7 other than the representative BLE communicator 7x may be configured to only perform observation of the received signal strength of the signal emitted by the mobile device 2. In this disclosure, BLE communicators 7 other than the representative BLE communicator 7 are referred to as observation devices or eavesdroppers. An observation device corresponds to a BLE communicator 7 that only receives signals and does not transmit them.

[0113] Sg_D, shown in Figure 9, represents the signal transmitted from mobile device 2 to BLE communication devices 7x / an unspecified number of recipients. Sg_D is a data signal after connection is established. Before connection is established, it is an advertisement signal. Sg_D may also be a CW signal. RSSI represents the received signal strength.

[0114] By the way, since frequency hopping occurs during data communication after a connection is established, normally only the BLE communicator 7x that is connected can capture data signals from the mobile device 2. In other words, the observation devices will not be able to observe signals from the mobile device 2. Therefore, the smart ECU 4 distributes the channel information and device ID obtained from the BLE communicator 7x, which is acting as the representative device, to each observation device as reference information.

[0115] Each observation device can recognize, based on the channel information shown in the reference information, which of the many channels available via BLE should be received to receive the signal from mobile device 2. As a result, the observation device can detect and report the received signal strength from mobile device 2 without establishing a communication connection.

[0116] In this disclosure, a method in which a representative unit performs bidirectional communication with the mobile device 2 and determines the device location based on the reception status of the signal sent from the mobile device 2 to the representative unit by an observation unit is also referred to as the sniffing method. According to the sniffing method, the number of BLE communication devices 7 that the mobile device 2 communicates with can be reduced to a minimum of one, thereby reducing the power consumption of the mobile device 2. In addition, according to the sniffing method, an indicator showing the distance from multiple BLE communication devices 7 to the mobile device 2 can be collected in parallel, thereby improving the system's responsiveness to the approach of a user carrying the mobile device 2. Of course, in other embodiments, each BLE communication device 7 may individually perform bidirectional communication with the mobile device 2 and provide information such as reception strength and reception phase to the smart ECU 4.

[0117] Step S32, following step S31, is a step in which the indoor unit observed strength (RSS_In) is determined based on the received strength of the signal from the portable device 2 observed by at least one indoor unit within a certain period of time in the most recent time. For example, the position estimation unit F3 calculates individual strength representative values ​​for each indoor unit as a preparatory process for determining the indoor unit observed strength. Then, the position estimation unit F3 adopts the maximum value among the individual strength representative values ​​for each indoor unit as the indoor unit observed strength.

[0118] The individual strength representative value is a value that representatively shows the received signal strength from the portable device 2 observed within a fixed time frame in the immediate vicinity of a single indoor unit. Here, as an example, the individual strength representative value is the average value of the received strength within the most recent 100 milliseconds or 200 milliseconds. The individual strength representative value, or the sampling period for the received strength used to determine the indoor unit observation strength, can be changed as appropriate. Such an individual strength representative value corresponds to a moving average of the received strength.

[0119] Individual intensity representative values ​​may be calculated for a single predetermined frequency, or they may be determined based on the received intensity of multiple frequencies. Furthermore, individual intensity representative values ​​may be calculated for each frequency. The representative value may be the median or maximum value, not just the mean. It may also be the mean, median, or maximum value of the population after excluding outliers. Outliers can be values ​​that are two or more standard deviations away from the mean or median of the original population. Various methods can be used to identify outliers, such as the Smirnov-Grubbs test or the Thompson test. Note that individual intensity representative values ​​do not necessarily need to be determined based on observations at multiple time points. Individual intensity representative values ​​may be observations at any single time point, for example, the most recent received intensity observation.

[0120] Furthermore, the indoor unit observation strength may be determined by methods other than those described above. For example, the nearest indoor unit, which is the BLE communication device 7 closest to the mobile device 2, may be identified using a method similar to that described in steps S42 to S42 below, and the individual strength representative value of that nearest indoor unit may be adopted as the indoor unit observation strength. Note that the nearest indoor unit may also be the indoor unit closest to the nearest outdoor unit. The processor 41 may refer to the communication device setting data and adopt the indoor unit located closest to the nearest outdoor unit as the nearest indoor unit.

[0121] Step S32 is the step of determining the outdoor unit observed strength (RSS_Out) based on the signal reception strength from the portable device 2 observed at at least one outdoor unit within a certain period of time. The method for determining the outdoor unit observed strength can be the same as the method for determining the indoor unit observed strength.

[0122] In step S34, it is determined whether the indoor unit observation intensity (RSS_In) and the outdoor unit observation intensity (RSS_Out) satisfy the in-vehicle determination condition. The in-vehicle determination condition is the condition for determining that the mobile device 2 is inside the vehicle. For example, the position estimation unit F3 determines that the mobile device 2 is inside the vehicle if the indoor-outdoor difference value (ΔRSS), obtained by subtracting the outdoor unit observation intensity from the indoor unit observation intensity, is greater than a predetermined difference threshold (ThGap) (step S35). In other words, if RSS_In-RSS_Out=ΔRSS>ThGap is satisfied, it is determined that the mobile device 2 is inside the vehicle. Also, if the indoor-outdoor difference value is less than or equal to the difference threshold, i.e., if ΔRSS≦ThGap is satisfied, it is determined that the mobile device 2 is outside the vehicle (step S36). The difference threshold can be 5dB, 10dB, 20dB, etc. The difference threshold may also be 0. A configuration where the differential threshold is set to 0 corresponds to a configuration that determines that the mobile device 2 is present inside the vehicle based on the indoor unit's observed signal strength being greater than the outdoor unit's observed signal strength.

[0123] Furthermore, even if ΔRSS≦ThGap is satisfied, the position estimation unit F3 may determine that the mobile device 2 is present inside the vehicle if the indoor unit observation intensity (RSS_In) exceeds a predetermined indoor determination value (ThIn). In other words, if RSS_In>ThIn is satisfied, the mobile device 2 may be determined to be present inside the vehicle regardless of ΔRSS. The indoor determination value (ThIn) used here is a threshold value for the indoor unit observation intensity used to determine that the mobile device 2 is present inside the vehicle. The indoor determination value is designed as appropriate through testing, etc. The indoor determination value is set to a sufficiently large value to suppress the possibility of false determination. For example, the indoor determination value is set to a value about 10 dB smaller than the maximum indoor unit observation intensity that can be observed when the key device Kd is present inside the vehicle.

[0124] Furthermore, even if ΔRSS > ThGap is satisfied, the position estimation unit F3 may determine that the mobile device 2 is outside the vehicle if the outdoor unit observation intensity (RSS_Out) exceeds the outdoor determination value (ThOut). In other words, if RSS_Out > ThOut is satisfied, the mobile device 2 may be determined to be outside the vehicle regardless of ΔRSS. The outdoor determination value (ThOut) used here is a threshold value for the outdoor unit observation intensity used to determine that the mobile device 2 is outside the vehicle. The outdoor determination value is also designed through appropriate testing, etc. The outdoor determination value is also set to a sufficiently large value to suppress the possibility of false determination. For example, the outdoor determination value is set to a value about 10 dB smaller than the maximum value of the outdoor unit observation intensity that can be observed when the key device Kd is in the locking / unlocking area Lx. Furthermore, even if ΔRSS > ThGap is satisfied, the position estimation unit F3 may determine that the mobile device 2 is outside the vehicle interior based on the fact that the device distance from a predetermined indoor unit is greater than or equal to a predetermined value. For example, if the distance from the BLE communication device 7x is 3m or more, the position estimation unit F3 may determine that the mobile device 2 is not inside the vehicle interior even if ΔRSS > ThGap is satisfied.

[0125] Next, the lock / unlock area determination process will be explained using Figure 10. The lock / unlock area determination process includes steps S41 to S46 as an example. The lock / unlock area Lx determination process may be performed on the condition that, for example, as a result of the aforementioned in-vehicle / out-of-vehicle determination process, it is determined that the mobile device 2 is not inside the vehicle, in other words, it is outside the vehicle. The lock / unlock area Lx determination process may be performed at a predetermined period, for example, every 200 milliseconds, on the condition that a mobile device 2 with a communication connection exists. Furthermore, the lock / unlock area determination process may be executed as a trigger when the door button 5 is pressed.

[0126] Step S41 is a step in which multiple outdoor units are instructed to sequentially communicate with the portable device 2 for distance measurement. In this embodiment, multi-frequency phase difference is used as a parameter that indirectly indicates ToF. Therefore, the smart ECU 4 obtains the transmission and reception phase difference at each frequency, which is used as material for calculating the multi-frequency phase difference, by having multiple outdoor units sequentially transmit and receive CW signals with the portable device 2. The communication control unit F2, for example, instructs BLE communicators 7a, 7b, and 7c to perform distance measurement communication in that order. Distance measurement communication by the outdoor units can be performed by temporarily changing the representative unit. In other words, step S41 may include the process of sequentially changing the representative unit. The CW signal and the signal for measuring RTT correspond to the predetermined signal for distance measurement.

[0127] Various methods can be used to calculate the transmission-transmission phase difference by transmitting and receiving CW signals, and specific examples will be described separately later. In BLE, the operating frequency is changed over time by frequency hopping. The processor 41, acting as the ToF-related value acquisition unit F23, collects the transmission-transmission phase difference at multiple frequencies for each outdoor unit by transmitting and receiving CW signals at each frequency. The processor 41 calculates the dual-frequency phase difference for each frequency combination by combining the transmission-transmission phase differences for each frequency observed at the same outdoor unit. The processor 41 acquires multi-frequency phase difference information for each outdoor unit by performing this dual-frequency phase difference calculation process for each outdoor unit.

[0128] Step S42 is a step in which the distance from each outdoor unit to the portable device 2 is estimated based on the observation values ​​collected in step S41. The position estimation unit F3 estimates the distance from each outdoor unit to the portable device 2 based on the multi-frequency phase difference information for each outdoor unit collected in S41. Note that the device distance estimation process may be performed by the communication microcontroller 74 of each BLE communication device 7 instead of the smart ECU 4. Some of the functions of the position estimation unit F3 may be provided by the communication microcontroller 74.

[0129] Furthermore, if the phase difference between the two frequencies is Δφ, the propagation speed of radio waves is C (3 × 10^8 m / sec), the difference between the two frequencies is Δf, and the distance to the mobile device 2 is L, then the relationship L = C·Δφ / (2πΔf) holds. However, the phase difference between the two frequencies based on one set of frequencies may contain errors due to multipath, etc. On the other hand, the degree of influence of multipath differs for each frequency. For these reasons, the processor 41 determines the device distance based on two or more sets of phase differences between the two frequencies. With this configuration, it is expected that the accuracy of distance measurement can be improved. Of course, in other embodiments, the position estimation unit F3 may estimate the device distance based on one phase difference between the two frequencies.

[0130] Furthermore, the position estimation unit F3 may estimate the device distance based on RTT instead of the two-frequency phase difference. RTT is the time from the transmission of a response request signal to the reception of a response signal. When using RTT, the device distance for each outdoor unit can be determined by each outdoor unit individually transmitting and receiving a distance measurement signal with the portable device 2. The distance measurement signal when performing distance measurement using RTT does not need to be a CW signal. Any configuration including any bit sequence can be used as the distance measurement signal for acquiring RTT. The position estimation unit F3 may estimate the device distance based on the observed RTT value at any one frequency, or it may estimate the device distance based on the average or median of the observed RTT values ​​at multiple frequencies.

[0131] Step S42 identifies the nearest outdoor unit, which is the BLE communication device 7 closest to the mobile device 2, based on the result of step S42. Step S44 determines whether the distance from the nearest outdoor unit to the mobile device 2 is less than a predetermined value. The predetermined value used in the determination process of step S44 can be the aforementioned operating distance.

[0132] If the distance from the nearest outdoor unit to the mobile device 2 is less than the operating distance, the process proceeds to step S45, where it is determined that the mobile device 2 is within the locking / unlocking area Lx. On the other hand, if the distance from the nearest outdoor unit to the mobile device 2 is greater than or equal to the operating distance, the process proceeds to step S46, where it is determined that the mobile device 2 is outside the locking / unlocking area Lx. Step S44 can be understood as a process to determine whether the minimum value among the distances for each of the multiple BLE communication devices 7 observed in step S42 is less than the operating distance.

[0133] The position estimation unit F3 may determine that the mobile device 2 is within the lock / unlock area Lx, provided that the distance from the nearest outdoor unit to the mobile device 2 is less than the operating distance, and the received signal strength at the nearest outdoor unit is greater than the indoor unit observed signal strength. The indoor unit observed signal strength used here may be a representative value (e.g., the maximum value) of the received signals from multiple indoor units, or it may be the received signal strength at the indoor unit closest to the nearest outdoor unit.

[0134] The position estimation unit F3 determines the location of the mobile device 2, and this location information is stored in the RAM 42. This location information is also used by various programs and functions through reference. The position estimation unit F3 also sequentially stores the distance information between the nearest outdoor unit and the mobile device 2, as identified in steps S41 to S42, in the RAM 42 as device location information. In other words, the RAM 42 may store not only whether the mobile device 2 is inside the vehicle, within the locking / unlocking area Lx, or outside the locking / unlocking area Lx, but also the distance information to the nearest communication device. The position estimation unit F3 may also store the device distance from other BLE communication devices in the RAM 42. Each piece of data may be stored along with a timestamp indicating the time of acquisition.

[0135] When the BLE communication device 7x receives signals from multiple mobile devices 2, the position estimation unit F3 determines the relative position and distance to the vehicle Hv for each mobile device 2. Furthermore, the position estimation unit F3 can determine whether a device is a smart key based on the ID of the mobile device 2 with which it is communicating.

[0136] Furthermore, the position estimation unit F3 may be configured to perform only the lock / unlock area determination when the vehicle Hv is parked, i.e., locked and the driving power is off, and assumes that the mobile device 2 is outside the vehicle. In other words, in scenes aimed at unlocking, only the lock / unlock area determination may be performed. Also, if the vehicle is unlocked, the interior / exterior area determination and the lock / unlock area determination may be performed sequentially. The position estimation unit F3 may also be triggered by the door button 5 being pressed while the vehicle Hv is unlocked, and then perform the interior / exterior area determination process followed by the lock / unlock area determination process. In order to prevent the mobile device 2 from being trapped inside the vehicle, it is preferable to perform the locking after confirming that the mobile device 2 is not inside the vehicle.

[0137] <Regarding effects, etc.> The above configuration corresponds to a configuration in which the physical parameters used for determining whether the vehicle is inside or outside the vehicle and whether it is a locked or unlocked area are changed. Specifically, the processor 41 uses the signal strength received by the outdoor and indoor units from the portable device 2 to determine whether the vehicle is inside or outside the vehicle, while it uses ToF-related values ​​such as dual-frequency phase difference and RTT to determine whether it is a locked or unlocked area.

[0138] Between the vehicle interior and exterior, there are elements that obstruct radio wave propagation, such as the vehicle body. Therefore, depending on whether the mobile device is inside or outside the vehicle, there may be a significant difference in the reception strength of the signal transmitted from the mobile device at the outdoor and indoor units. However, there are no structures like the vehicle body between the locking / unlocking area Lx and the non-operating area. Since the locking / unlocking area Lx and the non-operating area are spatially continuous, a significant difference in the reception strength of the signal from mobile device 2 is unlikely to occur.

[0139] Furthermore, BLE communication uses high-frequency radio waves, not LF (Low Frequency) band radio waves. Therefore, the signal strength received from mobile device 2 is prone to instability due to multipath and the influence of the human body. Thus, even if the signal strength received from mobile device 2 at the outdoor unit is strong, it does not necessarily mean that mobile device 2 is present in the lock / unlock area Lx. Similarly, even if the signal strength received from mobile device 2 at the outdoor unit is weak, it does not necessarily mean that mobile device 2 is not present in the lock / unlock area Lx.

[0140] According to the above configuration, whether or not the portable device 2 is present in the locking / unlocking area Lx is determined by ToF-related values, specifically multi-frequency phase difference and RTT, which are determined by the outdoor unit communicating with the portable device 2. ToF-related values ​​such as the transmit / receive phase difference and RTT, which are the basis of the multi-frequency phase difference, are less affected by the human body and are expected to take values ​​that correspond to the device distance compared to the received signal strength. Therefore, it is possible to determine with greater accuracy whether the portable device 2 is present in the locking / unlocking area Lx or in the non-operational area outside the vehicle compared to a configuration that simply determines this based on the strength of the received signal. In this disclosure, high-frequency radio waves refer to radio waves of 900 MHz or higher. High-frequency radio waves are not limited to radio waves of 1 GHz or higher, but also include sub-gigahertz radio waves such as 920 GHz.

[0141] On the other hand, the position estimation unit F3 determines whether or not the mobile device 2 is inside the vehicle using the received signal strength at the outdoor and indoor units. Specifically, it determines whether or not the mobile device 2 is inside the vehicle by a relative comparison of the received signal strength at the outdoor unit and the indoor unit, and / or by a threshold comparison of each received signal strength. As mentioned above, there are elements that hinder radio wave propagation, such as the vehicle body, between the inside and outside of the vehicle, so it is possible to make a determination with the desired accuracy using the received signal strength at the outdoor and indoor units. In addition, the received signal strength can be measured more easily than ToF-related values ​​such as dual-frequency phase difference and RTT. Furthermore, bidirectional communication is not required when measuring the received signal strength. Therefore, the processing load on the processor 41 and communication microcontroller 74 can be reduced compared to a configuration that uses ToF-related values ​​to determine whether the device is inside or outside.

[0142] In the above embodiment, since the outdoor unit is mounted near the door, the outdoor unit can be used for both determining whether the vehicle is inside or outside and determining whether the lock / unlock area is occupied. This configuration makes it possible to reduce costs compared to a configuration in which a separate communication device is provided for determining whether the vehicle is inside or outside and a separate communication device is provided for determining whether the lock / unlock area is occupied.

[0143] While embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above. Various modifications described below are also included within the technical scope of the present disclosure, and further modifications can be made in various ways without departing from the gist of the invention. For example, the various supplements and modifications described below can be combined as appropriate without causing any technical inconsistencies. In addition, components having the same function as those described above may be denoted by the same reference numerals, and their descriptions may be omitted. Also, if only a part of the configuration is referred to, the above description may be applied to the other parts.

[0144] <Adjusting transmission strength according to device location> The communication control unit F2 may change the strength of the radio wave output of the BLE communication device 7 depending on the distance from the vehicle Hv to the mobile device 2, in other words, the location of the device. For example, if it is determined that the mobile device 2 is within a predetermined distance from the vehicle Hv, the transmission power of the BLE communication device 7 may be changed to a suppression level that is a predetermined amount lower than a predetermined standard level. This configuration can reduce the power consumption of the in-vehicle system 1.

[0145] Figure 11 shows an example of the operation of the processor 41 corresponding to the above technical concept. The flowchart shown in Figure 11 can be performed sequentially, provided that a communication connection is established with the mobile device 2. First, the processor 41 obtains the device position as a result of, for example, the lock / unlock area determination process (step S51). In other words, the processor 41 obtains the device distance at each outdoor unit. Then, based on the presence of an outdoor unit whose device distance is less than a predetermined value (step S52 YES), the processor 41 reduces the transmission power at each outdoor unit from the standard level to a suppression level (step S52). The processor 41 also transmits a predetermined power suppression instruction signal to the mobile device 2 via the BLE communication device 7x (step S54). The power suppression instruction signal is an instruction signal that suppresses the transmission power by a predetermined amount.

[0146] The threshold used in step S52 can be, for example, 2m or 5m. The configuration that performs the processes in steps S51 to S52 reduces the power consumption of the in-vehicle system 1. Furthermore, the configuration that performs step S54 on the condition that the mobile device 2 is present near the vehicle Hv also reduces the power consumption of the mobile device 2.

[0147] Furthermore, the transmission power may be adjusted in multiple stages depending on the device location, as shown in Figure 12. Although Figure 12 shows a stepwise change in transmission power, the transmission power may also be changed in a curved or linear manner depending on the distance from the nearest outdoor unit. In Figure 12, Ps0 is the standard level, and Ps1 to Ps2 correspond to suppression levels. Ps1 to Ps2 have the relationship Ps1 > Ps2 > Ps2.

[0148] For example, the communication control unit F2 applies a standard level (Ps0) when the mobile device 2 is more than 5m away from the vehicle Hv, and applies a first suppression level (Ps1) when the mobile device 2 is located between 2m and 5m away. The distance from the vehicle Hv to the mobile device 2 can be determined by the minimum device distance relative to each outdoor unit. If the mobile device 2 is outside the vehicle but within 2m of the vehicle Hv, a second suppression level (Ps2) is applied. If the mobile device 2 is inside the vehicle, a second suppression level (Ps2) is applied. As shown in Figure 12, a configuration that performs fine-grained power control according to the device location can be expected to achieve even greater power saving effects. In addition, when the transmission power of the BLE communication device 7 is suppressed, the risk of a mobile device 2 located at a distance other than the mobile device 2 located around the vehicle responding can be reduced.

[0149] Furthermore, if the processor 41 determines that the mobile device 2 is outside the vehicle, it may suppress the transmission power of the BLE signal from the mobile device 2 according to its location. The amount of suppression may be increased the closer the device is, as illustrated in Figure 12. Suppression of the transmission power from the mobile device 2 can be achieved by transmitting a power suppression instruction signal. The power suppression instruction signal may include a suppression amount relative to the standard level or a target level. When the transmission power of the mobile device 2 is suppressed, the position estimation unit F3 may perform the vehicle-inside / outside determination by applying a correction to the threshold for determining whether the device is inside or outside the vehicle or to the observed value of the received strength according to the amount of transmission power suppression.

[0150] In addition, the communication control unit F2 may change the communication frequency / interval depending on the device location. For example, if the mobile device 2 is within 5m of the vehicle Hv, communication is performed at a predetermined standard interval. On the other hand, if the mobile device 2 is not within 5m of the vehicle Hv, communication is performed at a power-saving interval that is a predetermined amount longer than the standard interval. If the standard interval is 25 milliseconds, 50 milliseconds, or 100 milliseconds, the power-saving interval can be 200 milliseconds or 400 milliseconds, etc. The power-saving interval may also be twice the standard interval. With this configuration, the communication frequency with the mobile device 2 can be reduced, thereby suppressing power consumption in both the mobile device 2 and the in-vehicle system 1.

[0151] <Modified version of the lock / unlock area determination process> When the portable device 2 exists on the rear side of the user as viewed from the vehicle Hv and there are reflectors such as other vehicles nearby, the intensity of the reflected wave becomes higher than that of the direct wave, and the distance via the reflector can be calculated. And when the distance measurement value at the outdoor unit is a predetermined value or more, it is determined that it is outside the locking / unlocking area Lx. That is, in a situation where the intensity of the reflected wave is larger than that of the direct wave by a predetermined value or more, even though the portable device 2 exists within the locking / unlocking area Lx, it may be erroneously determined that it exists outside the locking / unlocking area Lx. The case where the portable device 2 exists on the rear side of the user as viewed from the vehicle Hv is, for example, a case where the portable device 2 is housed in a back pocket of trousers or a rucksack.

[0152] In view of such circumstances, the position estimation unit F3 may also use not only the outdoor unit but also the distance measurement value based on the ToF-related value at the indoor unit to determine whether the portable device 2 exists in the locking / unlocking area Lx. For example, when the device distance from a predetermined indoor unit is a predetermined value or less, the position estimation unit F3 may determine that the portable device 2 exists within the locking / unlocking area Lx even if the device distance from the outdoor unit is a predetermined value or more. The indoor units that measure the distance to the portable device 2 may be all of them, or may be the nearest indoor unit to the nearest outdoor unit. Also, based on the fact that the distance measurement value from the central unit, which is an indoor unit arranged at the center of the vehicle interior ceiling or on the center console, is less than a predetermined value (for example, 2 m), it may be determined that the portable device 2 exists in the locking / unlocking area Lx.

[0153] Note that the smart ECU 4 does not always use the distance measurement value of the indoor unit, but may perform the locking / unlocking area determination using the distance measurement value of the indoor unit only when it detects that the user has performed an operation of a predetermined pattern via the door button 5. The predetermined pattern of operation assumed here refers to an operation pattern that the user can perform, for example, when the door button 5 is repeatedly pressed, in a case where the system does not respond even though the user is in the locking / unlocking area Lx.

[0154] <Modification example of the mounting pattern of the BLE communication device> The number and location of the BLE communication devices 7 in the in-vehicle system 1 may be as shown in Figure 13. In other words, the indoor unit may consist of only one BLE communication device 7p. In this case, the BLE communication device 7p may be placed, for example, on the floor between the driver's seat and the passenger seat or on the center console, to prevent radio waves from leaking outside the vehicle. Alternatively, it may be placed in the center of the ceiling inside the vehicle, on the overhead console, or on the upper edge of the rear window, to facilitate reception of signals from a portable device 2 located outside the vehicle.

[0155] Furthermore, as shown in Figure 14, the indoor unit may consist of two BLE communication devices, 7p and 7q. In this case, BLE communication device 7p may be placed on the center console or instrument panel, while BLE communication device 7q may be placed on the upper edge of the rear window.

[0156] Figures 13 and 14 show a configuration similar to the embodiment, in which BLE communication devices 7a to 7c are placed in two locations: near the left and right B-pillars and near the trunk door. Of course, the number of outdoor units is not limited to this. For example, as shown in Figure 15, BLE communication devices 7a to 7b and 7d to 7e, which are outdoor units, may be arranged to form individual locking / unlocking areas Lx around the right front door, left front door, right rear door, and left rear door. For example, BLE communication device 7a is located on the outer door handle of the right front door or on the exterior surface of the door-side B-pillar. BLE communication device 7b is located on the outer door handle of the left front door or on the exterior surface of the door-side B-pillar. BLE communication device 7d is located on the outer door handle of the right rear door or on the C-pillar. BLE communication device 7e is located on the outer door handle of the right rear door or on the C-pillar. The right rear door and left rear door refer to the rear passenger doors provided on the left and right sides of the vehicle Hv. This configuration is equivalent to the setup in a hybrid vehicle where an outdoor unit is installed at each door.

[0157] According to the mounting pattern shown in Figure 15, each door's outdoor unit can individually identify users entering through each door based on the source information of the signal received from the mobile device 2, and consequently, it can identify the occupant of each seat. As a result, the smart ECU 4 can perform services such as adjusting the seat position according to the occupant, automatically changing the air conditioning settings, playing in-car video, and turning on the welcome lights. In addition, the BLE communication device 7 may also be provided at the front of the vehicle, as shown in Figure 16. The BLE communication device 7d shown in Figure 16 is located in the center of the front bumper in the width direction or near the emblem.

[0158] Furthermore, the BLE communication units 7a to 7d, which function as outdoor units, may be positioned at the front, rear, left, and right corners, as shown in Figure 17. For example, BLE communication units 7a and 7b are built into the left and right corners of the front bumper, and BLE communication units 7c to 7d are positioned at the left and right corners of the rear bumper.

[0159] <Application to remote operation> The smart ECU 4 may perform position determination for a remote parking function that parks the vehicle Hv by remote control using the mobile device 2. Regulations stipulate that remote parking is available only if the user is within a remote parking area Rm, which is within a predetermined distance from the vehicle Hv. The ECU providing the automatic parking function autonomously drives the vehicle toward the target parking position, provided that the smart ECU 4 determines that the user is within the remote parking area Rm and the user has pressed the automatic parking button on the mobile device 2.

[0160] The remote parking area Rm can be set, for example, within 5m of the vehicle Hv. Of course, the distance defining the size of the remote parking area could also be 6m or 10m, etc. The size of the remote parking area Rm is set to comply with the laws of the region / country in which the vehicle Hv is used.

[0161] The processor 41, for example as shown in Figure 16 or Figure 17, determines whether the portable device 2 is located within the remote parking area Rm when the outdoor units are positioned on the front, rear, left, and right sides of the vehicle body so as to have a clear view of all directions of the vehicle Hv, using these four outdoor units. Specifically, it causes each outdoor unit to perform distance measurement communication with the portable device 2 and obtains the device distance from each outdoor unit. When the minimum of these distances is less than or equal to a predetermined distance (e.g., 5m), it can be determined that the portable device 2 is located within the remote parking area Rm. The control signal from the portable device 2 related to remote parking is activated only if it has been determined that the portable device 2 is located within the remote parking area Rm. In this way, the position estimation unit F3 may also determine whether the portable device 2 is located within the remote parking area Rm. The remote parking area Rm is also a type of outdoor operating area.

[0162] <Automatic modification of the judgment algorithm according to the mounting pattern of the communication device> The processor 41 may, for example, obtain the mounting pattern of the BLE communication device 7 by referring to the communication device setting data in the storage 43, and automatically switch the algorithms for indoor / outdoor determination and lock / unlock area determination to correspond to the mounting pattern. The determination algorithm for each mounting pattern can be prepared in advance. The mounting pattern of the BLE communication device 7 includes the number of outdoor and indoor units and their respective mounting locations.

[0163] For example, regarding lock / unlock area determination, as shown in Figures 2, 13, 14, and 15, if outdoor units are arranged in each lock / unlock area Lx, it is determined that the user is located in the direction of the nearest outdoor unit. Then, it is determined that the mobile device 2 is located in the lock / unlock area Lx corresponding to the outdoor unit whose device distance is less than a predetermined value.

[0164] On the other hand, as shown in Figure 17, if outdoor units are located at the four corners of the vehicle body, the distance from each outdoor unit to the mobile device 2 is calculated to identify the nearest outdoor unit and the second nearest outdoor unit. The second nearest outdoor unit is the outdoor unit that is the second closest to the mobile device 2. Then, it is determined that the user is located in the direction where the outer surfaces connected to both the nearest outdoor unit and the second nearest outdoor unit exist. For example, if the nearest outdoor unit is the BLE communication device 7a and the second nearest outdoor unit is the BLE communication device 7c, it is determined that the mobile device 2 and the user are located on the right side of the vehicle. The position estimation unit F3 calculates the device position using two-point surveying based on the device distance from the nearest communication device and the second nearest outdoor unit, and if that device position is within the locking / unlocking area Lx, it is determined that the mobile device 2 is located in the locking / unlocking area Lx.

[0165] Furthermore, the details of the vehicle interior / exterior determination may be modified according to the number of indoor and outdoor units installed. For example, if there are three or more indoor units, as shown in Figures 2 and 15, the maximum value of the received signal strength from the portable device 2 observed by each of the multiple indoor units is adopted as the indoor unit observed strength (RSS_In). Also, if there is only one indoor unit, as shown in Figure 13, the individual strength representative value determined based on the received strength observed by that indoor unit is adopted as the indoor unit observed strength. If there are two indoor units, as shown in Figure 14, the larger of the individual strength representative values ​​observed by those indoor units is adopted as the indoor unit observed strength.

[0166] Furthermore, the BLE communication device 7x built into the smart ECU4 may be used as an indoor unit. Whether or not to use the BLE communication device 7x as an indoor unit should be determined based on its mounting location. Whether or not the BLE communication device 7x can be used as an indoor unit may be pre-registered in the communication device configuration data using a flag or similar method.

[0167] Incidentally, it is expected that the reception sensitivity will differ for each BLE communication device 7 depending on the antenna configuration and the environment in which it is installed. Therefore, the reception strength of each BLE communication device 7 may be used for various judgments after a correction value (offset) corresponding to its antenna characteristics and installation location is added.

[0168] Furthermore, information regarding the location and number of BLE communication devices 7 installed in the vehicle Hv may be obtained from the body ECU or other devices via the in-vehicle network Nw. The entity that holds data indicating the installation pattern of BLE communication devices 7 in the vehicle Hv does not have to be the smart ECU 4. Data indicating the installation pattern of BLE communication devices 7 may be input from an external server or a designated dedicated tool used by the dealer.

[0169] In addition, the processor 41 may flag applicable services from among the pre-prepared services, depending on the mounting pattern of the BLE communication device 7 in the vehicle Hv. For example, the flag value is set to 1 for services that can be implemented with the current mounting pattern, and the flag value is set to 0 for services that cannot be implemented with the current mounting pattern. Examples of service types include remote parking and the application of personal settings to the rear seats.

[0170] <Supplementary information on lock / unlock area determination process> The lock / unlock area determination process may be performed using the procedure shown in Figure 18. The flowchart shown in Figure 18 includes steps S41a to S47a. The flowchart shown in Figure 18 may be performed as an alternative process to that in Figure 10.

[0171] First, in step S41a, the communication control unit F2 causes the basic representative device to perform a communication for distance measurement and obtain ToF-related values. The basic representative device here refers to the BLE communication device 7 that is responsible for data communication with the mobile device 2 in the basic state. In this case, the BLE communication device 7x corresponds to the basic representative device. If there is a BLE communication device 7 installed in a position that allows a view not only inside the vehicle but also outside the vehicle, such as the upper edge of the rear window, the upper edge of the windshield, or the center of the ceiling inside the vehicle, that communication device may be set as the basic representative device.

[0172] In step S42a, the position estimation unit F3 determines the distance to the mobile device 2 based on the ToF-related values ​​obtained in step S41a. It then determines whether the distance between the basic representative unit and the mobile device 2 is less than a predetermined primary threshold. If the distance between the basic representative unit and the mobile device 2 is less than the predetermined primary threshold, the processor 41, in step S43a, identifies the nearest outdoor unit based on the signal reception strength from the mobile device 2 at each outdoor unit. For example, among the outdoor units, the one with the strongest signal reception strength from the mobile device 2 is selected as the nearest outdoor unit. Alternatively, if the basic representative unit is equipped with an array antenna and configured to estimate the direction of arrival of the signal from the mobile device 2 as the device direction, the processor 41 may select an outdoor unit located in the device direction as the nearest outdoor unit.

[0173] On the other hand, if the distance between the basic representative unit and the portable device 2 is greater than or equal to a predetermined primary threshold, it is determined that the portable device 2 is outside the locking / unlocking area Lx, i.e., in the non-operational area (step S47a). The primary threshold used here is a parameter for determining whether or not there is a possibility that the portable device 2 is inside the locking / unlocking area Lx. The primary threshold is set to a value obtained by adding a predetermined offset amount to the operating distance. The offset amount is set according to the distance from the basic representative unit to the locking / unlocking area Lx. For example, the primary threshold may be set to a length obtained by adding 1m or 2m to the operating distance. For example, the primary threshold may be set to 4m or 5m.

[0174] In step S44a, the communication control unit F2 causes the nearest outdoor unit determined in step S42a to perform a distance measurement communication and obtains ToF-related values ​​with the nearest outdoor unit as the observation point. This step may include a step of setting the nearest outdoor unit as a temporary representative unit.

[0175] In step S45a, the position estimation unit F3 determines the distance from the nearest outdoor unit to the portable device 2 based on the ToF-related values ​​obtained in step S44a. It then determines whether the distance between the nearest outdoor unit and the portable device 2 is less than a predetermined secondary threshold. The secondary threshold is a parameter used to determine whether the portable device 2 is within the locking / unlocking area Lx, and is set to the same value as the operating distance.

[0176] The position estimation unit F3 determines that if the distance between the nearest outdoor unit and the mobile device 2 is less than a predetermined secondary threshold, the mobile device 2 is located within the locking / unlocking area Lx corresponding to the nearest outdoor unit (step S46a). For example, if the nearest outdoor unit is a BLE communication device 7a, it is determined to be located in the right-hand area LxR. On the other hand, if the distance between the nearest outdoor unit and the mobile device 2 is greater than or equal to a predetermined secondary threshold, it is determined that the mobile device 2 is still located in the non-operating area (step S47a).

[0177] According to the above method, the number of communication devices performing distance measurement communication can be reduced compared to the embodiment described above. In other words, the frequency of performing distance measurement communication can be reduced. Therefore, power consumption in the portable device 2 and the in-vehicle system 1 can be reduced. Furthermore, if the device distance relative to the basic representative unit is greater than or equal to the primary threshold, the outdoor unit is not made to perform distance measurement communication. This makes it possible to reduce power consumption in the in-vehicle system 1 and the portable device 2 compared to the embodiment described above. The technical concept described here can also be applied to lock / unlock area determination such as in step S41. For example, when the communication control unit F2 detects that the device distance from the basic representative unit has fallen below the primary threshold, it may make each outdoor unit perform distance measurement communication in sequence.

[0178] <Supplementary information on the location determination method> In addition to the algorithm described above, a variety of algorithms can be used to determine whether or not the mobile device 2 is inside the vehicle. For example, the position estimation unit F3 may determine that the mobile device 2 is inside the vehicle based on the indoor unit's observed intensity being greater than or equal to the indoor determination value, and the outdoor unit's observed intensity being less than the outdoor determination value. In this determination algorithm, the mobile device 2 is determined to be inside the vehicle if the indoor unit's observed intensity is greater than or equal to the indoor determination value and the outdoor unit's observed intensity is less than the outdoor determination value. Furthermore, if the indoor unit's observed intensity is greater than or equal to the indoor determination value, but the outdoor unit's observed intensity is greater than or equal to the outdoor determination value, or if the indoor unit's observed intensity is less than the indoor determination value, the mobile device 2 may be determined to be outside the vehicle.

[0179] Furthermore, the position estimation unit F3 may be configured to determine whether or not the portable device 2 is inside the vehicle using two thresholds for the indoor unit's observed intensity, namely a high-level threshold and a low-level threshold. The high-level threshold is used to determine, based on the indoor unit's observed intensity, that the portable device 2 has entered the vehicle from outside. The low-level threshold is used to determine, based on the indoor unit's observed intensity, that the portable device 2 has left the vehicle from inside. The high-level threshold may be the same as the previously mentioned indoor determination value. Preferably, the low-level threshold is set to a value at least 10 dB lower than the high-level threshold.

[0180] In the above configuration, the position estimation unit F3 maintains the determination that the mobile device 2 is inside the vehicle until the indoor unit's observed signal strength falls below the low-level threshold, once the indoor unit's observed signal strength exceeds the high-level threshold. Furthermore, if the indoor unit's observed signal strength falls below the low-level threshold, the unit maintains the determination that the mobile device 2 is outside the vehicle until the indoor unit's observed signal strength exceeds the high-level threshold. In this case, the outdoor unit's observed signal strength is not used. Therefore, the process of calculating the outdoor unit's observed signal strength can be omitted.

[0181] The above describes one example of a method for determining whether or not the portable device 2 is present inside the vehicle. Similar to determining whether or not the portable device 2 is present inside the vehicle, a variety of determination algorithms can be applied to determine whether or not the portable device 2 is present in the locking / unlocking area Lx. For example, the method disclosed in Patent Document 2-6 can be used as a method for determining the presence of the portable device 2.

[0182] When the processor 41 periodically determines the location of the mobile device 2, it may use the latest determination result and past determination results in combination to finalize the current location. For example, if the last two determination results indicate that the location is outside the locking / unlocking area Lx, and the latest determination result indicates that the location is inside the locking / unlocking area Lx, the final determination of the current location of the mobile device 2 will be outside the locking / unlocking area Lx. On the other hand, if, for example, the determination result from two determinations prior to last indicated that the location was outside the locking / unlocking area Lx, and the previous and latest determination results indicated that the location is inside the locking / unlocking area Lx, the final determination of the current location of the mobile device 2 will be inside the locking / unlocking area Lx. This configuration corresponds to a configuration in which the final device location is determined by majority voting / averaging with past and latest determination results as the population.

[0183] By using a configuration that combines the latest judgment result with previous judgment results to determine the final current position, the risk of misjudging the device position due to momentary noise can be reduced. This technical concept is applicable not only to configurations that determine the device position on an area basis, but also to cases where the position is determined by coordinates, as will be described separately. In a configuration that calculates the relative position coordinates of the mobile device 2 with respect to the vehicle Hv, the final position coordinates may be determined by weighting and averaging the past predetermined number of estimation results and the latest estimation result.

[0184] The position estimation unit F3 may be configured to calculate the relative 2D / 2D position coordinates of the mobile device 2 with respect to the vehicle Hv. For example, the position estimation unit F3 may determine the position of the mobile device 2 using the RSSI method, which utilizes the received signal strength from the mobile device 2. The RSSI method is a method that estimates the distance from each BLE communication device 7 to the mobile device 2 by utilizing the characteristic that the electric field strength of a wireless signal attenuates with propagation distance, and then estimates the device position based on the distance from each BLE communication device 7.

[0185] The position estimation unit F3 converts the received signal strength information from the mobile device 2 observed by each BLE communication device 7 into distance information, and generates distance information from each BLE communication device 7 to the mobile device 2. Then, by integrating the distance information from each BLE communication device 7 to the mobile device 2, it calculates the position of the mobile device 2. For example, the position estimation unit F3 determines the position of the mobile device 2 relative to the vehicle Hv reference point using the principle of triplicate or triangulation, based on the distance calculated from each of the received strengths observed by two or more BLE communication devices 7, and the mounting positions of these BLE communication devices 7. The conversion from received strength to distance information can be realized using a model equation in which the received strength attenuates in proportion to the square of the distance or inversely to the square. The position of the mobile device 2 relative to the vehicle Hv can be represented as a point in the vehicle coordinate system.

[0186] In other embodiments, the position estimation unit F3 may determine the position of the mobile device 2 relative to the vehicle Hv using the AoA (Angle of Arrival) method, which uses the angle of arrival of radio waves. Alternatively, the position of the mobile device 2 relative to the vehicle Hv may be determined using distance information obtained by ToF. For example, the position estimation unit F3 may determine the detailed position of the mobile device 2 by combining the device distances from two or more BLE communication devices 7, which are determined based on ToF-related values. In addition, the position of the mobile device 2 relative to the vehicle Hv may be determined using the TDOA (Time Difference of Arrival) method, which uses the difference in radio wave arrival times for localization.

[0187] Furthermore, the position estimation unit F3 may estimate the device's position coordinates by combining multiple position estimation methods. For example, as shown in Figure 19, the smart ECU 4 may estimate the device position by combining the RSSI / ToF method and the AoA method. Sg_V shown in Figure 19 represents a signal transmitted by the in-vehicle system 1, specifically the BLE communication device 7x as a representative device. Sg_V may be a data signal specifying the mobile device 2 as the destination, or it may be a scan request signal. Also, Sg_V may be a CW signal.

[0188] For example, BLE communicators 7a to 7c output the arrival angle (in other words, the direction of arrival) and received strength of the signal from the mobile device 2, while BLE communicators 7p to 7r output the received strength. BLE communicators 7x perform distance measurement communication and provide the ToF itself or ToF-related values ​​to the processor 41. In this case, the position estimation unit F3 can estimate the device position by combining the direction of arrival observed by at least one of the BLE communicators 7a to 7c and 7x with the received strength observed by at least one of the BLE communicators 7p to 7r. Of course, distance information from BLE communicator 7x based on ToF-related values ​​may also be used in combination. The BLE communicator 7 that estimates the direction of arrival is assumed to be equipped with multiple antennas 72 as an array antenna. The BLE communicator 7 equipped with an array antenna can calculate the direction of arrival by analyzing the reception results and report it to the smart ECU 4. Multiple BLE communicators 7 may be configured to calculate at least one of the received signal strength, direction of arrival, and time of flight by individually transmitting and receiving radio signals with the mobile device 2.

[0189] Furthermore, when mobile device 2 is located in the locking / unlocking area Lx, the nearest outdoor unit can receive the signal directly from mobile device 2, resulting in little variation in reception strength due to frequency differences. In contrast, when mobile device 2 is located in the locking / unlocking area Lx, the indoor unit receives the signal from mobile device 2 through diffraction and reflection from the ceiling, etc. The degree to which reflection and diffraction affect reception strength varies depending on the frequency. In other words, when mobile device 2 is located in the locking / unlocking area Lx, the variation in reception strength for each frequency at the indoor unit becomes larger.

[0190] The position estimation unit F3 in this disclosure may determine whether or not the portable device 2 is inside the vehicle based on the degree of variation in received signal strength due to differences in frequency. For example, the position estimation unit F3 calculates the variance of received signal strength at the nearest outdoor unit and the variance of received signal strength at the nearest indoor unit based on the received signal strength at multiple frequencies observed at the nearest outdoor unit and the nearest indoor unit, respectively. Based on the fact that the variance of received signal strength at the nearest outdoor unit is less than or equal to a predetermined value than the variance of received signal strength at the nearest indoor unit, it may determine that the portable device 2 is in the lock / unlock area Lx. Similarly, it may determine that the portable device 2 is inside the vehicle based on the fact that the variance of received signal strength at a predetermined indoor unit is less than the variance of received signal strength at a predetermined outdoor unit. Of course, in addition to the variance of received signal strength at the outdoor / indoor units, the position estimation unit F3 may also use received signal strength, ToF, etc. in combination to perform vehicle interior / exterior determination and lock / unlock area determination.

[0191] <Supplementary information on the detection method for transmission / reception phase difference> Methods for detecting the transmission-reception phase difference include the active two-way method, the passive two-way method, and the one-way method. In the active two-way method, as shown in Figure 20, the initiator and the reflector transmit and receive CW signals to each other, and each detects the phase difference between the transmitted signal and the received signal. The phase difference observed by the reflector is then collected by the initiator to determine the transmission-reception phase difference. The initiator is the device that starts the communication, in other words, the device that requests a response. The reflector is the device that sends back the response. Here, the BLE communicator 7 corresponds to the initiator, and the key device Kd corresponds to the reflector. The reflector can also be called a responder. In the active two-way method, the portable device 2, acting as the reflector, sends a phase report signal indicating the phase difference (θr) it observed separately from the CW signal.

[0192] CW_I, shown in Figure 20, is the CW signal transmitted by the initiator, with an initial phase of δi. CW_R is the CW signal transmitted by the reflector, with an initial phase of δr. If φ is the phase difference that should be observed depending on the one-way distance between the initiator and the reflector, and f is the target frequency, then θr = φ + δi - δr. Also, θi = φ - δi + δr. RpSg, shown in Figure 20, is the received phase report signal that includes information on the received phase (θr) observed by the reflector.

[0193] The initiator uses the average of its own observed phase angle (θi) and the phase angle observed by the reflector (θr) as the transmit-receive phase difference (φ). Here, we are assuming a phase difference due to one-way propagation, so the average of θi and θr is used as the transmit-receive phase difference. In another embodiment, if we assume a phase difference due to round-trip propagation as the transmit-receive phase difference, the transmit-receive phase difference can be calculated as θi + θr = 2φ.

[0194] The phase difference (θi, θr) observed at each device may include the initial phase (δi, δr) at the time each device transmits the signal. However, in the average value of the phase difference observed at each device, the initial phase component at each device cancels out. According to the above method, the transmit / receive phase difference can be calculated even if the initial phase of the CW signal emitted from each device is unknown. Note that the portable device 2 acting as a reflector may transmit a received phase report signal individually for each frequency, or it may transmit the received phases for multiple frequencies together.

[0195] The passive two-way system, as shown in Figure 21, is a system in which the initiator and reflector transmit and receive CW signals to and from each other. The difference from the active two-way system is that the reflector reflects the received phase of the CW signal transmitted from the initiator into the initial phase of the transmitted signal before transmission. For example, if the received phase at the reflector is θr, the CW signal expressed as z(t)=A·exp{-i(ωt+θr+2πn)} is transmitted. A represents the amplitude. ω is the angular frequency corresponding to the target frequency (f), and the relationship ω=2πf exists. n is a natural number and corresponds to the interval from when the reflector receives the CW signal until when it transmits the CW signal.

[0196] According to the method described above, the received phase observed by the initiator is the same value as when receiving a CW signal reflected back by a reflector such as a wall (OBJ). Therefore, the received phase is the value after the initial phase component of the initiator has been canceled out. As a result, the transmit / receive phase difference can be calculated. Furthermore, the passive two-way method has the advantage of not requiring the reflector to transmit RpSg compared to the active two-way method.

[0197] The one-way method assumes that the initial phase / local oscillators between the devices are synchronized, as shown in Figure 22, and uses the received phase of the CW signal transmitted from the portable device 2 directly as the transmit / receive phase difference. Synchronization of the initial phase / local oscillators between the devices can be achieved, for example, by transmitting a predetermined synchronization signal. The method for determining the transmit / receive phase difference is not limited to the method described above; various methods can be employed. The portable device 2 can be configured to operate in accordance with the method adopted by the system.

[0198] <Supplementary information on the measurement method of ToF-related values ​​using the sniffing method> The estimation of device distance / ToF using RTT may be carried out by adopting the method described in Patent Document 2. In other words, instead of multiple BLE communicators 7 communicating with the mobile device 2 individually, the distance from the observer to the mobile device 2 may be calculated using a sniffing method. For example, a representative BLE communicator 7x measures the RTT from the time it transmits a response request signal until it receives a response signal from the mobile device 2 and reports it to the smart ECU 4. An observer, which is a BLE communicator 7 other than the representative, measures the reception interval from the time it receives the response request signal transmitted by the representative to the time it receives a response signal transmitted by the mobile device 2 and reports it to the smart ECU 4. Based on the RTT, the smart ECU 4 identifies the first time of flight, which is the signal flight time between the mobile device and the representative. The smart ECU 4 also identifies the second time of flight, which is the signal flight time between the mobile device and the observer, based on the reception interval at the observer and the first time of flight. The first time of flight and the second time of flight each correspond to ToF.

[0199] Furthermore, the in-vehicle system 1 may be configured to calculate the transmission / reception phase difference, and consequently the dual-frequency phase difference, as a distance indicator from the observation device to the mobile device 2 using a sniffing method. The transmission / reception phase difference as a distance indicator from a certain observation device to the mobile device 2 can be determined by combining the observed value at the observation device and the observed value at the representative device. The observed value at the observation device refers to the reception phase of the CW signal emitted from the BLE communication device 7x as a representative device, and the reception phase of the CW signal emitted from the mobile device 2, as detected by the observation device. The observed value at the representative device refers to the transmission / reception phase difference obtained by the representative device transmitting and receiving CW signals with the mobile device 2.

[0200] With this configuration, which identifies the transmission / reception phase difference between observation devices by sniffing, it becomes possible to acquire the transmission / reception phase difference for multiple observation devices in parallel while the representative device and the portable device 2 are communicating for distance measurement. Therefore, the device location can be identified more quickly than in the embodiment described above. Of course, the calculation of ToF-related values ​​for each observation device may be performed by each observation device rather than by the processor 41. Each observation device may be configured to detect ToF-related values ​​and received strength by sniffing signals from other BLE communication devices 7 and portable devices 2, and to output the detection results to the processor 41.

[0201] <Supplementary information on the entire distance measurement process> The transmission / reception phase difference and received signal strength may be extracted from the same received signal, or they may be extracted from different signals. Furthermore, there are mainly three patterns for the operation of the entire system. The first pattern involves multiple BLE communicators 7 individually performing bidirectional communication with the mobile device 2, thereby collecting ToF-related values ​​and received signal strength for each BLE communicator 7. The second pattern involves the mobile device 2 and a representative unit communicating bidirectionally, while multiple observation units collect ToF-related values ​​and received signal strength by sniffing the communication signal between the mobile device 2 and the representative unit. The second pattern corresponds to a pattern that utilizes the sniffing method in a two-way system.

[0202] The third pattern, i.e., the third pattern, is a pattern in which the representative device performs time synchronization processing by performing two-way communication with the mobile device 2, and then the representative device and the observation devices perform ranging based on signals from the mobile device 2 in a one-way manner. At this time, the representative device can share the time information synchronized with the mobile device 2 with each observation device through the in-vehicle network Nw. Also, in the third pattern, not only the representative device but also the mobile device 2 and each observation device may perform individual time synchronization by performing two-way communication. For ranging in the one-way manner, each observation device may synchronize with the mobile device 2 by eavesdropping (sniffing) on the signals during the two-way communication between the representative device and the mobile device 2. As described above, the wireless signal to be eavesdropped on can be specified by the reference information broadcast from the representative device. Sniffing may or may not be utilized in the third pattern.

[0203] The smart ECU 4 may be configured to be able to implement only any one of a plurality of patterns, or may be configured to be able to execute a plurality of patterns. When the smart ECU 4 is configured to be able to execute a plurality of patterns, which of the first to third patterns to adopt can be selected manually or automatically according to the performance / specifications of the mobile device 2 or the BLE communication device 7.

[0204] <Smart key activation control using LF> As described above, the mobile device 2 may be a smart key. However, it is highly likely that the smart key is configured to operate with a primary battery, and further power saving is required. For such reasons, the smart key as the mobile device 2 is preferably configured to basically maintain a sleep state in which BLE communication is not possible. Such a smart key temporarily transitions from the sleep mode to an active mode in which BLE communication is possible when it receives a predetermined wake-up signal realized using radio waves in the LF band or when a predetermined button is pressed by the user.

[0205] Considering the smart key configuration described above, the in-vehicle system 1 also requires equipment to transmit an LF band wake signal. For example, as shown in Figure 23, the in-vehicle system 1 may have an LF transmitter 8 positioned at any location inside the vehicle to transmit the wake signal. The LF transmitter 8 is a device that transmits a signal of a predetermined frequency belonging to the LF band based on instructions from the smart ECU 4. Here, the LF band refers to the range from 30kHz to 300kHz. The LF transmitter 8 is composed of an LF transmission circuit and an antenna. The LF transmission circuit is a circuit that performs predetermined signal processing such as digital-to-analog conversion, frequency conversion, and modulation. The LF transmission circuit may also be provided by the smart ECU 4.

[0206] The LF transmitter 8 is installed, for example, in the center of the instrument panel in the width direction of the vehicle, or near the center console box. The LF transmitter 8 may also be installed in the overhead console or on the ceiling of the vehicle. The LF transmitter 8 may be embedded in the seat surface of the rear seats, or placed in the trunk. Multiple LF transmitters 8 may be installed. The installation location and number of LF transmitters 8 can also be changed as appropriate. The transmission power and installation location of the LF transmitter 8 are set so that the effective communication area is within 5m of the vehicle Hv, including the vehicle interior. The effective communication area refers to the range in which the wake signal propagates while maintaining a predetermined strength.

[0207] The above configuration allows for reduced power consumption in the smart key. Furthermore, device authentication itself is performed via BLE communication even when the communication partner is a smart key. Since only the LF transmitter 8 is required for the smart key to be installed in the vehicle's hybrid system, system implementation costs can be reduced.

[0208] <Regarding the communication methods available for location estimation of mobile device 2> The communication method used for data communication between the in-vehicle system 1 and the mobile device 2 may be different from the communication method used to determine the device's location. For example, BLE communication may be used for data communication between the in-vehicle system 1 and the mobile device 2, while UWB communication may be used to determine the device's location. UWB communication refers to the UWB-IR (Ultra Wide Band - Impulse Radio) method. In the following, a system configuration that uses UWB communication for terminal location estimation will be referred to as a UWB combined configuration.

[0209] In a UWB-integrated configuration, a mobile terminal or smart key, which can be a mobile device 2, is equipped with a circuit module for transmitting and receiving impulse-like radio waves (hereinafter referred to as impulse signals) used in UWB communication, in addition to a BLE communication unit. Furthermore, the in-vehicle system 1 is equipped with multiple UWB communicators 9, as shown in Figure 24, for example. The UWB communicators 9 are communication modules for receiving impulse signals used in UWB communication. Impulse signals used in UWB communication are signals with an extremely short pulse width, such as 2 nanoseconds. UWB communication is sometimes called ultra-wideband communication. Frequency bands that can be used for UWB communication include, for example, 2.1GHz~10.6GHz, 2.4GHz~4.8GHz, and 22GHz~29GHz.

[0210] The in-vehicle system 1 includes UWB communication devices 9a-9c and 9p-9q, as shown in Figure 24, for example. UWB communication device 9a is located on the outer surface of the B-pillar on the right door. UWB communication device 9b is located on the outer surface of the B-pillar on the left door. UWB communication device 9c is located in the center of the rear bumper in the left-right direction. UWB communication devices 9a-9c correspond to the outdoor unit, which is the UWB communication device 9 located on the outer surface of the vehicle. UWB communication device 9p is located, for example, at a predetermined distance forward from the center of the interior ceiling. UWB communication device 9p is located, for example, at a predetermined distance rearward from the center of the interior ceiling.

[0211] The position estimation unit F3 estimates the distance from each of the multiple UWB communicators 9 to the mobile device 2 by having each of the UWB communicators 9 send and receive impulse signals to the mobile device 2 in a predetermined order. Distance estimation can be performed using methods such as ToF (Time of Flight). Then, the position of the mobile device 2 is estimated based on the distance information from each UWB communicator 9 to the mobile device 2 and the mounting position information of each UWB communicator 9 as shown in the communicator setting data. In this way, device position estimation is possible even if the UWB communicators 9 are used instead of the BLE communicator 7. That is, the BLE communicator 7 in this specification can be replaced with the UWB communicator 9.

[0212] <Additional Note> The devices, systems, and methods described in this disclosure may be implemented by a dedicated computer comprising a processor programmed to execute one or more functions embodied by a computer program. Alternatively, the devices and methods described in this disclosure may be implemented using dedicated hardware logic circuits. Furthermore, the devices and methods described in this disclosure may be implemented by one or more dedicated computers comprising a processor executing a computer program and one or more hardware logic circuits. For example, some or all of the functions of the smart ECU4 may be implemented as hardware. Embodiments of hardware implementation include those using one or more ICs. As the processor (processing core), a CPU, MPU, GPU, DFP (Data Flow Processor), etc., can be used. Also, some or all of the functions of the smart ECU4 may be implemented by combining multiple types of processing units. Some or all of the functions of the smart ECU4 may also be implemented using a system-on-chip (SoC), FPGA, ASIC, etc. FPGA stands for Field-Programmable Gate Array. ASIC stands for Application Specific Integrated Circuit. Computer programs may be stored on a computer-readable, non-transitory tangible storage medium as instructions executed by the computer. HDDs (Hard-disk drives), SSDs (Solid State Drives), flash memory, etc., can be used as program storage media. [Explanation of symbols]

[0213] 1 In-vehicle system, 2 Mobile device, 4 Smart ECU (vehicle authentication device), 5 Door button, 6 Start button, 7 BLE communicator, 8 LF transmitter, 9 UWB communication unit, 41 Processor, F2 Communication control unit, F21 Strength collection unit, F22 Representative unit selection unit, F23 ToF related value acquisition unit, F3 Position estimation unit, F4 Authentication processing unit, F5 Vehicle control unit, Lx Lock / unlock area (exterior operating area), Rm Remote parking area (exterior operating area)

Claims

1. A vehicle position determination system that determines the position of a portable device in relation to a vehicle by wirelessly communicating with a portable device carried by the vehicle user, A communication device configured to be able to communicate wirelessly with the aforementioned portable device, comprising a plurality of outdoor units (7a to 7e) installed at different locations on the exterior surface of the vehicle, The communication device, which is installed inside the vehicle, comprises at least one indoor unit (7p to 7r), A communication control unit (F2) that controls the operation of multiple outdoor units and at least one indoor unit, The system includes a position estimation unit (F3) that determines whether the portable device is located inside the vehicle, and whether the portable device is located outside the vehicle in an outdoor operating area (Lx, Rm) which is an area within a predetermined distance from the vehicle. The communication control unit, To obtain the signal strength received from the portable device in each of the multiple communication devices, The method involves obtaining a Time-of-Flight (ToF) related value, which is a parameter separate from the received signal strength, that directly or indirectly indicates the time of flight of radio waves from at least one of the outdoor units to the portable device, The position estimation unit, A location determination system that determines whether the mobile device is inside the vehicle based on the received signal strength observed by the outdoor unit and the received signal strength observed by the indoor unit, and if it is determined that the mobile device is outside the vehicle, determines whether the mobile device is in the outdoor operating area based on the ToF-related values.

2. A position determination system according to claim 1, The communication control unit obtains the ToF-related values ​​with respect to the basic representative unit by causing a predetermined basic representative unit among the plurality of communication units to send and receive predetermined signals for distance measurement with respect to the portable device. The position estimation unit is configured to determine that the portable device is located in the outdoor operating area based on the fact that the distance from the basic representative unit to the portable device, which is determined based on the ToF-related value with respect to the basic representative unit, is less than a predetermined value.

3. A position determination system according to claim 1, The communication control unit obtains the ToF-related values ​​for each of the outdoor units by sequentially having the multiple outdoor units send and receive predetermined signals for distance measurement to and from the portable device. The position estimation unit is configured to determine whether or not the portable device is located within the outdoor operating area based on the ToF-related values ​​for each outdoor unit.

4. A position determination system according to claim 1, The communication control unit, Based on the received signal strength observed at each of the multiple outdoor units, the nearest outdoor unit, which is the outdoor unit closest to the portable device, is identified. By having the nearest outdoor unit transmit and receive a predetermined signal for distance measurement with the portable device, the ToF-related values ​​are obtained with reference to the nearest outdoor unit. The position estimation unit is configured to determine whether or not the portable device is located within the outdoor operating area based on the ToF-related value with respect to the nearest outdoor unit.

5. A position determination system according to claim 1, The communication control unit, Based on the device direction, which is the direction in which the mobile device is located, determined by analyzing the received signal from the mobile device, the nearest outdoor unit, which is the outdoor unit closest to the mobile device among the multiple outdoor units, is identified. By having the nearest outdoor unit transmit and receive a predetermined signal for distance measurement with the portable device, the ToF-related values ​​are obtained with reference to the nearest outdoor unit. The position estimation unit is configured to determine whether or not the portable device is located within the outdoor operating area based on the ToF-related value with respect to the nearest outdoor unit.

6. A position determination system according to any one of claims 1 to 5, The communication control unit, By having a predetermined basic representative unit among the multiple communication devices transmit and receive a predetermined signal for distance measurement with the portable device, the ToF-related values ​​are obtained with the basic representative unit as the reference. Based on the fact that the distance from the basic representative unit to the portable device, determined based on the ToF-related value with respect to the basic representative unit, is less than a predetermined primary threshold, the ToF-related value with respect to the portable device is obtained by having at least one of the outdoor units transmit and receive a predetermined signal to the portable device, and the outdoor unit is then operated accordingly. The position estimation unit is configured to determine that the portable device is located within the outdoor operating area based on the existence of an outdoor unit where the distance to the portable device, determined based on the ToF-related value, is less than a predetermined secondary threshold which is smaller than the primary threshold.

7. A position determination system according to any one of claims 1 to 6, Multiple indoor units, The vehicle comprises a predetermined storage device (43) which stores communication device setting data indicating the mounting position of the communication device in the vehicle, The position estimation unit, Based on the reception status of signals from the mobile device at multiple outdoor units, the nearest outdoor unit, which is the outdoor unit closest to the mobile device, is identified. Based on the mounting position of each communication device as shown in the communication device setting data, the nearest indoor unit, which is the indoor unit closest to the nearest outdoor unit, is identified. The position estimation unit is a position determination system that determines whether or not the portable device is inside the vehicle based on the difference between the received signal strength at the nearest indoor unit and the received signal strength at the nearest outdoor unit.

8. A position determination system according to any one of claims 1 to 7, The communication control unit obtains the ToF-related values ​​with respect to the indoor unit by causing a predetermined indoor unit to send and receive a predetermined signal for distance measurement with respect to the portable device. The position estimation unit is a position determination system that determines that the portable device is not inside the vehicle based on the fact that the distance from the indoor unit to the portable device, which is determined based on the ToF-related value, is greater than or equal to a predetermined value.

9. A position determination system according to any one of claims 1 to 8, The wireless communication with the aforementioned mobile device uses multiple frequencies, The communication control unit collects the received signal strength for each frequency for each communication device. The position estimation unit is a position determination system that determines whether or not the portable device is inside the vehicle based on the average or variance of the received signal strength for each frequency in each of the plurality of communication devices.

10. A position determination system according to any one of claims 1 to 9, The communication control unit designates one of the multiple communication devices as a representative device to perform bidirectional communication with the portable device, while the other communication devices operate as observation devices that receive signals but do not transmit them. The communication control unit is a position determination system configured to acquire the received signal strength not only from the representative unit but also from the observation unit.

11. A position determination system according to any one of claims 1 to 10, The system comprises at least four of the aforementioned outdoor units, At least one of the multiple outdoor units is located at the front end of the vehicle. The communication control unit acquires the ToF-related values ​​for each outdoor unit, The position estimation unit determines the distance from the outdoor unit to the portable device based on the ToF-related values. A location determination system configured to determine that the mobile device is located within a remote parking area, which is the outdoor operating area for remote parking, based on the existence of an outdoor unit located at a predetermined distance or less from the mobile device.

12. A position determination system according to any one of claims 1 to 11, The communication control unit is configured to change the transmission power of the communication device or the frequency of communication with the mobile device based on the distance from the vehicle to the mobile device, as a position determination system.

13. A position determination system according to any one of claims 1 to 12, The position estimation unit is configured to automatically switch an algorithm for determining the position of the portable device according to the mounting pattern of the communication device in the vehicle, which is identified by referring to communication device setting data indicating the mounting position of the communication device in the vehicle.

14. A position determination system according to any one of claims 1 to 13, The aforementioned ToF-related value is the round-trip time, which is the time from the transmission of a response request signal to the reception of a response signal, or the transmission / reception phase difference for each frequency obtained by transmitting and receiving multiple continuous wave signals of different frequencies, in a position determination system.

15. A location determination method performed by at least one processor for determining the location of a portable device carried by a vehicle user, A communication device configured to wirelessly communicate with the aforementioned mobile device, which acquires data indicating the signal strength received from the mobile device from a plurality of outdoor units located at different positions on the exterior surface of the vehicle, To acquire data indicating the signal strength received from the portable device from at least one indoor unit, which is a communication device located inside the vehicle, Based on the received signal strength observed by the outdoor unit and the received signal strength observed by the indoor unit, it is determined whether or not the portable device is inside the vehicle. Obtaining a Time-of-Flight (Tof) related value, which is a parameter separate from the received signal strength, that directly or indirectly indicates the time of flight of radio waves from at least one of the outdoor units to the portable device, A location determination method that includes, if it is determined that the portable device is outside the vehicle based on the received signal strength, determining whether the portable device is located within an outdoor operating area (Lx, Rm), which is an area outside the vehicle that is within a predetermined distance from the vehicle, based on the ToF-related values.

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