Control device, control method, and program

Abstract

The purpose of the present invention is to provide a mechanism with which it is possible to further improve the accuracy of estimating the positional relationship between devices.　A control device (300) according to the present invention is provided with a control unit (310) that: repeatedly executes, for each of a plurality of wireless communication units (220) that perform wireless communication with another communication device (portable device 100), processing for calculating, on the basis of wireless signals transmitted and received by the respective wireless communication units (220), coordinates indicating the position of the other communication device (portable device 100) and a reliability parameter indicating the reliability of the coordinates; and estimates the presence area of the other communication device (portable device 100) upon preferentially referencing the coordinates obtained by the wireless communication unit (220) that obtained a greater number of high-reliability coordinates in the plurality of wireless communication units (220) that obtained high-reliability coordinates.

Description

Control device, control method, and program

[0001] The present invention relates to a control device, a control method, and a program.

[0002] In recent years, technologies have been developed that estimate the positional relationship between devices based on the results of transmitting and receiving wireless signals between the devices. For example, Patent Document 1 listed below discloses a technology that estimates the angle of arrival of a signal using UWB (Ultra-Wide Band).

[0003] International Publication No. 2015 / 176776

[0004] However, the technology described in Patent Document 1 above has the problem that no measures are taken to address the possibility that the accuracy of estimating the angle of arrival may decrease in environments where there are obstructions between the transmitter and receiver.

[0005] Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to provide a mechanism that can further improve the accuracy of estimating the positional relationship between devices.

[0006] In order to solve the above problem, according to one aspect of the present invention, a control device is provided that includes a control unit that repeatedly executes, for each of a plurality of wireless communication units, a process of calculating coordinates indicating the position of the other communication device and a reliability parameter indicating the reliability of the coordinates based on wireless signals transmitted and received by each of a plurality of wireless communication units that perform wireless communication with the other communication device, and that estimates the presence area of ​​the other communication device by preferentially referring to the coordinates obtained by the wireless communication units that obtained a greater number of highly reliable coordinates among the plurality of wireless communication units that obtained highly reliable coordinates.

[0007] In addition, in order to solve the above problem, according to another aspect of the present invention, there is provided a control method executed by a computer, which includes repeatedly executing, for each of a plurality of wireless communication units that perform wireless communication with another communication device, a process of calculating coordinates indicating the position of the other communication device and a reliability parameter indicating the reliability of the coordinates based on wireless signals transmitted and received by each of the plurality of wireless communication units that perform wireless communication with the other communication device, and estimating the presence area of ​​the other communication device by preferentially referring to the coordinates obtained by the wireless communication units that obtained a greater number of highly reliable coordinates among the plurality of wireless communication units that obtained highly reliable coordinates.

[0008] In addition, in order to solve the above problem, according to another aspect of the present invention, a program is provided to cause a computer to function as a control unit that repeatedly executes, for each of a plurality of wireless communication units that perform wireless communication with other communication devices, a process of calculating coordinates indicating the position of the other communication device and a reliability parameter indicating the reliability of the coordinates based on wireless signals transmitted and received by each of the plurality of wireless communication units that perform wireless communication with the other communication device, and that estimates the presence area of ​​the other communication device by preferentially referring to the coordinates obtained by the wireless communication units that obtained a greater number of highly reliable coordinates among the plurality of wireless communication units that obtained highly reliable coordinates.

[0009] As described above, according to the present invention, a mechanism is provided that can further improve the accuracy of estimating the positional relationship between devices.

[0010] FIG. 1 is a block diagram showing an example of the configuration of a system according to an embodiment of the present invention; FIG. 2 is a diagram for explaining an example of an antenna arrangement according to the present embodiment; FIG. 3 is a diagram showing an example of a processing block of a wireless communication unit according to the present embodiment; FIG. 4 is a graph showing an example of a CIR according to the present embodiment; FIG. 5 is a sequence diagram for explaining an example of a processing flow relating to estimation of location parameters executed in the system according to the present embodiment; FIG. 6 is a diagram for explaining an example of a process for estimating the presence area of ​​a portable device according to the present embodiment; and FIG. 7 is a flowchart showing an example of a processing flow executed by a control device according to the present embodiment.

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations will be omitted.

[0012] Furthermore, in this specification and drawings, elements having substantially the same functional configuration may be distinguished by adding different letters after the same reference numeral. For example, multiple elements having substantially the same functional configuration may be distinguished as necessary, such as in-vehicle devices 200A and 200B. However, if there is no particular need to distinguish between multiple elements having substantially the same functional configuration, only the same reference numeral may be used. For example, if there is no particular need to distinguish between in-vehicle devices 200A and 200B, they will simply be referred to as in-vehicle device 200.

[0013] 1 is a block diagram showing an example of the configuration of a system 1 according to an embodiment of the present invention. As shown in FIG. 1, the system 1 according to this embodiment includes a portable device 100, a plurality of vehicle-mounted devices 200 (200A and 200B), a control device 300, and a controlled device 400.

[0014] The in-vehicle device 200, the control device 300, and the controlled device 400 according to this embodiment are mounted on a vehicle 20. The vehicle 20 is an example of a moving body, and is, for example, a vehicle in which a user is permitted to ride (for example, a vehicle owned by the user or a vehicle temporarily loaned to the user). Note that the moving body according to this embodiment includes not only the vehicle 20 but also an airplane, a ship, etc.

[0015] (Portable Device 100) The portable device 100 is an example of another communication device, and is a device carried by a user who uses the vehicle 20. The portable device 100 may be an electronic key, a smartphone, a tablet terminal, a wearable terminal, or the like. As shown in FIG. 1 , the portable device 100 includes a control unit 110 and a wireless communication unit 120.

[0016] The control unit 110 controls the overall operation of the portable device 100. For example, the control unit 110 controls the wireless communication unit 120 so as to transmit and receive wireless signals to and from the vehicle-mounted device 200. The control unit 110 is configured by an electronic circuit such as a CPU (Central Processing Unit) or a microprocessor.

[0017] The wireless communication unit 120 performs wireless communication with the in-vehicle device 200. Such wireless communication may be performed using, for example, signals using UWB (hereinafter also referred to as UWB signals). In wireless communication using UWB signals, if an impulse method is used, the propagation delay time of the radio waves can be measured with high precision by using radio waves with an extremely short pulse width of nanoseconds or less, and distance measurement based on the propagation delay time can be performed with high precision. The wireless communication unit 120 is configured as, for example, a communication interface capable of communication using UWB signals.

[0018] The wireless communication unit 120 also has at least one antenna 121. The wireless communication unit 120 transmits and receives wireless signals via the at least one antenna 121.

[0019] (In-vehicle device 200) The in-vehicle device 200 is an example of a communication device, and is a device mounted on the vehicle 20. The number of in-vehicle devices 200 mounted on the vehicle 20 is not limited to two, and may be three or more. As shown in FIG. 1 , the in-vehicle device 200 includes a control unit 210 and a wireless communication unit 220.

[0020] The control unit 210 controls the overall operation of the in-vehicle device 200. For example, the control unit 210 controls the wireless communication unit 220 so as to transmit and receive wireless signals to and from the portable device 100. The control unit 210 is configured by an electronic circuit such as an ECU (Electronic Processing Unit) or a microprocessor.

[0021] The wireless communication unit 220 performs wireless communication with the portable device 100. This wireless communication can be performed using, for example, UWB signals. The wireless communication unit 220 is configured as, for example, a communication interface capable of communication using UWB signals.

[0022] The wireless communication unit 220 also has at least three or more antennas 221. The wireless communication unit 220 transmits and receives wireless signals via the three or more antennas 221.

[0023] In the following description, it is assumed that the wireless communication unit 220 has four antennas 221. An example of the arrangement of the four antennas 221 will be described with reference to FIG.

[0024] FIG. 2 is a diagram illustrating an example of the arrangement of antennas 221 according to this embodiment. As shown in FIG. 2, the four antennas 221 (221A to 221D) may be arranged in positions forming a square on the wireless communication unit 220. Antennas 221A and 221C, as well as antennas 221B and 221D, are arranged parallel to the X axis. The X axis may be, for example, an axis extending in the front-to-rear direction of the vehicle 20. On the other hand, antennas 221A and 221B, as well as antennas 221C and 221D, are arranged parallel to the Y axis. The Y axis may be, for example, an axis extending in the left-to-right direction of the vehicle 20. The axis perpendicular to the X axis and the Y axis is defined as the Z axis. The Z axis may be an axis extending in the up-down direction of the vehicle.

[0025] The arrangement and scale of the wireless communication unit 220 and the antennas 221 are not limited to the example shown in FIG. 2 . For example, the distance between adjacent antennas 221 in the X-axis direction or the Y-axis direction may be approximately 1 / 2 the wavelength of the wireless signal. The arrangement shape of the four antennas may be a square, parallelogram, trapezoid, rectangle, or any other shape. However, it is desirable that the multiple antennas 221 be arranged on a plane rather than on the same straight line.

[0026] (Control device 300) The control device 300 has a function of controlling other devices mounted on the vehicle 20. The control device 300 communicates with and controls the in-vehicle device 200 and the controlled device 400 via an in-vehicle network such as a Controller Area Network (CAN) or a Local Interconnect Network (LIN). As shown in FIG. 1 , the control device 300 includes a control unit 310.

[0027] The control unit 310 controls the overall operation of the control device 300. As one example, the control unit 310 controls the in-vehicle device 200 to perform wireless communication with the portable device 100. As another example, the control unit 310 estimates the position of the portable device 100 based on the result of the wireless communication by the portable device 100. As another example, the control unit 310 controls the operation of the controlled device 400 based on the estimated position of the portable device 100. The control unit 310 is configured by an electronic circuit such as an ECU or a microprocessor.

[0028] (Controlled Device 400) Controlled device 400 is a device that operates under the control of control device 300. Controlled device 400 may be a door lock of vehicle 20 or an engine of vehicle 20. For example, control device 300 may lock or unlock the door lock of vehicle 20, or permit or restrict starting of the engine of vehicle 20.

[0029] The configuration example of the system 1 according to this embodiment has been described above.

[0030] 2. Technical Features 2.1. Estimation of Location Parameters (CIR) Each of the portable device 100 (more specifically, the control unit 110) and the vehicle-mounted device 200 (more specifically, the control unit 210) can calculate a CIR (Channel Impulse Response).

[0031] The CIR is a response when an impulse is input to the system, and indicates the characteristics of the wireless communication path between the portable device 100 and the vehicle-mounted device 200.

[0032] The CIR can be calculated by performing a sliding correlation between a wireless signal transmitted by a transmitting side (hereinafter also referred to as a transmitted signal) and a wireless signal received by a receiving side (hereinafter also referred to as a received signal). More specifically, the receiving side calculates a value obtained by performing a correlation between the received signal and a transmitted signal delayed by a certain delay time as the characteristic at that delay time (hereinafter also referred to as a CIR value). The receiving side then calculates the CIR by calculating the CIR value for each delay time. In other words, the CIR is a time-series progression of the CIR value. Here, the CIR value is a complex number having an I component and a Q component. The sum of the squares of the I component and the Q component of the CIR value may also be referred to as the power value of the CIR. In ranging techniques using UWB, the CIR value is also referred to as a delay profile. In ranging techniques using UWB, the sum of the squares of the I component and the Q component of the CIR value is also referred to as a power delay profile.

[0033] Hereinafter, the CIR calculation process when the transmitting side is the portable device 100 and the receiving side is the vehicle-mounted device 200 will be described in detail with reference to FIGS.

[0034] 3 is a diagram showing an example of processing blocks of the wireless communication unit 220 according to this embodiment. As shown in FIG. 3, the wireless communication unit 220 includes an antenna 221, an oscillator 222, a multiplier 223, a 90-degree phase shifter 224, a multiplier 225, LPFs (Low Pass Filters) 226 and 227, a correlator 228, and an integrator 229.

[0035] The oscillator 222 generates a signal having the same frequency as the frequency of the carrier wave that carries the transmission signal, and outputs the generated signal to the multiplier 223 and the 90-degree phase shifter 224 .

[0036] Multiplier 223 multiplies the signal received by antenna 221 by the signal output from oscillator 222, and outputs the multiplication result to LPF 226. LPF 226 outputs, of the input signals, signals having a frequency equal to or lower than the frequency of the carrier wave carrying the transmission signal to correlator 228. The signal input to correlator 228 is the I component (i.e., the real part) of the component corresponding to the envelope of the received signal.

[0037] The 90-degree phase shifter 224 delays the phase of the input signal by 90 degrees and outputs the delayed signal to the multiplier 225. The multiplier 225 multiplies the signal received by the antenna 221 by the signal output from the 90-degree phase shifter 224, and outputs the multiplication result to the LPF 227. The LPF 227 outputs, of the input signals, signals having a frequency equal to or lower than the frequency of the carrier wave carrying the transmission signal to the correlator 228. The signal input to the correlator 228 is the Q component (i.e., the imaginary part) of the components corresponding to the envelope of the received signal.

[0038] The correlator 228 calculates the CIR by taking a sliding correlation between the reference signal and the received signal consisting of the I and Q components output from the LPFs 226 and 227. Note that the reference signal here is the same signal as the transmitted signal before being multiplied by the carrier wave.

[0039] The accumulator 229 accumulates the CIR output from the correlator 228 and outputs the accumulated result.

[0040] Here, the transmitting side may transmit a signal including a preamble, which includes one or more preamble symbols, as a transmission signal. A preamble is a sequence known between the transmitting and receiving sides. A preamble is typically placed at the beginning of a transmission signal. A preamble symbol is a pulse sequence including one or more pulses. A pulse sequence is a collection of multiple pulses separated in the time direction. The preamble symbols are the target of integration by the accumulator 229. That is, the correlator 228 calculates the CIR for each preamble symbol by performing a sliding correlation between each of the portions corresponding to the multiple preamble symbols included in the received signal and the preamble symbols included in the transmission signal. The accumulator 229 then integrates the CIR for each preamble symbol for one or more preamble symbols included in the preamble, and outputs the integrated CIR. Hereinafter, unless otherwise specified, CIR refers to the integrated CIR.

[0041] The wireless communication unit 220 performs the above processing on each of the signals received by the multiple antennas 221 .

[0042] (Detection of First Arrival Wave) FIG. 4 is a graph showing an example of the CIR output from the integrator 229. The horizontal axis of the graph represents delay time, and the vertical axis represents the delay profile. In the CIR, a piece of information that constitutes information that changes over time, such as the CIR value at a certain delay time, is also referred to as a sampling point. In the CIR, typically, a set of sampling points between zero-crossing points corresponds to one pulse. A zero-crossing point is a sampling point where the value becomes zero. However, this is not the case in a noisy environment. For example, a set of sampling points between the intersections of a non-zero reference level and the transition of the CIR value may be considered to correspond to one pulse. The CIR shown in FIG. 4 includes a set of sampling points 21 corresponding to a certain pulse and a set of sampling points 22 corresponding to another pulse.

[0043] Set 21 corresponds to, for example, fast path signals (hereinafter also referred to as first arriving waves). A fast path refers to the shortest path between a transmitter and a receiver, and in an environment without obstructions, refers to the straight-line distance between a transmitter and a receiver. A first arriving wave is a signal that has reached the receiver via a fast path. Set 22 corresponds to, for example, signals that have reached the receiver via a path other than the fast path.

[0044] The receiving side detects, as the first arriving wave, the signal that first satisfies a predetermined criterion among the received radio signals. One example of the predetermined detection criterion is that the CIR value (e.g., amplitude or power) first exceeds a predetermined threshold. That is, the receiving side may detect, as the first arriving wave, the signal corresponding to the portion of the CIR where the CIR value first exceeds the predetermined threshold.

[0045] The first arriving wave can be either a direct wave, a delayed wave, or a composite wave. A direct wave is a signal that is received by the receiving side directly (i.e., without being reflected, etc.) via the shortest path between the transmitter and receiver. A delayed wave is a signal that is received by the receiving side indirectly via a path that is not the shortest between the transmitter and receiver, i.e., due to reflection, etc. A delayed wave is received by the receiving side with a delay relative to the direct wave. A composite wave is a signal that is received by the receiving side in a state where multiple signals that have traveled multiple different paths are combined.

[0046] It should be noted here that the signal detected as the first arriving wave is not necessarily the direct wave. For example, if the direct wave and the delayed wave are received in a state where they cancel each other out, the CIR value of the direct wave may fall below a predetermined threshold, and the direct wave may not be detected as the first arriving wave. In this case, a delayed wave or a composite wave that arrives later than the direct wave may be detected as the first arriving wave.

[0047] Typically, in a line of sight (LOS) state, the receiving side is likely to successfully detect the direct wave as the first arriving wave. The LOS state refers to a state in which there is line of sight between the transmitting and receiving sides, such as when there is no obstruction between the transmitting and receiving sides.

[0048] On the other hand, in a non-line of sight (NLOS) state, the receiving side may fail to detect the direct wave as the first arriving wave. The NLOS state refers to a state in which line of sight between the transmitting and receiving sides is not possible, for example, due to the presence of an obstruction between the transmitting and receiving sides.

[0049] In the following, unless otherwise specified, the signal refers to the first arriving wave.

[0050] (Estimation of Position Parameter) The control device 300 (more specifically, the control unit 310) according to this embodiment estimates a position parameter indicating the position where the portable device 100 is located, based on the result of the wireless communication (particularly, the first incoming wave) performed between the portable device 100 and the vehicle-mounted device 200. The position parameter is information indicating the relative position of the portable device 100 with respect to the vehicle-mounted device 200.

[0051] An example of the location parameter is the distance between the portable device 100 and the vehicle-mounted device 200. The distance between the portable device 100 and the vehicle-mounted device 200 can be estimated based on, for example, a propagation delay time (i.e., ToF (Time of Flight)). The estimated distance is also referred to as a ranging value.

[0052] An example of the position parameter is the angle of arrival of a wireless signal received by the in-vehicle device 200 from the portable device 100. The angle of arrival of the wireless signal can be estimated based on the phase difference of the received wireless signal in an antenna array formed by two antennas 221, for example.

[0053] An example of the position parameter is the coordinates of the portable device 100. The coordinates of the portable device 100 can be estimated, for example, by combining an estimation result of the distance between the portable device 100 and the vehicle-mounted device 200 and an estimation result of the angle of arrival of the wireless signal received by the vehicle-mounted device 200 from the portable device 100.

[0054] An example of the flow of processing related to estimation of position parameters will be described below with reference to FIG.

[0055] FIG. 5 is a sequence diagram for explaining an example of the flow of processing related to estimation of position parameters executed in the system 1 according to this embodiment.

[0056] First, the antenna 121 of the portable device 100 transmits a Poll (Polling) signal (step S101).

[0057] Next, when the antenna 221A of the vehicle-mounted device 200 receives the Poll signal, it transmits a Resp (Response) signal in response to the received Poll signal (step S103).

[0058] Then, when the antenna 121 of the portable device 100 receives the Resp signal, it transmits a Final signal in response to the received Resp signal (steps S105a to S105d). The Final signal is received by the antennas 221A to 221D of the vehicle-mounted device 200.

[0059] Here, the time length from when the portable device 100 transmits the Poll signal to when it receives the Resp signal is defined as time length T1, the time length from when it receives the Resp signal to when it transmits the Final signal is defined as time length T2, the time length from when the in-vehicle device 200 receives the Poll signal to when it transmits the Resp signal is defined as time length T3, and the time length from when it transmits the Resp signal to when it receives the Final signal is defined as time length T4.

[0060] The control device 300 calculates the propagation delay time τ of the signal using the time lengths T1 to T4. For example, the control device 300 calculates the propagation delay time τ using the following equation: Then, the control device 300 may estimate the distance between the portable device 100 and the in-vehicle device 200 by multiplying the calculated propagation delay time τ of the signal by the known speed of the signal.

[0061]

[0062] Furthermore, the control device 300 estimates the angle of arrival of the signal received by the vehicle-mounted device 200 from the portable device 100 based on the phase of the signal received by the antennas 221A to 221D. For example, the control device 300 estimates the angle of arrival of the Final signal using the following equation.

[0063]

[0064]

[0065] Note that Pd is the phase difference of the signals received by adjacent antennas, as indicated by the accompanying index. For example, Pd ＡＣ is the phase difference between the signals received by antenna 221A and antenna 221C.

[0066] λ is the wavelength of the radio wave. d is the distance between the antennas 221. α is the angle of arrival of the signal relative to the X axis. β is the angle of arrival of the signal relative to the Y axis.

[0067] Furthermore, the control device 300 may estimate the coordinates of the portable device 100 based on the estimated distance and angle of arrival. For example, the control device 300 estimates the coordinate x on the X axis, the coordinate y on the Y axis, and the coordinate z on the Z axis of the portable device 100 using the following equations.

[0068]

[0069] It should be noted that R is an estimated value (i.e., a measured distance value) of the distance between the portable device 100 and the vehicle-mounted device 200 .

[0070] 2.2. Calculation of Reliability Parameter The control device 300 according to this embodiment calculates a reliability parameter indicating the reliability of the signal (i.e., the first arriving wave) received by the in-vehicle device 200. The reliability of a signal is an index indicating its suitability for use in estimating a position parameter. The reliability of a signal may be understood as an index indicating the likelihood that the signal is a direct wave, that is, an index indicating the likelihood that the signal was detected in an LOS state. The higher the reliability of a signal, the higher the estimation accuracy of the position parameter calculated based on that signal. On the other hand, the lower the reliability of a signal, the lower the estimation accuracy of the position parameter calculated based on that signal.

[0071] There are various examples of the reliability parameter. As one example, the reliability parameter may be the signal-to-noise ratio (SNR) of the signal. As another example, the reliability parameter may be the received signal strength of the signal (e.g., a received signal strength indicator (RSSI)). As another example, the reliability parameter may be the variance in the reception time of the Final signal (i.e., the detection time of the first arriving wave) between the antennas 221.

[0072] 2.3. Estimation of Presence Area Based on Reliability Parameter The control device 300 causes each of the multiple in-vehicle devices 200 to perform wireless communication multiple times to obtain multiple estimation results of the coordinates of the portable device 100 (hereinafter also referred to as first coordinates). Next, the control device 300 estimates final values ​​of the coordinates of the portable device 100 (hereinafter also referred to as second coordinates) based on the multiple first coordinates. The control device 300 then estimates an area corresponding to the second coordinates as an area where the portable device 100 is present (hereinafter also referred to as the presence area). Examples of areas where the portable device 100 may be present include spaces based on the vehicle 20, such as an area outside the vehicle cabin, an area in front of the vehicle, an area behind the vehicle, an area around the driver's seat, or an area around the passenger seat.

[0073] The process of estimating the area where the portable device 100 is located will be described in detail below.

[0074] First, the control device 300 repeatedly executes a process for calculating, for each of the multiple in-vehicle devices 200, first coordinates indicating the position of the portable device 100 and reliability parameters indicating the reliability of the first coordinates, based on wireless signals transmitted and received by each of the multiple in-vehicle devices 200 that wirelessly communicate with the portable device 100. The reliability parameter of the first coordinates is synonymous with the reliability parameter calculated for the signals used to estimate the first coordinates. High reliability of the signals used to estimate the first coordinates indicates high reliability of the estimated first coordinates, i.e., high estimation accuracy of the estimated first coordinates. Through this process, the control device 300 acquires multiple combinations of first coordinates and reliability parameters for the first coordinates.

[0075] The control device 300 then estimates the presence area of ​​the portable device 100 based on multiple combinations of the acquired first coordinates and reliability parameters. Specifically, the control device 300 estimates second coordinates based on first coordinates with high reliability indicated by the reliability parameters (hereinafter also referred to as highly reliable first coordinates), and estimates the area corresponding to the second coordinates as the presence area of ​​the portable device 100. The highly reliable first coordinates here may be first coordinates whose reliability indicated by the reliability parameters is equal to or greater than a certain threshold.

[0076] The control device 300 estimates the location area of ​​the portable device 100 by preferentially referring to the first coordinates obtained by the vehicle-mounted devices 200 from which a greater number of highly reliable first coordinates have been obtained, among the plurality of vehicle-mounted devices 200 from which highly reliable first coordinates have been obtained. With this configuration, it is possible to improve the accuracy of estimating the location area of ​​the portable device 100.

[0077] In particular, when the number of highly reliable first coordinates obtained by the multiple in-vehicle devices 200 is not equal, the control device 300 estimates the presence area of ​​the portable device 100 by preferentially referencing the first coordinates obtained by the in-vehicle devices 200 that obtained a greater number of highly reliable first coordinates. Depending on the positional relationship between the multiple in-vehicle devices 200 and the portable device 100, some in-vehicle devices 200 may be in a LOS state and have high estimation accuracy for the first coordinates, while others may be in a NLOS state and have low estimation accuracy for the first coordinates. Therefore, if the first coordinates obtained by all in-vehicle devices 200 are treated equally to estimate the second coordinates, the estimation accuracy of the second coordinates may decrease, and as a result, the estimation accuracy of the presence area of ​​the portable device 100 may decrease. In this regard, with this configuration, data obtained by in-vehicle devices 200 that are likely to be in a LOS state can be preferentially referenced, thereby improving the estimation accuracy of the presence area of ​​the portable device 100.

[0078] When the number of highly reliable first coordinates obtained from the multiple in-vehicle devices 200 is equal, the control device 300 may estimate the location area of ​​the portable device 100 by equally referring to the first coordinates obtained from each of the multiple in-vehicle devices 200. Even in this case, the control device 300 can refer to the data obtained from the in-vehicle device 200 that is likely to be in an LOS state, thereby improving the accuracy of estimating the location area of ​​the portable device 100.

[0079] An example of a process for estimating the location area of ​​the portable device 100 will be described below with reference to Fig. 6. Fig. 6 is a diagram for explaining an example of a process for estimating the location area of ​​the portable device 100 according to this embodiment. As shown in Fig. 6, it is assumed that the in-vehicle device 200A is disposed in the front of the interior of the vehicle 20, and the in-vehicle device 200B is disposed in the rear of the interior of the vehicle 20.

[0080] As shown in Table 1 below, the control device 300 acquires a number of first coordinates acquired by the in-vehicle device 200A and b number of first coordinates acquired by the in-vehicle device 200B. The control device 300 calculates reliability parameters of these first coordinates.

[0081]

[0082] Next, as shown in Table 2 below, the control device 300 extracts A first coordinates having high reliability indicated by the reliability parameter from the a first coordinates obtained by the in-vehicle device 200A. Also, the control device 300 extracts B first coordinates having high reliability indicated by the reliability parameter from the b first coordinates obtained by the in-vehicle device 200B.

[0083]

[0084] Then, the control device 300 estimates the presence area of ​​the portable device 100 based on the median value of the extracted A + B highly reliable first coordinates. More specifically, as shown in Fig. 6, the control device 300 estimates the median value (Xm, Ym) of the A + B highly reliable first coordinates shown in Table 2 as the second coordinate. In this case, the control device 300 estimates the driver's seat surrounding area 30 corresponding to the estimated second coordinates (Xm, Ym) as the presence area of ​​the portable device 100.

[0085] If A and B are not the same, i.e., if the number of highly reliable first coordinates obtained is not equal between the in-vehicle device 200A and the in-vehicle device 200B, taking the median results in preferentially referencing the first coordinates obtained by the in-vehicle device 200 from which a greater number of highly reliable first coordinates have been obtained. The in-vehicle device 200 from which a greater number of highly reliable first coordinates have been obtained refers to the in-vehicle device 200 that is likely to be in an LOS state. In other words, with this configuration, it is possible to preferentially refer to data obtained by the in-vehicle device 200 that is likely to be in an LOS state, thereby improving the accuracy of estimating the presence area of ​​the portable device 100.

[0086] The median of the plurality of first coordinates is obtained by calculating the median for each of the X coordinate and the Y coordinate. If A+B is an even number, the median may be the arithmetic mean of the two middle first coordinates.

[0087] An example of the flow of the above-described processing will now be described with reference to FIG.

[0088] FIG. 7 is a flowchart showing an example of the flow of processing executed by the control device 300 according to this embodiment.

[0089] 7, first, the control device 300 executes wireless communication multiple times for each vehicle-mounted device 200 (step S202), thereby acquiring multiple first coordinates.

[0090] Next, the control device 300 extracts highly reliable data (step S204). For example, the control device 300 calculates a reliability parameter for each of the first coordinates acquired in step S202, and extracts the first coordinates whose reliability indicated by the reliability parameter is equal to or greater than a certain threshold.

[0091] Next, the control device 300 estimates the area where the portable device 100 is located based on the extracted highly reliable data (step S206). For example, the control device 300 estimates the median value of the extracted multiple highly reliable first coordinates as the second coordinates, and estimates the area corresponding to the estimated second coordinates as the area where the portable device 100 is located.

[0092] Then, the control device 300 controls the operation of the controlled device 400 based on the estimated location area of ​​the portable device 100 (step S208). For example, the control device 300 unlocks the door when it estimates that the portable device 100 is in the area around the driver's seat, or allows the engine to start when it estimates that the portable device 100 is in the passenger compartment.

[0093] 3. Modifications 3.1. Modifications Related to the Method of Calculating Second Coordinates In the above embodiment, an example has been described in which the median value of a plurality of extracted highly reliable first coordinates is estimated as the second coordinate, but the present invention is not limited to this example. Other examples will be described below.

[0094] (First Example) The control device 300 may estimate, as the second coordinate, one of two or more highly reliable first coordinates near the median of the extracted multiple highly reliable first coordinates, and estimate the presence area of ​​the portable device 100 based on the estimated second coordinate. Here, the two or more highly reliable first coordinates near the median may be, for example, the middle two or three first coordinates. With this configuration, the presence area of ​​the portable device 100 can be estimated based on the signal that is most likely to have been detected in an LOS state, thereby improving the accuracy of estimating the presence area of ​​the portable device 100.

[0095] (Second Example) The control device 300 may estimate two or more presence areas of the portable device 100 based on each of two or more highly reliable first coordinates near the median value among the extracted plurality of highly reliable first coordinates. For example, assume that (Xm1, Ym1) and (Xm2, Ym2) are obtained as two or more highly reliable first coordinates near the median value among the extracted plurality of highly reliable first coordinates. If the area corresponding to (Xm1, Ym1) is the driver's seat surrounding area and the area corresponding to (Xm2, Ym2) is the passenger seat surrounding area, the control device 300 may estimate the driver's seat surrounding area and the passenger seat surrounding area as the presence areas of the portable device 100.

[0096] Although the estimation result does not narrow down the area where the portable device 100 is located to one, it may be a sufficient estimation result depending on the application. An example of such an application is when a door lock is unlocked when the area where the portable device 100 is located is the area around the driver's seat or the area around the passenger seat.

[0097] (Third Example) The control device 300 may estimate the area where the portable device 100 is located by taking a majority vote from multiple areas corresponding to each of the extracted multiple highly reliable first coordinates. For example, assume that the combinations of highly reliable first coordinates and areas corresponding to the highly reliable first coordinates shown in Table 3 below are obtained. In this case, since the number of areas D (areas around the driver's seat) is greater than the number of areas P (areas around the passenger's seat), the control device 300 estimates that the area where the portable device 100 is located is area D.

[0098]

[0099] Even with this configuration, when the number of highly reliable first coordinates obtained by the in-vehicle device 200A and the in-vehicle device 200B is not equal, the data obtained by the in-vehicle device 200 that is likely to be in an LOS state can be referenced preferentially. As a result, it is possible to improve the accuracy of estimating the location area of ​​the portable device 100.

[0100] (Fourth Example) The control device 300 may estimate the presence area of ​​the portable device 100 based on the first coordinates obtained by the in-vehicle device 200 from which a certain threshold or more of highly reliable first coordinates have been obtained. In other words, the control device 300 may discard the first coordinates obtained by the in-vehicle device 200 from which the number of highly reliable first coordinates obtained is less than a certain threshold. With this configuration, it is possible to refer to only the data obtained by the in-vehicle device 200 that is likely to be in an LOS state, thereby improving the accuracy of estimating the presence area of ​​the portable device 100.

[0101] 3.2. Modification of the Method for Extracting Highly Reliable First Coordinates In the above embodiment, an example has been described in which a first coordinate whose reliability indicated by a reliability parameter is equal to or greater than a certain threshold is extracted as a highly reliable first coordinate, but the present invention is not limited to such an example. Other examples will be described below.

[0102] As an example, the control device 300 may extract, as highly reliable first coordinates, first coordinates acquired within a recent predetermined period or a predetermined number of first coordinates acquired most recently. Considering that the positional relationship between the portable device 100 and the in-vehicle device 200 may change from moment to moment, such a configuration makes it possible to improve the accuracy of estimating the area where the portable device 100 is located. The recency of the acquisition time may be regarded as a reliability parameter.

[0103] As another example, the control device 300 may extract, from among the first coordinates acquired in the most recent specified period, those first coordinates whose reliability indicated by the reliability parameter is equal to or greater than a certain threshold, as highly reliable first coordinates.

[0104] As another example, the control device 300 may extract as highly reliable first coordinates the first coordinates obtained in the most recent specified period, the first coordinates having a reliability indicated by the reliability parameter equal to or greater than a certain threshold, and the first coordinates having the highest reliability indicated by the reliability parameter.

[0105] As another example, the control device 300 may extract as highly reliable first coordinates the first coordinates acquired within the most recent specified period, the first coordinates having a reliability indicated by a reliability parameter equal to or greater than a certain threshold and having the most recent acquisition time.

[0106] Note that extracting a predetermined number of first coordinates may refer to extracting a predetermined number of first coordinates from each of the in-vehicle device 200A and the in-vehicle device 200B. Alternatively, extracting a predetermined number of first coordinates may refer to extracting a total of a predetermined number of first coordinates from the in-vehicle device 200A and the in-vehicle device 200B.

[0107] 3.3. Modified Examples of Reliability Parameter The control device 300 may calculate a reliability parameter based on the degree of coincidence between the presence area of ​​the portable device 100 estimated based on the first coordinates and the presence area of ​​the portable device 100 estimated based on parameters other than the first coordinates. Here, the higher the degree of coincidence, the higher the reliability, and the lower the degree of coincidence, the lower the reliability.

[0108] As described in the above embodiment, the first coordinate is calculated based on the angle of arrival of the wireless signal received by the vehicle-mounted device 200. Since the phase used to calculate the angle of arrival of the wireless signal is prone to error, the first coordinate estimated based on the angle of arrival may contain an error.

[0109] An example of a parameter other than the first coordinates is a distance measurement value calculated based on the ToF of the wireless signal. The coordinates of the portable device 100 and the presence area of ​​the portable device 100 can be roughly estimated by combining the coordinates of the in-vehicle device 200A and the distance measurement value obtained by the in-vehicle device 200A, and by combining the coordinates of the in-vehicle device 200B and the distance measurement value obtained by the in-vehicle device 200B. Therefore, it is possible to evaluate the reliability of the first coordinates based on the degree of agreement between the presence area of ​​the portable device 100 estimated based on the first coordinates and the presence area roughly estimated based on the distance measurement value calculated based on the ToF of the wireless signal.

[0110] Another example of a parameter other than the first coordinates is the received signal strength of the wireless signal (e.g., RSSI (Received Signal Strength Indicator)). When the vehicle-mounted device 200 is placed inside the vehicle, it is possible to roughly estimate whether the presence area of ​​the portable device 100 is inside or outside the vehicle depending on whether the RSSI is greater than a certain threshold. Therefore, it is possible to evaluate the reliability of the first coordinates based on the degree of agreement between the presence area of ​​the portable device 100 estimated based on the first coordinates and the presence area roughly estimated based on the RSSI of the wireless signal.

[0111] <4. Supplementary Information> Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical idea described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0112] The series of processes performed by each device described herein may be implemented using software, hardware, or a combination of software and hardware. The software programs may be stored in advance, for example, on a recording medium (more specifically, a non-transitory computer-readable storage medium) internal or external to each device. Each program is then loaded into a random access memory (RAM) and executed by a processing circuit such as a central processing unit (CPU). The recording medium may be, for example, a magnetic disk, an optical disk, a magneto-optical disk, or a flash memory. The computer program may also be distributed, for example, via a network, without using a recording medium. The computer may be, for example, an application-specific integrated circuit (ASIC), a general-purpose processor that executes functions by loading a software program, or a computer on a server used in cloud computing. The series of processes performed by each device described herein may be centrally processed by a single computer or distributed across multiple computers. Furthermore, in each of the above embodiments, two or more communication means present in a single device may be physically implemented on a single medium.

[0113] Furthermore, the processes described herein using flowcharts or sequence diagrams do not necessarily have to be performed in the order shown. Some process steps may be performed in parallel. Furthermore, additional process steps may be employed, and some process steps may be omitted.

[0114] 1: System, 100: Portable device, 110: Control unit, 120: Wireless communication unit, 121: Antenna, 20: Vehicle, 200: Vehicle-mounted device, 210: Control unit, 220: Wireless communication unit, 221: Antenna, 300: Control device, 310: Control unit, 400: Controlled device

Claims

1. A control device comprising: a control unit that repeatedly executes, for each of a plurality of wireless communication units that perform wireless communication with another communication device, a process of calculating coordinates indicating the position of the other communication device and a reliability parameter indicating the reliability of the coordinates based on wireless signals transmitted and received by each of the plurality of wireless communication units that perform wireless communication with the other communication device; and a control unit that estimates the presence area of ​​the other communication device by preferentially referring to the coordinates obtained by the wireless communication units that obtained a greater number of highly reliable coordinates among the plurality of wireless communication units that obtained highly reliable coordinates.

2. The control device according to claim 1, wherein, when the number of highly reliable coordinates obtained is not equal among the multiple wireless communication units, the control unit estimates the presence area of ​​the other communication device by preferentially referring to the coordinates obtained by the wireless communication unit that has obtained a greater number of highly reliable coordinates.

3. The control device according to claim 1, wherein the control unit estimates the presence area of ​​the other communication device based on a median value of a plurality of highly reliable coordinates.

4. The control device according to claim 1, wherein the control unit estimates the presence area of ​​the other communication device based on one of two or more highly reliable coordinates near a median value of the multiple highly reliable coordinates, the most reliable coordinate being one of the two or more highly reliable coordinates.

5. The control device according to claim 1, wherein the control unit estimates two or more of the presence areas of the other communication devices based on each of two or more highly reliable coordinates near a median value among the multiple highly reliable coordinates.

6. The control device according to claim 1, wherein the control unit estimates the presence area of ​​the other communication device by taking a majority vote from a plurality of areas corresponding to each of a plurality of highly reliable coordinates.

7. The control device according to claim 1, wherein the control unit estimates the presence area of ​​the other communication device based on the coordinates obtained by the wireless communication unit when a number of highly reliable coordinates equal to or greater than a certain threshold value has been obtained.

8. A control device as described in any one of claims 1 to 7, wherein the control unit calculates the reliability parameter based on the degree of coincidence between the presence area of ​​the other communication device estimated based on the coordinates and the presence area of ​​the other communication device estimated based on parameters other than the coordinates.

9. The control device according to claim 8, wherein the control unit calculates the coordinates based on an angle of arrival of the radio signal received by the wireless communication unit, and a parameter other than the coordinates is a distance measurement value calculated based on the ToF (Time of Flight) of the radio signal or a received signal strength of the radio signal.

10. A control method executed by a computer, comprising: repeatedly executing, for each of a plurality of wireless communication units that perform wireless communication with the other communication device, a process of calculating coordinates indicating the position of the other communication device and a reliability parameter indicating the reliability of the coordinates based on wireless signals transmitted and received by each of the plurality of wireless communication units; and estimating the presence area of ​​the other communication device by preferentially referring to the coordinates obtained by the wireless communication units that obtained a greater number of highly reliable coordinates, among the plurality of wireless communication units that obtained highly reliable coordinates.

11. A program for causing a computer to function as a control unit that repeatedly executes, for each of a plurality of wireless communication units that perform wireless communication with another communication device, a process of calculating coordinates indicating the position of the other communication device and a reliability parameter indicating the reliability of the coordinates based on wireless signals transmitted and received by each of the plurality of wireless communication units that perform wireless communication with the other communication device, and that estimates the presence area of ​​the other communication device by preferentially referring to the coordinates obtained by the wireless communication units that obtained a greater number of highly reliable coordinates among the plurality of wireless communication units that obtained highly reliable coordinates.

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