Position estimation device

Abstract

To provide a position estimation device with excellent estimation accuracy of a position of a human in a detection range.SOLUTION: According to a getting-on position estimation device 40, since a getting-on position is estimated by transmitting / receiving an electric wave, increase in the number of components can be suppressed in comparison to a case where a sensor is installed on each seat. The getting-on position estimation device 40 being a control unit estimates the getting-on position by using a time variation amount. The time variation amount becomes the different variation amounts between a package and an occupant. By using this time variation amount, such a possibility that the package is erroneously detected as the occupant can be reduced in a case where the package is in the seat. Consequently, the position estimation device with the excellent estimation accuracy of the getting-on position can be realized.SELECTED DRAWING: Figure 6

Description

Technical Field

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[0001] The disclosure in this specification relates to a position estimation device for estimating a human position.

Background Art

[0002] In Japan, along with the obligation to wear seat belts in the rear seats in addition to the driver's seat and the front passenger seat, vehicle manufacturers are obliged to install a system that warns passengers when the seat belt is not worn. To warn of not wearing a seat belt, it is necessary to detect whether the passenger is seated or not. As such a detection device for detecting seating, for example, it is realized by embedding a pressure sensor that senses pressure in the seating part of the seat. However, if dedicated pressure sensors are installed in all seats for seating detection, the number of parts increases and the cost rises.

[0003] Therefore, in the detection system described in Patent Document 1, wireless signals are transmitted and received to detect the boarding and alighting of passengers. Specifically, based on the received power value of the wireless signal and the delay spread value of the wireless signal, the boarding and alighting state of the passenger with respect to the vehicle is determined and the boarding position is estimated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technology described in the aforementioned Patent Document 1, there is a risk of misdetecting a large luggage as a human even when there is a large luggage instead of a human within the detection range inside the vehicle cabin.

[0006] Therefore, the purpose of the disclosure is to provide a position estimation device that excels in estimating the position of a person within the detection range, taking into consideration the aforementioned problems. [Means for solving the problem]

[0007] This disclosure employs the following technical means to achieve the aforementioned objectives.

[0008] The position estimation device disclosed herein is A person who is riding in vehicle (105), and Humans within a specific detection range Boarding A position estimation device for estimating a position, comprising: at least two antennas (106) that transmit and receive radio waves within a detection range; and a control unit (40) that causes the antennas to transmit radio waves and processes the radio waves received by the antennas, wherein the control unit controls the antennas to transmit radio waves for position estimation multiple times, and obtains the received signal strength when the transmitting antenna receives the radio waves corresponding to the radio waves transmitted by the antennas. Obtain the vehicle speed, The time variation, which is the amount of change in the acquired received signal strength over the reception time, is calculated, and the reception time at which the time variation is calculated is used Boarding Estimate location Furthermore, if the vehicle speed is below a predetermined set speed, the riding position is estimated using the degree of agreement between the time variation and the pre-set respiratory variation, which is a variation caused by human breathing. If the vehicle speed is above a predetermined set speed, the riding position is estimated using the degree of agreement between the pre-set position variation, which is a variation caused by human vibration, and the time variation, and the position variation is a value greater than the respiratory variation. It is a position estimation device.

[0009] According to this type of position estimation device, the human position is estimated by transmitting and receiving radio waves, thus suppressing the increase in the number of parts compared to installing multiple sensors within the detection range. Furthermore, the control unit estimates the human position using reception time, which has a time-varying amount. Experiments by the inventors have revealed that the time-varying amount differs between luggage and humans. By using reception time with such time-varying amount, the possibility of misidentifying luggage as a human can be reduced. This makes it possible to realize a position estimation device with superior accuracy in estimating the human position.

[0010] The symbols in parentheses for each of the aforementioned means are examples that indicate the correspondence with the specific means described in the embodiments described later. [Brief explanation of the drawing]

[0011] [Figure 1] Figure showing the vehicle communication system of the first embodiment [Figure 2] Block diagram showing a mobile terminal [Figure 3] Block diagram showing the vehicle side unit [Figure 4] Block diagram for explaining the function of the collation ECU [Figure 5] Figure for explaining the position estimation process[[ID=1s]] [Figure 6] Flowchart showing the position estimation process [Figure 7] sWaveform showing an example of the radio wave for position estimation [Figure 8] Waveform showing an example of the reflected wave [Figure 9] Waveform showing a plurality of reflected waves superimposed [Figure 10] Waveform showing an example of the reflected wave of the driver's seat in the second embodiment [Figure 11] Waveform showing an example of the reflected wave of the rear seat [Figure 12] Figure for explaining the process of obtaining the rise time [Figure 13] Waveform showing the change in reception intensity at a certain time in the third embodiment [Figure 14] Figure showing the result of frequency analysis of the waveform in FIG. 13 [Figure 15] Waveform showing the change in reception intensity at another certain time [Figure 16] Figure showing the result of frequency analysis of the waveform in FIG. 15 [Figure 17] Flowchart showing the position estimation process of the fourth embodiment [Figure 18] Figure for explaining the antenna arrangement of the fifth embodiment [Figure 19] Figure for explaining the position estimation process of the rear seat[[ID=ss]] [Figure 20] Figure for explaining another antenna arrangement [[ID=sst]]

Mode for Carrying Out the Invention

[0012] Hereinafter, the embodiments for implementing this disclosure will be described using multiple embodiments with reference to the drawings. In each embodiment, parts corresponding to matters described in a prior embodiment will be given the same reference numeral, or one character may be added to the prior reference numeral to omit redundant explanations. Also, if a part of the configuration is described in each embodiment, the other parts of the configuration will be the same as in the previously described embodiment. Not only are combinations of the parts specifically described in each embodiment possible, but it is also possible to partially combine embodiments if there is no particular impediment to the combination.

[0013] (First Embodiment) A first embodiment of this disclosure will be described with reference to Figures 1 to 11. In this embodiment, the position estimation device for estimating the position of a person is a passenger position estimation device 40 that estimates the position of a person, i.e., an occupant, riding in the vehicle 105. The position estimation device estimates the position of a person within a specific detection range, and in the passenger position estimation device 40 of this embodiment, the specific detection range is the interior of the vehicle.

[0014] First, the configuration of the entire vehicle communication system 200, including the passenger position estimation device 40, will be explained. The vehicle communication system 200 shown in Figure 1 includes a mobile terminal 102 and a vehicle-side unit 103. The vehicle communication system 200 uses a cloud system to exchange information between the mobile terminal 102 and the vehicle-side unit 103, and also communicates directly between the mobile terminal 102 and the vehicle-side unit 103.

[0015] The mobile terminal 102 has a speaker 22, a microphone 23, and communication functions. Details of the mobile terminal 102 will be described later. The mobile terminal 102 also functions as an electronic key for the vehicle 105. Therefore, the mobile terminal 102 also functions as an authentication terminal with an authentication function for operating the vehicle 105.

[0016] The vehicle-side unit 103 is an in-vehicle device installed in and used in vehicle 105. The vehicle-side unit 103 is capable of communicating with the mobile terminal 102, and authentication regarding the use of vehicle 105 is performed through verification via this communication. Details of the vehicle-side unit 103 will be described later.

[0017] The cloud system uses servers located in the cloud to exchange information between the mobile terminal 102 and the vehicle-side unit 103. In other words, the mobile terminal 102 and the vehicle-side unit 103 communicate via the cloud system. The cloud system can also be described as a network, for example.

[0018] Next, the general configuration of the mobile terminal 102 will be described using Figure 2. As shown in Figure 2, the mobile terminal 102 includes a terminal control unit 20, a terminal communication module 21, a speaker 22, a microphone 23, an operation unit 24, and a display unit 25. The terminal communication module 21 is a communication module for communication via a cloud system. The terminal communication module 21 functions as a terminal communication unit that communicates with the vehicle-side unit 103.

[0019] The terminal communication module 21 includes memory, which pre-stores, for example, identification information unique to each mobile terminal 102 (hereinafter referred to as terminal-side ID). When establishing a communication connection, the terminal communication module 21 transmits, for example, the terminal-side ID stored in memory to the communication destination.

[0020] The terminal communication module 21 transmits information to the communication destination in accordance with the instructions of the terminal control unit 20. The information transmitted from the terminal communication module 21 is sent via the cloud system to the vehicle-side unit 103 which is pre-linked to the mobile terminal 102 as its own terminal. The terminal communication module 21 also receives information transmitted from the vehicle-side unit 103 which is pre-linked to the mobile terminal 102 via the cloud system.

[0021] As an example, the linking of the mobile terminal 102 and the vehicle-side unit 103 is performed by associating the terminal-side ID with identification information (hereinafter referred to as the vehicle-side ID) used to identify the vehicle 105 that uses the vehicle-side unit 103. The vehicle-side ID can be, for example, the vehicle ID and the device ID of the vehicle communication module 31, described later, included in the vehicle-side unit 103. This vehicle-side ID is the identification information of the matching ECU 30, described later, included in the vehicle-side unit 103. For example, the server on the cloud system has in advance the correspondence between the vehicle-side ID and the terminal-side ID of the mobile terminal 102 of the user authorized to use the vehicle 105 corresponding to this vehicle-side ID. The cloud system then refers to this correspondence between the vehicle-side ID and the terminal-side ID to send and receive information between the vehicle-side unit 103 and the mobile terminal 102 of the user authorized to use the vehicle 105 that uses this vehicle-side unit 103.

[0022] Speaker 22 is an audio output device that outputs sound. Speaker 22 outputs sound according to the instructions of the terminal control unit 20. For example, when Speaker 22 is making a call with another mobile terminal 102, it outputs the sound from the other mobile terminal 102. Also, when the mobile terminal 102 is functioning as a music player, Speaker 22 outputs the music that is being played. Microphone 23 is an audio input device that collects sound. Microphone 23 converts the collected sound into an electrical audio signal and outputs it to the terminal control unit 20.

[0023] The operation unit 24 receives user input and provides the received operation information to the terminal control unit 20. The operation unit 24 is implemented, for example, by mechanical buttons or a touch panel integrated with the display unit 25. The touch panel is constructed by layering a colorless, transparent touch sensor onto the display screen of the display unit 25. The touch panel detects changes in capacitance or pressure caused by the user's fingers or other body parts touching the display screen. The display unit 25 displays the information provided by the terminal control unit 20 on its screen. The display unit 25 may be a liquid crystal display or an EL display, for example.

[0024] The terminal control unit 20 includes, for example, a processor, memory, I / O, and a bus connecting them, and performs various processes related to the functions of the mobile terminal 102 by executing a control program stored in memory. The memory is a non-transitory tangible storage medium that non-temporarily stores programs and data that can be read by a computer. The non-transitory tangible storage medium is implemented by semiconductor memory or the like.

[0025] Next, the schematic configuration of the vehicle-side unit 103 will be explained using Figure 3. As shown in Figure 3, the vehicle-side unit 103 includes a passenger position estimation device 40, a matching ECU 30, a vehicle communication module 31, a vehicle status sensor 32, a start switch 33, a lock / unlock switch 34, a body ECU 35, and a power unit ECU 36.

[0026] The vehicle communication module 31 is an in-vehicle communication module. The vehicle communication module 31 functions as a device communication unit that communicates with the mobile terminal 102. The vehicle communication module 31 connects to a network and communicates via a cloud system. The vehicle communication module 31 includes memory, and for example, the aforementioned vehicle-side ID is pre-stored in this memory. When establishing a communication connection, the vehicle communication module 31 sends, for example, the vehicle-side ID stored in memory to the communication destination.

[0027] The vehicle communication module 31 is connected to multiple, at least two, antennas 106. In this embodiment, the vehicle communication module 31 is connected to three antennas 106. The three antennas 106 are mounted at different locations on the vehicle 105, for example, on the left side, the front side, and the right side, as shown in Figure 5.

[0028] The mobile terminal 102 and the vehicle communication module 31 perform wireless communication using impulse signals used in ultra-wideband (UWB) communication. An impulse signal used in UWB communication is a signal with an ultra-wide bandwidth, having a pulse width of very short time, for example, 2 ns, and a bandwidth of 500 MHz or more. The antenna 106 may be, for example, a transmitting and receiving antenna, but it may also be configured to have separate transmitting and receiving antennas.

[0029] The vehicle condition sensor 32 is a group of sensors for detecting information related to the behavior of the vehicle 105, such as the vehicle's driving state and operating state. Examples of vehicle condition sensors 32 include a vehicle speed sensor for detecting vehicle speed and a shift position sensor for detecting the shift position.

[0030] The start switch 33 is a switch used to request the start of the vehicle's drive system. The start switch 33 is located, for example, in front of the driver's seat. A mechanical button switch can be used as the start switch 33.

[0031] The lock / unlock switch 34 is a switch used to request the locking or unlocking of the vehicle doors, such as the driver's side door, passenger's side door, and trunk door. For the driver's side and passenger's side doors, the lock / unlock switch 34 is provided, for example, on the outer door handle. For the trunk door, the lock / unlock switch 34 is provided, for example, on the rear bumper. The lock / unlock switch 34 can be, for example, a touch switch or a mechanical button switch.

[0032] The body ECU 35 controls the locking and unlocking of each vehicle door by outputting drive signals to the door lock motors provided on each vehicle door. The body ECU 35 locks the doors by outputting a lock signal to the door lock motor. The body ECU 35 unlocks the doors by outputting an unlock signal to the door lock motor. A lock / unlock switch 34 is connected to the body ECU 35 for each vehicle door. The body ECU 35 acquires signals from the lock / unlock switch 34 and detects the operation of the lock / unlock switch 34.

[0033] The Power Unit ECU 36 is an electronic control unit that controls the vehicle's internal combustion engine or motor generator, which is the vehicle's driving source. When the Power Unit ECU 36 receives a start permission signal for the driving source from the Verification ECU 30, it starts the vehicle's driving source. The Power Unit ECU 36 also functions as an ECU that performs processes to assist the driver's operations of the occupant seated in the driver's seat.

[0034] The verification ECU30 includes, for example, a processor, memory, I / O, and a bus connecting them, and performs various authentication processes to authorize the use of the vehicle by executing a control program stored in memory.

[0035] Next, an example of the schematic configuration of the matching ECU 30 will be explained using Figure 4. As shown in Figure 4, the matching ECU 30 is equipped with a trigger detection unit 301, a transmission processing unit 302, a storage unit 303, a reception processing unit 304, a matching unit 305, a permission unit 306, and a position estimation unit 307 as functional blocks.

[0036] The receiving processing unit 304 receives the response signal transmitted from the mobile terminal 102 via the vehicle communication module 31. The transmitting processing unit 302 causes the vehicle communication module 31 to transmit a request signal.

[0037] The receiving processing unit 304 also acquires information about the radio waves received by the three antennas 106. This information includes, for example, the strength of the received radio waves, the time it takes for the radio waves to arrive from the source to the antennas 106, the frequency of the radio waves, and the signals contained in the radio waves. The receiving processing unit 304 provides the position estimation unit 307 with the information about the received radio waves. The strength of the radio waves is also called the received signal strength, or RSSI (Received Signal Strength Indication).

[0038] The position estimation unit 307 estimates the radio wave source location from the RSSI values ​​received by the three antennas 106. The RSSI value increases as the radio wave source location is closer. Also, the three antennas 106 are mounted at different locations. Therefore, three circles are drawn with the mounting location of each of the three antennas 106 as the center of the circle, and the propagation distance determined from the RSSI value as the radius, and the radio wave source location is estimated using the three-point positioning method.

[0039] The storage unit 303 is, for example, an electrically rewritable non-volatile memory, and stores an identification code that identifies the mobile terminal 102 of a legitimate user. The method for registering the identification code of the mobile terminal 102 in the storage unit 303 is the same as the method for registering multiple electronic keys as electronic keys of legitimate users in a well-known electronic key system.

[0040] The verification unit 305 authenticates whether the mobile terminal 102 is a pre-configured legitimate mobile terminal 102 by communicating with the mobile terminal 102. Specifically, the verification unit 305 verifies whether the mobile terminal 102, which has received a signal from the receiving processing unit 304, is the mobile terminal 102 of a legitimate user. Verification is performed between the identification code contained in the verification request response signal received from the mobile terminal 102 and the identification code registered in the storage unit 303. If verification is successful, authentication that the mobile terminal 102 belongs to a legitimate user is established.

[0041] The trigger detection unit 301 detects triggers related to the use of the vehicle. Situations in which the vehicle is used include opening the vehicle doors for the user to get in, starting the vehicle, and opening the trunk door.

[0042] The trigger detection unit 301 detects entry triggers related to the opening of the vehicle doors for the user to enter the vehicle. Specifically, the trigger detection unit 301 detects an entry trigger when it determines that the vehicle is parked based on the detection results from the vehicle status sensor 32 and also detects that the lock / unlock switch 34 for the driver's or passenger's door has been operated. The vehicle being parked is determined, for example, by the shift position detected by the shift position sensor, which indicates a parked position. Alternatively, it may be determined by the vehicle speed detected by the vehicle speed sensor, which indicates a stopped position. The operation of the lock / unlock switch 34 is detected from the signal of the lock / unlock switch 34.

[0043] The trigger detection unit 301 also detects the start trigger related to the starting of the vehicle. Specifically, the trigger detection unit 301 detects the start trigger when it detects that the start switch 33 has been operated. The operation of the start switch 33 is detected from the signal of the start switch 33.

[0044] The authorization unit 306 functions as a device control unit that, based on the authentication result of the verification unit 305, authorizes the use of the vehicle 105 if it is a legitimate mobile terminal 102, and prohibits the use of the vehicle 105 if it is not a legitimate mobile terminal 102. Furthermore, the authorization unit 306 decides whether to authorize or prohibit the use of the vehicle 105 based on whether the radio wave generation location estimated by the position estimation unit 307 is within a predetermined range.

[0045] When the trigger detection unit 301 detects a boarding trigger, the radio wave generation position is within a predetermined range of the vehicle 105, and authentication is successful by the verification unit 305, the authorization unit 306 outputs an unlocking signal to the door lock motors of all vehicle doors, thereby unlocking all vehicle doors.

[0046] When the trigger detection unit 301 detects a start trigger, the radio wave generation location is inside the vehicle interior, and the verification unit 305 confirms that verification is successful, the authorization unit 306 outputs a start authorization signal for the drive source to the power unit ECU 36 and starts the drive source.

[0047] Furthermore, the authorization unit 306, based on the authentication result of the verification unit 305, normally prohibits the use of the function on the vehicle 105 if the signal is not from a legitimate mobile terminal 102. This is to prevent the unauthorized use of the vehicle 105. In addition, the authorization unit 306, based on the authentication result of the verification unit 305, normally prohibits the use of the function on the vehicle 105 even if the signal is from a legitimate mobile terminal 102, if the radio wave generation location is outside a predetermined range. This is to improve security.

[0048] Next, we will explain the process for estimating the seating positions of occupants in vehicle 105. The process shown in Figure 6 is performed by the seating position estimation device 40. The process shown in Figure 6 is performed repeatedly in short intervals while the ignition of vehicle 105 is turned on.

[0049] In step S1, an unmeasured antenna 106 is selected, and the system is controlled to transmit position estimation radio waves from the selected antenna 106, before proceeding to step S2. As shown in Figure 7, the position estimation radio waves are transmitted multiple times during a predetermined transmission period, each transmission time being shorter than the transmission period, with varying transmission signal strengths. In the example shown in Figure 7, the envelope formed by the transmission signal strengths is bell-shaped. In other words, the transmission signal strength is lowest at the beginning and end of the transmission period, and highest in the middle of the transmission period. The width of the bell shape is, for example, 1.5 ns.

[0050] In step S1, the position estimation radio waves shown in Figure 7 are transmitted multiple times. The transmission interval is set to a sufficiently small interval compared to human respiration and body movement cycles, for example, every 100ms. Furthermore, in step S1, the position estimation radio waves are transmitted from only one of the three antennas 106. This is because if two or more antennas 106 transmit simultaneously, it becomes difficult to determine which radio wave is being reflected. Therefore, the antenna 106 that has not yet measured distance is the antenna 106 that has not yet transmitted the position estimation radio waves, and in this embodiment, there are three antennas 106, so the transmission process is repeated three times.

[0051] In step S2, the radio waves corresponding to the position estimation radio waves transmitted in step S1 are received, and the received signal strength of the received radio waves is obtained. Figure 8 shows an example of how the received signal strength changes over time. Figure 8 shows the waveform of the received signal strength received up to 20 ns after the transmission of the position estimation radio waves. As shown in Figure 8, a waveform is obtained that is a composite of waveforms reflected back from various obstacles. If there are obstacles nearby, the time it takes for the reflected waves to arrive is shortened. In the example shown in Figure 8, there are four peaks, so there is a possibility that there are obstacles in four locations.

[0052] In step S3, the location of the fluctuation is identified, and the process moves to step S4. The location of the fluctuation is the point where the time fluctuates when multiple reflected waves from Figure 8 are superimposed, as shown in Figure 9. In the example shown in Figure 9, it can be seen that the fluctuation occurs around 8 ns. If the vehicle 105 is stationary, the most likely cause of the time fluctuation is a human being. Cargo and other items do not vibrate on their own, but living beings such as humans cannot remain completely still and shake due to breathing and other factors.

[0053] In step S4, the position of the crew is measured, and the process moves to step S5. The position of the crew is estimated by comparing the variation in Figure 8 with the respiratory variation, which is the variation caused by the crew's breathing. If the variation in Figure 8 matches the respiratory variation well, it is estimated that the crew is present at the time the variation begins. The respiratory variation is determined in advance by simulation and experiment. Since breathing is a periodic operation, the respiratory variation can be used to separate it from other time variations. The respiratory variation may be within a predetermined range of values, or it may be the value itself. A high degree of agreement means that the time variation is within the range of the respiratory variation value, and that the value is close to the respiratory variation value. Then, using the peak time of the largest time variation, a ranging circle L2 centered on antenna 106 is created. An example of the ranging circle L2 is shown in Figure 5 using a dashed line.

[0054] In step S5, it is determined whether distance measurement has been completed for all antennas 106. If it has been completed, the process moves to step S6; otherwise, it returns to step S1. Therefore, in order to prevent interference between each antenna 106, the antennas 106 operating at a predetermined period are switched, and the process from steps S1 to S4 is repeated until a distance measurement circle L2 is created with the three antennas 106.

[0055] In step S6, if two or three range-measuring circles L2 are formed by the three antennas 106, the seating position of the occupants is estimated using two-point or three-point positioning. In Figure 5, circles are used to indicate the occupants' positions. In step S6, there are also cases where there is only one range-measuring circle L2, or where there are no range-measuring circles L2 at all. For example, if the fluctuating area cannot be measured, or if the peak cannot be identified from the reflected wave, the occupant's position cannot be determined. In this case, the result indicating that no occupants were detected is output. Then, in step S6, the result of determining the occupant's position is output, and this flow ends.

[0056] In this way, the passenger position estimation device 40 controls the vehicle communication module 31 and antenna 106 to transmit radio waves with different transmission signal strengths multiple times within a predetermined transmission period, with transmission times shorter than the transmission period. The passenger position estimation device 40 then acquires the received signal strength when the transmitting antenna 106 receives the radio waves corresponding to the radio waves transmitted by antenna 106. The passenger position estimation device 40 then estimates the passenger position using the time variation amount, which is the amount of variation in the acquired received signal strength over the reception time. This makes it possible to estimate the passenger position using the respiratory component originating from the passenger, and to distinguish it from luggage, etc.

[0057] As explained above, according to the passenger position estimation device 40 of this embodiment, the passenger position is estimated by transmitting and receiving radio waves, so the increase in the number of parts can be suppressed compared to installing sensors on each seat. Furthermore, the passenger position estimation device 40, which is the control unit, estimates the passenger position using a time variation. The time variation will be different for luggage and passengers. By using such a time variation, the possibility of misidentifying luggage as a passenger when luggage is on a seat can be reduced. This makes it possible to realize a position estimation device with superior accuracy in estimating the passenger position.

[0058] In this embodiment, UWB, which is used for communication with the mobile terminal 102, is used to determine whether a passenger is seated and their position without installing any new sensors. UWB is a frequency band that can be used over a wide bandwidth, and in environments with a clear line of sight, it is possible to measure distances with high accuracy on the order of a few centimeters. In this embodiment, the antenna 106, which normally communicates with the mobile terminal 102, is operated as a radar to estimate the position of the occupant. In other words, this embodiment estimates the occupant's position by improving the software of the existing communication system. This makes it possible to estimate the occupant's position without adding any physical sensors.

[0059] In this embodiment, the amount of time variation is compared with the amount of respiratory variation caused by a preset occupant's breathing, and the degree of agreement is used to determine whether or not it is a human. Since breathing and body movement, which are signal components of human origin, are detected, the degree of agreement can be used to distinguish it from other obstacles such as luggage. This improves the accuracy of detecting the occupant's position.

[0060] In other words, the passenger position estimation device 40 has the following configuration. The passenger position estimation device 40 has two or more antennas 106 that transmit and receive radio waves generated based on a certain frequency and bandwidth, and determines the position of the living person based on the received values ​​of the antennas 106. The antennas 106 transmit and receive multiple times at a certain interval, and the passenger position estimation device 40 determines the distance of the living person based on the amount of time variation of the multiple received values ​​of each antenna 106. The occupant position detection device then determines the distance and position of the living person based on the amount of time variation caused by respiration.

[0061] (Second Embodiment) Next, a second embodiment of the present disclosure will be described with reference to Figures 10 to 12. This embodiment is characterized by a method for determining the amount of time variation in order to improve the accuracy of determining the respiratory position.

[0062] Figure 10 shows the waveform obtained when measuring the distance to the driver's seat using antenna 106 positioned at the front of the vehicle. Figure 11 shows the waveform obtained when measuring the distance to the rear seats of the vehicle using antenna 106 positioned at the front of the vehicle. Comparing Figure 10 and Figure 11, it can be seen that the rising edge of the time-varying portion is elongated in Figure 11. This is because it is combined with reflected waves from the body of the vehicle 105, and this elongation of the rising edge results in an error in calculating the distance between the person and antenna 106.

[0063] When antenna 106 is located in front of the driver's seat, the detection delay is likely to occur when the detection target is far away, for example, in the back seat. Experiments have shown that the farther the detection target is, the more likely it is that the peak value corresponding to the human position will be shifted backward due to the inclusion of reflected waves from various obstacles and the overlapping of multiple reflected waves. In the case without delay shown in Figure 10, the peak value is 1.5 ns from the rising edge, but in the case with delay shown in Figure 11, the peak value is shifted backward to 2.5 ns from the rising edge. Therefore, a method is needed to correct the signal to correspond to the human position, taking into account the case of delay.

[0064] In other words, if the time variation is not stretched out as shown in Figure 10, the peak value of the time variation point is estimated to be the distance measurement point where the occupant is located. However, if the time variation is stretched out as shown in Figure 11, estimating the peak value of the time variation point as the distance measurement point may result in a discrepancy with the actual occupant's position. Therefore, to improve accuracy, it is necessary to use parameters other than the peak after the rise. One such method is the respiratory variation onset timing shown in Figure 12. The respiratory variation onset timing can also be described as the rise timing of the time variation.

[0065] When a position-estimating radio wave with a UWB pulse waveform, as shown in Figure 7, is transmitted, the waveform returned from the human body fluctuates with respiration across the entire shape of Figure 7. Therefore, as shown in the lower waveform of the position-estimating radio wave in Figure 12, it is estimated that the starting point T1 of the time variation and the rising edge of the position-estimating radio wave are equal.

[0066] Then, the value at time T2, which is corrected by a predetermined time, for example 1.5 ns, from the time T1 when breathing begins, is used as the so-called peak value to create the ranging circle L2. This solves the problem of stretching caused by the synthesis of reflected waves, and ensures accuracy even in the rear seat scene shown in Figure 11, where the distance between antenna 106 and the person is long.

[0067] (Third embodiment) Next, a third embodiment of this disclosure will be described with reference to Figures 13 to 16. This embodiment is related to the second embodiment described above and is characterized by a method for determining the timing of the onset of respiratory variation.

[0068] As explained in the second embodiment described above, as shown in Figure 12, if a single point in the radar reception waveform for 20 ns is plotted moment by moment, a waveform like Figure 13 is obtained when a respiratory component is superimposed, and a waveform like Figure 15 is obtained when there is no respiratory component. Figures 14 and 16 are the waveforms obtained by frequency analysis of these, respectively. Figure 14 is the waveform obtained by frequency analysis of Figure 13, and Figure 15 is the waveform obtained by frequency analysis of Figure 15.

[0069] As shown in Figure 14, when breathing is superimposed, certain frequency components stand out, while as shown in Figure 16, when breathing is not superimposed, only noise components are present, resulting in an overall uniform frequency response.

[0070] By using values ​​that quantify variability characteristics, such as those in the entropy equation (1), it becomes possible to determine the timing of the onset of respiratory variation.

[0071]

number

[0072] (Fourth Embodiment) Next, a fourth embodiment of the present disclosure will be described with reference to Figure 17. This embodiment is characterized by taking into account vehicle vibration according to vehicle speed.

[0073] During driving, the occupants are shaken by vehicle vibrations, making it difficult to accurately detect body surface vibrations caused by breathing. Therefore, in this embodiment, when the vehicle speed exceeds a certain value, the vibration of the human body is detected using the magnitude of the fluctuation as an indicator, rather than determining the presence or absence of breathing based on frequency characteristics as in the third embodiment described above.

[0074] The specific process will be explained using Figure 17. The process shown in Figure 17 is repeatedly executed in a short period of time by the passenger position estimation device 40.

[0075] In step S11, it is determined whether the vehicle speed is greater than a predetermined set vehicle speed V. If it is greater, the process proceeds to step S15; otherwise, the process proceeds to step S12.

[0076] In step S12, since the vehicle speed is not high, distance measurement is performed by detection using breathing, and the process moves to step S13. In step S13, the seating position is estimated, and the process moves to step S14. Therefore, the processing in steps S12 and S13 is the same as the processing in Figure 6.

[0077] In step S15, since the vehicle speed is high, distance measurement is performed by detecting body movement, and the process moves to step S16. In step S15, the positional variation and time variation, which are pre-set fluctuations caused by the vibration of the occupant, are compared, and the degree of agreement is used to estimate the riding position. As the vehicle speed increases, the time variation increases, so the positional variation, which is larger than the breathing variation, is used to estimate the riding position. In step S16, the seating position is estimated using the distance measurement circle L2, and the process moves to step S14. In other words, the processing in steps S15 and S16 is the same as the processing in Figure 6, where the positional variation is used instead of the breathing variation.

[0078] In step S14, it is determined whether the termination condition for estimating the position has been met. If it has been met, this flow is terminated; otherwise, the process returns to step S11. The termination conditions include cases where estimating the passenger's position is unnecessary, such as when the ignition is turned off or when the likelihood of passenger movement is low, such as when driving on a highway.

[0079] The most critical time for estimating the passenger's position is when vehicle 105 switches from ignition off to ignition on, and then issues a seatbelt reminder after driving. Therefore, it may be determined that the termination condition has been met after a predetermined time has elapsed since the vehicle started driving, for example, after 10 minutes. Alternatively, the passenger position estimation process may be performed periodically, for example, every few minutes. This reduces power consumption compared to a configuration that constantly senses the passenger's position.

[0080] The occupant position estimation process may also be initiated based on, for example, the locking and unlocking of vehicle 105, the opening and closing of doors, and the on / off status of ACC. This is because these actions are likely to change the occupant's position.

[0081] In this embodiment, breathing detection and body movement detection are switched according to the vehicle speed. In body movement detection, since the vehicle speed is high, it is necessary to consider the vibration of the vehicle. Since the entire vehicle, including the occupants, vibrates similarly, the time variation differs from that caused by breathing. Therefore, by determining the amount of time variation due to vehicle vibration in advance through simulations and experiments, occupant detection can be performed while taking vehicle vibration into consideration. It is also preferable to set the amount of position variation according to the vehicle speed.

[0082] This allows for accurate estimation of passenger positions even at high vehicle speeds. Furthermore, assuming that passengers do not move significantly while driving and that the number of occupants remains constant, the detection range, for example, the search time interval shown in Figure 9 above, can be narrowed based on the human position results obtained from breathing detection while the vehicle is stopped. By tracking changes over time in this way, movement while driving can also be tracked.

[0083] (Fifth embodiment) Next, a fifth embodiment of the present disclosure will be described with reference to Figures 18 to 20. In this embodiment, the antenna 106 is characterized by having two points. In the case of two radars, depending on the arrangement of the antennas 106, two intersection points may be created by two-point positioning, which may make it impossible to uniquely identify the seating position.

[0084] Therefore, the position of the antenna 106 is offset to one of the four directions (front, rear, left, or right) of the vehicle 105. For example, if it is offset to the front of the vehicle as shown in Figure 18, when the person is seated in seat D, the two intersection points from the two-point positioning will fall within seat D. Also, as shown in Figure 19, when the person is seated in the rear seat, one of the intersection points will appear outside the vehicle compartment and can be excluded, making it possible to determine the seating position.

[0085] Similarly, as shown in Figure 20, the same effect can be achieved by arranging the two antennas 106 on the rear side of the vehicle 105.

[0086] Thus, it is preferable that the two antennas 106 are located outside the virtual enclosure L1 that surrounds all the seat positions of the vehicle 105, and are positioned on one of the four directions of the vehicle 105: front, rear, left, or right. The virtual enclosure L1 is set to surround all the seat positions, as shown in Figures 18 to 20, and is, for example, rectangular in shape. As long as the antennas are outside this virtual enclosure L1, even if there are only two antennas 106 as described above, one intersection point will be located inside the virtual enclosure L1 and the other intersection point will be located outside the virtual enclosure L1, so the intersection point located inside the virtual enclosure L1 can be estimated as the occupant's position. This makes it possible to estimate the occupant's position without reducing accuracy, even with a small number of antennas 106.

[0087] (Other embodiments) While preferred embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above and can be implemented in various modified forms without departing from the spirit of this disclosure.

[0088] The structures of the embodiments described above are illustrative only, and the scope of this disclosure is not limited to those described. The scope of this disclosure is indicated by the claims and includes all modifications within the meaning and scope equivalent to the claims.

[0089] In the first embodiment described above, the radio waves for position estimation had the pulse shape shown in Figure 7, but they are not limited to this shape. The method of transmitting the radio waves may be a pulse wave created from a certain bandwidth, or it may be a method of intermittently transmitting CW waves.

[0090] In the first embodiment described above, a mobile terminal 102 is used, but the mobile terminal 102 may simply be a key device for the vehicle 105. That is, it may be a device that functions as an electronic key without having a microphone 23, speaker 22, etc.

[0091] In the first embodiment described above, the functions implemented by the terminal control unit 20 of the mobile terminal 102 and the control units such as the matching ECU 30 and the passenger position estimation device 40 of the vehicle-side unit 103 may be implemented by different hardware and software, or a combination thereof. These control units may communicate with other control units, for example, and the other control units may perform some or all of the processing. If these control units are implemented by electronic circuits, they may be implemented by digital circuits including a large number of logic circuits, or by analog circuits.

[0092] Furthermore, these control units may implement certain functions as hardware, including implementations using one or more ICs. As the processor (processing core), a CPU, MPU, GPU, DFP (Data Flow Processor), etc., can be employed. Also, some or all of the functions of the processor may be implemented by combining multiple types of processing units. Some or all of the functions of the processor may also be implemented using a system-on-a-chip (SoC), FPGA, ASIC, etc. FPGA stands for Field-Programmable Gate Array. ASIC stands for Application Specific Integrated Circuit.

[0093] In the first embodiment described above, the passenger position estimation device 40 is used in the vehicle 105, but it is not limited to being mounted in the vehicle 105, and at least a part of it may not be mounted in the vehicle 105. [Explanation of Symbols]

[0094] 20...Terminal control unit 21...Terminal communication module 22...Speaker 23...Microphone 24...Operation Unit 25...Display Unit 30...Verification ECU 31...Vehicle Communication Module 32...Vehicle status sensor 33...Start switch 34...Lock / unlock switch 35...Body ECU 36...Power Unit ECU 40...Boarding position estimation device (control unit) 102...Mobile terminal 103...Vehicle-side unit 105...Vehicle 106...Antenna 200...Vehicle communication system 301...Trigger detection unit 302...Transmission processing unit 303...Storage unit 304...Receiving Processing Unit 305...Verification Unit 306...Permission Unit 307...Position Estimation Unit L1…Virtual border

Claims

1. A position estimation device for estimating the position of a person who is riding in a vehicle (105) and is within a specific detection range, Within the aforementioned detection range, at least two antennas (106) that transmit and receive radio waves, The system includes a control unit (40) that causes the antenna to transmit radio waves and processes the radio waves received by the antenna, The control unit, The antenna is controlled to transmit radio waves for position estimation multiple times. The received signal strength is obtained when the transmitting antenna receives the radio wave corresponding to the radio wave transmitted by the aforementioned antenna. The vehicle speed of the aforementioned vehicle is obtained, The time variation, which is the amount of change in the received signal strength over the reception time, is determined, and the boarding position is estimated using the reception time at which the time variation exists. If the vehicle speed is less than a predetermined set vehicle speed, the degree of agreement between the time variation and the respiratory variation, which is a predetermined variation caused by human respiration, is used to estimate the riding position. If the vehicle speed is equal to or greater than a predetermined set vehicle speed, the riding position is estimated using the degree of agreement between the positional fluctuation amount, which is a predetermined fluctuation amount caused by human vibration, and the time fluctuation amount. A position estimation device in which the amount of position variation is greater than the amount of respiratory variation.

2. The position estimation device according to claim 1, wherein all of the antennas are located outside a virtual enclosure line that surrounds all of the seat positions of the vehicle, and are positioned on one of the four directions of the vehicle: front, rear, left, or right.

3. The position estimation device according to claim 1, wherein the control unit determines, using information acquired from the vehicle, that a person has disembarked or boarded, and then starts a process to estimate the boarding position.

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