Living body detecting device

Abstract

This living body detecting device includes at least one radar and an ECU. The radar is installed in a vehicle, transmits a pulse wave having a predetermined frequency, and receives a reflected wave of the pulse wave. The radar executes transmission and reception a plurality of times at predetermined intervals. The reception time of the reflected wave is longer than a time corresponding to the distance between the radar and a position farthest from the radar at the end of the vehicle. The ECU detects the presence or absence of a living body on the basis of reception signals of the plurality of transmissions and receptions.

Description

Biodetection Device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-161604 filed in Japan on September 25, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The disclosure herein relates to a biometric detection device.

[0003] Patent Document 1 discloses an occupant detection device equipped with a radar that transmits pulse waves and receives reflected waves. The contents of the prior art document are incorporated by reference as an explanation of the technical elements in this specification.

[0004] Japanese Patent Application Laid-Open No. 2017-181225

[0005] In the case of a living body detection device using a pulse wave, there is a problem in that the accuracy of detecting a living body is low. In the above-mentioned respects and in other respects not mentioned, further improvement of the living body detection device is required.

[0006] The present disclosure has been made in consideration of such problems, and aims to provide a living body detection device that can improve the accuracy of detecting a living body inside a vehicle.

[0007] In a living body detection device using pulse waves, transmission and reception are performed multiple times at predetermined intervals to detect the presence or absence of a living body. After careful consideration, it was found that multiple transmissions and receptions cause a time lag in the received waveform, i.e., sampling variation, and fluctuations due to the living body are buried in the changes caused by the sampling variation, resulting in the risk of not being able to detect the living body. The disclosed living body detection device is based on this finding.

[0008] One disclosed aspect of the living body detection device comprises at least one radar mounted on a vehicle, which transmits pulse waves of a predetermined frequency and receives reflected waves of the pulse waves, and a detection unit which detects the presence or absence of a living body inside the vehicle based on the received signals of the radar, wherein the radar transmits and receives multiple times at predetermined intervals, the reception time of the reflected waves is longer than the time corresponding to the distance between the radar and the farthest position from the radar at the end of the vehicle, and the detection unit detects the presence or absence of a living body based on the received signals from the multiple transmissions and receptions.

[0009] The disclosed living body detection device transmits and receives signals multiple times, and detects the presence or absence of a living body based on the multiple received signals. By extending the reception time, the radar receives indirect waves from the living body that pass through the metal object in the vehicle. In this way, multipath is actively utilized. Even if sampling variations occur due to indirect waves that are received with a delay compared to the direct waves from the metal object, the presence or absence of a living body can be detected. This improves the accuracy of detecting a living body inside the vehicle.

[0010] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and technical concepts are intended to exemplify the correspondence with the embodiments described below and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become clearer with reference to the following detailed description and the accompanying drawings.

[0011] 10 is a diagram showing the detection principle. FIG. 10 is a diagram showing an example of a received waveform of a radar. FIG. 11 is a diagram showing temporal fluctuations in the received strength of a reflected wave. FIG. 11 is a diagram showing the mounting position of a radar in a vehicle. FIG. 12 is a diagram showing the results of measuring the reflected strength. FIG. 12 is a diagram in which the time shown in FIG. 5 is replaced with distance. FIG. 13 is a diagram showing temporal fluctuations in the received strength of a reflected wave when a child is present in the P seat. FIG. 14 is a diagram showing the waveform obtained by filtering the waveform of FIG. 7. FIG. 15 is a diagram showing sampling variations in multiple transmissions and receptions. FIG. 16 is a diagram showing temporal fluctuations in the received strength of a reflected wave when a child is present in the trunk. FIG. 17 is a diagram showing the waveform obtained by filtering the waveform of FIG. 15. FIG. 18 is a diagram showing the biological detection device according to the first embodiment. FIG. 19 is a diagram showing indirect waves that pass from a biological body via a metal object. A flowchart showing biological detection processing. A diagram showing temporal fluctuations in the received strength at point SP1. A diagram showing the waveform obtained by filtering the waveform of FIG. 15. A flowchart showing biological detection processing executed by a biological detection device according to a second embodiment. A flowchart showing biological detection processing executed by a biological detection device according to a third embodiment. A diagram showing a modified example. A flowchart showing biological detection processing executed by a biological detection device according to a fourth embodiment. A diagram showing an example of displacement of a moving body relative to a radar. A diagram showing changes in relative speed. FIG. 19 is a diagram showing an example of radar arrangement in a biological detection device according to a fifth embodiment. A flowchart showing biological detection processing. 13 is a diagram showing waveforms of one pulse received by an in-vehicle radar and an external radar, and FIG. 14 is a diagram showing an example of mounting positions of a plurality of radars on a vehicle in a living body detection device according to a sixth embodiment, and FIG. 15 is a diagram showing a living body detection process.

[0012] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0013] (First embodiment) As an in-vehicle occupant sensing app, a child abandonment detection app will be added to EuroNCAP from 2023 and will be eligible for additional points. In particular, it has been decided that from 2025 onwards, only apps that directly detect abandoned children will be evaluated. EuroNCAP is an abbreviation for European New Car Assessment Program.

[0014] For this reason, it is necessary to detect biological information such as breathing and body movements throughout the vehicle to determine whether a child is present. One of the evaluation conditions is that it needs to be detected whether the child is covered with a blanket or in a child seat, which is difficult to achieve using cameras, and so radio waves are considered the most promising option.

[0015] The living body detection device according to this embodiment detects the presence or absence of a living body inside a vehicle using pulse waves, as will be described later. The living body detection device can be used, for example, to detect the presence or absence of a child left behind. Living bodies inside a vehicle that can be detected by the living body detection device are not limited to children, but may also include passengers other than children, and animals such as dogs and cats.

[0016] First, the principle of detecting a living body using a pulse wave as a radio wave will be described with reference to FIGS.

[0017] <Detection principle> Fig. 1 shows the detection principle. Fig. 1 shows displacement of the body surface due to breathing. In Fig. 1, the transmitted pulse wave (transmitted wave) is indicated by a solid arrow, the reflected wave by the human body is indicated by a dashed arrow, and the transmitted wave that passes through the human body is indicated by a two-dot chain arrow. Fig. 2 shows an example of a radar received waveform. Fig. 3 shows the time variation in the received wave strength of the reflected wave. Fig. 3 shows the time variation in the received wave strength over multiple transmissions and receptions. Here, a human body is shown as an example of the living body 100.

[0018] As shown in FIG. 1, when a high-frequency pulse wave is irradiated from a radar 30 onto a living body 100 (human body), part of the wave passes through the living body 100, and the other part is reflected by the body surface 100s. The high frequency wave is, for example, a frequency of 1 GHz or higher. The radar 30 is, for example, a UWB radar. UWB is an abbreviation for Ultra Wide Band. Since the body surface 100s is displaced by breathing, the distance between the radar 30 (antenna) and the living body 100 changes depending on breathing. The displacement Δd of the body surface 100s due to breathing is, for example, about 1 mm to 10 mm.

[0019] Therefore, the received strength of the reflected wave changes in response to respiration, as shown by the arrow in Fig. 2. Fig. 2 shows the received waveform at a predetermined transmission and reception timing. By monitoring the received waveform for each of multiple transmissions and receptions, it is possible to obtain the waveform shown in Fig. 3, which shows the time variation of the received strength of the reflected wave. The time variation shown in Fig. 3 is specific to the respiration of the living body 100. Therefore, the presence or absence of a living body can be detected using the time variation. Body movement can also be detected by monitoring the received waveform, as the distance between the radar 30 and the living body 100 changes.

[0020] <Sampling Variation> Figure 4 shows the installation position of the radar (UWB radar) when measuring the reflection intensity. Figure 5 shows the results of measuring the reflection intensity. Figure 6 is a diagram in which the time shown in Figure 5 is replaced with distance. For convenience, Figure 6 shows the distance as half the distance (round-trip distance) corresponding to the reception intensity, i.e., the one-way distance. Figure 7 shows the time variation in the reception intensity of the reflected wave when a child (living body) is present in seat P. Figure 7 corresponds to Figure 3. Figure 7 shows the time variation in the reception intensity when a child is present at distance L1. Figure 8 shows the waveform obtained by filtering the waveform shown in Figure 7. Figure 8 shows the waveform after frequency filtering (0.1 to 1 Hz). Figure 9 shows the sampling variation over multiple transmissions and receptions.

[0021] As shown in Figure 4, when measuring the reflection intensity, the radar 30 was placed near the front end of the vehicle ceiling and near the center in the left-right direction, specifically on the overhead console. The received waveform in Figure 5 shows the waveform (base waveform) when no living body is present inside the vehicle. The time on the horizontal axis represents the elapsed time from the transmission of the pulse wave to the reception of the reflected wave, i.e., the reception time. As shown in Figure 5, the area where the reception intensity is high near time zero (0) is due to reflection (direct wave) from the metal ceiling. Reflections from not only the ceiling but also metal objects such as the body are superimposed on the received waveform depending on the distance from the radar 30. In areas where the reception time is short, the influence of the direct wave from the metal object is large, and the reception intensity is high.

[0022] When detecting the presence or absence of a living body in a vehicle, for example, the presence or absence of a child, it is possible to monitor the reception intensity corresponding to the distance between each seat where a child may be present and the radar 30. In this case, time is converted to distance as shown in FIG. 6, and fluctuations at points corresponding to the distance from the radar 30 to each seat are detected. The relationship in Equation 1 below holds between the distance (one-way distance) shown in FIG. 6 and the time Δt from transmission to reception of the pulse wave. c is the speed of light (3×10 ８ The round trip distance is twice the one-way distance. One-way distance x 2 = c x Δt (Equation 1)

[0023] The dashed dotted lines in FIG. 6 indicate the positions of the front seats (seat D, seat P), rear seats (behind seat D, behind seat P), and trunk. The front seats are located at a distance L1 from the radar 30. The rear seats are located at a distance L2 from the radar 30. The trunk is located at a distance L3 from the radar 30. The distances L1, L2, and L3 satisfy the relationship L1<L2<L3. Seat D is the driver's seat, and seat P is the passenger seat.

[0024] However, it has become clear that even if a child is present in the front seat, a waveform corresponding to breathing cannot be detected, as shown in Figures 7 and 8. The reason that detection is not possible in positions close to the radar 30, such as seats D and P, is due to sampling variations in the radar 30. In multiple transmissions and receptions, a time lag of the order of nanoseconds occurs in the received waveforms, as shown in Figure 9. This causes variations in the base reception strength at a given sampling point.

[0025] The greater the reception strength, the greater the influence of this variation. For example, if a child is sitting in a seat where the influence of reflection from the ceiling remains (e.g., the front seat), minute fluctuations such as breathing will be buried in the change in reception strength caused by sampling variation. In this way, it became clear that there is a risk that the variation caused by a living body will be buried in the change caused by sampling variation, and the living body may not be detected.

[0026] Fig. 10 shows the time variation in the received strength of the reflected wave when a child is present in the trunk. Fig. 10 corresponds to Fig. 3. Fig. 10 shows the time variation in the received strength when a child is present at distance L3. Fig. 11 shows the waveform after filtering has been applied to Fig. 10. Like Fig. 8, Fig. 11 shows the waveform after frequency filtering (0.1 to 1 Hz).

[0027] Even when a child is present in the trunk, a waveform corresponding to breathing cannot be detected, as shown in Figures 10 and 11. The trunk is located far from the radar 30, and there are obstacles such as seats on the straight path from the radar 30 to the trunk. This is thought to attenuate the radio waves, making breathing detection difficult.

[0028] The living body detection device according to this embodiment is based on the above findings. Next, the general configuration of the living body detection device will be described.

[0029] <Living body detection device> Fig. 12 shows a schematic configuration of a living body detection device according to this embodiment. Fig. 13 shows an indirect wave. As shown in Fig. 12, the living body detection device 20 includes at least one radar 30 and an ECU 40. ECU is an abbreviation for Electronic Control Unit. The ECU 40 is sometimes called an electronic control unit.

[0030] The radar 30 transmits pulse waves of a predetermined frequency and receives reflected waves of the pulse waves. The radar 30 has an antenna 31. The antenna 31 may include a transmitting antenna and a receiving antenna, or may include a dual-purpose antenna for transmitting and receiving. As described above, the frequency of the pulse waves is high, for example, a frequency of 1 GHz or higher. The radar 30 is a UWB radar or a millimeter-wave radar. As an example, the radar 30 of this embodiment is an IR-type UWB radar. IR is an abbreviation for Impulse Radio. The impulse signal used in UWB communication may be a signal having an extremely short pulse width (for example, 2 ns) and a bandwidth of 500 MHz (strictly speaking, 499.2 MHz) or higher, i.e., an ultra-wide bandwidth.

[0031] The radar 30 is attached to the vehicle 10. The living body detection device 20 may include only one radar 30 or may include multiple radars 30. As an example, the living body detection device 20 of this embodiment includes only one radar 30. As shown in Figures 4 and 13, the radar 30 is located inside the vehicle near the front end of the ceiling 11 and near the center in the left-right direction. The radar 30 is located in the overhead console. The radar 30 may also be used as a radar for a smart entry system, for example. The antenna 31 may be, for example, an omnidirectional antenna.

[0032] The radar 30 transmits and receives signals multiple times at predetermined intervals during a living body detection period (described below). The radar 30 transmits and receives signals multiple times at intervals sufficiently short compared to the breathing cycle. The reception time of the reflected wave is longer than the time corresponding to the distance between the radar 30 and the farthest point from the radar 30 at the end of the vehicle 10. Therefore, as shown in FIG. 13 , the radar 30 receives indirect waves from the living body via the metal body of the vehicle 10. In this manner, the living body detection device 20 actively utilizes multipath. As an example, in this embodiment, the vehicle 10 is a five-seater passenger car. The end of the vehicle 10 farthest from the radar 30 is the rear end of the vehicle, and the distance from the radar 30 to the rear end is approximately 2 m. The reception time of the reflected wave is longer than the time corresponding to the 2 m distance to the rear end of the vehicle. The reception time may be, for example, a time corresponding to a round-trip distance of 4 m between the radar 30 and the rear end of the vehicle (approximately 13 ns). The radar 30 may perform the next transmission and reception after 100 ms has elapsed since the previous transmission and reception.

[0033] The ECU 40 controls the operation of the radar 30. The ECU 40 detects the presence or absence of a living body inside the vehicle based on the received signal of the radar 30. The ECU 40 corresponds to a detection unit. The ECU 40 detects the presence or absence of a living body based on multiple received signals. As an example, the ECU 40 of this embodiment detects the presence or absence of a living body based on the amount of time variation in the received signals. The ECU 40 is configured with a processor 41, a memory 42, a storage 43, etc.

[0034] The processor 41 executes various processes by accessing the memory 42. The memory 42 is a rewritable volatile storage medium. The memory 42 is, for example, a RAM. RAM is an abbreviation for Random Access Memory. The storage 43 is a rewritable non-volatile storage medium. The storage 43 stores programs executed by the processor 41. The ECU 40 executes programs while accessing the memory, thereby constructing multiple functional units. The execution of a program by the processor 41 corresponds to the execution of a living body detection method described below. The ECU 40 may include multiple processors 41. The ECU 40 may also serve as an ECU for a smart entry system, for example. The ECU 40 may include a function to detect the presence or absence of a living body in the vehicle together with the radar 30, such as a function to detect whether a child has been left behind.

[0035] 14 is a flowchart showing a process executed by the living body detection device, that is, a living body detection method. When the doors of the vehicle 10 are locked, for example, the living body detection device 20 executes the living body detection process shown in FIG.

[0036] The ECU 40 controls the operation of the radar 30 so that the transmission and reception process is performed for a predetermined period (step S10). This causes the radar 30 to perform the transmission and reception process. In this embodiment, the predetermined period is set to 10 seconds after the door is locked, as an example. During the predetermined period, the radar 30 repeatedly performs multiple transmissions and receptions at predetermined intervals. As described above, the reception time for one transmission is set to 13 ns, and multiple transmissions and receptions are performed at intervals of 100 ms.

[0037] Next, the ECU 40 acquires a plurality of received signals from the radar 30 during the predetermined period and starts loop processing (step S20). The ECU 40 executes the loop processing sequentially for preset sampling points. The sampling points are, for example, predetermined distance values ​​shown in FIG. 6 or predetermined time values ​​shown in FIG. 5. A plurality of sampling points may be set at predetermined distances or predetermined times. The sampling points may be set, for example, every 0.1 m or every 1 ns. The sampling points may be set based on data obtained through testing or the like.

[0038] The ECU 40 calculates the time variation of the reception strength at a predetermined sampling point, i.e., the amplitude (step S30). Next, the ECU 40 compares the calculated amplitude with a threshold value and determines whether the amplitude is greater than the threshold value (step S40). As described above, the reception strength of the base waveform generally increases the closer it is to the radar 30. The threshold value is set according to the sampling point. The threshold value is set according to the amplitude of the base waveform. The threshold value is set taking into account sampling variation, i.e., variation in the reception strength of the base waveform. This makes it possible to suppress erroneous determinations.

[0039] If the amplitude is equal to or less than the threshold, the ECU 40 executes the processing of steps S30 and S40 for the next sampling point. If the amplitude is equal to or less than the threshold for all sampling points, the ECU 40 ends the loop processing (step S50). Next, the ECU 40 determines that the living body 100 is not present in the vehicle (step S60) and ends the series of processing. If the amplitude is greater than the threshold in step S40, the ECU 40 determines that breathing or body movement is superimposed on the base waveform, that is, that the living body 100 is present in the vehicle (step S70) and ends the series of processing.

[0040] The ECU 40 detects the presence or absence of the living body 100 based on the temporal variation in the reception strength at the sampling point. As described above, the sampled reflected wave immediately after transmission is superimposed with a direct wave from a metal object such as the ceiling 11. Therefore, variations such as breathing are likely to be hidden by the change in reception strength due to sampling variations.

[0041] On the other hand, when the reflected wave is sampled after a certain time has passed since transmission, the influence of the direct wave by the metal object has weakened, and a waveform is observed in which the reflected wave from the living body 100 is further diffused inside the vehicle body and reaches the radar 30. The indirect wave that travels from the living body 100 via the metal object reaches the radar 30 later than the direct wave from the metal object. Therefore, fluctuations such as respiration are more likely to appear in this area than in areas where the reflection strength of the base waveform is high.

[0042] FIG. 15 shows the time variation of the reception intensity at sampling point SP1, indicated by the two-dot chain line in FIG. 6. FIG. 15 corresponds to FIG. 3. FIG. 16 shows the waveform after filtering of FIG. 15. Like FIG. 8, FIG. 16 shows the waveform after frequency filtering (0.1 to 1 Hz). Sampling point SP1 is located at a distance greater than 2 m to the rear end of the vehicle, for example, 2.4 m. The distance of sampling point SP1 is greater than twice the distance to the front seat (distance L1). The ECU 40 includes sampling point SP1 as a sampling point. As shown in FIG. 16, at sampling point SP1, the influence of the direct wave from the metal object is weakened, and an indirect wave passing through the metal object from the living body 100 is observed. In FIG. 16, fluctuations due to breathing appear as amplitude.

[0043] Furthermore, in a location distant from the radar 30, such as the trunk, the direct wave may attenuate as described above and may not reach the living body 100 present in the trunk. However, the pulse wave may reach the living body 100 via a reflection path from the floor, and the reflected wave from the living body 100 may be diffused inside the vehicle body and reach the radar 30. Therefore, as described above, fluctuations due to breathing, etc., can be detected at the sampling point where the influence of the direct wave from the metal object is weakened.

[0044] Summary of the First Embodiment This embodiment focuses on the fact that reflected waves that strike a living body (occupant) are superimposed on the received waveform of the radar 30 while being delayed in the time direction along various paths within the vehicle. According to the living body detection device 20 of this embodiment, the radar 30 transmits and receives signals multiple times, and the ECU 40 (detection unit) detects the presence or absence of a living body 100 based on the multiple received signals. In each transmission and reception, the reception time of the reflected waves is longer than the time corresponding to the distance between the radar 30 and the farthest position from the radar 30 at the end of the vehicle 10. By lengthening the reception time, the radar 30 receives indirect waves from the living body 100 that pass through a metal object of the vehicle 10. In this way, multipath is actively utilized.

[0045] At sampling points where indirect waves are superimposed, the influence of direct waves from metal objects is small, and for example, the received strength of the base waveform is low. Therefore, as shown in FIG. 9, even if there is a time lag of the order of nanoseconds due to multiple receptions, i.e., sampling variations, the presence or absence of a living body 100 can be detected. This improves the detection accuracy of a living body 100 inside a vehicle. For example, it improves the accuracy of detecting whether a child has been left behind.

[0046] The ECU 40 may detect the presence or absence of the living body 100 based on the time variation in the reception strength over multiple receptions, i.e., the amplitude. Fluctuations such as respiration and body movement are superimposed on the base waveform. In other words, the amplitude increases by the amount of respiration and body movement. Therefore, the presence or absence of the living body 100 can be detected based on the amplitude. By using the amplitude, it is possible to detect not only respiration but also fluctuations due to body movement.

[0047] A UWB radar may be used as the radar 30. In recent years, there has been a growing market need for using smartphones as car keys. One method, UWB, uses pulsed radio waves to measure the communication time between the smartphone and the car, thereby locating the smartphone's location and using this as a trigger for unlocking the car door and starting the engine. By using a UWB radar, it can be used in conjunction with a smart entry system, reducing costs. There is no need to install a separate sensing radar. Note that a millimeter wave radar may be used instead of a UWB radar.

[0048] Second Embodiment This embodiment is a modification of the preceding embodiment as a basic form, and the description of the preceding embodiment can be used. In the preceding embodiment, the presence or absence of a living body is detected based on amplitude. Alternatively, the presence or absence of a living body may be detected based on frequency characteristics.

[0049] Fig. 17 shows the process executed by the living body detection device according to this embodiment, i.e., the living body detection method. In the living body detection process shown in Fig. 17, the processes of steps S130 and S140 are different from the processes of steps S30 and S40 shown in Fig. 14. The other processes are the same as those shown in Fig. 14.

[0050] For example, when the doors of the vehicle 10 are locked, the living body detection device 20 executes the living body detection process shown in FIG. 17 . The processes of steps S110 and S120 are the same as the processes of steps S10 and S20 shown in FIG. 14 . In the loop process, the ECU 40 calculates frequency characteristics (step S130). The ECU 40 calculates the frequency characteristics based on, for example, the time fluctuation of the reception strength at a predetermined sampling point. The ECU 40 calculates the frequency characteristics by using a fast Fourier transform (FFT) on the time fluctuation (amplitude) of the reception strength. The ECU 40 calculates, for example, kurtosis as the frequency characteristic. The kurtosis is calculated by dividing the reception strength at the peak frequency by the average strength of the other frequencies.

[0051] Next, the ECU 40 compares the calculated kurtosis with a threshold value and determines whether the kurtosis is greater than the threshold value (step S140). If the kurtosis is equal to or less than the threshold value, the ECU 40 executes the processes of steps S130 and S140 for the next sampling point. If the kurtosis is equal to or less than the threshold value for all sampling points, the ECU 40 ends the loop process (step S150), determines that no living body 100 is present in the vehicle (step S160), and ends the series of processes. The process of step S150 is the same as the process of step S50. The process of step S160 is the same as the process of step S60.

[0052] In step S140, if the kurtosis is greater than the threshold value, the ECU 40 detects breathing, that is, determines that the living body 100 is present in the vehicle (step S170), and ends the series of processes. The process in step S170 is the same as the process in step S70. The other configurations are the same as those described in the preceding embodiment.

[0053] Summary of the Second Embodiment This embodiment can achieve the same effects as the preceding embodiment. For example, even if there is a time lag of the order of nanoseconds due to multiple receptions, i.e., sampling variations, it is possible to detect the presence or absence of the living body 100. Therefore, it is possible to improve the detection accuracy of the living body 100 inside the vehicle.

[0054] The ECU 40 may detect the presence or absence of the living body 100 based on the frequency characteristics of the signals received multiple times. The presence or absence of the living body 100 can be detected based on whether or not the frequency characteristics are specific to breathing.

[0055] (Third Embodiment) This embodiment is a modification of the preceding embodiment as a basic form, and the description of the preceding embodiment can be used. In the preceding embodiment, the presence or absence of a living body is detected based on amplitude or frequency characteristics. Alternatively, the presence or absence of a living body may be detected based on amplitude and frequency characteristics.

[0056] Fig. 18 shows the process executed by the living body detection device according to this embodiment, i.e., the living body detection method. The living body detection process shown in Fig. 18 is configured by adding steps S130 and S140 of Fig. 17 to the process shown in Fig. 14.

[0057] For example, when the doors of the vehicle 10 are locked, the living body detection device 20 executes the living body detection process shown in FIG. 18 . The processes of steps S210, S220, S230, and S240 are the same as the processes of steps S10, S20, S30, and S40 shown in FIG. 14 . If the amplitude is equal to or less than the amplitude threshold in step S240, the ECU 40 calculates frequency characteristics (step S250). The ECU 40 calculates, for example, kurtosis as the frequency characteristic. Next, the ECU 40 determines whether the kurtosis is greater than the kurtosis threshold (step S260). The processes of steps S250 and S260 are the same as the processes of steps S130 and S140 shown in FIG. 17 .

[0058] If the kurtosis is equal to or less than the threshold, the ECU 40 executes the process from step S230 onwards for the next sampling point. If the amplitude is equal to or less than the amplitude threshold and the kurtosis is equal to or less than the kurtosis threshold for all sampling points, the ECU 40 ends the loop process (step S270), determines that the living body 100 is not present in the vehicle (step S280), and ends the series of processes. The processes of steps S270 and S280 are the same as the processes of steps S50 and S60.

[0059] If the amplitude is greater than the amplitude threshold in step S240, the ECU 40 determines that the living body 100 is present in the vehicle (step S290) and ends the series of processes. If the kurtosis is greater than the kurtosis threshold in step S260, the ECU 40 also executes the process of step S290 and ends the series of processes. The process of step S290 is the same as the process of step S70. The other configurations are the same as those described in the preceding embodiment.

[0060] Summary of the Third Embodiment This embodiment can achieve the same effects as the preceding embodiments. For example, even if there is a time lag of the order of nanoseconds due to multiple receptions, i.e., sampling variations, it is possible to detect the presence or absence of the living body 100. Therefore, it is possible to improve the detection accuracy of the living body 100 inside the vehicle.

[0061] The ECU 40 may first determine the presence or absence of the living organism 100 based on the time fluctuation of the received signal multiple times, i.e., the amplitude, and if the living organism 100 is not detected based on the amplitude, determine the presence or absence of the living organism 100 based on the frequency characteristics of the received signal multiple times. By using the amplitude as described above, it is possible to detect not only fluctuations due to breathing of the living organism 100 but also fluctuations due to body movement. Furthermore, even if minute fluctuations due to breathing are buried in fluctuations in the received signal caused by sampling variations and the living organism 100 cannot be detected based on the amplitude, it is possible to detect breathing, i.e., detect the living organism 100, by using the frequency characteristics. In other words, the accuracy of detecting the living organism 100 inside the vehicle can be further improved.

[0062] <Modification> The ECU 40 may first detect the presence or absence of a living organism 100 based on the amplitude, and if the living organism 100 is detected based on the amplitude, may then detect the presence or absence of the living organism 100 based on the frequency characteristics of multiple received signals. As shown in FIG. 19 , the ECU 40 determines whether the amplitude is greater than an amplitude threshold (step S240), and if the amplitude is greater than the amplitude threshold, calculates the frequency characteristics (step S250). The ECU 40 determines whether the kurtosis is greater than a kurtosis threshold (step S260), and if the kurtosis is greater than the kurtosis threshold, determines that a living organism is present (step S290). In other words, if the amplitude > the amplitude threshold and the kurtosis > the kurtosis threshold, it determines that a living organism is present. If the results in steps S240 and S260 are equal to or less than the thresholds, it executes a loop process until no sampling points remain. When no sampling points remain, the loop process ends (step S270) and determines that no living organism is present (step S280).

[0063] Increasing the number of sampling points increases the possibility of detecting the living organism 100, but also increases the possibility of responding to disturbances such as pedestrians outside the vehicle. When amplitude is used, for example, when the radar 30 is attached to the ceiling, the amount of minute breathing fluctuations at a position far from the radar 30, such as at the feet, may be equivalent to the amount of breathing fluctuations outside the vehicle. According to this embodiment, not only amplitude but also frequency characteristics are used. Since the presence or absence of the living organism 100 is detected in two stages, erroneous detection can be suppressed.

[0064] (Fourth embodiment) This embodiment is a modification of the preceding embodiment as a basic form, and the description of the preceding embodiment can be used. In the preceding embodiment, an example was shown in which disturbances were removed by using amplitude and frequency characteristics. Instead of this, or in addition, disturbances may be removed by using relative velocity.

[0065] Fig. 20 shows the process executed by the living body detection device according to this embodiment, i.e., the living body detection method. Fig. 21 shows an example of the displacement of a moving object relative to a radar (e.g., UWB radar). Fig. 22 shows the change in relative velocity.

[0066] For example, when the doors of the vehicle 10 are locked, the living body detection device 20 executes the living body detection process shown in Fig. 20. The processes of steps S310, S320, S330, and S340 are similar to the processes of steps S10, S20, S30, and S40 shown in Fig. 14.

[0067] If the amplitude is greater than the threshold value in step S340, the ECU 40 calculates the relative velocity based on an arbitrary waveform among the multiple received signals (received waveforms) (step S350).The ECU 40 determines whether the detected object is a moving object 110 outside the vehicle based on the relative velocity (step S360).

[0068] By using the radar 30 as a Doppler sensor, the relative velocity of the moving object 110 with respect to the radar 30 can be calculated. When calculating the relative velocity using the Doppler principle, the time interval used for measurement, i.e., the reception time of the reflected wave, is lengthened. This results in a result that includes the relative velocity component during that time interval. As shown in FIG. 21 , when the moving object 110 moves across the radar 30, if the time interval is extended, the relative velocity will change from moment to moment because a line-of-sight component is obtained. As a result, as shown in FIG. 22 , the relative velocity has various values, and this can be used as a feature to determine whether the moving object 110 is outside the vehicle. The moving object 110 outside the vehicle could be, for example, a pedestrian outside the vehicle or an adjacent vehicle.

[0069] It is also possible to calculate the distance to the moving object 110 together with the relative speed, and determine whether the moving object 110 is outside the vehicle based on the distance and the relative speed. By adding the distance, it is possible to more reliably detect whether the moving object 110 is outside the vehicle.

[0070] If the amplitude is equal to or less than the threshold value in step S340 or if it is determined in step S360 that the object is a moving object 110 outside the vehicle, the ECU 40 executes the loop process until there are no more sampling points. When there are no more sampling points, the loop process ends (step S370) and it is determined that there is no living body (step S380). The processes of steps S370 and S80 are the same as the processes of steps S50 and S60.

[0071] If it is determined in step S360 that the object is not a moving object 110 outside the vehicle, the ECU 40 determines that a living body is present (step S390). That is, if the amplitude is greater than the threshold and the object is not a moving object 110 outside the vehicle, the ECU 40 determines that a living body is present. The processing in step S390 is the same as the processing in step S70. The other configurations are the same as those described in the preceding embodiment.

[0072] Summary of the Fourth Embodiment This embodiment can achieve the same effects as the preceding embodiments. For example, even if there is a time lag of the order of nanoseconds in multiple receptions, i.e., sampling variation, it is possible to detect the presence or absence of the living body 100. Therefore, it is possible to improve the accuracy of detecting the living body 100 inside the vehicle.

[0073] When detecting the presence or absence of the living body 100 inside the vehicle, the ECU 40 may calculate the relative speed of the moving body 110 based on any received signal and determine whether the moving body 110 is present outside the vehicle. By using the relative speed, it is possible to determine whether the living body 100 detected using the amplitude is a moving body 110 outside the vehicle. By using the relative speed, it is possible to remove external disturbances such as pedestrians outside the vehicle or adjacent vehicles and suppress false detection. In other words, it is possible to improve the accuracy of detecting the presence or absence of the living body 100 inside the vehicle.

[0074] Although an example in which the detection of the living body 100 using the amplitude and the detection of the moving body 110 outside the vehicle using the relative speed are combined has been shown, the present invention is not limited to this. The detection of the living body 100 using the frequency characteristics and the detection of the moving body 110 outside the vehicle using the relative speed may be combined. The detection of the living body 100 using the amplitude and frequency characteristics and the detection of the moving body 110 outside the vehicle using the relative speed may be combined.

[0075] Fifth Embodiment This embodiment is a modification of the preceding embodiment as a basic form, and the description of the preceding embodiment can be used. In the preceding embodiment, the living body detection device includes only one radar disposed inside the vehicle. Instead, the living body detection device may include a radar disposed inside the vehicle and a radar disposed outside the vehicle.

[0076] Fig. 23 shows an example of radar arrangement in the living body detection device according to this embodiment. Fig. 24 shows the process executed by the living body detection device, i.e., the living body detection method. Fig. 25 shows the received waveforms of one pulse from the in-vehicle radar and the external radar.

[0077] As illustrated in FIG. 23 , the biological detection device 20 includes an in-vehicle radar 301 and an external radar 302 as radars 30. The in-vehicle radar 301 is a radar 30 arranged inside the vehicle, and the external radar 302 is a radar 30 arranged outside the vehicle. In this embodiment, as an example, the multiple radars 30 are also used as a smart entry system. The multiple radars 30 are, for example, UWB radars. The radars 30 include one in-vehicle radar 301 and four external radars 302. The in-vehicle radar 301 is used, for example, to start the engine. The external radars 302 are arranged near the four corners of the vehicle 10. The external radars 302 are used to unlock the door.

[0078] For example, when the doors of the vehicle 10 are locked, the living body detection device 20 executes the living body detection process shown in FIG. 24 . The living body detection device 20 controls the operation of the radar 30 (301, 302) so that the transmission and reception process is executed for a predetermined period of time (step S410). The ECU 40 operates the external radar 302 in parallel with the interior radar 301. For example, the ECU 40 controls the interior radar 301 and the exterior radar 302 so that the pulse transmission timing, reflected wave reception time, and transmission and reception interval are approximately the same. The processes of steps S410, S420, S430, and S440 are the same as the processes of steps S10, S20, S30, and S40 shown in FIG. 14 . The ECU 40 executes steps S430 and S440 based on the signal received by the interior radar 301. If the amplitude is greater than the threshold value in step S440, the ECU 40 calculates the amount of fluctuation in the reception strength caused by the moving object 110 (step S450). The ECU 40 determines whether the received signal is from the moving object 110 outside the vehicle based on the magnitude of the amount of fluctuation (step S460).

[0079] As described above, the living body detection device 20 includes the interior radar 301 and the exterior radar 302. Disturbances from the moving object 110 outside the vehicle can be removed based on the difference between the reception strength of the interior radar 301 and the reception strength of the exterior radar 302. For example, when a moving object 110 such as a pedestrian or an adjacent vehicle crosses the vehicle, the fluctuations in the reception strength of the interior radar 301 are small and the fluctuations in the reception strength of the exterior radar 302 are large, as shown by the arrows in FIG. 25 . Therefore, this difference can be used to determine whether or not the moving object is an exterior moving object 110. For example, if the amount of fluctuation of the exterior radar 302 is larger than the amount of fluctuation of the interior radar 301, the ECU 40 determines that the moving object is an exterior moving object 110.

[0080] If the amplitude is equal to or less than the threshold value in step S440, or if it is determined in step S460 that the object is a moving object 110 outside the vehicle, the ECU 40 executes the loop process until there are no more sampling points. When there are no more sampling points, the loop process ends (step S470) and it is determined that there is no living body (step S480). The processes in steps S470 and S480 are the same as those in steps S50 and S60.

[0081] If it is determined in step S460 that the object is not a moving object 110 outside the vehicle, the ECU 40 determines that a living body is present (step S490). That is, if the amplitude is greater than the threshold and the object is not a moving object 110 outside the vehicle, the ECU 40 determines that a living body is present. The processing in step S490 is the same as the processing in step S70. The other configurations are the same as those described in the preceding embodiment.

[0082] Summary of the Fifth Embodiment The present embodiment can achieve the same effects as the preceding embodiments. For example, even if there is a time lag of the order of nanoseconds in multiple receptions, i.e., sampling variation, the presence or absence of the living body 100 can be detected. Therefore, the accuracy of detecting the living body 100 inside the vehicle can be improved.

[0083] The radar 30 may include an interior radar 301 and an exterior radar 302. The ECU 40 may detect the presence or absence of a living organism 100 based on the received signals of the interior radar 301 and the exterior radar 302. The exterior radar 302 is more susceptible to the influence of moving objects 110 outside the vehicle, such as pedestrians outside the vehicle and adjacent vehicles, than the interior radar 301. By using the received signals of the interior radar 301 and the exterior radar 302, disturbances such as pedestrians outside the vehicle and adjacent vehicles can be removed, and false detections can be suppressed. In other words, the accuracy of detecting the presence or absence of a living organism 100 inside the vehicle can be improved.

[0084] Although an example has been shown in which detection of the moving object 110 outside the vehicle using the received signals of the interior radar 301 and the exterior radar 302 is combined with detection of the living body 100 using amplitude, this is not limiting. Detection of the moving object 110 outside the vehicle using the received signals of the interior radar 301 and the exterior radar 302 may be combined with detection of the living body 100 using frequency characteristics. Detection of the moving object 110 outside the vehicle using the received signals of the interior radar 301 and the exterior radar 302 may be combined with detection of the living body 100 using amplitude and frequency characteristics.

[0085] Sixth Embodiment This embodiment is a modification of the preceding embodiment as a basic form, and the description of the preceding embodiment can be used. In the preceding embodiment, the living body detection device includes only one radar disposed inside the vehicle. Instead, the living body detection device may include multiple radars disposed inside the vehicle.

[0086] Fig. 26 shows an example of the positions at which a plurality of radars are attached to a vehicle. Fig. 27 shows the process executed by the living body detection device according to this embodiment, that is, the living body detection method.

[0087] As illustrated in Fig. 26, the living body detection device 20 includes a plurality of radars 30 arranged inside the vehicle. The plurality of radars 30 are, for example, UWB radars. The plurality of radars 30 are arranged at predetermined intervals in the longitudinal direction of the vehicle 10. Each radar 30 is attached to the ceiling. In this embodiment, the vehicle 10 is a bus as an example. Three radars 30 are attached to the vehicle 10.

[0088] For example, when the doors of the vehicle 10 are locked, the living body detection device 20 executes the living body detection process shown in FIG. 27 . The ECU 40 first starts loop process 1 (step S510). The living body detection device 20 executes loop process for each of the plurality of radars 30 in turn. Next, the ECU 40 controls the operation of the radar 30 so that the transmission and reception process is executed for a predetermined period (step S520). The ECU 40 acquires multiple received signals from the radar 30 during the predetermined period and starts loop process 2 (step S530). Steps S520, S530, S540, S550, S560, S570, and S580 are the same as steps S10, S20, S30, S40, S50, S60, and S70 shown in FIG. 14 . Loop process 2 (loop 2) corresponds to the loop process described in the preceding embodiment.

[0089] After executing the process of step S570 or step S580 for one of the radars 30, the ECU 40 executes the biological detection process from step S520 onwards for the other radar 30. When the biological detection process has been completed for all radars 30, the ECU 40 ends the loop process (step S590) and ends the series of processes. The other configurations are the same as those described in the preceding embodiment.

[0090] Summary of the Sixth Embodiment The present embodiment can achieve the same effects as the preceding embodiments. For example, even if there is a time lag of the order of nanoseconds in multiple receptions, i.e., sampling variation, the presence or absence of the living body 100 can be detected. Therefore, the detection accuracy of the living body 100 inside the vehicle can be improved.

[0091] The living body detection device 20 may include multiple radars 30 installed inside the vehicle. The multiple radars 30 may transmit and receive signals multiple times at different times, and the ECU 40 may detect the presence or absence of a living body 100 based on the received signals from each radar 30. In the case of a large vehicle 10, such as a bus, multiple radars 30 may be installed inside the vehicle to detect the presence or absence of a living body 100. In this case, if a direct wave from one radar 30 penetrates directly into another radar 30, the received signal strength increases as described above, and there is a risk that fluctuations due to the living body 100 will be overwhelmed by fluctuations in the received signal strength caused by sampling variations. In this embodiment, the multiple radars 30 transmit and receive signals multiple times at different times, so each radar 30 does not receive direct signals from the other radars 30. This makes it possible to detect the presence or absence of a living body 100 in a spacious vehicle while suppressing degradation of detection accuracy for the living body 100 due to the influence of other radars 30. For example, the accuracy of detecting abandoned children can be improved.

[0092] The method for reducing or eliminating the influence of the direct wave from the other radar 30 is not limited to the method of shifting the transmission and reception timing illustrated in Fig. 27. For example, a method of removing the received direct wave based on a predetermined positional relationship of the antennas may be adopted.

[0093] The configuration described in this embodiment can be combined with any of the configurations described in the preceding embodiments.

[0094] (Other Embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0095] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0096] When an element or layer is referred to as being "on," "coupled," "connected," or "coupled," it may be directly on, coupled, connected, or coupled to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly coupled" to another element or layer, no intervening elements or layers are present. Other terms used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items. That is, a reference to A and / or B means at least one of A and B.

[0097] Spatially relative terms such as "inside," "outside," "back," "below," "low," "top," "top," and the like are used herein to facilitate the description of one element or feature's relationship to other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, elements described as "below" or "directly below" other elements or features would then be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may also be oriented in other ways (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0098] The processor 41 may be a CPU, an MPU, a GPU, a DFP, or the like. CPU is an abbreviation for Central Processing Unit. MPU is an abbreviation for Micro-Processing Unit. GPU is an abbreviation for Graphics Processing Unit. DFP is an abbreviation for Data Flow Processor.

[0099] Some or all of the functions of the processor 41 may be realized by combining multiple types of arithmetic processing devices. Some or all of the functions of the processor 41 may be realized using SoC, ASIC, FPGA, etc. SoC is an abbreviation for System on Chip. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field-Programmable Gate Array. Some or all of the functions of the processor 41 may be realized using hardware logic circuits.

[0100] The program may be stored as instructions to be executed by a computer on a computer-readable non-transitory tangible storage medium. The program storage medium may be an HDD, an SSD, a flash memory, or the like. HDD is an abbreviation for Hard-disk Drive. SSD is an abbreviation for Solid State Drive.

[0101] In the above embodiment, an example of detecting the presence or absence of a living organism using the intensity obtained from an IQ signal has been described, but this is not limiting. For example, the presence or absence of a living organism may be detected using the IQ signal itself, or the phase obtained from the IQ signal. The phase corresponds to the output value of the arctangent whose input value is the ratio of the Q (Quadrature-Phase) component to the I (In-Phase) component of the received signal. The magnitude of the I component corresponds to the intensity of the in-phase component of the received signal. The magnitude of the Q component corresponds to the intensity of the quadrature component of the received signal. The I component is obtained by multiplying the received signal by a carrier wave output by a local oscillator. The Q component is obtained by multiplying the received signal by a signal whose phase is shifted by 90° from the output signal of the local oscillator. Furthermore, the presence or absence of a living organism may be detected using only the I component of the IQ signal, or only the Q component.

[0102] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple claims. Some claims may be described in a multiple dependent form, alternatively referencing preceding claims in a subsequent claim. Furthermore, some claims may be described in a multiple dependent form, referencing other multiple dependent form claims. These multiple dependent form claims define multiple technical ideas.

[0103] <Technical Idea 1> A living body detection device comprising: at least one radar (30) mounted on a vehicle (10), which transmits pulse waves of a predetermined frequency and receives reflected waves of the pulse waves; and a detection unit (40) which detects the presence or absence of a living body inside the vehicle based on a received signal of the radar, wherein the radar transmits and receives multiple times at predetermined intervals, the reception time of the reflected wave is longer than the time corresponding to the distance between the radar and a position at the end of the vehicle farthest from the radar, and the detection unit detects the presence or absence of the living body based on the received signal from the multiple transmissions and receptions.

[0104] <Technical Concept 2> The living body detection device according to Technical Concept 1, wherein the detection unit detects the presence or absence of the living body based on a time variation of the plurality of received signals.

[0105] <Technical Concept 3> The living body detection device according to Technical Concept 1 or 2, wherein the detection unit detects the presence or absence of the living body based on frequency characteristics of the multiple received signals.

[0106] <Technical Idea 4> The living body detection device according to Technical Idea 2, wherein the detection unit detects the presence or absence of the living body based on the time variation, and then detects the presence or absence of the living body based on frequency characteristics of the multiple received signals.

[0107] <Technical Idea 5> The living body detection device according to any one of Technical Ideas 1 to 4, wherein the detection unit calculates a relative speed of a moving object based on any of the received signals and determines whether the moving object is present outside the vehicle.

[0108] <Technical Idea 6> The radar includes an in-vehicle radar (301) arranged inside the vehicle and an external radar (302) arranged outside the vehicle, and the detection unit detects the presence or absence of the living body based on the received signal of the in-vehicle radar and the received signal of the external radar, in accordance with any one of Technical Ideas 1 to 4.

[0109] <Technical Idea 7> A living body detection device according to any one of Technical Ideas 1 to 6, comprising a plurality of radars arranged inside a vehicle, wherein the plurality of radars transmit and receive multiple times at mutually different timings, and the detection unit detects the presence or absence of the living body based on the received signals from the multiple transmissions and receptions of each radar.

[0110] <Technical Concept 8> The biological detection device according to any one of Technical Concepts 1 to 7, wherein the radar is an UWB radar.

Claims

1. A living body detection device comprising: at least one radar (30) mounted on a vehicle (10), which transmits pulse waves of a predetermined frequency and receives reflected waves of the pulse waves; and a detection unit (40) which detects the presence or absence of a living body inside the vehicle based on the received signal of the radar, wherein the radar transmits and receives multiple times at predetermined intervals, the reception time of the reflected wave is longer than the time corresponding to the distance between the radar and the farthest position from the radar at the end of the vehicle, and the detection unit detects the presence or absence of the living body based on the received signal from the multiple transmissions and receptions.

2. The living body detection device according to claim 1, wherein the detection section detects the presence or absence of the living body based on a time variation of the multiple received signals.

3. The living body detection device according to claim 1, wherein the detection unit detects the presence or absence of the living body based on frequency characteristics of the multiple received signals.

4. The living body detection device according to claim 2, wherein the detection unit detects the presence or absence of the living body based on the time variation, and then detects the presence or absence of the living body based on the frequency characteristics of the multiple received signals.

5. A living body detection device according to any one of claims 1 to 4, wherein the detection unit calculates the relative speed of a moving object based on any one of the received signals and determines whether or not the moving object is present outside the vehicle.

6. A living body detection device as described in any one of claims 1 to 4, wherein the radar includes an in-vehicle radar (301) arranged inside the vehicle and an external radar (302) arranged outside the vehicle, and the detection unit detects the presence or absence of the living body based on the received signal of the in-vehicle radar and the received signal of the external radar.

7. A living body detection device as described in any one of claims 1 to 4, comprising a plurality of the radars arranged inside a vehicle, the plurality of the radars transmitting and receiving a plurality of times at mutually different timings, and the detection unit detecting the presence or absence of the living body based on the received signals from the plurality of transmissions and receptions of each radar.

8. A biological detection device according to any one of claims 1 to 4, wherein the radar is an UWB radar.

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