Detection device, detection method, and vehicle

Abstract

To provide a detection device, a detection method, and a vehicle that can detect a living body inside a vehicle compartment with higher accuracy while reducing manufacturing costs and size by using as few transmitting antennas and receiving antennas as possible.SOLUTION: A detection device 1 has: a first transmitting antenna 31 and a second transmitting antenna 32 that transmit radio waves; and a first receiving antenna 41 and a second receiving antenna 42 that receive reflected waves generated by the radio waves being reflected by an object. In addition, in a planar view of a vehicle 10, a first virtual straight line L1 connecting the first transmitting antenna 31 and the second transmitting antenna 32 and a second virtual straight line L2 connecting the first receiving antenna 41 and the second receiving antenna 42 intersect, and at least one of the first virtual straight line L1 and the second virtual straight line L2 is arranged in a passenger compartment 10 so that it is inclined at an angle of less than 90 degrees with respect to a first direction X of the passenger compartment 100. The detection device 1 detects a living body H in the passenger compartment, which is a detection target, using the reflected waves.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a detection device, a detection method, and a vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses an abandoned body detection device that detects a living body (e.g., an infant) left inside the vehicle and issues an alarm. In this abandoned body detection device, a timer is activated when the portable device goes outside the communication area of ​​the vehicle, and when the set timer time is reached, an alarm is issued that a predetermined time has passed since the infant was left inside the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-149487 A Summary of the Invention [Problem to be solved by the invention]

[0004] Moreover, the abandoned vehicle detection device described in Patent Document 1 uses a radio wave sensor to detect a living body in the vehicle. The radio wave sensor detects a living body in the vehicle based on a received signal obtained by transmitting radio waves to the surroundings and receiving the reflected waves. According to the method of detecting a living body in the vehicle using a radio wave sensor, radio waves can penetrate obstacles covering the living body in the vehicle, such as a blanket, and minute movements (gestures) of the living body in the vehicle, such as slight movements of the limbs and chest movements due to breathing, and high detection accuracy can be expected.

[0005] However, on the other hand, the method of detecting a living body in the vehicle using a radio wave sensor has the following problems: When a moving object outside the vehicle, such as a walking person, grass or trees swaying in the wind, or a moving car, enters the vicinity of the outside of the vehicle that is at a distance equal to or closer than the distance from the radio wave sensor to the position where the living body may be present, the detection of the living body in the vehicle may be hindered. For example, when a passerby is present in the vicinity of the outside of the vehicle, the passerby may be erroneously detected as a living body in the vehicle.

[0006] One method for avoiding such false detections is to increase the number of transmitting antennas that transmit radio waves and receiving antennas that receive reflected waves, and to distinguish and detect living bodies inside the vehicle and moving objects outside the vehicle in terms of angle and direction.

[0007] However, increasing the number of transmitting antennas and receiving antennas indiscriminately leads to an increase in the manufacturing cost of the device. In particular, the size of the transmitting antennas and receiving antennas increases in inverse proportion to the frequency of the radio waves. Therefore, in a radio wave sensor using UWB (Ultra-Wide Band) radar that operates in a relatively low frequency range, the increase in the size of the device due to the increase in the number of transmitting antennas and receiving antennas becomes significant.

[0008] The present invention has been made in consideration of the above points, and aims to provide a detection device that can accurately detect living organisms inside the vehicle cabin while reducing manufacturing costs and size by using as few transmitting antennas and receiving antennas as possible, a detection method using the detection device, and a vehicle equipped with the detection device. [Means for solving the problem]

[0009] Such an object can be achieved by the present invention as set forth below in (1) to (3).

[0010] (1) A detection device for detecting an object present in a vehicle cabin, comprising: a first transmitting antenna and a second transmitting antenna for transmitting radio waves; a first receiving antenna and a second receiving antenna for receiving a reflected wave generated by the radio wave being reflected by an object; the antenna is disposed in the vehicle cabin such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the vehicle cabin; A detection device that detects the detection target by using the reflected wave.

[0011] (2) A detection method for detecting a detection target present in a vehicle cabin, comprising: a first transmitting antenna and a second transmitting antenna for transmitting radio waves; a detection device having a first receiving antenna and a second receiving antenna for receiving a reflected wave generated by the radio wave being reflected by an object, the antennas are disposed in the vehicle cabin such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect with each other, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the vehicle cabin; A detection method comprising: detecting the detection target by using the reflected wave.

[0012] (3) A vehicle equipped with a detection device that detects a detection target present in the vehicle cabin, the detection device includes a first transmitting antenna and a second transmitting antenna that transmit radio waves, and a first receiving antenna and a second receiving antenna that receive reflected waves generated when the radio waves are reflected by an object, the antenna is disposed in the vehicle cabin such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the vehicle cabin; A vehicle that detects the detection target by using the reflected wave. Effect of the Invention

[0013] The detection device of the present invention is arranged in the vehicle cabin such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the vehicle cabin. By arranging the four antennas in this manner, it is possible to improve the angular resolution with respect to the first direction while keeping the number of antennas small. Therefore, the detection device is low-cost and small, and can detect a detection target with high accuracy.

[0014] Furthermore, in the detection method of the present invention, a detection target is detected using reflected waves acquired by a detection device disposed in a vehicle cabin such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the vehicle cabin. This improves the angular resolution with respect to the first direction, enabling the detection target to be detected with high accuracy.

[0015] The vehicle of the present invention has a detection device that is disposed in the vehicle cabin such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the vehicle cabin, and detects a detection target using reflected waves. Therefore, the angular resolution with respect to the first direction is improved, and the detection target can be detected with high accuracy. In addition, since the detection device 1 is low-cost and small-sized, the cost of the vehicle 10 can be reduced, and the detection device 1 can be easily mounted on the vehicle 10. [Brief description of the drawings]

[0016] [Figure 1]1 is a schematic diagram of a vehicle according to a first embodiment, viewed from above. [Diagram 2] FIG. 2 is an enlarged schematic view of a rear seat of the vehicle shown in FIG. [Diagram 3] 2 is a plan view showing a detection device disposed in the vehicle shown in FIG. 1. [Figure 4] 4 is a schematic diagram showing types of signals transmitted and received by the detection device shown in FIG. 3. [Diagram 5] FIG. 1 is a schematic diagram for explaining a problem with a detection device. [Figure 6] FIG. 4 is a diagram showing an example of vehicle interior shape data. [Figure 7] FIG. 1 is a schematic diagram for explaining a problem with a detection device. [Figure 8] 4 is a plan view showing a modified example of the detection device shown in FIG. [Figure 9] 4 is a plan view showing a modified example of the detection device shown in FIG. [Figure 10] FIG. 2 is a block diagram showing a configuration of a control unit. [Figure 11] FIG. 2 is a block diagram showing a configuration of a control unit. [Figure 12] 11 is a graph showing an example of a first received signal time series. [Figure 13] FIG. 1 is a diagram showing an example of a two-dimensional spectrum indicating the direction in which a moving object exists. [Figure 14] 3A to 3C are diagrams illustrating examples of a first received signal, a second received signal, a third received signal, and a fourth received signal. [Figure 15] FIG. 4 is a plan view showing a comparative example of the detection device shown in FIG. [Figure 16] 16 is a diagram showing an example of a first received signal, a second received signal, a third received signal, and a fourth received signal acquired by the detection device shown in FIG. 15. FIG. [Figure 17] 4 is a diagram showing an example of a two-dimensional spectrum indicating the direction of a moving object analyzed by the detection device shown in FIG. 3. [Figure 18] 18 is a graph showing the spectrum at latitude θ=0 in FIG. 17. [Figure 19]16 is a diagram showing an example of a two-dimensional spectrum indicating the direction of a moving object analyzed by the detection device shown in FIG. 15. FIG. [Figure 20] 20 is a graph showing the spectrum at latitude θ=0 in FIG. 19. [Figure 21] 11 is a flowchart illustrating a detection method using the detection device. [Figure 22] FIG. 11 is a plan view showing a detection device according to a second embodiment. [Diagram 23] FIG. 1 is a schematic diagram showing an example of a vehicle. [Figure 24] FIG. 23 is a plan view showing a modified example of the detection device shown in FIG. [Diagram 25] 4 is a plan view showing a modified example of the detection device shown in FIG. [Figure 26] 4 is a plan view showing a modified example of the detection device shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A detection device, a detection method, and a vehicle according to the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

[0018] First Embodiment FIG. 1 is a schematic diagram of a vehicle according to a first embodiment seen from above. FIG. 2 is a schematic diagram showing an enlarged view of the rear seat of the vehicle shown in FIG. 1. FIG. 3 is a plan view showing a detection device disposed in the vehicle shown in FIG. 1. FIG. 4 is a schematic diagram showing the type of signal transmitted and received by the detection device shown in FIG. 3. FIG. 5 is a schematic diagram for explaining a problem of the detection device. FIG. 6 is a diagram showing an example of shape data of the vehicle interior. FIG. 7 is a schematic diagram for explaining a problem of the detection device. FIG. 8 is a plan view showing a modified example of the detection device shown in FIG. 3. FIG. 9 is a plan view showing a modified example of the detection device shown in FIG. 3. FIG. 10 is a block diagram showing the configuration of a control unit. FIG. 11 is a block diagram showing the configuration of a control unit. FIG. 12 is a graph showing an example of a first reception signal time series. FIG. 13 is a diagram showing an example of a two-dimensional spectrum showing the direction of the presence of a moving object. FIG. 14 is a diagram showing an example of the first reception signal, the second reception signal, the third reception signal, and the fourth reception signal. FIG. 15 is a plan view showing a comparative example of the detection device shown in FIG. 3. FIG. 16 is a diagram showing an example of the first received signal, the second received signal, the third received signal, and the fourth received signal acquired by the detection device shown in FIG. 15. FIG. 17 is a diagram showing an example of a two-dimensional spectrum indicating the direction of a moving object analyzed by the detection device shown in FIG. 3. FIG. 18 is a graph showing the spectrum at latitude θ=0 in FIG. 17. FIG. 19 is a diagram showing an example of a two-dimensional spectrum indicating the direction of a moving object analyzed by the detection device shown in FIG. 15. FIG. 20 is a graph showing the spectrum at latitude θ=0 in FIG. 19. FIG. 21 is a flowchart explaining a detection method using the detection device.

[0019] A vehicle 10 shown in Fig. 1 includes a detection device 1 arranged in a vehicle interior 100, and a vehicle control unit 11 that controls each part of the vehicle 10. The detection device 1 detects a living body H in the vehicle interior, which is a detection target, present in the vehicle interior 100, and notifies a user's terminal 9 of the detection device. Such a detection device 1 is preferably used to detect a living body H, particularly an infant, left in the vehicle interior 100. This can effectively reduce the risk that the infant is exposed to danger due to the harsh environment in the vehicle interior 100. However, the use of the detection device 1 is not particularly limited.

[0020] The vehicle 10 is not particularly limited, but is typically a passenger vehicle such as a light vehicle, a small vehicle, a normal vehicle, or a medium-sized or larger vehicle. However, the vehicle 10 is not limited to a passenger vehicle, and may be, for example, a train, an airplane, a ship, or the like. The terminal 9 is not particularly limited as long as it can receive a signal from the detection device 1, but is typically a smartphone. However, the terminal 9 is not limited to a smartphone, and may be, for example, a wearable terminal such as a smart watch, a tablet terminal, a notebook computer, a desktop computer, or the like.

[0021] Here, a brief description will be given of the vehicle 10 shown in Fig. 1. The vehicle 10 has a front row of seats 101 in which a driver's seat and a passenger seat are arranged side by side, and a rear row of seats 102 in which three seats are arranged side by side, located behind the front row of seats 101. The vehicle 10 also has a windshield GL1 as a window arranged at the front of the vehicle interior 100, and a rear glass GL2 as a window arranged at the rear of the vehicle interior 100. Front doors FD1 and FD2 for getting on and off are arranged on both the left and right sides of the front row of seats 101, and further, front door glasses GL3 and GL4 as windows are arranged in the front doors FD1 and FD2. Further, rear doors RD1 and RD2 for getting on and off are arranged on both the left and right sides of the rear row of seats 102, and further, rear door glasses GL5 and GL6 as windows are arranged in the rear doors RD1 and RD2.

[0022] However, the configuration of the vehicle 10 is not particularly limited. For example, the rear seat 102 may be omitted, or third and fourth row seats may be arranged behind the rear seat 102.

[0023] The detection device 1 is disposed, for example, on the ceiling of the vehicle interior 100 so as to more reliably detect the living body H in the vehicle. This makes it difficult for an obstacle to be present between the detection device 1 and the living body H in the vehicle, so that the radio waves transmitted from the detection device 1 can more easily reach the living body H in the vehicle. Therefore, the living body H in the vehicle can be more reliably detected.

[0024] However, the location of the detection device 1 is not particularly limited, and it may be located on a side wall or floor of the vehicle interior 100, for example.

[0025] In this case, it is preferable to arrange at least one detection device 1 for each seat row of the vehicle 10. This makes it possible to more reliably detect the living body H in the vehicle compartment without being affected by the seating position of the living body H in the vehicle compartment. As described above, the vehicle 10 has a two-row structure having a front row of seats 101 and a rear row of seats 102. Therefore, in this embodiment, one detection device 1 for the front row of seats 101 is arranged on the ceiling in the center of the front row of seats 101, and one detection device 1 for the rear row of seats 102 is arranged on the ceiling in the center of the rear row of seats 102.

[0026] However, the arrangement of the detection device 1 is not particularly limited. For example, one detection device 1 may be arranged on the front seat 101, and this detection device 1 may detect both the living body H in the vehicle interior seated on the front seat 101 and the living body H in the vehicle interior seated on the rear seat 102. Also, one detection device 1 may be arranged on the rear seat 102, and this detection device 1 may detect both the living body H in the vehicle interior seated on the front seat 101 and the living body H in the vehicle interior seated on the rear seat 102. Also, the detection device 1 may be arranged in the center of the vehicle interior 100 (for example, between the front seat 101 and the rear seat 102), and this detection device 1 may detect both the living body H in the vehicle interior seated on the front seat 101 and the living body H in the vehicle interior seated on the rear seat 102.

[0027] In addition, since a living body H in a vehicle compartment, particularly an infant, is mostly left behind in the rear seat 102, the following will representatively describe a case where a living body H in a vehicle compartment seated in the rear seat 102 is detected by the detection device 1 on the rear seat 102 for convenience of explanation. Also, in the following, for convenience of explanation, the direction in which the rear doors RD1, RD2 are aligned in a plan view of the vehicle 10 seen from above (hereinafter simply referred to as a "plan view of the vehicle 10"), that is, the left-right direction of the vehicle 10, will also be referred to as a "first direction X". Also, the direction in which the front glass GL1 and the rear glass GL2 are aligned, that is, the front-rear direction of the vehicle 10, will also be referred to as a "second direction Y". Therefore, in this embodiment, the first direction X and the second direction Y are perpendicular to each other.

[0028] However, the first direction X and the second direction Y are not particularly limited and can be set appropriately depending on the configuration of the vehicle 10, in particular the arrangement of the windows. For example, the front-rear direction of the vehicle 10 may be the first direction X, and the left-right direction of the vehicle 10 may be the second direction Y. In addition, the first direction X and the second direction Y do not have to be perpendicular to each other, and may intersect at an angle of less than 90 degrees.

[0029] The detection device 1 is a UWB communication device that performs UWB (Ultra-Wide Band) communication with a terminal 9 or a vehicle 10 as an external device, and can be used as a UWB radar that detects a living body H inside the vehicle. However, the radar used in the detection device 1 is not particularly limited, and may be, for example, an FMCW (Frequency Continuously Modulated Wave) radar or a CW (Continuous Wave) radar. Furthermore, the radio waves used for communication with the terminal 9 or the vehicle 10 and the radio waves used for detection of a living body H inside the vehicle may be different from each other. For example, communication may be performed by UWB communication, and detection of a moving body may be performed by an FMCW radar or a CW radar.

[0030] As shown in FIG. 2, the detection device 1 is disposed in an area Q where the rear door glasses GL5 and GL6 face each other in a plan view of the vehicle 10.

[0031] 3, the detection device 1 includes a wiring board 2, a transmitting antenna group 3 and a receiving antenna group 4 arranged on the wiring board 2, and a control unit 5 arranged on the wiring board 2 and controls the detection device 1. The transmitting antenna group 3 includes a first transmitting antenna 31 and a second transmitting antenna 32. The receiving antenna group 4 includes a first receiving antenna 41 and a second receiving antenna 42. These four antennas 31, 32, 41, and 42 are electrically connected to the control unit 5 via the wiring board 2.

[0032] In this embodiment, the detection device 1 includes the control unit 5, but the present invention is not limited to this. For example, the control unit 5 may be incorporated in a vehicle control unit 11 included in the vehicle 10.

[0033] The wiring board 2 may be a rigid board or a flexible board having flexibility, but in this embodiment, a rigid board is used. The first and second transmitting antennas 31, 32 and the first and second receiving antennas 41, 42 are arranged discretely on the wiring board 2. Among them, the first and second transmitting antennas 31, 32 transmit radio waves into the vehicle interior 100. As described above, since the detection device 1 is a UWB radar, the radio waves transmitted by the first and second transmitting antennas 31, 32 are UWB pulse signals having a short pulse width, such as microwaves. On the other hand, the first and second receiving antennas 41, 42 receive reflected waves generated when the radio waves transmitted by the first and second transmitting antennas 31, 32 are reflected by an object.

[0034] As shown in Figures 4(A) to (D), the detection device 1 obtains a first reception signal Sg1 obtained by the first receiving antenna 41 receiving a reflected wave generated when the radio waves transmitted from the first transmitting antenna 31 are reflected by surrounding objects; a second reception signal Sg2 obtained by the second receiving antenna 42 receiving a reflected wave generated when the radio waves transmitted from the first transmitting antenna 31 are reflected by surrounding objects; a third reception signal Sg3 obtained by the first receiving antenna 41 receiving a reflected wave generated when the radio waves transmitted from the second transmitting antenna 32 are reflected by surrounding objects; and a fourth reception signal Sg4 obtained by the second receiving antenna 42 receiving a reflected wave generated when the radio waves transmitted from the second transmitting antenna 32 are reflected by surrounding objects, and detects a living body H in the vehicle cabin using these first to fourth reception signals Sg1 to Sg4.

[0035] Here, the rear door glasses GL5 and GL6 transmit radio waves transmitted from the first and second transmitting antennas 31 and 32. Therefore, as shown in Fig. 5, when a moving object W is present near the rear door glass GL6 even outside the vehicle interior 100, the detection device 1 detects the presence of the moving object W through the rear door glass GL6. By using the UWB radar, the distance r from the detection device 1 to the moving object W can be easily detected.

[0036] However, as shown in FIG. 5, even if the distance r0 is the same, depending on the direction from the detection device 1, the moving object W may be a living body H inside the vehicle compartment 100, or may be a moving object A outside the vehicle compartment 100. Therefore, in order to identify whether the moving object W is a living body H inside the vehicle compartment or a moving object A outside the vehicle compartment, the distance r alone is not enough, and in addition to the distance r, it is necessary to detect the direction, i.e., the angle (longitude φ and latitude θ) of the moving object W relative to the detection device 1. In this way, if the distance r and the angle are known, the position of the moving object W can be estimated, and by comparing the estimated position with the shape data of the vehicle compartment 100 prepared in advance, it is possible to more accurately identify whether the moving object W is a living body H inside the vehicle compartment or a moving object A outside the vehicle compartment.

[0037] The moving object W is not particularly limited, and may be, for example, a living body such as a human, a bird, a dog, a cat, a roadside tree, a plant such as a weed, a moving car, a motorcycle, a bicycle, etc. The shape data of the vehicle interior 100 is not particularly limited, and for example, as shown in Fig. 6, a table T or the like that determines in advance whether each combination of polar coordinates (r, θ, φ) is inside or outside the vehicle interior 100 may be used. According to this method, a living body H inside the vehicle interior and a moving object A outside the vehicle interior can be distinguished in a simple manner.

[0038] The same is true for the second direction Y in which the front glass GL1 and the rear glass GL2 are aligned. For example, as shown in Fig. 7, when a moving object W is present near the rear glass GL2 even outside the vehicle interior 100, the detection device 1 detects the presence of the moving object W through the rear glass GL2. In order to distinguish whether the moving object W is a living organism H inside the vehicle interior or a moving object A outside the vehicle interior, the distance r alone is not enough; it is necessary to detect the direction of the moving object W relative to the detection device 1, that is, the angle (longitude φ and latitude θ) in addition to the distance r.

[0039] In view of the above, in the detection device 1, by carefully considering the number and arrangement of the first and second transmitting antennas 31, 32 and the first and second receiving antennas 41, 42, an increase in the number of antennas is suppressed to reduce the cost and size of the device, while improving the angular resolution in the first direction X in which the rear door glasses GL5, GL6 are aligned and the angular resolution in the second direction Y in which the front glass GL1 and the rear glass GL2 are aligned, thereby improving the accuracy of identifying whether the moving object W is a living organism H inside the vehicle compartment or a moving object A outside the vehicle compartment. This results in a detection device 1 that is low-cost, small-sized, and capable of accurately detecting a living organism H inside the vehicle compartment.

[0040] The arrangement of the first and second transmitting antennas 31, 32 and the first and second receiving antennas 41, 42 will be described in detail below with reference to Fig. 3. In a plan view of the vehicle 10, the first and second transmitting antennas 31, 32 and the first and second receiving antennas 41, 42 are arranged symmetrically with respect to the central axis of the vehicle 10. Note that in Fig. 3, the first transmitting antenna 31 and the second transmitting antenna 32 are illustrated as being circular for the sake of convenience of explanation, but these shapes are not particularly limited. The same applies to the first receiving antenna 41 and the second receiving antenna 42.

[0041] The first transmitting antenna 31 and the second transmitting antenna 32 are arranged offset from each other in the first direction X, with the second transmitting antenna 32 arranged outside (toward the rear door glass GL6) the first transmitting antenna 31. The first transmitting antenna 31 and the second transmitting antenna 32 are arranged offset from each other in the second direction Y, with the second transmitting antenna 32 arranged behind (toward the rear glass GL2) the first transmitting antenna 31.

[0042] Similarly, the first receiving antenna 41 and the second receiving antenna 42 are arranged offset from each other in the first direction X, with the second receiving antenna 42 arranged on the outer side (the rear door glass GL5 side) of the first receiving antenna 41. Moreover, the first receiving antenna 41 and the second receiving antenna 42 are arranged offset from each other in the second direction Y, with the second receiving antenna 42 arranged on the rear side (the rear window GL2 side) of the first receiving antenna 41.

[0043] The first transmitting antenna 31 and the first receiving antenna 41 are arranged side by side in the first direction X, and the second transmitting antenna 32 and the second receiving antenna 42 are also arranged side by side in the first direction X.

[0044] Therefore, when the straight line connecting the first transmitting antenna 31 and the second transmitting antenna 32 is defined as the first virtual straight line L1, and the straight line connecting the first receiving antenna 41 and the second receiving antenna 42 is defined as the second virtual straight line L2, in a planar view, the first virtual straight line L1 and the second virtual straight line L2 extend in different directions and intersect at an intersection O.

[0045] The first virtual straight line L1 may be any straight line that connects an arbitrary point on the first transmitting antenna 31 and an arbitrary point on the second transmitting antenna 32 in a plan view. The arbitrary points can be freely set for each of the first transmitting antenna 31 and the second transmitting antenna 32, but it is preferable to set them in correspondence with each other. In other words, it is preferable to set the first virtual straight line L1 as a straight line that connects the same points of the first transmitting antenna 31 and the second transmitting antenna 32. In this embodiment, the first transmitting antenna 31 and the second transmitting antenna 32 have the same configuration, and the straight line that connects their centers (origins) is set as the first virtual straight line L1.

[0046] The same applies to the second virtual straight line L2, and the second virtual straight line L2 may be a straight line connecting an arbitrary point on the first receiving antenna 41 and an arbitrary point on the second receiving antenna 42 in a plan view. The arbitrary points can be freely set for each of the first receiving antenna 41 and the second receiving antenna 42, but it is preferable to set them in correspondence with each other. In other words, it is preferable to set the second virtual straight line L2 as a straight line connecting the same points of the first receiving antenna 41 and the second receiving antenna 42. In this embodiment, the first receiving antenna 41 and the second receiving antenna 42 have the same configuration, and the straight line connecting their centers (origins) is set as the second virtual straight line L2.

[0047] In plan view, the first virtual straight line L1 is inclined at an angle θx1 less than 90 degrees with respect to the first direction X. Furthermore, the first virtual straight line L1 is inclined at an angle θy1 less than 90 degrees with respect to the second direction Y. In other words, the first virtual straight line L1 is inclined with respect to both the first direction X and the second direction Y.

[0048] Similarly, in a plan view, the second virtual straight line L2 is inclined at an angle θx2 less than 90 degrees with respect to the first direction X. Furthermore, the second virtual straight line L2 is inclined at an angle θy2 less than 90 degrees with respect to the second direction Y. In other words, the second virtual straight line L2 is inclined with respect to both the first direction X and the second direction Y.

[0049] As described above, by arranging the four antennas 31, 32, 41, 42 so that the first virtual straight line L1 and the second virtual straight line L2 intersect and are inclined at an angle of less than 90 degrees with respect to the first direction X and the second direction Y, respectively, it is possible to improve the angular resolution with respect to the first direction X and the second direction Y without excessively increasing the number of antennas. Therefore, the detection device 1 can accurately detect a living body H in the vehicle compartment without being affected by a moving object A outside the vehicle compartment detected through the windshield GL1, the rear glass GL2, and the rear door glasses GL5 and GL6. Furthermore, by limiting the number of antennas to four, it is possible to reduce the cost and size of the detection device 1.

[0050] Here, the crossing angle θL between the first virtual straight line L1 and the second virtual straight line L2 is not particularly limited, but is preferably closer to 90 degrees (right angle). Specifically, the crossing angle θL is preferably 45 degrees to 135 degrees, more preferably 60 degrees to 120 degrees, and even more preferably 85 degrees to 95 degrees. The crossing angle θL in this embodiment is 90 degrees. The angles θx1, θy1 and the angles θx2, θy2 are not particularly limited, but are preferably closer to 45 degrees. Specifically, the angles θx1, θx2, θy1, θy2 are preferably 30 degrees to 60 degrees, more preferably 35 degrees to 55 degrees, and even more preferably 40 degrees to 50 degrees. The angles θx1, θx2, θy1, θy2 in this embodiment are all 45 degrees. By adopting such an arrangement, the angular resolution in the first direction X and the angular resolution in the second direction Y can be improved in a well-balanced manner.

[0051] The distance between the first transmitting antenna 31 and the second transmitting antenna 32 and the distance between the first receiving antenna 41 and the second receiving antenna 42 are preferably arranged to be within 16 mm to 25 mm, in accordance with the wavelength in free space of radio waves in the UWB frequency band (approximately 6.0 GHz to 8.5 GHz), but if the radiation beam width of each antenna is narrow, that is, if the angle range detectable by the UWB radar is narrow, a higher angular resolution can be obtained by increasing the distance between each antenna. For example, if the radiation beam width of the antennas 31, 32, 41, and 42 is narrow, such as -45 degrees to 45 degrees, the angular resolution can be roughly doubled by increasing the distance between each antenna to 50 mm.

[0052] Although the arrangement of the four antennas 31, 32, 41, and 42 has been described in detail above, the arrangement is not particularly limited as long as the first virtual straight line L1 and the second virtual straight line L2 intersect and at least one of the first virtual straight line L1 and the second virtual straight line L2 is inclined at an angle of less than 90 degrees with respect to the first direction X. For example, as shown in Fig. 8, the arrangement of the antennas 31, 32, 41, and 42 may be reversed left to right with respect to this embodiment. Also, as shown in Fig. 9, the arrangement of the antennas 31, 32, 41, and 42 may be reversed front to back with respect to this embodiment.

[0053] As shown in FIG. 10, the control unit 5 has a transmitting section 51, a receiving section 52, a received signal holding section 53, a received signal analyzing section 54, an abandoned vehicle determining section 55, and an alarm issuing section 56.

[0054] The control unit 5 is configured, for example, by a computer, and has one or more processors 501 for processing information, and a memory 502 communicatively connected to the processor 501, as shown in FIG.

[0055] Moreover, the processor 501 is an arithmetic unit that performs arithmetic processing, such as signal manipulation, based on computer-readable instructions, such as one or more microprocessors, microcomputers, microcontrollers, digital signal processors (DSPs), central processing units (CPUs), memory control units (MCUs), graphics processing units (GPUs), state machines, logic circuits, application specific integrated circuits (ASICs), or combinations thereof. In particular, the processor 501 is configured to fetch computer-readable instructions (e.g., data, programs, etc.) stored in the memory 502 and perform arithmetic operations, signal manipulation, and control.

[0056] The memory 502 may also be a computer-readable medium including, for example, a volatile storage medium (e.g., RAM, SRAM, DRAM), a non-volatile storage medium (e.g., ROM, EPROM, EEPROM, flash memory, a hard disk, a solid-state drive, an optical disk, a CD-ROM, a digital versatile disk (DVD), a Blu-ray disk, a magnetic cassette, a magnetic tape, a magnetic disk), or a combination thereof.

[0057] Such memory 502 is communicably connected to the processor 501, and stores programs and data executable by the processor 501. The processor 501 reads and executes the programs stored in the memory 502. In this way, the control unit 5 functions as a transmitter 51, a receiver 52, a received signal storage unit 53, a received signal analyzer 54, an abandoned object determination unit 55, and an alarm issuing unit 56.

[0058] 10, the transmitting unit 51 generates a pulse signal. The pulse signal generated by the transmitting unit 51 is multiplied by a local oscillation signal transmitted from the local oscillator 50 in the multiplier 57a, and is modulated (up-converted) to a predetermined frequency band, for example, a short wavelength of about 6.0 GHz to 8.5 GHz. The pulse signal up-converted by the multiplier 57a is transmitted as a pulsed radio wave (pulse wave) from the first transmitting antenna 31 or the second transmitting antenna 32 via the RF switch 58a.

[0059] The RF switch 58a periodically switches between a state in which the multiplier 57a is connected to the first transmitting antenna 31 and radio waves are transmitted from the first transmitting antenna 31 and a state in which the multiplier 57a is connected to the second transmitting antenna 32 and radio waves are transmitted from the second transmitting antenna 32. The switching period of the RF switch 58a is not particularly limited, but may be, for example, about 100 Hz.

[0060] The radio waves transmitted from the first transmitting antenna 31 or the second transmitting antenna 32 reach and are reflected by an object present within the detection area of ​​the detection device 1. The reflected waves are then received by the first receiving antenna 41 or the second receiving antenna 42. The first receiving antenna 41 and the second receiving antenna 42 are connected to the RF switch 58b.

[0061] The RF switch 58b periodically switches between a state in which the reflected wave is received by the first receiving antenna 41 and a state in which the reflected wave is received by the second receiving antenna 42. The switching period of the RF switch 58b is equal to the switching period of the RF switch 58a and is shifted in phase from the switching period of the RF switch 58a by 180 degrees.

[0062] Therefore, the state switches at a cycle of 50 Hz among a first receiving state in which the first receiving antenna 41 receives a reflected wave of the radio wave transmitted from the first transmitting antenna 31, a second receiving state in which the second receiving antenna 42 receives a reflected wave of the radio wave transmitted from the first transmitting antenna 31, a third receiving state in which the first receiving antenna 41 receives a reflected wave of the radio wave transmitted from the second transmitting antenna 32, and a fourth receiving state in which the second receiving antenna 42 receives a reflected wave of the radio wave transmitted from the second transmitting antenna 32. In other words, one cycle consisting of the first receiving state, the second receiving state, the third receiving state, and the fourth receiving state is repeated at a cycle of 200 Hz.

[0063] The reflected wave received by the first receiving antenna 41 or the second receiving antenna 42 is branched and introduced into the multiplier 57b and the quadrature multiplier 57c. In the multiplier 57b, the reflected wave received by the first and second receiving antennas 41 and 42 is demodulated (down-converted) in a form in which it is in phase with the pulse signal transmitted from the transmitter 51. Then, in the receiver 52, an in-phase component signal SgA indicating a time response characteristic based on the pulse signal transmitted from the transmitter 51 is derived. On the other hand, in the quadrature multiplier 57c, the reflected wave received by the first and second receiving antennas 41 and 42 is demodulated (down-converted) in a form in which it is in quadrature phase with the pulse signal transmitted from the transmitter 51, that is, in a form shifted by 1 / 4 cycle. Then, in the receiver 52, an orthogonal phase component signal SgB indicating a time response characteristic based on a signal orthogonal to the pulse signal transmitted from the transmitter 51 is derived. Phase information is contained in the correlation between the in-phase component signal SgA and the quadrature-phase component signal SgB obtained in this manner. As a result of the above, a received signal Sg containing the in-phase component signal SgA and the quadrature-phase component signal SgB is obtained.

[0064] The received signal holding unit 53 is synchronized with the timing at which the transmitter 51 generates a pulse signal and the switching timing of the RF switches 58a, 58b. Based on these timings, the received signal holding unit 53 divides the received signal Sg derived by the receiver 52 into a first received signal Sg1 obtained in the first receiving state, a second received signal Sg2 obtained in the second receiving state, a third received signal Sg3 obtained in the third receiving state, and a fourth received signal Sg4 obtained in the fourth receiving state, and holds these signals.

[0065] 12, the received signal holding unit 53 generates and holds a first received signal time series Sg1t in which the first received signals Sg1 obtained repeatedly at a cycle of 200 Hz are arranged in chronological order. Similarly, the received signal holding unit 53 generates and holds a second received signal time series Sg2t in which the second received signals Sg2 are arranged in chronological order, a third received signal time series Sg3t in which the third received signals Sg3 are arranged in chronological order, and a fourth received signal time series Sg4t in which the fourth received signals Sg4 are arranged in chronological order.

[0066] 12 is an image diagram for ease of explanation, with the horizontal axis being the distance r from the detection device 1, the vertical axis being the amplitude (strength) of the reflected wave received by the first receiving antenna 41, and the depth axis being time. From this first reception signal time series Sg1t, it can be seen that there is some moving object, that is, a living body H in the vehicle compartment or a moving object A outside the vehicle compartment, at the distance r (distance shown by hatching) where the amplitude of the reflected wave changes over time. Although not shown, the same is true for the other second, third, and fourth reception signal time series Sg2t, Sg3t, and Sg4t. In other words, the distance r from the detection device 1 to the moving object can be detected from the first, second, third, and fourth reception signal time series Sg1t, Sg2t, Sg3t, and Sg4t.

[0067] Although the first, second, third and fourth received signal time series Sg1t, Sg2t, Sg3t and Sg4t alone can detect the distance r from the detection device 1 to the moving object, the direction in which the moving object exists, that is, the angle (longitude φ and latitude θ), cannot be detected. Therefore, the received signal analysis unit 54 analyzes the first, second, third and fourth received signal time series Sg1t, Sg2t, Sg3t and Sg4t to estimate the direction in which the detected moving object exists.

[0068] The estimation method is not particularly limited, and may be any known analysis method such as the MUSIC (Multiple Signal Classification) method, the ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) method, the beamformer method, the Capon method, the linear prediction method, etc. In this embodiment, the MUSIC method is used to analyze the correlation between the four received signal time series Sg1t, Sg2t, Sg3t, and Sg4t to perform the above estimation. In this way, by using the MUSIC method, the above estimation can be performed with higher accuracy.

[0069] The received signal analysis unit 54 obtains a two-dimensional spectrum showing the direction of the moving object as shown in FIG. 13 by analysis using the MUSIC method. In this two-dimensional spectrum, the vertical axis is latitude θ (see FIG. 7) showing the position in the second direction Y, and the horizontal axis is longitude φ (see FIG. 5) showing the position in the first direction X, and the detection device 1 is located at the origin where longitude φ and latitude θ are both 0. The received signal analysis unit 54 can estimate that the moving object is located at the position of the spectrum peak in the two-dimensional spectrum, that is, in the whitest part in the figure. This makes it possible to easily and accurately detect the direction of the moving object, that is, the angle (longitude φ and latitude θ) of the moving object relative to the detection device 1. The received signal analysis unit 54 also detects the distance r from the detection device 1 to the moving object using at least one of the first, second, third, and fourth received signal time series Sg1t, Sg2t, Sg3t, and Sg4t. The received signal analysis unit 54 can estimate the position of the moving object based on the distance r, longitude φ, and latitude θ obtained as described above.

[0070] The abandoned object determination unit 55 compares the position of the moving object estimated by the received signal analysis unit 54 with shape data of the vehicle interior 100 previously stored in the memory 502 to determine whether the moving object is a living body H inside the vehicle interior 100 or an outside moving object A outside the vehicle interior 100. The shape data of the vehicle interior 100 is not particularly limited, but for example, a table T as shown in Fig. 6 can be used which determines whether each combination of (r, θ, φ) is inside or outside the vehicle interior 100.

[0071] Here, FIG. 14 shows the first reception signal Sg1, the second reception signal Sg2, the third reception signal Sg3, and the fourth reception signal Sg4 when a living body H in the vehicle compartment and a moving object A outside the vehicle compartment are present at the same distance r (=r0) from the detection device 1 as shown in FIG. 5. As shown in FIG. 14, in the detection device 1, the first reception signal Sg1 and the fourth reception signal Sg4 are similar, but the other three signals, that is, the first and fourth reception signals Sg1 and Sg4 and the second and third reception signals Sg2 and Sg3, are sufficiently different from each other. Therefore, in the detection device 1, three types of reception signals are substantially obtained as waveform information used for analysis in the reception signal analysis unit 54.

[0072] Here, as a comparative example, when using a detection device 1A in which four antennas 31, 32, 41, and 42 are arranged as shown in FIG. 15, the first reception signal Sg1, the second reception signal Sg2, the third reception signal Sg3, and the fourth reception signal Sg4 obtained in the same environment as FIG. 7 are shown in FIG. 16. As shown in FIG. 16, in the detection device 1A, the first reception signal Sg1 and the second reception signal Sg2 are similar, the third reception signal Sg3 and the fourth reception signal Sg4 are similar, and only the first and second reception signals Sg1, Sg2 and the third and fourth reception signals Sg3, Sg4 are sufficiently different from each other. Therefore, in the detection device 1A, only two types of reception signals are obtained substantially as waveform information used for analysis in the reception signal analysis unit 54.

[0073] In this way, according to the detection device 1, three types of received signals, one more than the detection device 1A which is a comparative example, can be used to perform analysis in the received signal analysis unit 54. Since the more types of received signals used in the analysis, the higher the accuracy of the analysis, according to the detection device 1, the angle of the detected moving object can be estimated with higher accuracy than the detection device 1A.

[0074] Here, Fig. 17 shows a two-dimensional spectrum indicating the direction of the moving object obtained by analysis using the detection device 1, and Fig. 18 shows a graph showing the spectrum at latitude θ=0 in Fig. 17. Similarly, Fig. 19 shows a two-dimensional spectrum indicating the direction of the moving object obtained by analysis using the detection device 1A, and Fig. 20 shows a graph showing the spectrum at latitude θ=0 in Fig. 19. As is clear from both figures, in the detection device 1, the peaks are separated into a living body H inside the vehicle and a moving object A outside the vehicle, whereas in the detection device 1A, the peaks are not separated into a living body H inside the vehicle and a moving object A outside the vehicle. From this, it can be seen that the accuracy of the analysis is significantly improved by increasing the number of received signals used for analysis from two to three.

[0075] In the example shown in FIG. 17 and FIG. 18, the received signal analysis unit 54 detects the presence of a moving object at a first position of (r, θ, φ)=(100 cm, 0 deg, -60 deg) and a second position of (r, θ, φ)=(100 cm, 0 deg, +45 deg). Then, the abandoned object determination unit 55 determines whether the first position and the second position are located inside the vehicle interior 100 or outside the vehicle interior 100 based on the table T. In this embodiment, the first position is located inside the vehicle interior 100, and the second position is located outside the vehicle interior 100. Therefore, the received signal analysis unit 54 determines the moving object present at the first position as a moving object A outside the vehicle interior, and determines the moving object present at the second position as a living body H inside the vehicle interior. According to such a determination method, it is possible to easily and accurately identify whether the detected moving object is a living body H inside the vehicle interior or a moving object A outside the vehicle interior.

[0076] When the abandoned-inside living body H is detected by the abandoned-inside determination unit 55, the alarm issuing unit 56 wirelessly communicates with the terminal 9 to notify the terminal 9 that the living body H has been detected, that is, that the living body H has been abandoned in the vehicle interior 100, and issues a warning to the user. This makes it possible to warn the user of the presence of the living body H in the vehicle interior in a simple and reliable manner.

[0077] Communication with the terminal 9 is performed using the transmitting antenna group 3 and the receiving antenna group 4. That is, radio waves are transmitted to the terminal 9 from at least one of the first transmitting antenna 31 and the second transmitting antenna 32, and radio waves from the terminal 9 are received from at least one of the first receiving antenna 41 and the second receiving antenna 42. By sharing the transmitting antenna group 3 and the receiving antenna group 4 for both detection of a living body H in the vehicle compartment and communication with the terminal 9 in this way, the configuration of the detection device 1 is simplified and the detection device 1 can be made more compact.

[0078] As described above, in this embodiment, the alarm issuing unit 56 transmits to the user's terminal 9 the presence of the living organism H in the vehicle compartment, but the method of issuing the alarm is not limited to this. For example, an alarm may be output to inform people around the vehicle 10 that the living organism H is present in the vehicle compartment 100. In this case, the alarm issuing unit 56 can output the alarm by communicating with the vehicle control unit 11 of the vehicle 10, by flashing the lights of the vehicle 10 or sounding a warning sound such as a horn.

[0079] The detection method of the living body H in the vehicle interior by the detection device 1 has been described above. The detection device 1 starts detecting the living body H in the vehicle interior by using a specific operation on the vehicle 10 side as a trigger. The specific operation is not particularly limited, but may be, for example, the timing when the vehicle 10 is locked, the timing when the front doors FD1, FD2 or the rear doors RD1, RD2 are opened or closed, the timing when the engine is stopped, the timing when the gear is switched from drive or the like to parking, the timing when the handbrake is applied, the timing when the vehicle 10 is stopped, and the like. In this way, the detection device 1 starts detection by using an operation caused by the user getting off the vehicle, that is, an operation that may cause the living body H in the vehicle interior to be left behind as a trigger, so that the living body H left behind in the vehicle interior can be detected more reliably. In addition, unnecessary driving of the detection device 1 can be suppressed, and power saving can be achieved.

[0080] The timing for ending the detection of the living organism H in the vehicle compartment is not particularly limited, but may be, for example, ended after a predetermined time has elapsed since the start of the detection. The predetermined time is also not particularly limited, and may be, for example, about 5 seconds, 10 seconds, or 20 seconds. By setting the time to this extent, a sufficient time for detecting the living organism H in the vehicle compartment is ensured, and it is possible to prevent the detection period from becoming excessively long. Therefore, it is possible to effectively reduce the power consumption of the detection device 1.

[0081] Furthermore, the detection of the living organism H in the vehicle compartment may be terminated using a specific operation on the vehicle 10 side as a trigger. The specific operation is not particularly limited, but may be, for example, the timing when the vehicle 10 is unlocked, the timing when the front doors FD1, FD2 or the rear doors RD1, RD2 are opened or closed, the timing when the engine is started, the timing when the gear is switched from parking to drive or the like, the timing when the handbrake is released, the timing when the vehicle 10 starts to move, etc. In this way, by terminating the detection by the detection device 1 using an operation caused by the user getting in, that is, an operation that may resolve the situation where the living organism H is left behind in the vehicle compartment as a trigger, it is possible to suppress unnecessary detection by the detection device 1 and effectively reduce the power consumption of the detection device 1.

[0082] The configuration of the detection device 1 has been described above. Next, a method for detecting a living organism H in the vehicle compartment by the detection device 1 will be described. As shown in Fig. 21, the method for detecting a living organism H in the vehicle compartment by the detection device 1 includes a received signal acquisition step S1 for obtaining a first received signal Sg1, a second received signal Sg2, a third received signal Sg3, and a fourth received signal Sg4, and a detection step S2 for detecting a living organism H in the vehicle compartment using the first received signal Sg1, the second received signal Sg2, the third received signal Sg3, and the fourth received signal Sg4. Below, these steps S1 and S2 will be described in order.

[0083] <Received signal acquisition step S1> As shown in FIG. 21, the received signal acquisition step S1 includes a detection start determination step S11 for determining whether or not to start detection of a living body H in the vehicle cabin, a radio wave transmission and reception step S12 for transmitting and receiving radio waves while changing the combination of the first and second transmitting antennas 31, 32 and the first and second receiving antennas 41, 42, and a received signal generation step S13 for processing the received reflected waves to generate a first received signal Sg1, a second received signal Sg2, a third received signal Sg3 and a fourth received signal Sg4.

[0084] In the detection start determination step S11, the control unit 5 determines whether a specific motion has occurred in the vehicle 10 by communicating with the vehicle control unit 11. If a specific motion has occurred in the vehicle 10, the control unit 5 proceeds to a radio wave transmission / reception step S12.

[0085] In the radio wave transmission / reception step S12, the control unit 5 transmits and receives radio waves while changing the combination of the first and second transmitting antennas 31, 32 and the first and second receiving antennas 41, 42. That is, the control unit 5 transmits and receives radio waves while periodically switching among a first receiving state in which the first transmitting antenna 31 transmits radio waves and the first receiving antenna 41 receives the reflected waves, a second receiving state in which the first transmitting antenna 31 transmits radio waves and the second receiving antenna 42 receives the reflected waves, a third receiving state in which the second transmitting antenna 32 transmits radio waves and the first receiving antenna 41 receives the reflected waves, and a fourth receiving state in which the second transmitting antenna 32 transmits radio waves and the second receiving antenna 42 receives the reflected waves.

[0086] In the received signal generating step S13, first, the control unit 5 branches the received reflected wave and introduces it to the multiplier 57b and the quadrature multiplier 57c. Then, the receiver 52 derives an in-phase component signal SgA indicating a time response characteristic based on the pulse signal transmitted from the transmitter 51, and a quadrature component signal SgB indicating a time response characteristic based on a signal orthogonal to the pulse signal transmitted from the transmitter 51. This results in a received signal Sg including the in-phase component signal SgA and the quadrature component signal SgB.

[0087] Next, the control unit 5 divides and holds the reception signal Sg derived by the reception section 52 into a first reception signal Sg1 obtained in the first reception state, a second reception signal Sg2 obtained in the second reception state, a third reception signal Sg3 obtained in the third reception state, and a fourth reception signal Sg4 obtained in the fourth reception state, based on the timing at which the transmission section 51 generates a pulse signal and the switching timing of the RF switches 58a, 58b in the reception signal holding section 53. In this way, the first reception signal Sg1, the second reception signal Sg2, the third reception signal Sg3, and the fourth reception signal Sg4 are generated.

[0088] <Detection step S2> In the detection step S2, first, in step S21, the control unit 5 generates and holds in the received signal holding section 53 a first received signal time series Sg1t in which the first received signal Sg1 obtained repeatedly at a predetermined period is arranged in chronological order, a second received signal time series Sg2t in which the second received signal Sg2 obtained repeatedly at a predetermined period is arranged in chronological order, a third received signal time series Sg3t in which the third received signal Sg3 obtained repeatedly at a predetermined period is arranged in chronological order, and a fourth received signal time series Sg4t in which the fourth received signal Sg4 obtained repeatedly at a predetermined period is arranged in chronological order.

[0089] Next, in step S22, the control unit 5 calculates the power value of the amplitude fluctuation component of the reflected wave based on the first, second, third, and fourth received signal time series Sg1t, Sg2t, Sg3t, and Sg4t, and determines whether the calculated power value is equal to or greater than a predetermined threshold. If the calculated power value is equal to or greater than the threshold, it is determined that a moving object is present within the detection area, and position detection of the moving object is started. According to this method, for example, slight fluctuations in the power value due to signal noise or the like can be substantially ignored, and unnecessary detection by the detection device 1 can be suppressed.

[0090] In detecting the position of a moving object, first, in step S23, the control unit 5 detects the distance r from the detection device 1 to the moving object using any one of the first, second, third, and fourth received signal time series Sg1t, Sg2t, Sg3t, and Sg4t in the received signal analysis section 54. Furthermore, in step S24, the control unit 5 analyzes the first, second, third, and fourth received signal time series Sg1t, Sg2t, Sg3t, and Sg4t by the MUSIC method in the received signal analysis section 54 to detect the direction, that is, the angle (longitude φ and latitude θ) in which the moving object exists. Then, in step S25, the control unit 5 detects the position of the moving object based on the distance r, longitude φ, and latitude θ in the received signal analysis section 54. The order of steps S23 and S24 is not particularly limited.

[0091] Next, in step S26, the control unit 5, in the abandonment determination section 55, compares the position of the moving object detected by the received signal analysis section 54 with the table T to determine whether the detected moving object is a living organism H located inside the vehicle compartment 100 or an outside moving object A located outside the vehicle compartment 100. If it is determined that the moving object is a living organism H inside the vehicle compartment, the control unit 5, in step S27, performs wireless communication with the terminal 9 in the alarm issuing section 56, notifies the terminal 9 of the presence of a living organism H inside the vehicle compartment, and issues a warning to the user.

[0092] The detection method has been described above. According to this detection method, the four antennas 31, 32, 41, and 42 are arranged so that the first virtual straight line L1 and the second virtual straight line L2 intersect and are inclined at an angle of less than 90 degrees with respect to the first direction X of the vehicle interior 100, so that the angular resolution with respect to the first direction X and the angular resolution with respect to the second direction Y can be improved without excessively increasing the number of antennas. Therefore, the living body H in the vehicle interior can be accurately detected without being affected by the moving object A outside the vehicle interior detected through the windshield GL1, the rear glass GL2, and the rear door glasses GL5 and GL6.

[0093] The detection device 1, the detection method, and the vehicle 10 have been described above. As described above, the detection device 1 is a detection device 1 that detects a living body H in the vehicle interior, which is a detection target present in the vehicle interior 100 of the vehicle 10, and has a first transmitting antenna 31 and a second transmitting antenna 32 that transmit radio waves, and a first receiving antenna 41 and a second receiving antenna 42 that receive reflected waves generated by the radio waves being reflected by an object. The detection device 1 is also arranged in the vehicle interior 100 so that, in a plan view of the vehicle 10, a first virtual straight line L1 connecting the first transmitting antenna 31 and the second transmitting antenna 32 and a second virtual straight line L2 connecting the first receiving antenna 41 and the second receiving antenna 42 intersect, and at least one of the first virtual straight line L1 and the second virtual straight line L2 is inclined at an angle of less than 90 degrees with respect to the first direction X of the vehicle interior 100. The detection device 1 detects the living body H in the vehicle interior using the reflected wave. With this configuration, the angular resolution with respect to the first direction X can be improved to increase the detection accuracy of the living body H in the vehicle interior. Furthermore, the number of antennas can be prevented from increasing, thereby reducing the cost and size of the device. Therefore, the detection device 1 can be made small and low-cost, and capable of detecting a living organism H in the vehicle compartment with high accuracy.

[0094] As described above, the living body H in the vehicle is detected using the first reception signal Sg1 obtained by the first reception antenna 41 receiving the reflected wave of the radio wave transmitted from the first transmission antenna 31, the second reception signal Sg2 obtained by the second reception antenna 42 receiving the reflected wave of the radio wave transmitted from the first transmission antenna 31, the third reception signal Sg3 obtained by the first reception antenna 41 receiving the reflected wave of the radio wave transmitted from the second transmission antenna 32, and the fourth reception signal Sg4 obtained by the second reception antenna 42 receiving the reflected wave of the radio wave transmitted from the second transmission antenna 32. In the detection device 1, due to the arrangement of the four antennas 31, 32, 41, and 42, differences in waveforms are likely to occur between the first reception signal Sg1, the second reception signal Sg2, the third reception signal Sg3, and the fourth reception signal Sg4. Therefore, according to this configuration, the angular resolution in the first direction X is improved, and the living body H in the vehicle can be detected with high accuracy.

[0095] As described above, the vehicle 10 has rear door glasses GL5 and GL6 as windows located on at least one side of the first direction X, or on both sides in this embodiment. In such a configuration, the detection device 1 may detect not only a living organism H inside the vehicle cabin, but also an external moving object A outside the vehicle cabin 100 through the rear door glasses GL5 and GL6. However, even in such a case, the angular resolution in the first direction X is high, so that the living organism H inside the vehicle cabin and the moving object A outside the vehicle cabin can be accurately distinguished from each other. Therefore, the living organism H inside the vehicle cabin can be accurately detected.

[0096] As described above, the first direction X is the lateral direction of the vehicle 10. Since the rear door glasses GL5 and GL6 are arranged along the lateral direction of the vehicle 10, by setting the direction of the rear door glasses GL5 and GL6 as the first direction X, it is possible to accurately distinguish between a living body H in the vehicle compartment and a moving object A outside the vehicle compartment detected through the rear door glasses GL5 and GL6. Therefore, it is possible to accurately detect the living body H in the vehicle compartment.

[0097] As described above, the detection device 1 is disposed such that, in a plan view of the vehicle 10, the first virtual straight line L1 and the second virtual straight line L2 are inclined at angles less than 90 degrees with respect to both the first direction X and the second direction Y intersecting with the first direction X. With this configuration, in addition to the angular resolution with respect to the first direction X, the angular resolution with respect to the second direction Y can be improved.

[0098] As described above, the vehicle 10 has a windshield GL1 and a rear window GL2 as windows located on at least one side of the second direction Y, or on both sides in this embodiment. In such a configuration, the detection device 1 may detect not only a living organism H inside the vehicle cabin, but also an external moving object A outside the vehicle cabin 100 through the windshield GL1 and the rear window GL2. However, even in such a case, since the angular resolution in the second direction Y is high, the living organism H inside the vehicle cabin and the moving object A outside the vehicle cabin can be accurately distinguished. Therefore, the living organism H inside the vehicle cabin can be accurately detected.

[0099] As described above, the second direction Y is the front-rear direction of the vehicle 10. Since the windshield GL1 and the rear window GL2 are arranged along the front-rear direction of the vehicle 10, by setting the direction as the second direction Y, it is possible to accurately distinguish between a living body H in the vehicle compartment and a moving object A outside the vehicle compartment detected through the windshield GL1 or the rear window GL2. Therefore, it is possible to accurately detect the living body H in the vehicle compartment.

[0100] As described above, the distance r to a moving object located inside or outside the vehicle compartment 100 and the angle (longitude φ and latitude θ) which is the direction in which the moving object is located are detected based on the first reception signal Sg1, the second reception signal Sg2, the third reception signal Sg3, and the fourth reception signal Sg4, and it is determined whether the moving object is a living organism H inside the vehicle compartment based on the distance r and the angle and the shape of the vehicle compartment 100. According to this method, it is possible to distinguish between a living organism H inside the vehicle compartment and a moving object A outside the vehicle compartment in a simple manner.

[0101] As described above, the detection device 1 communicates with external devices such as the terminal 9 and the vehicle 10 using at least one of the first transmitting antenna 31 and the second transmitting antenna 32 and at least one of the first receiving antenna 41 and the second receiving antenna 42. With this configuration, the first transmitting antenna 31, the second transmitting antenna 32, the first receiving antenna 41, and the second receiving antenna 42 can be used both for detecting the living body H in the vehicle compartment and for communicating with the terminal 9 and the vehicle 10. This simplifies the configuration of the detection device 1, and the detection device 1 can be made smaller in size.

[0102] As described above, the detection method is a method for detecting a living body H in a vehicle interior, which is a detection target present in the vehicle interior 100 of the vehicle 10, and the detection device 1 having the first transmitting antenna 31 and the second transmitting antenna 32 for transmitting radio waves and the first receiving antenna 41 and the second receiving antenna 42 for receiving reflected waves generated by the radio waves being reflected by an object is arranged in the vehicle interior 100 so that, in a plan view of the vehicle 10, a first virtual straight line L1 connecting the first transmitting antenna 31 and the second transmitting antenna 32 and a second virtual straight line L2 connecting the first receiving antenna 41 and the second receiving antenna 42 intersect, and at least one of the first virtual straight line L1 and the second virtual straight line L2 is inclined at an angle of less than 90 degrees with respect to the first direction X of the vehicle interior 100, and the living body H in the vehicle interior is detected using the reflected waves. According to this method, the angular resolution with respect to the first direction X can be improved to improve the detection accuracy of the living body H in the vehicle interior. In addition, since a small and low-cost detection device 1 with a reduced number of antennas can be used, this detection method is easy to introduce.

[0103] As described above, the vehicle 10 is equipped with the detection device 1 that detects a living body H in the vehicle interior, which is a detection target present in the vehicle interior 100. The detection device 1 has a first transmitting antenna 31 and a second transmitting antenna 32 that transmit radio waves, and a first receiving antenna 41 and a second receiving antenna 42 that receive reflected waves generated by the radio waves being reflected by an object, and is disposed in the vehicle interior 100 such that, in a plan view of the vehicle 10, a first virtual straight line L1 connecting the first transmitting antenna 31 and the second transmitting antenna 32 and a second virtual straight line L2 connecting the first receiving antenna 41 and the second receiving antenna 42 intersect, and at least one of the first virtual straight line L1 and the second virtual straight line L2 is inclined at an angle of less than 90 degrees with respect to the first direction X of the vehicle interior 100. Then, the reflected wave is used to detect the living body H in the vehicle interior. With this configuration, the angular resolution of the detection device 1 with respect to the first direction X can be improved to increase the detection accuracy of the living body H in the vehicle interior. Furthermore, since a small-sized, low-cost detection device 1 with a reduced number of antennas can be used, an increase in the cost of the vehicle 10 is suppressed, and the detection device 1 can be easily arranged on the vehicle 10.

[0104] <Second embodiment> Fig. 22 is a plan view showing a detection device according to a second embodiment, Fig. 23 is a schematic view showing an example of a vehicle, and Fig. 24 is a plan view showing a modified example of the detection device shown in Fig. 22.

[0105] The detection device 1 of this embodiment is similar to the detection device 1 of the first embodiment described above, except that the configuration of the receiving antenna group 4, specifically, the orientation of the second virtual straight line L2, is different. Therefore, in the following description, the present embodiment will be described mainly with respect to the differences from the first embodiment described above, and the description of the similar points will be omitted. In addition, in each drawing of this embodiment, the same reference numerals are used for the configurations similar to those of the above-mentioned embodiment.

[0106] As shown in Fig. 22, in the detection device 1 of this embodiment, the first virtual straight line L1 connecting the first transmitting antenna 31 and the second transmitting antenna 32 is inclined at an angle θx1 of less than 90 degrees with respect to the first direction X, and is inclined at an angle θy1 of less than 90 degrees with respect to the second direction Y, as in the first embodiment described above. In contrast, the second virtual straight line L2 connecting the first receiving antenna 41 and the second receiving antenna 42 is aligned with the first direction X. In other words, the second virtual straight line L2 is parallel to the first direction X. By arranging the four antennas 31, 32, 41, and 42 in this way, the angular resolution in the second direction Y is reduced compared to the first embodiment described above, but the angular resolution in the first direction X can be further improved.

[0107] For example, in the case of a typical sedan-type vehicle in which an engine room and a trunk room are arranged in front of and behind the vehicle interior 100 as shown in FIG. 23, the area in which the moving object A outside the vehicle interior may exist is sufficiently far from the area in which the living body H inside the vehicle interior may exist, that is, the vehicle interior 100. In other words, the shortest distance from the detection device 1 to the moving object A outside the vehicle interior in the second direction Y is sufficiently longer than the longest distance from the detection device 1 to the living body H inside the vehicle interior in the second direction Y. In such a case, by using only the distance r in the second direction Y, the living body H inside the vehicle interior can be detected without being affected by the moving object A outside the vehicle interior. Therefore, a high angular resolution in the second direction Y is not required. Therefore, as in this embodiment, by further increasing the angular resolution in the first direction X, the living body H inside the vehicle interior can be detected more accurately.

[0108] As described above, in this embodiment, the first virtual straight line L1 is inclined with respect to the first direction X, and the second virtual straight line L2 is aligned along the first direction X, but the present invention is not limited to this, and for example, as shown in Fig. 24, the first virtual straight line L1 may be aligned along the first direction X, and the second virtual straight line L2 may be inclined with respect to the first direction X. Even with such a configuration, it is possible to achieve the same effect as this embodiment.

[0109] As described above, in the detection device 1 of this embodiment, one of the first virtual straight line L1 and the second virtual straight line L2 is inclined at an angle of less than 90 degrees with respect to the first direction X, and the other is disposed along the first direction X. This makes it possible to further improve the angular resolution with respect to the first direction X.

[0110] The second embodiment as described above can also achieve the same effects as the first embodiment described above.

[0111] Although the detection device, detection method, and vehicle of the present invention have been described above based on the illustrated embodiment, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration or any step having a similar function. In addition, any other configuration or any step may be added to the present invention.

[0112] In the above-described embodiment, the transmitting antenna group 3 includes two transmitting antennas 31 and 32, but the number of transmitting antennas may be three or more. Similarly, the receiving antenna group 4 includes two receiving antennas 41 and 42, but the number of receiving antennas may be three or more. That is, for example, as shown in FIG. 25, the transmitting antenna group 3 may include a first transmitting antenna 31, a second transmitting antenna 32, and a third transmitting antenna 33, and the receiving antenna group 4 may include a first receiving antenna 41, a second receiving antenna 42, and a third receiving antenna 43. In FIG. 25, the third transmitting antenna 33 is located on the first virtual straight line L1, and the third receiving antenna 43 is located on the second virtual straight line L2, but this is not limited thereto. For example, as shown in FIG. 26, the third transmitting antenna 33 may be located offset from the first virtual straight line L1, and the third receiving antenna 43 may be located offset from the second virtual straight line L2. 25 and 26 are illustrated as modified examples of the detection device shown in FIG. 3, but the same applies to the detection devices shown in FIGS. 8, 9, 15, 22 and 24. [Explanation of symbols]

[0113] 1...detection device 1A...detection device 10...vehicle 100...vehicle interior 101...front row seat 102...rear row seat 11...vehicle control unit 2...wiring board 3...transmitting antenna group 31...first transmitting antenna 32...second transmitting antenna 33...third transmitting antenna 4...receiving antenna group 41...first receiving antenna 42...second receiving antenna 43...third receiving antenna 5...control unit 50...local oscillator 501...processor 502...memory 51...transmitting section 52...receiving section 53...receiving signal holding section 54...receiving signal analysis section 55...abandonment determination section 56...alarm issuing section 57a...multiplier 57b...multiplier 57c...quadrature multiplier 58a...RF switch 58b...RF switch 9...terminal A...moving object outside vehicle interior FD1...front door FD2...front door GL1...windshield GL2...Rear glass GL3...Front door glass GL4...Front door glass GL5...Rear door glass GL6...Rear door glass H...Vital presence in vehicle interior L1...First virtual line L2...Second virtual line O...Intersection Q...Area RD1...Rear door RD2...Rear door S1...Received signal acquisition step S11...Detection start determination step S12...Radio wave transmission and reception step S13...Received signal generation step S2...Detection step S21...Step S22...Step S23...Step S24...Step S25...Step S26...Step S27...Step Sg...Received signal Sg1...First received signal Sg1t...First received signal time series Sg2...Second received signal Sg2t...Second received signal time series Sg3...Third received signal Sg3t...Third received signal time series Sg4...Fourth received signal Sg4t...Fourth received signal time series SgA...In-phase component signal SgB...Quadrature-phase component signal T...Table W...Moving object X…First direction Y…Second direction r…Distance r0…Distance θ…Latitude θL…Cross angle θx1…Angle θx2…Angle θy1…Angle θy2…Angle φ…Longitude

Claims

1. A detection device that detects a detection target present in a vehicle cabin, a first transmitting antenna and a second transmitting antenna for transmitting radio waves; a first receiving antenna and a second receiving antenna for receiving a reflected wave generated by the radio wave being reflected by an object; the antenna is disposed in the passenger compartment such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect with each other, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the passenger compartment; A detection device that detects the detection target by using the reflected wave.

2. a first reception signal obtained by the first reception antenna receiving the reflected wave of the radio wave transmitted from the first transmission antenna; a second reception signal obtained by receiving, by the second reception antenna, the reflected wave of the radio wave transmitted from the first transmission antenna; a third reception signal obtained by the first reception antenna receiving the reflected wave of the radio wave transmitted from the second transmission antenna; The detection device according to claim 1 , further comprising a fourth reception signal obtained by receiving the reflected wave of the radio wave transmitted from the second transmitting antenna by the second receiving antenna, and detecting the detection target using the fourth reception signal.

3. The detection device according to claim 1 , wherein the vehicle has a window located in at least one of the first directions.

4. The detection device according to claim 3 , wherein the first direction is a lateral direction of the vehicle.

5. 2. The detection device according to claim 1, wherein, in a plan view of the vehicle, the first virtual straight line and the second virtual straight line are each arranged to be inclined at an angle of less than 90 degrees with respect to both the first direction and a second direction intersecting the first direction.

6. The detection device according to claim 5 , wherein the vehicle has a window located in at least one of the second directions.

7. The detection device according to claim 6 , wherein the second direction is a front-to-rear direction of the vehicle.

8. The detection device according to claim 1 , wherein one of the first virtual straight line and the second virtual straight line is inclined at an angle of less than 90 degrees with respect to the first direction, and the other is disposed along the first direction.

9. Detecting a distance to a moving object located inside or outside the vehicle compartment and a direction in which the moving object is present based on the first reception signal, the second reception signal, the third reception signal, and the fourth reception signal; The detection device according to claim 2 , wherein the detection device determines whether the moving object is the detection target based on the distance, the direction of the moving object, and the shape of the vehicle interior.

10. The detection device according to claim 1 , wherein communication with an external device is performed using at least one of the first transmitting antenna and the second transmitting antenna, and at least one of the first receiving antenna and the second receiving antenna.

11. A detection method for detecting a detection target present in a vehicle cabin, comprising: a first transmitting antenna and a second transmitting antenna for transmitting radio waves; a detection device having a first receiving antenna and a second receiving antenna for receiving a reflected wave generated by the radio wave being reflected by an object, the antennas are disposed in the passenger compartment such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect with each other, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the passenger compartment; A detection method comprising: detecting the detection target by using the reflected wave.

12. A vehicle equipped with a detection device that detects a detection target present in a vehicle cabin, the detection device includes a first transmitting antenna and a second transmitting antenna that transmit radio waves, and a first receiving antenna and a second receiving antenna that receive a reflected wave generated when the radio waves are reflected by an object, the antenna is disposed in the passenger compartment such that, in a plan view of the vehicle, a first virtual line connecting the first transmitting antenna and the second transmitting antenna and a second virtual line connecting the first receiving antenna and the second receiving antenna intersect with each other, and at least one of the first virtual line and the second virtual line is inclined at an angle of less than 90 degrees with respect to a first direction of the passenger compartment; A vehicle that detects the detection target by using the reflected wave.

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