Object detection device, radar device, and object detection method

Abstract

The object detection device (8) comprises: a fluctuation data acquisition unit (821) which acquires fluctuation data; a speed acquisition unit (822) which acquires the moving speed of the radar device (1); a target data estimation unit (831) which estimates the relative distance between the radar device (1) and the target, the incident angle of the reflected signal from the target, and the first relative speed between the radar device (1) and the target using the fluctuation data; and a stationary object determination unit (832) which estimates the second relative speed between the target and the radar device (1) when the target is a stationary object based on the moving speed acquired by the speed acquisition unit (822) and the relative distance and incident angle estimated by the target data estimation unit (831), compares the first relative speed with the second relative speed, and thereby determines whether the target is a stationary object.

Description

Technical Field

[0001] The present invention relates to an object detection device, a radar device and an object detection method. Background Art

[0002] For example, an on-board radar device irradiates millimeter-wave radio waves toward the exterior of the vehicle, receives the reflected waves from objects outside the vehicle, and analyzes the received signals generated using these radio waves to calculate the relative distance and speed between the target and the on-board radar device. Objects observed by on-board radar devices include not only moving objects such as pedestrians but also stationary objects such as guardrails. The on-board radar device must determine in advance whether the observed object is a moving object such as a pedestrian that could potentially jump from the roadside toward the vehicle.

[0003] Vehicle-mounted radar systems use object detection devices and methods that determine whether an observed object is a stationary object or a moving object. For example, Patent Document 1 describes an object detection device and method that analyzes received signals of radio waves emitted from the radar system and reflected by an object using a multipath environment model representing the path of radio waves reflected by a stationary object and a non-multipath environment model representing the path of reflected waves in a non-multipath environment. The method then determines whether the received signal originates from a stationary object.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-20158 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] The object detection device described in Patent Document 1 determines whether a target is a stationary object based on the fact that the relative distance to the target and the angle of incidence of radio waves reflected by the target differ between moving and stationary objects. Consequently, conventional object detection devices suffer from the following problem: they cannot accurately determine whether a target is a stationary object when a moving object and a stationary object at the same relative distance and angle of incidence are contained within the target.

[0009] The present invention solves the above-mentioned problems and aims to provide an object detection device, a radar device, and an object detection method capable of determining whether a target is a stationary object even when a moving object and a stationary object having equal relative distances and incident angles are included in the target.

[0010] Means for solving problems

[0011] The object detection device of the present invention comprises: a fluctuation data acquisition unit that acquires fluctuation data obtained by observing a target through a radar device for an observation time with a speed resolution smaller than the average moving speed of the moving object; a speed acquisition unit that acquires the moving speed of the radar device; a target data estimation unit that uses the fluctuation data to estimate the relative distance between the radar device and the target, the angle of incidence of a signal irradiated from the radar device and reflected at the target and incident on the radar device, and a first relative speed between the radar device and the target; and a stationary object determination unit that estimates the second relative speed between the target and the radar device when the target is a stationary object based on the moving speed acquired by the speed acquisition unit and the relative distance and angle of incidence estimated by the target data estimation unit, and compares the first relative speed with the second relative speed to thereby determine whether the target is a stationary object.

[0012] Effects of the Invention

[0013] According to the present invention, by using fluctuation data obtained by observing a target with a radar device over an observation period with a velocity resolution smaller than the average speed of moving objects, it is possible to estimate a second relative velocity when the target is a stationary object based on the radar device's speed, the relative distance between the radar device and the target, and the angle of incidence at which a signal emitted from the radar device and reflected from the target enters the radar device. Consequently, the object detection device of the present invention can determine whether a target is a stationary object even when the targets observed by the radar device include both moving and stationary objects at equal relative distances and angles of incidence. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] [ Figure 1 ] is a block diagram showing the structure of the radar device according to embodiment 1.

[0015] [ Figure 2 ] is a flowchart showing the operation of the object detection device of embodiment 1.

[0016] [ Figure 3 ] is shown Figure 1 Flowchart of the detailed processing of step ST2.

[0017] [ Figure 4 ] is shown Figure 1 Flowchart of the detailed processing of step ST3.

[0018] [ Figure 5 ] is a schematic diagram showing the relationship between a radar device and a moving object.

[0019] [ Figure 6 ] is a schematic diagram showing the relationship between a radar device and a stationary object.

[0020] [ Figure 7 ] is shown Figure 1 Flowchart of the detailed processing of step ST4.

[0021] [ Figure 8 ] is a schematic diagram showing the positional relationship between the target and the radar device when there is no possibility of collision between the target and the radar device.

[0022] [ Figure 9 ] is a schematic diagram showing the positional relationship between a target and a radar device when there is a possibility of a collision between the target and the radar device.

[0023] [ Figure 10 ] is a schematic diagram showing the positional relationship between the predicted line of the two-dimensional curve and the radar device.

[0024] [ Figure 11 ] Figure 11 A is a block diagram showing a hardware configuration that realizes the functions of the object detection device according to Embodiment 1. Figure 11 B is a block diagram showing a hardware configuration that executes software that realizes the functions of the object detection device according to the first embodiment. DETAILED DESCRIPTION

[0025] Implementation Method 1

[0026] Figure 1 This is a block diagram showing the structure of the radar device 1 according to the first embodiment. The radar device 1 is mounted on a mobile body, for example, and irradiates electromagnetic waves to the outside of the mobile body, receives reflected waves after the electromagnetic waves are reflected at a target, and observes the target based on the received signals of the reflected waves. In the following description, it is assumed that the mobile body is a vehicle. Figure 1 As shown, the radar device 1 includes an antenna 2 , a transmission / reception switch 3 , a transmitter 4 , a receiver 5 , an A / D converter 6 , a speedometer 7 , and an object detection device 8 .

[0027] Antenna 2 is a transceiver antenna connected to a transceiver switch 3, transmitting a transmit RF signal as an electromagnetic wave and receiving a receive RF signal as a reflected wave from a target. The type of antenna 2 is selected based on, for example, the environment in which radar apparatus 1 is used. Examples of antenna 2 include a patch antenna and a horn antenna. Alternatively, antenna 2 may be an array antenna composed of multiple element antennas. In the following description, antenna 2 is assumed to be an array antenna. Transceiver switch 3 switches the timing of outputting a transmit RF signal to antenna 2 and the timing of receiving a reflected wave after reflection from a target in a time series.

[0028] Transmitter 4 pulse-modulates the transmit RF signal and outputs the pulse-modulated transmit RF signal to transmit / receive switch 3 and A / D converter 6. When transmit / receive switch 3 is switched to the transmit side, the transmit RF signal is radiated into space by antenna 2. When transmit / receive switch 3 is switched to the receive side, receiver 5 receives a signal including a reflected signal of the transmit RF signal at the target as a received RF signal.

[0029] Transmitter 4 and receiver 5 are configured to observe targets for an observation time in which the radar device 1's velocity resolution is smaller than the average speed of moving objects. For example, if a pedestrian is assumed as the moving object, transmitter 4 and receiver 5 are configured to observe targets for an observation time in which the radar device 1's velocity resolution is smaller than the average speed of pedestrians. Furthermore, if the moving object carrying radar device 1 is a vehicle, the assumed moving object may include vehicles, bicycles, animals, and other similar objects in addition to pedestrians. The average speed of moving objects is calculated, for example, based on statistical data related to the movement of moving objects and is pre-set in radar device 1.

[0030] A / D converter 6 performs A / D conversion on the transmission RF signal generated by transmitter 4 and the reception RF signal received by receiver 5, respectively, and outputs the A / D-converted signals to object detection device 8. Speedometer 7 measures the moving speed of radar device 1. For example, when radar device 1 is mounted on a vehicle, speedometer 7 measures the absolute speed of radar device 1 based on the moving speed of the vehicle.

[0031] The object detection device 8 determines whether a target observed by the radar device 1 is a stationary object. It includes a data storage unit 81, a data acquisition unit 82, a signal processing unit 83, and an output data storage unit 84. The data storage unit 81 is a storage device included in the object detection device 8. The data storage unit 81 stores the received RF signal output from the A / D converter 6 as fluctuation data and the moving speed of the radar device 1 measured by the speedometer 7 as speed data. Alternatively, the data storage unit 81 may be a separate storage device from the object detection device 8.

[0032] The data acquisition unit 82 acquires the fluctuation data and speed data used to determine whether the target observed by the radar device 1 is a stationary object from the data stored in the data storage unit 81. For example, when the data storage unit 81 is configured as a storage device provided separately from the object detection device 8, the data acquisition unit 82 acquires the fluctuation data and moving speed data from the storage device via a wired or wireless communication path. Figure 1 As shown, the data acquisition unit 82 includes a fluctuation data acquisition unit 821 and a speed acquisition unit 822 .

[0033] The fluctuation data acquisition unit 821 acquires fluctuation data from the data stored in the data storage unit 81. Fluctuation data is data obtained by the radar device 1 observing a target at an observation time with a velocity resolution smaller than the average moving speed of the moving object. It is complex data including received RF signals and reflected signals from the target, obtained through multiple hits between the transmitter 4 and the receiver 5. The speed acquisition unit 822 acquires speed data indicating the moving speed of the radar device 1 from the data stored in the data storage unit 81.

[0034] The signal processing unit 83 performs signal processing using the fluctuation data and velocity data acquired by the data acquisition unit 82 to determine whether the target observed by the radar device 1 is a stationary object. If the target is a moving object, the signal processing unit 83 determines the likelihood of a collision between the vehicle carrying the radar device 1 and the target. Furthermore, the output data storage unit 84 is configured as a storage device included in the object detection device 8. Data obtained through signal processing by the signal processing unit 83 is stored as output data in the output data storage unit 84. Alternatively, the output data storage unit 84 may be configured as a storage device separate from the object detection device 8.

[0035] Figure 1 The signal processing unit 83 shown includes a target data estimation unit 831, a stationary object determination unit 832, and a final determination unit 833. The target data estimation unit 831 uses the fluctuation data acquired by the fluctuation data acquisition unit 821 to estimate the relative distance between the radar device 1 and the target, the incident angle of the received RF signal, and the relative speed between the radar device 1 and the target.

[0036] The relative distance between radar device 1 and the target is the relative distance between radar device 1, which is moving with the vehicle, and the target observed by radar device 1. The incident angle of the received RF signal is the angle of incidence of the signal emitted from radar device 1 and reflected from the target when it enters radar device 1. For example, it is the angle between the direction of movement of radar device 1 and the direction of reception of the reflected signal from the target. Furthermore, the relative speed between radar device 1 and the target is a first relative speed indicating the relative speed between radar device 1 and the target.

[0037] The stationary object determination unit 832 estimates the relative speed between the target and the radar device 1, if the target is a stationary object, based on the speed data acquired by the speed acquisition unit 822 and the relative distance and angle of incidence estimated by the target data estimation unit 831. The stationary object determination unit 832 compares the estimated relative speed with the relative speed estimated by the target data estimation unit 831 to determine whether the target is a stationary object. The relative speed between the target and the radar device 1, if the target is a stationary object, is the relative speed of the radar device 1 relative to the stationary target, and is therefore the second relative speed.

[0038] The final determination unit 833 determines the likelihood of a collision between the target and the radar apparatus 1. For example, the fluctuation data acquisition unit 821, the velocity acquisition unit 822, the target data estimation unit 831, and the stationary object determination unit 832 repeat their respective processes over multiple cycles. The final determination unit 833 estimates the target's movement direction using the target's velocity vector obtained through multiple cycles of determination by the stationary object determination unit 832. Based on the estimated target's movement direction, the final determination unit 833 determines the likelihood of a collision between the target and the radar apparatus 1. The determination result of the final determination unit 833 is stored in the output data storage unit 84.

[0039] If the output data storage unit 84 is configured as a storage device separate from the object detection device 8, the final determination unit 833 outputs data representing the determination result to the storage device via a wired or wireless communication path. Furthermore, if the object detection device 8 merely determines whether the target observed by the radar device 1 is a stationary object, the final determination unit 833 is omitted from the components of the object detection device 8.

[0040] The operation of the object detection device 8 according to the first embodiment is as follows.

[0041] Figure 2 : is a flowchart showing the operation of the object detection device 8 . Figure 2 The processing of steps ST1 to ST3 in exemplifies the object detection method of the first embodiment.

[0042] The data acquisition unit 82 acquires fluctuation data and speed data from the data stored in the data storage unit 81 (step ST1). For example, the fluctuation data acquisition unit 821 acquires fluctuation data for a plurality of hit counts from the data storage unit 81. Furthermore, the speed acquisition unit 822 acquires speed data of the radar device 1 from the data storage unit 81 at the same time as the observation time of the fluctuation data acquired by the fluctuation data acquisition unit 821. The speed data acquired by the speed acquisition unit 822 is output to the stationary object determination unit 832.

[0043] The number of hits of the fluctuation data acquired by the fluctuation data acquisition unit 821 can be expressed as the velocity resolution Δv expressed by the following equation (1): reso The number of hits during observation time that is less than the average moving speed of the moving object. In the following formula (1), λ is the wavelength of the electromagnetic wave transmitted and received by the transmitter 4 and the receiver 5 per hit. obs It is the observation time of the target by the radar device 1. obs Alternatively, the time may be obtained by summing the observation time of each target hit by several hits. For example, assuming that a pedestrian is a moving object and the average walking speed of the pedestrian is v pedIn the case of reso Specific speed v ped Small observation time T obs The fluctuation data acquired by the fluctuation data acquisition unit 821 is output to the target data estimation unit 831.

[0044]

[0045] Next, the target data estimation unit 831 estimates target data indicating the relative distance, relative speed, and incident angle to the target observed by the radar device 1 using the fluctuation data acquired by the fluctuation data acquisition unit 821 (step ST2 ). Figure 3 It shows Figure 1 The flowchart of the detailed processing of step ST2 shows the target data estimation processing performed by the target data estimation unit 831. The target data estimation unit 831 performs a fast Fourier transform (FFT) on the fluctuation data in the distance direction, thereby calculating the relative distance γ' between the radar device 1 and the target. tgt (Step ST1a) Alternatively, the target data estimation unit 831 may perform a digital Fourier transform (DFT) on the fluctuation data in the distance direction instead of the FFT to calculate the relative distance γ' tgt .

[0046] Next, the target data estimation unit 831 performs FFT on the fluctuation data in the hitting direction and calculates the relative speed v′ between the moving speed of the radar device 1 and the speed in the sight direction of the target. tgt (Step ST2a) Alternatively, the target data estimation unit 831 may perform DFT on the fluctuation data in the hitting direction instead of FFT to calculate the relative speed v' tgt In the case where the target is a moving object, the target's sight direction is the direction in which the moving object is moving.

[0047] The target data estimation unit 831 performs coherent integration on the received signal of each of the multiple element antennas constituting antenna 2, which is included in the fluctuation data (step ST3a). The target data estimation unit 831 detects the target in the incident angle direction of the received RF signal based on the received strength of the signal after coherent integration, for example, by using constant false alarm rate (CFAR) processing. In this process, the target data estimation unit 831 can use the relative distance γ' to the target estimated in step ST1a. tgt The relative distance between the target and the object near the target may be calculated by using only the relative speed v′ between the target and the object estimated in step ST2a. tgt and the relative velocity between the target and objects near it.

[0048] Next, the target data estimation unit 831 performs a single pulse angle measurement process on the data related to the target detected in step ST3a, thereby estimating the incident angle θ of the reflected signal from the target. tgt (Step ST4a) Alternatively, the target data estimation unit 831 may estimate the incident angle θ using an angle measurement process such as multiple signal classification (MUSIC) instead of the monopulse angle measurement process. tgt The relative distance γ′ between the radar device 1 and the target estimated by the target data estimation unit 831 is tgt , the relative speed v' between the radar device 1 and the target tgt and the incident angle θ of the reflected signal from the target tgt The signal is output to the stationary object determination unit 832 .

[0049] exist Figure 2 The stationary object determination unit 832 determines the speed V0 of the radar device 1 and the relative distance γ′ tgt and the incident angle θ tgt , when the target is a stationary object, the relative speed V' between the target and the radar device 1 is estimated 2,estimation , for the estimated relative velocity V' 2,estimation and relative velocity v' tgt By making a comparison, it is determined whether the target is a stationary object (step ST3). Figure 4 It shows Figure 1 The flowchart of the detailed processing of step ST3 shows the stationary object determination processing performed by the stationary object determination unit 832.

[0050] The stationary object determination unit 832 uses the velocity V0 of the radar device 1 and the relative distance γ′ to the target. tgt and the incident angle θ of the reflected signal from the target tgt , when the target is a stationary object, the relative speed V' between the radar device 1 and the target is estimated 2,estimation (Step ST1b). Figure 5 is a schematic diagram showing the relationship between the radar device 1 and the moving object 9A. Figure 5 As shown, in a case where the radar device 1 moves at a speed V0 and the target is a moving object 9A moving in a direction (x direction) perpendicular to the traveling direction (y direction) of the radar device 1, the relative speed V'1(t) between the radar device 1 and the moving object 9A can be calculated by the following formula (2) using the traversing speed V1 of the moving object 9A and the incident angle θ1 of the reflected signal from the moving object toward the radar device 1.

[0051] V′1(t)=V0 cosθ1-V1 sinθ1 (2)

[0052] Figure 6 is a schematic diagram showing the relationship between the radar device 1 and the stationary object 9B. Figure 6 In the radar device 1 and Figure 5 Similarly, the target is stationary object 9B, moving in the y direction at velocity V0. In this case, velocity V2 does not occur at stationary object 9B. Therefore, the relative velocity V'2(t) between radar device 1 and stationary object 9B can be calculated using the following equation (3) using the incident angle θ2 of the reflected signal from stationary object 9B toward radar device 1.

[0053] V′2(t)=V0 cosθ2 (3)

[0054] When the relative speed V′ between the radar device 1 and the moving object 9A is calculated using the above formula (2), 2,estimation In the case of , the traversing speed V1 of the moving object 9A is required. On the other hand, when the target is a stationary object 9B, according to the above formula (3), by using the speed V0 of the radar device 1 and the incident angle θ2, the relative speed V'2(t) between the radar device 1 and the stationary object 9B can be calculated.

[0055] The incident angle θ of the reflected signal from the target toward the radar device 1 tgt (t) changes moment by moment according to the positional relationship between the radar device 1 and the target, for example, according to the following formula (4). In the following formula (4), x(t) is the distance to the target in the direction perpendicular to the direction of travel of the radar device 1. y(t) is the distance to the target in the direction horizontal to the direction of travel of the radar device 1. For example, Figure 5 In this case, x(t) is W0 and y(t) is L0.

[0056]

[0057] x(t) and y(t) vary with time t, as shown in the following equation (5), depending on the direction or speed of travel of the radar device 1 or the target. In the following equation (5), W0 is the initial distance to the target in the direction perpendicular to the direction of travel of the radar device 1. L0 is the initial distance to the target in the direction horizontal to the direction of travel of the radar device 1. V tgt It is the target's traversing speed, and is 0 m / s when the target is a stationary object.

[0058] x(t)=W0-V tgt t

[0059] y(t)=L0-V0t (5)

[0060] The stationary object determination unit 832 estimates the relative speed V′ between the radar device 1 and the stationary object using the above equations (3), (4), and (5). 2，estimation . For example, as shown in the following formula (6), the stationary object determination unit 832 sets the distance to the target in the direction perpendicular to the direction of travel of the radar device 1 to an arbitrary value, and sets the distance to the target in the direction horizontal to the direction of travel of the radar device 1 to an arbitrary value, and uses a matrix W and a matrix L whose elements are a plurality of set values at arbitrary intervals related to these distances to calculate the estimated value of the relative speed between the radar device 1 and the stationary object. In the following formula (6), the bold characters L are the matrix L, and the set values of the matrix L are N. The bold characters W are the matrix W, and the set values of the matrix w are M. ΔL and ΔW are arbitrary intervals related to their respective set values. For example, when ΔL and ΔW are set to 10 cm, the estimated value of the relative speed between the radar device 1 and the stationary object can be calculated with an accuracy of 10 cm.

[0061]

[0062] By using the matrix L and matrix W shown in equation (6), the stationary object determination unit 832 can calculate the relative distance R' between the radar device 1 and the stationary object using equation (7). In equation (7), the relative distance R' is represented by a matrix including the matrix L and the matrix W.

[0063]

[0064] Next, the stationary object determination unit 832 uses the above equations (4) to (7) to calculate the incident angle θ of the reflected signal from the stationary object toward the radar device 1 according to the following equation (8): 2,estimation (t) is an estimated value of a change with time related to t. In the following equation (8), R in bold is a matrix having set values of relative distances R' as elements.

[0065]

[0066] The stationary object determination unit 832 uses the incident angle θ 2,estimation (t), the relative speed V' between the target and the radar device 1 is calculated according to the following formula (9) when the target is a stationary object 2,estimation estimated value.

[0067] V' 2，estimation (t)=V0 cos(tan -1 (θ 2，estimation (t))) (9)

[0068] exist Figure 4In the example, the stationary object determination unit 832 determines the relative speed V′ of the stationary object. 2,estimation and the relative speed v′ between the radar device 1 and the target estimated by the target data estimation unit 831 tgt The stationary object determination unit 832 compares the relative speed V' with the target and determines whether the target is a stationary object (step ST2b). 2,estimation (t) and relative velocity v' tgt Compare and determine whether the target is a stationary object. In the following formula (10), γ obj Is the value indicating the judgment. margin Is the margin of relative speed. margin Set an arbitrary value to avoid ambiguity in judgment.

[0069]

[0070] In the determination using the above formula (10), when the target is a stationary object, the determination result γ obj becomes "1", and when the target is a moving object, the judgment result γ obj Become "0". Figure 2 The series of processing from step ST1 to step ST3 is the object detection method of embodiment 1. In addition, when it is difficult for the stationary object determination unit 832 to determine a stationary object, the object detection device 8 may notify the outside of the device that it is difficult to determine a stationary object and then enter the processing of the final determination unit 833. In addition, if it is difficult to determine, the object detection device 8 may also return to Figure 2 The processing of step ST1 is repeated and the determination of the stationary object in step ST3 is performed again.

[0071] The determination result of the stationary object determination unit 832 is output to the final determination unit 833. Figure 2 In the final step, the determination unit 833 uses the determination result of the stationary object determination unit 832 to determine the possibility of collision between the target and the radar device 1 (step ST4). Figure 2 For example, when the fluctuation data acquisition unit 821, the speed acquisition unit 822, the target data estimation unit 831, and the stationary object determination unit 832 perform their respective processes, i.e., the series of processes from step ST1 to step ST3, for two or more cycles, the positions of the targets at different times are obtained.

[0072] Based on the determination results, the stationary object determination unit 832 also outputs the target's position at different times to the final determination unit 833. The final determination unit 833 uses the target's position at different times to calculate the target's velocity vector, and uses the target's velocity vector to estimate the target's direction of movement. Based on the estimated target's direction of movement, the final determination unit 833 determines the likelihood of a collision between the target and the radar device 1. A collision between the target and the radar device 1 means a collision between the vehicle carrying the radar device 1 and the target.

[0073] When the series of processes from step ST1 to step ST3 is executed three or more times, the target acceleration can be calculated using the target position at different times. In this case, the final determination unit 833 can use the target acceleration to determine the possibility of collision between the target and the radar device 1.

[0074] Figure 7 It shows Figure 1 The flowchart of the detailed processing of step ST4 shows the final determination processing performed by the determination unit 833. Figure 7 In the process, it is assumed that the cycle is carried out for more than 2 times. Figure 2 The series of processing from step ST1 to step ST3 is output from the stationary object determination unit 832 to the final determination unit 833. obj And data representing the position of the target at different times as data representing the determination result. Figure 8 1 is a schematic diagram showing the positional relationship between the target and the radar device 1 when there is no possibility of collision between the target and the radar device 1 . Figure 9 1 is a schematic diagram showing the positional relationship between a target and the radar device 1 when there is a possibility of collision between the target and the radar device 1 .

[0075] exist Figure 8 and Figure 9 The target is the moving object 9A. k The position of the moving object 9A determined as a stationary object is set to p(t k ), the next time t k The position of the moving object 9A determined as a stationary object with a value of +1 is expressed as p(t k +1). The final determination unit 833 uses the position p(t k ) and p(t k +1), estimate the velocity vector P of the moving object 9A k As the moving direction of the moving object 9A (step ST1c). Figure 8 and Figure 9 As shown, the final determination unit 833 obtains the velocity vector P k Extend to any time t K The vector obtained is used as the predicted line P of movement of the moving object 9A. K.

[0076] Next, the final determination unit 833 sets the position of the radar device 1 as the center and the distance threshold value P thresh For example, the distance threshold P thresh The value is set based on a plurality of parameters such as the moving speed or acceleration of the radar device 1 and the relative distance from the radar device 1 to the target, and observation conditions.

[0077] The final determination unit 833 determines the expected line P K Whether the collision prediction domain A intersects with the moving object 9A is determined, and the possibility of collision between the moving object 9A and the radar device 1 is determined (step ST3c). Figure 8 As shown, on the expected line P K If the moving object 9A deviates from the collision prediction region A, the final determination unit 833 determines that the moving object 9A is unlikely to collide with the radar device 1. Figure 9 As shown, on the expected line P K When the moving object 9A intersects with the collision prediction domain A, the final determination unit 833 determines that there is a possibility that the moving object 9A will collide with the radar device 1 .

[0078] exist Figure 8 and Figure 9 In the example, the target velocity vector is extended to any time t K The vector obtained is set as the expected line P K However, the envisioned line can also be represented by a multi-dimensional curve. Figure 10 : is a schematic diagram showing the positional relationship between the predicted line of the two-dimensional curve and the radar device 1. Figure 10 As shown, the envisioned line can be defined by a quadratic curve.

[0079] For example, the final determination unit 833 uses the arbitrary time t output from the stationary object determination unit 832. k The target position P(t k ), the next moment t k+1 The target position P(t k+1 ) and the next moment t k+2 The target position P(t k+2 ), when the target is expected to move along a quadratic curve, the calculation is extended to an arbitrary time t K The expected line P of the quadratic curve is obtained K Similar to the expected line of the one-dimensional vector, the final determination unit 833 determines the expected line P. K The possibility of a collision between the target and the radar device 1 is determined based on whether the target intersects with the collision prediction domain A.

[0080] Next, the final determination unit 833 outputs the target collision possibility determination result and the stationary object determination result as output data to the output data storage unit 84. The output data stored in the output data storage unit 84 is output to, for example, a display device mounted on the vehicle. Thus, the vehicle occupants can identify whether the target observed by the radar device 1 is a moving object based on the output data displayed on the display device, and can determine the possibility of a collision between the target and the vehicle.

[0081] Alternatively, the object detection device 8 may be provided separately from the radar device 1. In this case, the object detection device 8 obtains the fluctuation data and speed data from the radar device 1 via a wired or wireless communication path. Furthermore, the mobile object equipped with the radar device 1 is not limited to a vehicle; it may also be a railway, a ship, or an aircraft.

[0082] Alternatively, antenna 2 may comprise at least two transmitting and receiving antennas arranged parallel to or perpendicular to the direction of movement of radar apparatus 1. Transmitter 4 and receiver 5 perform multiple-input multiple-output (MIMO) processing using the signals transmitted and received by the transmitting and receiving antennas. This virtually enlarges the aperture diameter of antenna 2 using the two or more transmitting and receiving antennas, thereby improving the angular resolution of the incident angle of reflected signals from a target toward radar apparatus 1 in radar apparatus 1.

[0083] The hardware configuration for realizing the functions of the object detection device 8 is as follows.

[0084] The functions of the fluctuation data acquisition unit 821, the speed acquisition unit 822, the target data estimation unit 831, the stationary object determination unit 832 and the final determination unit 833 of the object detection device 8 are realized by the processing circuit. Figure 2 The processing circuit for the processes of steps ST1 to ST4 shown in the figure may be dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in a memory.

[0085] Figure 11 A is a block diagram showing a hardware configuration for realizing the functions of the object detection device 8 . Figure 11 B is a block diagram showing the hardware structure for executing software that realizes the functions of the object detection device 8. Figure 11 A and Figure 11In Figure B, the input / output interface 100 is, for example, an interface that relays data from the A / D converter 6 to the data storage unit 81 and relays data from the output data storage unit 84 to a display device (not shown). The storage device 101 is a storage device having storage areas that function as the data storage unit 81 and the output data storage unit 84. Furthermore, the various components are interconnected by signal lines 103.

[0086] The processing circuit is Figure 11 In the case of the dedicated hardware processing circuit 102 shown in A, the processing circuit 102 may be, for example, a single circuit, a composite circuit, a programmable processor, a parallel programmable processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. The functions of the fluctuation data acquisition unit 821, velocity acquisition unit 822, target data estimation unit 831, stationary object determination unit 832, and final determination unit 833 of the object detection device 8 may be implemented by separate processing circuits, or these functions may be integrated into a single processing circuit.

[0087] The processing circuit is Figure 11 In the case of processor 104 shown in B, the functions of the fluctuation data acquisition unit 821, velocity acquisition unit 822, target data estimation unit 831, stationary object determination unit 832, and final determination unit 833 of object detection device 8 are implemented by software, firmware, or a combination of software and firmware. Software or firmware is described as a program and is stored in memory 105.

[0088] The processor 104 reads and executes the program stored in the memory 105 , thereby realizing the functions of the fluctuation data acquisition unit 821 , speed acquisition unit 822 , target data estimation unit 831 , stationary object determination unit 832 , and final determination unit 833 of the object detection device 8 .

[0089] For example, the object detection device 8 has a memory 105 for storing the result of executing the program when executed by the processor 104. Figure 2The program for the processing of steps ST1 to ST4 in the flowchart shown in FIG. These programs cause a computer to execute the steps or methods of the fluctuation data acquisition unit 821, the speed acquisition unit 822, the target data estimation unit 831, the stationary object determination unit 832, and the final determination unit 833. The memory 105 may also be a computer-readable storage medium storing a program for causing a computer to function as the fluctuation data acquisition unit 821, the speed acquisition unit 822, the target data estimation unit 831, the stationary object determination unit 832, and the final determination unit 833.

[0090] The memory 105 is, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically-EPROM), a magnetic disk, a floppy disk, an optical disk, a high-density disk, a mini disk, a DVD, etc.

[0091] Alternatively, the functions of the fluctuation data acquisition unit 821, velocity acquisition unit 822, target data estimation unit 831, stationary object determination unit 832, and final determination unit 833 of the object detection device 8 may be partially implemented by dedicated hardware, while others may be implemented by software or firmware. For example, the functions of the fluctuation data acquisition unit 821 and velocity acquisition unit 822 may be implemented by the processing circuit 102, which is dedicated hardware, while the functions of the target data estimation unit 831, stationary object determination unit 832, and final determination unit 833 may be implemented by the processor 104 reading and executing a program stored in the memory 105. Thus, the processing circuit may implement the aforementioned functions by hardware, software, firmware, or a combination thereof.

[0092] As described above, the object detection device 8 of the first embodiment includes a fluctuation data acquisition unit 821 that acquires fluctuation data; a speed acquisition unit 822 that acquires the moving speed of the radar device 1; a target data estimation unit 831 that uses the fluctuation data to estimate the relative distance between the radar device 1 and the target, the angle of incidence of the reflected signal from the target, and a first relative speed between the radar device 1 and the target; and a stationary object determination unit 832 that estimates the second relative speed between the target and the radar device 1 if the target is a stationary object based on the moving speed acquired by the speed acquisition unit 822 and the relative distance and angle of incidence estimated by the target data estimation unit 831. The first relative speed and the second relative speed are compared to determine whether the target is a stationary object. Fluctuation data is data obtained by the radar device 1 observing the target over an observation period with a speed resolution smaller than the average moving speed of the moving object. Therefore, the second relative speed can be estimated if the target is a stationary object using the moving speed of the radar device 1, the relative distance between the radar device 1 and the target, and the angle of incidence of the reflected signal from the target. Thus, even when the targets observed by the radar device 1 include a moving object and a stationary object at the same relative distance and incident angle, the object detection device 8 can determine whether the target is a stationary object.

[0093] Furthermore, the object detection device 8 of the first embodiment includes a final determination unit 833 that determines the possibility of a collision between the target and the radar device 1. This allows the object detection device 8 to determine whether the target is a stationary object and, further, the possibility of a collision between the target and the radar device 1.

[0094] Furthermore, the radar device 1 of the first embodiment includes a transmitter 4 that generates a transmission signal emitted into space; a receiver 5 that receives a signal after the transmission signal emitted into space is reflected by a target; a speedometer 7 that measures the moving speed of the radar device 1; and an object detection device 8. Thus, even if the observed target includes a moving object and a stationary object at equal relative distances and angles of incidence, the radar device 1 can determine whether the target is a stationary object and can determine the likelihood of a collision between the target and the radar device 1.

[0095] Furthermore, any structural elements of the embodiments may be modified or omitted.

[0096] Industrial applicability

[0097] The object detection device of the present invention can be used in, for example, an in-vehicle radar device.

[0098] Description of labels

[0099] 1: Radar device; 2: Antenna; 3: Transmitter / receiver switch; 4: Transmitter; 5: Receiver; 6: A / D converter; 7: Speedometer; 8: Object detection device; 9A: Moving object; 9B: Stationary object; 81: Data storage unit; 82: Data acquisition unit; 83: Signal processing unit; 84: Output data storage unit; 821: Fluctuation data acquisition unit; 822: Speed acquisition unit; 831: Target data estimation unit; 832: Stationary object determination unit; 833: Final determination unit.

Claims

1. An object detection device, characterized in that: The object detection device has: a fluctuation data acquisition unit that acquires fluctuation data obtained by observing a target with a radar device during an observation time with a velocity resolution smaller than an average moving speed of a moving object, the average moving speed of the moving object being calculated based on statistical data related to the movement of the moving object and preset in the radar device; a speed acquisition unit configured to acquire a moving speed of the radar device; a target data estimating unit that estimates, using the fluctuation data, a relative distance between the radar device and the target, an incident angle at which a signal irradiated from the radar device and reflected from the target enters the radar device, and a first relative speed between the radar device and the target; as well as A stationary object determination unit estimates a second relative speed between the target and the radar device when the target is a stationary object based on the moving speed acquired by the speed acquisition unit and the relative distance and the incident angle estimated by the target data estimation unit, and compares the first relative speed with the second relative speed to thereby determine whether the target is a stationary object.

2. The object detection device according to claim 1, wherein The object detection device includes a final determination unit that determines a possibility of a collision between the target and the radar device.

3. The object detection device according to claim 2, wherein: The fluctuation data acquisition unit, the speed acquisition unit, the target data estimation unit, and the stationary object determination unit repeatedly perform their respective processes for a plurality of cycles. The final determination unit estimates a moving direction of the target using a velocity vector of the target obtained by the plurality of determination cycles performed by the stationary object determination unit, and determines a possibility of a collision between the target and the radar device based on the estimated moving direction of the target.

4. The object detection device according to claim 2, wherein: The fluctuation data acquisition unit, the speed acquisition unit, the target data estimation unit, and the stationary object determination unit repeat their respective processes at least twice. The final judgment unit calculates the velocity vector of the target using the position of the target at different times obtained by the multiple cycles of judgment performed by the stationary object judgment unit, and determines the possibility of the target colliding with the radar device based on the expected line of movement of the target estimated using the velocity vector of the target.

5. A radar device, characterized in that: The radar device has: a transmitter that generates a transmission signal to be radiated into space; a receiver configured to receive a signal of the transmission signal irradiated into space after being reflected at the target; a speedometer for measuring the moving speed of the radar device; as well as The object detection device according to any one of claims 1 to 4, wherein the fluctuation data is obtained from a signal received by the receiver, and the moving speed is obtained from the speedometer.

6. The radar device according to claim 5, characterized in that The radar device has at least two transmitting antennas and receiving antennas in a direction parallel to or perpendicular to a moving direction of the radar device. The transmitter and the receiver perform multiple-input multiple-output processing using the signals transmitted and received by the transmitting antenna and the receiving antenna.

7. An object detection method, characterized in that: The object detection method has the following steps: a fluctuation data acquisition unit acquiring fluctuation data obtained by observing a target with a radar device during an observation time with a speed resolution smaller than an average speed of a moving object, the average speed of the moving object being calculated based on statistical data related to the movement of the moving object and being preset in the radar device; The speed acquisition unit acquires the moving speed of the radar device; a target data estimation unit, using the fluctuation data, estimating a relative distance between the radar device and the target, an incident angle of a signal emitted from the radar device and reflected from the target onto the radar device, and a first relative speed between the radar device and the target; as well as The stationary object determination unit estimates a second relative speed between the target and the radar device when the target is a stationary object based on the moving speed obtained by the speed acquisition unit and the relative distance and the incident angle estimated by the target data estimation unit, and compares the first relative speed and the second relative speed to thereby determine whether the target is a stationary object.

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