Track Establishment Device, Radar Device, and Target Detection Program

Abstract

To provide a track establishing device, a radar device, and a target detection program capable of precisely detecting a target.SOLUTION: A track establishing device includes a plot data creation section, a storage section, a track estimation section, and a target detection section. The plot data creation section creates plot data showing a detection point detected as a target candidate from a reception signal received by an antenna. The storage section stores plot data created by the plot data creation section in a storage device. The track estimation section extracts a detection point as an object of track estimation from a detection point shown by past time series plot data stored in the storage device on the basis of time-series correlation for a detection point shown by plot data created by the plot data creation section, and estimates a track by using a detection point as an object of track estimation. The target detection section outputs detection of a target when multiple detection points estimated as a track by the track estimation section satisfy a reference to be detected as a target.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a trajectory establishment device, a radar device, and a target detection program.

Background Art

[0002] Conventionally, there is a radar device that uses radio waves as a system for detecting a moving object such as a flying object arriving from a distance (hereinafter also referred to as a target). In recent years, since the moving speed of the target has been increasing, the radar device has been required to detect the target early at a distance. In order to detect the target early at a distance, research has been conducted on improving basic performance such as increasing the size and output power of the radar device, research on target detection technology at low SN, and research on target trajectory extraction technology.

[0003] As a conventional technique, there is a method of arranging a plurality of frames as one observation value in three-dimensional or two-dimensional coordinates and detecting a target point. However, in the above-described conventional technique, when the speed of the target is high, the interval (period) for observing the target with a plurality of frames becomes long, so there is a problem that noise is likely to be selected as a target candidate. In addition, since it is necessary to detect a point with a small SN ratio in order to detect a target at a distance, there is a problem that the point detected as a target candidate is likely to include noise.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a trajectory establishment device, a radar device, and a target detection program capable of detecting a target with high accuracy.

Means for Solving the Problems

[0006] According to an embodiment, the trajectory establishment device includes a plot data creation unit, a storage unit, a trajectory estimation unit, and a target detection unit. The plot data creation unit creates plot data indicating detection points detected as candidates for a target from reception signals received by an antenna. The storage unit stores the plot data created by the plot data creation unit in a storage device. The trajectory estimation unit extracts detection points to be the target of trajectory estimation from detection points indicated by past time-series plot data stored in the storage device based on the time-series correlation with respect to the detection points indicated by the plot data created by the plot data creation unit, and estimates a trajectory using the detection points to be the target of trajectory estimation. The target detection unit outputs that a target has been detected when a plurality of detection points estimated as a trajectory by the trajectory estimation unit satisfy a criterion for detecting the target. The trajectory estimation unit sets an estimated position range for each plot data in the past relative to the detection point in the current plot data created by the plot data creation unit, starting from the detection point, and targets the detection points indicated by the past plot data within the estimated position range for trajectory estimation.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a radar device 1 including a track establishment device 12 according to an embodiment of the present invention. The radar device 1 is a device that detects a moving object (hereinafter referred to as a target) including a flying object such as an aircraft, an airplane, or a drone by radio waves. The radar device 1 scans (scans) a predetermined range (scan range) using radio waves to detect an object existing in the scan range. The radar device 1 according to the present embodiment is assumed to detect a target approaching a predetermined radar position. As a specific example, the radar device 1 sets a radar position at a specific facility (target facility) or around the target facility to detect a target that is an object approaching the target facility.

[0009] In the configuration example shown in FIG. 1, the radar device 1 includes an antenna 11 and a track establishment device 12. The radar device 1 only needs to have a configuration in which the track establishment device 12 acquires the signal received by the antenna 11. The radar device 1 may be configured by integrating the antenna 11 and the track establishment device 12, or may be configured with the antenna 11 and the track establishment device 12 installed at separate locations.

[0010] Furthermore, the radar device 1 may be configured such that the antenna 11 is installed on a flying object (moving object) such as a UAV (drone), and the track establishment device 12 acquires the received signal from the antenna 11. Also, the radar device 1 may be configured such that the antenna 11 and the track establishment device 12 are installed on a moving object such as a flying object, and the track establishment device 12 outputs information such as a target detection result to an external device provided at a predetermined position.

[0011] The antenna 11 transmits and receives radio waves. The antenna 11 transmits radio waves for detecting a target and receives the reflected wave of the transmitted radio waves. The antenna 11 is configured to send radio waves to a predetermined scan range. An object existing in the scan range reflects the radio waves sent from the antenna 11. The antenna 11 receives radio waves including the reflected wave reflected by an object existing in the scan range.

[0012] That is, the antenna 11 receives, as a reception signal, radio waves including reflected waves from objects existing within a predetermined scan range in one scan operation. The antenna 11 outputs the reception signal, which is the result of scanning the scan range, to the track establishment device 12. The antenna 11 outputs to the track establishment device 12 the reception signal obtained by scanning the scan range at predetermined intervals by performing the scan operation at predetermined intervals.

[0013] The track establishment device 12 acquires the reception signal, which is the radio wave received by the antenna 11. The track establishment device 12 acquires the reception signal, which is the result of scanning the scan range at predetermined intervals. The track establishment device 12 detects detection points (plots) that seem to be moving objects in the reception signal from the antenna 11. The track establishment device 12 creates plot data indicating the detection points for each scan (frame). Here, one scan is also referred to as one frame, and the plot data created from the reception signal obtained in one scan is also referred to as plot data for one frame.

[0014] The track establishment device 12 estimates the track (trajectory) of each detection point from the plot data of a plurality of scans (frames). The track establishment device 12 excludes detection points that become noise from the detection points in a plurality of past frames based on the temporal correlation between frames, classifies the detection points that are the targets of track estimation after excluding the detection points that become noise, and determines whether the detection point is a target to be detected based on the track of the detection point group. When it is determined that the detection point is a target based on the estimated track, the track establishment device 12 outputs that the target has been detected.

[0015] The track establishment device 12 is composed of a computer including a processor, a memory, and an interface. The computer as the track establishment device 12 executes various processes by the processor executing a program stored in the memory. For example, the computer as the track establishment device 12 may install a target detection program for executing the processes described later in the memory, and the processor may execute the target detection program to realize the operations described later.

[0016] The trajectory establishment device 12 has storage devices such as a memory for storing time-series plot data described later and a memory for storing setting information. The trajectory establishment device 12 includes an interface for acquiring a received signal from the antenna 11. Further, the trajectory establishment device 12 may include one or more circuits for processing the received signal from the antenna 11.

[0017] In the configuration example shown in FIG. 1, the trajectory establishment device 12 has functions such as an interface unit 120, a plot data creation unit 121, a plot data storage unit (storage unit) 122, a trajectory estimation unit 123, and a trajectory determination unit (target detection unit) 124. The interface unit 120, the plot data creation unit 121, the plot data storage unit 122, the trajectory estimation unit 123, and the trajectory determination unit 124 are functions realized by a computer including a processor, a memory, and an interface as the trajectory establishment device 12 executing a program. Note that some or all of the functions of the interface unit 120, the plot data creation unit 121, the plot data storage unit 122, the trajectory estimation unit 123, and the trajectory determination unit 124 may be realized by hardware such as a circuit.

[0018] The interface unit 120 acquires the received signal received by the antenna 11 from the antenna 11. The interface unit 120 supplies the received signal of the antenna 11 to the plot data creation unit 121. The interface unit 120 may include a signal circuit for processing the received signal acquired from the antenna 11.

[0019] The plot data creation unit 121 acquires the reception signal of the antenna 11 indicating the information on the position in the three-dimensional space and the amplitude of the radio wave via the interface unit 120. The plot data creation unit 121 detects (extracts) detection points that are candidates for targets in the scan range based on the reception signal of the antenna 11 acquired by the interface unit 120. Since the plot data creation unit 121 also detects targets such as a moving object approaching at high speed or a distant moving object, it detects detection points that are candidates for targets under conditions allowing false detection of noise.

[0020] The plot data creation unit 121 creates plot data indicating the detection points detected in the scan range for each scan (one frame). For example, the plot data creation unit 121 generates plot data of amplitudes indicating the amplitude values of the reception signals at each point in the space defined by the distance, azimuth angle, and elevation angle as the scan range. The plot data creation unit 121 compares the amplitude value of each point in the scan range indicated by the amplitude plot data with a threshold for plot detection (threshold).

[0021] The threshold for plot detection is set to detect detection points that are candidates for targets from the radio waves (reception signals) received by the antenna 11. In the trajectory establishment device 12 according to the present embodiment, since points with a small SNR such as a moving object approaching at high speed or a distant moving object are also detected as candidates for targets, a value allowing false detection of noise is set as the threshold for plot detection. That is, the plot data creation unit 121 of the trajectory establishment device 12 uses a threshold for plot detection that allows detection points that are noise to be included while being able to detect candidates for targets with a small SNR such as a moving object approaching at high speed or a distant moving object, and detects the detection points.

[0022] FIG. 2 is a diagram schematically showing an example of plot data indicating an example of detection of detection points in the scan range obtained by one scan operation. The plot data creation unit 121 determines whether each point in the scan range, which is a three-dimensional space defined by the distance, azimuth angle, and elevation angle based on the radar position R (see FIG. 4) as the reference position, is a detection point that is a candidate for the target (detection presence or absence). The plot data creation unit 121 determines whether each point is a detection point that is a candidate for the target by comparing the amplitude value of each point in the scan range with the threshold for plot detection.

[0023] For example, the plot data creation unit 121 detects, as detection points, points in the scan range whose amplitude exceeds the threshold for plot detection. As described above, the threshold for plot detection is set to a value that allows for misdetection of noise in order to detect detection points that are candidates for targets with a low SNR. The plot data creation unit 121 uses the data indicating the distance, azimuth angle, elevation angle, and amplitude for all the detection points detected in the scan range by one scan operation as the plot data for one frame.

[0024] That is, when the plot data creation unit 121 detects detection points using the threshold for plot detection, it creates, as plot data, the data indicating the detection points in the scan range based on the detection results of the detection points. The plot data creation unit 121 supplies the created plot data to the plot data storage unit 122 and the track estimation unit 123.

[0025] The plot data storage unit 122 stores the plot data created by the plot data creation unit 121 in the storage device (memory) provided in the track establishment device 12 in chronological order. For example, the plot data storage unit 122 assigns identification information (e.g., ID) indicating the chronological order to the plot data (frame) for each scan created by the plot data creation unit 121 and stores it in the storage device.

[0026] The trajectory estimation unit 123 executes a trajectory estimation process for estimating the trajectory of a detection point that is a candidate for a target based on a plurality of time-series plot data. The trajectory estimation unit 123 acquires the plot data (current frame) created by the plot data creation unit 121. Further, the trajectory estimation unit 123 acquires the past plot data (past frames) in time series stored in the plot data storage unit 122. The trajectory estimation unit 123 estimates the trajectory of the detection point based on the current plot data created by the plot data creation unit 121 and the past plot data in time series stored in the plot data storage unit 122.

[0027] FIG. 3 is a diagram schematically showing detection points indicated by plot data of a plurality of frames. In FIG. 3, an example of a detection point in the current plot data (current frame) created by the plot data creation unit 121 and detection points in N past plot data (past frames) stored in the plot data storage unit 122 is schematically shown.

[0028] In the example shown in FIG. 3, the N past frames are set as "past 1 frame",..., "past N frame" in time series order from the current frame. For example, the "past 1 frame" is past plot data (past frame) that is the closest to the current frame when arranged in time series order (the time series order from the current frame is "1"), and the "past N frame" is past plot data (past frame) whose time series order from the current frame is "N" when arranged in time series order.

[0029] In the example shown in FIG. 3, it is assumed that detection points indicated by black dots are detected in the current frame and the past frames. By arranging the detection points in each frame at one coordinate, data indicating the detection points in time series can be obtained. The trajectory estimation unit 123 excludes detection points determined to be noise based on the time correlation between frames from the plurality of detection points obtained in time series, and estimates a trajectory based on the detection points from which the noise has been excluded.

[0030] The trajectory estimation unit 123 of the trajectory establishment device 12 according to this embodiment extracts detection points to be subject to trajectory estimation based on the distance based on the time correlation between the detection points in the frame serving as the starting point (current frame) and the detection points in a plurality of frames in the past. In other words, the trajectory estimation unit 123 sets a distance for excluding detection points that become noise based on the assumed speed of the target and the time series order from the frame serving as the starting point.

[0031] That is, the trajectory estimation unit 123 uses the detection points in the current frame as the starting point, and selects the detection points to be subject to trajectory estimation and the detection points to be excluded as noise from the detection points in a plurality of past frames based on the distance based on the time correlation. For example, the trajectory estimation unit 123 sets the distance according to "distance = assumed speed of the target × time series order (N) from the current frame" for each past frame in the time series. The trajectory estimation unit 123 sets a lower limit and an upper limit assuming the speed change of the target, and sets an estimated position range that is between the distance based on the lower limit of the speed change (lower limit of the assumed speed of the target) and the distance based on the upper limit (upper limit of the assumed speed of the target) for each past frame.

[0032] In addition, since the trajectory establishment device 12 according to the embodiment detects a target moving toward the radar position R, the trajectory estimation unit 123 sets the area on the radar position R side of the detection point in the current frame outside the estimated position range. When the trajectory estimation unit 123 sets the estimated position range for each past frame, the detection points existing within the estimated position range among the detection points in the past frames are targeted for estimation as a trajectory.

[0033] When estimating a trajectory, the trajectory estimation unit 123 sets the number of past frames (n) and the minimum value of detection points (MinPts). In order to extract the detection points to be subject to trajectory estimation from the detection points in n past frames, the trajectory estimation unit 123 checks whether there are detection points within the estimated position range for each past frame. If the number of frames with detection points within the estimated position range is equal to or greater than MinPts, the trajectory estimation unit 123 estimates those detection point groups as a trajectory.

[0034] In this embodiment, the process of selecting a plurality of detection points in time series to be estimated as a trajectory is referred to as clustering. The number of past frames n and the minimum value of detection points MinPts used for clustering by the trajectory estimation unit 123 are stored in the setting storage unit 123a. The number of past frames n and the minimum value of detection points MinPts used for clustering can be set according to the operation of the radar device 1. For example, when n = 3 and MinPts = 3, the detection points in a total of 4 frames including the current frame and 3 past frames are targeted for clustering. If there are 3 frames with detection points within the estimated position range, even if there is 1 frame (non-detection frame) outside the estimated position range, clustering will be performed.

[0035] FIG. 4 is a diagram for explaining an example of clustering based on detection points in the current frame and detection points in N past frames. FIG. 4 is assumed to be an example of clustering with N = 4 and MinPts = 5. In the example shown in FIG. 4, the detection point P0 is a point detected in the current frame and is assumed to be the starting point of clustering. Each detection point P11,..., P43 other than the detection point is a detection point in a frame past the current frame.

[0036] In the example shown in FIG. 4, the detection points P11, P12, P13 are points detected in the first (nearest) past frame (past 1 frame) in time series order from the current frame. The detection points P21, P22, P23 are points detected in the second past frame (past 2 frames) in time series order from the current frame. The detection points P31, P32 are points detected in the third past frame (past 3 frames) in time series order from the current frame. The detection points P41, P42, P43 are points detected in the fourth past frame (past 4 frames) in time series order from the current frame.

[0037] The trajectory estimation unit 123 sets the lower and upper limits for the assumed speed of the target, and sets the estimated position ranges G1, G2, G3, and G4 starting from the detection point P0 for each past frame. The estimated position ranges GN (G1, G2, G3, G4) are set on the side farther from the radar position R starting from the detection point P0, and are set based on the distance (assumed speed × N) corresponding to the chronological order (N) from the current frame.

[0038] For example, the estimated position range G1 is set based on the distance (assumed speed × 1) corresponding to the past 1 frame. The estimated position range G1 is an area surrounded by a line (semicircle) indicating the distance calculated from the lower limit of the assumed speed of the target and a line (semicircle) indicating the distance calculated from the upper limit of the assumed speed of the target, starting from the detection point P0. The estimated position range G2 is set based on the distance (assumed speed × 2) corresponding to the past 2 frames. The estimated position range G2 is an area surrounded by a line (semicircle) indicating the distance calculated by multiplying the lower limit of the assumed speed of the target by 2 and a line (semicircle) indicating the distance calculated by multiplying the upper limit of the assumed speed of the target by 2, starting from the detection point P0.

[0039] The estimated position range G3 is set based on the distance (assumed speed × 3) corresponding to the past 3 frames. The estimated position range G3 is an area surrounded by a line (semicircle) indicating the distance calculated by multiplying the lower limit of the assumed speed of the target by 3 and a line (semicircle) indicating the distance calculated by multiplying the upper limit of the assumed speed of the target by 3, starting from the detection point P0. The estimated position range G4 is set based on the distance (assumed speed × 4) corresponding to the past 4 frames. The estimated position range G4 is an area surrounded by a line (semicircle) indicating the distance calculated by multiplying the lower limit of the assumed speed of the target by 3 and a line (semicircle) indicating the distance calculated by multiplying the upper limit of the assumed speed of the target by 3, starting from the detection point P0.

[0040] The trajectory estimation unit 123 determines whether each of the detection points P11, P12, and P13 in the first past frame (the past 1 frame) in the time series from the current frame of the detection point PO as the starting point is within the estimated position range G1. In the example shown in FIG. 4, the detection point P11 is within the estimated position range G1, and the detection points P12 and P13 are outside the estimated position range G1. As a result, the trajectory estimation unit 123 targets the detection point P11 for trajectory estimation and excludes the detection points P12 and P13 from the target of trajectory estimation in the past 1 frame.

[0041] The trajectory estimation unit 123 determines whether the detection points P21, P22, and P23 in the second past frame (the past 2 frames) in the time series from the current frame are within the estimated position range G2. In the example shown in FIG. 4, the detection points P21 and P22 are within the estimated position range G2, and the detection point P23 is outside the estimated position range G2. As a result, the trajectory estimation unit 123 targets the detection points P21 and P22 for trajectory estimation and excludes the detection point P23 from the target of trajectory estimation in the past 2 frames.

[0042] The trajectory estimation unit 123 determines whether the detection points P31 and P32 in the third past frame (the past 3 frames) in the time series from the current frame are within the estimated position range G3. In the example shown in FIG. 4, the detection point P31 is within the estimated position range G3, and the detection point P32 is outside the estimated position range G3. As a result, the trajectory estimation unit 123 targets the detection point P31 for trajectory estimation and excludes the detection point P32 from the target of trajectory estimation in the past 3 frames.

[0043] The trajectory estimation unit 123 determines whether the detection points P41, P42, and P43 in the fourth past frame (the past 4 frames) in the time series from the current frame are within the estimated position range G4. In the example shown in FIG. 4, the detection points P41 and P42 are within the estimated position range G4, and the detection point P43 is outside the estimated position range G4. As a result, the trajectory estimation unit 123 targets the detection points P41 and P42 for trajectory estimation and excludes the detection point P43 from the target of trajectory estimation in the past 4 frames.

[0044] When the trajectory estimation unit 123 extracts the detection points P11, P21, P22, P31, P41, and P42 to be estimated for the trajectory, it executes a process of classifying (grouping) these detection points into a group of detection points estimated as a trajectory. That is, the trajectory estimation unit 123 classifies the detection points P11, P21, P22, P31, P41, and P42 to be estimated for the trajectory into a group including the detection point P0 in chronological order. For example, the trajectory estimation unit 123 selects the detection points of the past frames connected in chronological order from the detection point P0 according to the positional relationship of the detection points between each frame.

[0045] According to the example shown in FIG. 4, the trajectory estimation unit 123 extracts the detection points to be connected to the detection point P11 based on the moving speed and moving direction estimated from the positional relationship between the detection point P0 of the current frame and the detection point P11 of the past one frame. In the example shown in FIG. 4, the trajectory estimation unit 123 connects the detection point P21 of the past two frames to the detection point P11 of the past one frame, and determines that the detection point P22 of the past two frames belongs to a different group. Further, the trajectory estimation unit 123 connects the detection point P31 of the past three frames to the detection point P21 of the past two frames, and connects the detection point P41 of the past four frames to the detection point P31 of the past three frames.

[0046] As a result, the trajectory estimation unit 123 selects one group O1 including the detection points P0, P11, P21, P31, and P41. In addition, the trajectory estimation unit 123 connects the detection point P22 that was not connected to the detection point P11 to the detection point P42, and selects the detection points P22 and P42 as the group O2.

[0047] The trajectory estimation unit 123 supplies the detection point group obtained by grouping a plurality of detection points to be estimated for the trajectory to the trajectory determination unit 124 as the estimation result of the trajectory. According to the example shown in FIG. 4, the trajectory estimation unit 123 supplies the detection point group composed of the detection points P0, P11, P21, P31, and P41 of the group O1 and the detection point group composed of the detection points P22 and P42 of the group O2 to the trajectory determination unit 124 as the estimation result of the trajectory.

[0048] Note that although FIG. 4 simply shows an example of the estimated position range G in two dimensions, when the detection point P is detected as a three-dimensional position, the trajectory estimation unit 123 sets a three-dimensional estimated position range G. Thereby, the trajectory estimation unit 123 can exclude detection points that become noise from the three-dimensional detection points and estimate a trajectory composed of detection points that are targets for trajectory estimation.

[0049] The trajectory determination unit 124 determines whether to detect a detection point as a target based on the trajectory estimation result by the trajectory estimation unit 123. The trajectory determination unit 124 determines whether a trajectory obtained by connecting a plurality of detection points estimated as a trajectory is the trajectory of a moving object targeted. When the detection point estimated as a trajectory is determined to be a target, the trajectory determination unit 124 outputs that the detection point has been detected as a target.

[0050] The trajectory determination unit 124 sets a determination condition (target criterion) for determining whether a detection point estimated as a trajectory is a target, and determines whether the trajectory estimated based on the determination condition is the target trajectory. For example, the trajectory determination unit 124 may determine whether it is a target based on whether the cumulative value of the detection probability based on the amplitude of each detection point estimated as a trajectory exceeds a threshold value (target criterion) for target determination.

[0051] Next, the flow of the operation of the trajectory establishment device 12 according to the embodiment will be described. FIG. 5 is a flowchart for explaining an operation example until target detection by the trajectory establishment device 12 according to the embodiment. First, in the radar device 1, the antenna 11 scans a predetermined scan range at a predetermined scan interval. Each time the antenna 11 scans the scan range, the antenna 11 supplies a reception signal indicating the received radio wave to the trajectory establishment device 12.

[0052] The trajectory establishment device 12 acquires the received signal received by the antenna 11 through the interface unit 120 (step ST11). Assume that the received signal acquired by the interface unit 120 from the antenna 11 is a signal indicating the information of the position in the three-dimensional space including the scan range and the amplitude of the received radio wave. In the trajectory establishment device 12, the interface unit 120 supplies the received signal of the antenna 11 to the plot data creation unit 121.

[0053] The plot data creation unit 121 of the trajectory establishment device 12 creates plot data for one scan based on the received signal acquired by the interface unit 120 from the antenna 11 (step ST12). The plot data creation unit 121 detects detection points that are candidates for the target (moving object) in the scan range from the received signal which is the scan data for one time, and creates plot data indicating the detection points in the scan range.

[0054] For example, the plot data creation unit 121 detects, as detection points, the points that exceed the threshold for plot detection among the amplitudes of the received signals at each point in the scan range indicated by the distance, azimuth angle, and elevation angle, and creates plot data indicating the detected detection points. However, as described above, the threshold for plot detection for detecting detection points is set to a value that allows noise detection so that points with low SN are also detected as candidates for the target.

[0055] When the plot data creation unit of the trajectory establishment device 12 creates plot data for one scan, the plot data storage unit 122 stores the plot data created by the plot data creation unit 121 in the storage device in chronological order (step ST13).

[0056] The trajectory estimation unit 123 of the trajectory establishment device 12 executes a trajectory estimation process based on the plot data for one scan (current frame) created by the plot data creation unit and the past plot data (past frame) stored by the plot data storage unit 122 (steps ST14 - 17).

[0057] The trajectory estimation unit 123 acquires the plot data (current frame) created by the plot data creation unit 121 and the past plot data (past frames) in chronological order stored by the plot data storage unit 122 in the storage device (step ST14). The trajectory estimation unit 123 acquires from the storage device the number of past frames (n frames) used for clustering in chronological order from the current frame. When the trajectory estimation unit 123 acquires the current frame and the n past frames, it arranges the detection points of the current frame and the detection points of the past frames at one coordinate.

[0058] Starting from the detection point in the current frame, the trajectory estimation unit 123 sets an estimated position range for each of the n past frames (step ST15). The trajectory estimation unit 123 sets a lower limit value and an upper limit value of the assumed speed of the target based on the speed change with respect to the assumed speed of the target, and sets an estimated position range based on the lower limit value and the upper limit value of the assumed speed of the target. For example, the trajectory estimation unit 123 estimates the distance from the starting point to the Nth past frame in chronological order from the current frame as the assumed speed (lower limit and upper limit) of the target × N. Therefore, the trajectory estimation unit 123 sets, for the Nth past frame, the range where the distance from the starting point is from the lower limit of the assumed speed × N to the upper limit × N as the estimated position range.

[0059] After setting the estimated position range for each past frame, the trajectory estimation unit 123 extracts the detection points to be the target of trajectory estimation using the estimated position range for each past frame (step ST16). The trajectory estimation unit 123 determines whether each detection point in the past N frames exists within the estimated position range corresponding to the past N frames. The trajectory estimation unit 123 targets the detection points within the estimated position range for the past N frames for trajectory estimation.

[0060] After extracting the detection points to be the target of trajectory estimation, the trajectory estimation unit 123 executes a process of grouping the extracted detection points into a time-series of detection points estimated as a trajectory (step ST17). The trajectory estimation unit 123 supplies the result of grouping the detection points estimated as a trajectory into the trajectory determination unit 124 as the estimation result of the trajectory.

[0061] When the trajectory determination unit 124 of the trajectory establishment device 12 obtains the trajectory estimation result by the trajectory estimation unit 123, it executes a trajectory establishment process (target detection process) for determining whether or not to detect a detection point as a target based on the trajectory estimation result (steps ST18-20).

[0062] The trajectory determination unit 124 determines whether or not to detect the grouped detection points as a target as the trajectory estimation result by the trajectory estimation unit 123 (step ST18). For example, the trajectory determination unit 124 sets a determination condition (target criterion) for determining that the trajectory composed of the detected point group estimated as the trajectory is the target trajectory, and determines whether or not the estimated trajectory is the target trajectory based on whether or not the determination condition for determining as the target is satisfied. The determination condition may be a threshold value for the cumulative value of the detection probability based on the amplitude of each detection point or the like, or may be a condition based on the actual trajectory of the moving object to be targeted.

[0063] When the trajectory determination unit 124 determines not to detect the detected point estimated as the trajectory as a target (step ST19, NO), it returns to step ST11 above and repeats the above-described process. When the trajectory determination unit 124 determines to detect the detected point estimated as the trajectory as a target (step S19, YES), it outputs that the target has been detected (step ST20). For example, when the target is detected, the trajectory establishment device 12 displays information indicating that the target has been detected on a display device. Further, the trajectory establishment device 12 may output information indicating the detected point detected as the target as the position of the target existing in the scan range. Further, the trajectory establishment device 12 may output the trajectory composed of the detected point group determined as the target as the detected target trajectory.

[0064] As described above, the trajectory establishment device according to the embodiment creates plot data indicating detection points detected as candidates for a target from radio waves (received signals) received by the antenna, stores the created plot data in the memory, and uses the detection points indicated by the created plot data as starting points. Detection points indicated by past time-series plot data existing within the estimated position range based on the time-series correlation are extracted as targets for trajectory estimation, a trajectory is estimated using the detection points to be the targets for trajectory estimation, and when it is determined that the detection points estimated as the trajectory are the target, it outputs that the target has been detected.

[0065] Thereby, according to the trajectory establishment device according to the embodiment, it is possible to eliminate detection points determined as noise by time correlation from a plurality of time-series plot data created from received signals obtained by the antenna scanning the scan range a plurality of times, and even when detecting detection points at a low SN containing noise, it is possible to accurately detect the target. Further, according to the trajectory establishment device according to the embodiment, since it is possible to detect detection points that are candidates for the target at a low SN, it is possible to detect even a fast-moving moving object at a distance.

[0066] (Modification example) As the moving object that is the target to be detected by the trajectory establishment device 12, various moving objects such as flying objects, drones, or airplanes are assumed. It is considered that the moving objects that can be targets have different speeds (assumed speeds) and trajectories that can be moved depending on the type of the aircraft. For this reason, the radar device 1 including the trajectory establishment device 12 may be configured to be able to detect a plurality of types of targets. As a modification example of the trajectory establishment device 12, an example will be described in which for a plurality of types of targets, an estimated position range corresponding to the assumed speed and the like is set for each type of target.

[0067] The trajectory establishment device 12 according to such a modification example can be realized by setting the lower limit and the upper limit of the assumed speed for each type of target for a plurality of types of targets with the same configuration as described above. When setting a plurality of types of targets, the trajectory establishment device 12 may execute the above-described trajectory estimation process and trajectory determination process for each target by setting an estimated position range for each of the plurality of types of targets.

[0068] In addition, the trajectory establishment device 12 may set the trajectories of the actually detected targets for each of the plurality of types of targets, and identify the type of the target by comparing the preset trajectories of the various targets with the trajectories of the detected targets.

[0069] When the trajectory establishment device 12 identifies the type of the detected target, it may output information indicating what type of target the detected target is. For example, when the trajectory establishment device 12 identifies that the detected target is a flying object, it may output that a flying object has been detected, and when it identifies that the detected target is an aircraft, it may output that an aircraft has been detected.

[0070] As described above, the trajectory establishment device according to the modification of the embodiment sets an estimated position range for each target for a plurality of types of targets, and estimates a trajectory for each type of target using the estimated position ranges set for each of the plurality of types of targets. As a result, according to the trajectory establishment device described as a modification, a plurality of types of targets can be detected from the detection points of a plurality of frames.

[0071] Note that each of the above-described processes can be executed by some software. Therefore, these programs can be installed and executed on a computer as a trajectory establishment device through a computer-readable storage medium storing some programs that execute the procedure of the above-described process. For example, the computer constituting the trajectory establishment device may download the program via a network and install the program by storing the downloaded program. Also, the computer as a trajectory establishment device may install the program by reading the above-described program from various information storage media and storing the read program.

[0072] Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Signs

[0073] 1…Radar device, 11…Antenna, 12…Track establishment device, 120…Interface section, 121…Plot data creation section, 122…Plot data storage section (storage section), 123…Track estimation section, 123a…Setting storage section, 124…Track determination section (target detection section), P (P0, P11, …, P43)…Detection point, R…Radar position, G (G1, …, G4)…Estimated position range.

Claims

1. A plot data creation unit that creates plot data indicating detection points detected as candidates for a target from the received signal received by the antenna; A storage unit that stores the plot data created by the plot data creation unit in a storage device; Based on the time-series correlation for the detection points indicated by the plot data created by the plot data creation unit, extract the detection points to be the target of track estimation from the detection points indicated by the past time-series plot data stored in the storage device, and use the detection points to be the target of track estimation to estimate a track. A track estimation unit; A target detection unit that outputs that a target has been detected when a plurality of detection points estimated as a track by the track estimation unit satisfy the criteria for detecting the target; The track estimation unit starts from the detection point in the current plot data created by the plot data creation unit, sets an estimated position range for each past plot data from the detection point as the starting point, and sets the detection points indicated by the past plot data within the estimated position range as the target of track estimation. A track establishment device.

2. The plot data creation unit uses, as detection points, points having an amplitude exceeding a threshold for plot detection in the received signal. The track establishment device according to claim 1.

3. The track estimation unit sets an estimated position range for each past plot data based on the assumed speed of the target and the time-series order from the detection point as the starting point. The track establishment device according to claim 1.

4. The track estimation unit sets the estimated position range for each past plot data to be between the distance calculated from the lower limit value of the assumed speed of the target and the distance calculated from the upper limit of the assumed speed of the target. The track establishment device according to claim 3.

5. The track estimation unit sets an estimated position range for each of a plurality of types of targets. The target detection unit detects targets for multiple types of targets and outputs the types of the detected targets. The trajectory establishment device according to any one of claims 1 to 4.

6. An antenna that receives radio waves within a predetermined scan range, A plot data creation unit that creates plot data indicating detection points detected as target candidates from the received signals received by the antenna, A storage unit that stores the plot data created by the plot data creation unit in a storage device, Based on the time-series correlation of the detection points indicated by the plot data created by the plot data creation unit, extract the detection points to be the target of trajectory estimation from the detection points indicated by the past time-series plot data stored in the storage device, and use the detection points to be the target of the trajectory estimation to estimate the trajectory. A trajectory estimation unit, A target detection unit that outputs that a target has been detected when a plurality of detection points estimated as a trajectory by the trajectory estimation unit satisfy the criteria for detecting the target, and The trajectory estimation unit sets an estimated position range for each past plot data starting from the detection point in the current plot data created by the plot data creation unit, and the detection points indicated by the past plot data within the estimated position range are the targets of trajectory estimation. A radar device.

7. On a computer, A process of creating plot data indicating detection points detected as target candidates from the received signals received by the antenna, A process of storing the created plot data in a storage device, Based on the time-series correlation for the detection points indicated by the created plot data, extract the detection points to be the target of trajectory estimation from the detection points indicated by the past time-series plot data stored in the storage device. Further, starting from the detection points in the currently created plot data, set an estimated position range for each of the past time-series plot data stored in the storage device that is older than the starting detection point, and extract the detection points indicated by the past plot data within the estimated position range as the detection points to be the target of trajectory estimation, and perform a process of estimating a trajectory using the extracted detection points to be the target of trajectory estimation, When a plurality of detection points estimated as the trajectory satisfy the criteria for detecting a target, perform a process of outputting that the target has been detected, A program for causing the above to be executed.

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