Track establishing 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 selects multiple detection points that become candidates from a detection point of plot data created by the plot data creation section and a detection point of past plot data stored in the storage device, and estimates multiple detection points that become a track along a target track assumed by a track obtained by connecting some of multiple detection points that become selected candidates in time series as a track. 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] FIELD OF THE DISCLOSURE The present invention relates to a track establishment device, a radar device, and a target detection program. [Background technology]

[0002] Conventionally, there is a radar device that uses radio waves as a system for detecting moving objects (hereinafter also referred to as targets) such as flying objects approaching from afar. In recent years, as the moving speed of targets has been increasing, it has become necessary for the radar device to detect targets at long distances and early. In order to detect targets at long distances and early, the basic performance of the radar device has been improved, such as by increasing the size and output, and research has been conducted on target detection technology with low signal-to-noise ratio and target trajectory extraction technology.

[0003] In the conventional technology, multiple frames are arranged in three-dimensional or two-dimensional coordinates as one observation value to detect the target point. However, the above-mentioned conventional technology has a problem that when the target is moving fast, the interval (period) for observing the target in multiple frames becomes long, making it difficult to assume the target's wake. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-174004 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a track establishment device, a radar device, and a target detection program that are capable of detecting targets with high accuracy. [Means for solving the problem]

[0006] According to an embodiment, the track establishment device has a plot data creation unit, a storage unit, a track estimation unit, and a target detection unit. The plot data creation unit creates plot data indicating detection points to be detected as target candidates from a signal received by the antenna. The storage unit stores the plot data created by the plot data creation unit in a storage device. The track estimation unit selects multiple candidate detection points from the detection points of the plot data created by the plot data creation unit and the detection points of past plot data stored in the storage device, and estimates, as a track, multiple detection points whose trajectory, when connected in time series, is a trajectory that follows the track of an assumed target among the multiple selected candidate detection points. The target detection unit outputs that a target has been detected when the multiple detection points estimated as a track by the track estimation unit satisfy a criterion for detection as a target. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a radar device including a track establishing device according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of plot data indicating detection points in a scan range of the track establishment device according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing an example of a current frame and N past frames that are created as plot data by the track establishment device according to the embodiment. [Figure 4] FIG. 4 is a diagram showing an example of detection points of a current frame, detection points of four past frames, and an estimated position range for each past frame, which are set by the track establishing device according to the embodiment. [Diagram 5] FIG. 5 is a diagram for explaining an example in which the track establishment device according to the embodiment selects a group of detection points to be estimated as a track from the classified detection points. [Figure 6] FIG. 6 is a flowchart for explaining an example of an operation up to target detection by the track establishment device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of the configuration of a radar device 1 including a track establishing device 12 according to an embodiment of the present invention. The radar device 1 is a device that detects moving objects (hereinafter referred to as targets) including flying objects such as flying objects, aircraft, and drones, by using radio waves. The radar device 1 detects objects present within a predetermined range (scan range) by scanning the range using radio waves. The radar device 1 according to this embodiment detects targets approaching a predetermined radar position. As a specific example, the radar device 1 detects targets, which are objects approaching a specific facility (target facility), by setting the radar position at or near the target facility.

[0009] 1, the radar device 1 has an antenna 11 and a track establishing device 12. The radar device 1 may have a configuration in which the track establishing device 12 acquires a signal received by the antenna 11. The radar device 1 may have the antenna 11 and the track establishing device 12 configured integrally, or may have the antenna 11 and the track establishing device 12 installed at separate locations.

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

[0011] Antenna 11 transmits and receives radio waves. Antenna 11 transmits radio waves for detecting targets and receives reflected waves of the transmitted radio waves. Antenna 11 is configured to transmit radio waves to a predetermined scan range. Objects present within the scan range reflect the radio waves transmitted from antenna 11. Antenna 11 receives radio waves including reflected waves reflected by objects present within the scan range.

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

[0013] The track establishment device 12 acquires a received signal, which is a radio wave received by the antenna 11. The track establishment device 12 acquires a received signal that is a result of scanning a scan range at a predetermined interval. The track establishment device 12 detects detection points (plots) that seem to be moving objects in the received signal from the antenna 11. The track establishment device 12 creates plot data that indicates the detection points for each scan (frame). Here, one scan is also referred to as one frame, and the plot data created from the received 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 plot data of multiple scans (frames). The track establishment device 12 eliminates detection points that are noise from detection points in multiple past frames based on the time correlation between frames, and determines whether or not a detection point is a target to be detected based on the tracks of a group of detection points obtained by classifying detection points to be subject to track estimation after eliminating the detection points that are noise. When the track establishment device 12 determines that a detection point is a target based on the estimated track, it outputs that a target has been detected.

[0015] The track establishment device 12 is composed of a computer having a processor, memory, and an interface. The computer as the track establishment device 12 executes various processes by the processor executing programs 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 below in the memory, and the processor may execute the target detection program to realize the operations described below.

[0016] The track 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 track establishment device 12 has an interface for acquiring a received signal from the antenna 11. The track establishment device 12 may also have one or more circuits for processing the received signal from the antenna 11.

[0017] In the example configuration shown in FIG. 1, the track 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 track estimation unit 123, an information management unit 124, a track learning unit 125, and a track determination unit (target detection unit) 126. The interface unit 120, plot data creation unit 121, plot data storage unit 122, track estimation unit 123, information management unit 124, track learning unit 125, and track determination unit 126 are functions realized by a computer equipped with a processor, memory, and interface as the track establishment device 12 executing a program. In addition, some or all of the functions of the interface unit 120, plot data creation unit 121, plot data storage unit 122, track estimation unit 123, information management unit 124, track learning unit 125, and track determination unit 126 may be realized by hardware such as a circuit.

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

[0019] The plot data creation unit 121 acquires, via the interface unit 120, a signal received by the antenna 11 indicating information indicating a position in three-dimensional space and the amplitude of radio waves. The plot data creation unit 121 detects (extracts) detection points to be candidates for targets within the scan range based on the signal received by the antenna 11 acquired via the interface unit 120. The plot data creation unit 121 detects detection points to be candidates for targets under conditions that allow for erroneous detection of noise in order to detect targets such as moving objects approaching at high speed and moving objects in the distance.

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

[0021] The plot detection threshold is set in order to detect detection points that are candidate targets from the radio waves (received signals) received by the antenna 11. In the track establishment device 12 according to this embodiment, a value that allows for erroneous detection of noise is set as the plot detection threshold in order to detect points with a low S / N ratio, such as fast approaching moving objects and distant moving objects, as target candidates. In other words, the plot data creation unit 121 of the track establishment device 12 detects detection points using a plot detection threshold that allows for the detection of target candidates with a low S / N ratio, such as fast approaching moving objects and distant moving objects, while allowing for the inclusion of detection points that are noise.

[0022] FIG. 2 is a diagram showing an example of plot data illustrating an example of detection points in a scan range obtained by one scan operation. The plot data creation unit 121 determines whether or not each point in the scan range, which is a three-dimensional space defined by the distance, azimuth angle, and elevation angle with respect to the radar position R (see FIG. 4) as the reference position, is a detection point that is a target candidate (presence or absence of detection). The plot data creation unit 121 determines whether or not each point is a detection point that is a target candidate by comparing the amplitude value of each point in the scan range with a plot detection threshold.

[0023] For example, the plot data creation unit 121 detects points in the scan range where the amplitude exceeds a plot detection threshold as detection points. As described above, the plot detection threshold is a value that allows for erroneous detection of noise in order to detect detection points that are candidates for targets with a low S / N ratio. The plot data creation unit 121 creates one frame of plot data that indicates the distance, azimuth angle, elevation angle, and amplitude for all detection points detected in the scan range by one scan operation.

[0024] That is, when the plot data creation unit 121 detects a detection point using a plot detection threshold, the plot data creation unit 121 creates data indicating the detection point in the scan range as plot data based on the detection result of the detection point. 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 chronological order in a storage device (memory) provided in the track establishment device 12. For example, the plot data storage unit 122 assigns identification information (e.g., an ID) indicating the chronological order to the plot data (frame) for each scan created by the plot data creation unit 121 and stores the data in the storage device.

[0026] The track estimation unit 123 executes a track estimation process to estimate the track of a detection point that is a target candidate based on multiple pieces of chronologically ordered plot data. The track estimation unit 123 acquires plot data (current frame) created by the plot data creation unit 121. The track estimation unit 123 also acquires past plot data (past frames) in chronological order stored by the plot data storage unit 122. The track estimation unit 123 estimates the track of the detection point based on the current plot data created by the plot data creation unit 121 and the past plot data in chronological order stored by the plot data storage unit 122.

[0027] FIG. 3 is a diagram showing a schematic diagram of detection points indicated by plot data of a plurality of frames. FIG. 3 shows an example of a detection point in the current plot data (current frame) created by the plot data creating unit 121 and a detection point in N pieces of past plot data (past frames) stored by the plot data storing unit 122. In FIG.

[0028] 3, the N past frames are referred to in chronological order from the current frame as "past frame", ..., "past N frames". For example, "past frame" refers to past plot data (past frame) that is immediately prior to the current frame (chronological order from the current frame is "1") when arranged in chronological order, and "past N frames" refers to past plot data (past frames) that is "N" chronologically from the current frame when arranged in chronological order.

[0029] In the example shown in Fig. 3, detection points indicated by black dots are detected in the current frame and past frames. Data indicating detection points in a time series is obtained by arranging the detection points in each frame in a single coordinate system. The track estimation unit 123 eliminates detection points determined to be noise based on the time correlation between frames from the multiple detection points obtained in the time series, and estimates a track based on the detection points from which noise has been eliminated.

[0030] The track estimation unit 123 of the track establishment device 12 according to this embodiment extracts detection points to be subjected to track estimation by distance based on the time correlation between detection points in a starting frame (current frame) and detection points in multiple previous frames. In other words, the track estimation unit 123 sets a distance for eliminating detection points that become noise based on the assumed target speed and the time series order from the starting frame.

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

[0032] Furthermore, since the track establishment device 12 according to the embodiment detects targets moving toward the radar position R, the track estimation unit 123 sets the area on the radar position R side of the detection point of the current frame outside the estimated position range. When the track estimation unit 123 sets the estimated position range for each past frame, it sets the detection points in the past frames that exist within the estimated position range as targets to be estimated as tracks.

[0033] When estimating a wake, the wake estimation unit 123 sets the number of past frames (n) and the minimum number of detection points (MinPts). In order to extract detection points for estimating a wake from the detection points in n past frames, the wake estimation unit 123 checks whether or not there are detection points within the estimated position range for each past frame. If the number of frames in which there are detection points within the estimated position range is equal to or greater than MinPts, the wake estimation unit 123 estimates the group of detection points as a wake.

[0034] In this embodiment, the process of selecting a plurality of detection points in a time series to be estimated as a wake is referred to as clustering. The number of past frames n and the minimum value of detection points MinPts used for clustering by the wake 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, detection points in a total of four frames, including the current frame and three past frames, are targeted for clustering, and if there are three frames with detection points within the estimated position range, clustering is performed even if there is one frame that is not within the estimated position range (non-detected frame).

[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 previous frames. 4, detection point P0 is a point detected in the current frame and is the starting point of clustering. Detection points P11, ..., P43 other than the detection point P0 are detection points in frames earlier than the current frame.

[0036] In the example shown in Fig. 4, detection points P11, P12, and P13 are points detected in the first (closest) previous frame (one previous frame) in chronological order from the current frame. Detection points P21 and P22 are points detected in the second previous frame (two previous frames) in chronological order from the current frame. Detection points P31 and P32 are points detected in the third previous frame (three previous frames) in chronological order from the current frame. Detection points P41, P42, and P43 are points detected in the fourth previous frame (four previous frames) in chronological order from the current frame.

[0037] The track estimation unit 123 sets a lower limit and an upper limit for the assumed speed of the target, and sets estimated position ranges G1, G2, G3, and G4 with the detection point P0 as the starting point for each past frame. The estimated position range GN (G1, G2, G3, and G4) is set with the detection point P0 as the starting point, on the far side of the radar position R, and is 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 (estimated speed x 1) corresponding to the past frame. The estimated position range G1 is an area starting from the detection point P0 and 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. The estimated position range G2 is set based on the distance (estimated speed x 2) corresponding to the past two frames. The estimated position range G2 is an area starting from the detection point P0 and surrounded by a line (semicircle) indicating the distance calculated from the lower limit of the assumed speed of the target x 2 and a line (semicircle) indicating the distance calculated from the upper limit of the assumed speed of the target x 2.

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

[0040] The track estimation unit 123 determines whether or not each of detection points P11, P12, and P13 in the first past frame in time series from the current frame of detection point PO serving as the starting point (past frame) is within estimated position range G1. In the example shown in Fig. 4, detection points P11 and P12 are within estimated position range G1, and detection point P13 is outside estimated position range G1. As a result, the track estimation unit 123 targets detection points P11 and P12 for track estimation in the past frame, and excludes detection point P13 from the target of track estimation.

[0041] The track estimation unit 123 determines whether or not the detection points P21 and P22 in the second most recent frame in time series from the current frame (the past two frames) are within the estimated position range G2. In the example shown in Fig. 4, the detection points P21 and P22 are present within the estimated position range G2. As a result, the track estimation unit 123 targets the detection points P21 and P22 in the past two frames for track estimation.

[0042] The track estimation unit 123 determines whether or not the detection points P31 and P32 in the third past frame in time series from the current frame (past three frames) are within the estimated position range G3. In the example shown in Fig. 4, the detection points P31 and P32 are present within the estimated position range G3. As a result, the track estimation unit 123 targets the detection points P31 and P32 in the past three frames for track estimation.

[0043] The track estimation unit 123 determines whether or not detection points P41, P42, and P43 in the fourth past frame in chronological order from the current frame (past four frames) are within estimated position range G4. In the example shown in Fig. 4, detection points P41 and P42 are within estimated position range G4, and detection points P42 and P43 are outside estimated position range G4. As a result, the track estimation unit 123 targets detection points P41 and P42 in the past four frames for track estimation, and excludes detection point P43 from the target of track estimation.

[0044] When the track estimation unit 123 extracts detection points P11, P12, P21, P22, P31, P32, P41, and P42 as targets for track estimation, it executes a process of classifying (grouping) these detection points into detection point groups for estimating tracks. That is, the track estimation unit 123 classifies the detection points P11, P21, P22, P31, P41, and P42 into a group including the detection point P0 in chronological order by clustering. For example, the track estimation unit 123 selects detection points of past frames that are connected in chronological order from the detection point P0 according to the positional relationship of the detection points between the frames.

[0045] According to the example shown in Fig. 4, the track estimation unit 123 extracts detection points connected to detection point P11 based on the moving speed and moving direction estimated from the positional relationship between detection point P0 of the current frame and detection point P11 of the previous frame. In the example shown in Fig. 4, the track estimation unit 123 connects detection point P21 of the previous two frames to detection point P11 of the previous frame, and determines detection point P22 of the previous two frames to be in a different group. In addition, the track estimation unit 123 connects detection point P31 of the previous three frames to detection point P21 of the previous two frames, and connects detection point P41 of the previous four frames to detection point P31 of the previous three frames. As a result of these, the track estimation unit 123 selects one group O1 including detection points P0, P11, P21, P31, and P41.

[0046] Furthermore, the track estimation unit 123 connects the detection point P22 of the past two frames, which was not connected to the detection point P11 of the past frame, with the detection point P42 of the past four frames, and selects the detection points P22 and P42 as a group O2. Furthermore, the track estimation unit 123 connects the detection point P12 of the past frame with the detection point P32 of the past three frames, and selects the detection points P12 and P32 as a group O3.

[0047] The track estimation unit 123 determines whether or not a detection point group, which is obtained by grouping multiple detection points to be the subject of track estimation, is to be used as a track estimation result, based on information (management information) managed by the information management unit 124. In other words, the track estimation unit 123 selects a detection point group to be estimated as a track from the grouped detection point groups based on the management information, and supplies information indicating the detection point group estimated as a track to the track learning unit 125 as a track estimation result.

[0048] The information management unit 124 manages information for determining whether or not to estimate the grouped detection points as a wake. The information management unit 124 supplies information indicating the position of the target facility (target position) stored in the storage device, information regarding the assumed target (assumed target information), and other information to the wake estimation unit 123 as management information for wake estimation. The assumed target information includes information indicating a wake (assumed wake) that the target may take when the target moves toward the target position. The assumed target information includes information indicating the movement capability, such as the moving speed and turning angle (maximum turning angle) of the target moving object, for example.

[0049] According to the example shown in FIG. 4, the track estimation unit 123 determines whether or not a detection point group O1 consisting of detection points P0, P11, P21, P31, and P41, a detection point group O2 consisting of detection points P22 and P42, and a detection point group O3 consisting of detection points P12 and P32 should be treated as track estimation results.

[0050] FIG. 5 is a diagram for explaining whether or not the detection points grouped as shown in FIG. 4 are estimated as a wake. The detection points of group O1 shown in Fig. 5 correspond to detection points P0, P11, P21, P31, and P41 shown in Fig. 4. When the detection points constituting group O1 are connected in chronological order, the trajectory of the detection points P0, P11, P21, P31, and P41 connected in order becomes a wake toward the target position, as shown in Fig. 5. Therefore, the wake estimation unit 123 estimates the detection points P0, P11, P21, P31, and P41 constituting group O1 as a likely wake of the target.

[0051] Moreover, the detection points of group O2 shown in Fig. 5 correspond to detection points P22 and P42 shown in Fig. 4. A track obtained by connecting detection points P22 and P42 constituting group O2 in chronological order is a track that moves in a direction different from the target position, as shown in Fig. 5. For this reason, track estimation unit 123 determines that the track consisting of detection points P22 and P42 of group O2 is not the track of the target (does not estimate it as a track).

[0052] Moreover, the detection points of group O3 shown in Fig. 5 correspond to detection points P12 and P32 shown in Fig. 4. A track obtained by connecting detection points P12 and P32 constituting group O3 in chronological order is a track moving in a direction different from the target position, as shown in Fig. 5. For this reason, the track estimation unit 123 determines that the track consisting of detection points P22 and P42 of group O3 is not the track of the target either (does not estimate it as a track).

[0053] 4 and 5 show an example of the estimated position range G in two dimensions for simplicity, but when the detection point P is detected as a three-dimensional position, the track estimation unit 123 sets a three-dimensional estimated position range G. This allows the track estimation unit 123 to determine whether or not to estimate, as the track of the target, a trajectory connecting the detection points classified by eliminating detection points that become noise even from the detection points in three dimensions. 5, a case has been described in which a trajectory connecting detection points shown simply in two dimensions is a straight line, but the trajectory estimated as a wake may be not only a two-dimensional straight line but also a three-dimensional curve, etc. Even when a trajectory connecting a plurality of classified detection points is a three-dimensional curve, the wake estimation unit 123 may compare it with the wake specified by the expected target information and determine whether or not to estimate it as the wake of the target.

[0054] The track learning unit 125 selects the track of the target from the track estimation result supplied by the track estimation unit 123. The track learning unit 125 also learns the track of the target moving object in advance. For example, the track learning unit 125 acquires information indicating a track actually detected as a target from an external device or the track determination unit 126, and learns the track of the target moving object. The track learning unit 125 holds the learning result, and selects the track of the target from the track estimation result by the track estimation unit 123 based on the learning result. The track learning unit 125 supplies the track of the target selected based on the learning result to the track determination unit 126.

[0055] The track determination unit 126 determines whether or not to detect, as a target, a detection point selected as the track of a target by the track learning unit 125. The track determination unit 126 determines whether or not to detect, as a target, a plurality of detection points selected as the track of a target by the track learning unit 125. When the track determination unit 126 determines to detect, as a target, a detection point estimated as a track, the track determination unit 126 outputs a signal indicating that the detection point has been detected as a target.

[0056] The track determination unit 126 sets a determination condition (target criterion) for determining whether or not a detection point selected as the track of a target is a target, and determines whether or not a track selected based on the determination condition is a track of a target. For example, the track determination unit 126 may determine whether or not a track is a target based on whether or not a cumulative value of detection probability based on the amplitude of each detection point selected as the track of a target exceeds a target determination threshold (target criterion).

[0057] Next, the flow of operations of the track establishing device 12 according to the embodiment will be described. FIG. 6 is a flowchart for explaining an example of an operation up to target detection by the track establishing 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. The antenna 11 supplies the track establishment device 12 with a reception signal indicating the received radio wave every time the antenna 11 scans the scan range.

[0058] The track establishment device 12 acquires the reception signal received by the antenna 11 through the interface unit 120 (step ST11). The reception signal acquired by the interface unit 120 from the antenna 11 is a signal indicating information indicating a position in a three-dimensional space including the scan range and an amplitude of the received radio wave. In the track establishment device 12, the interface unit 120 supplies the reception signal of the antenna 11 to the plot data creation unit 121.

[0059] The plot data creation unit 121 of the track 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 targets (moving objects) within the scan range from the received signal, which is one scan data, and creates plot data that indicates the detection points within the scan range.

[0060] For example, the plot data creation unit 121 detects points that exceed a plot detection threshold among the amplitudes of the received signals at each point in the scan range indicated by the distance, azimuth angle, and elevation angle as detection points, and creates plot data indicating the detected detection points. However, as described above, the plot detection threshold for detecting detection points is set to a value that allows the detection of noise so that points with low SN are also detected as target candidates.

[0061] When the plot data creation unit of track establishing device 12 creates plot data for one scan, plot data storage unit 122 stores the plot data created by plot data creation unit 121 in a storage device in chronological order (step ST13).

[0062] The track estimation unit 123 of the track establishment device 12 executes a track estimation process based on one scan's worth of plot data (current frame) created by the plot data creation unit and past plot data (past frames) stored by the plot data storage unit 122 (step ST14-18).

[0063] The track estimation unit 123 acquires the plot data (current frame) created by the plot data creation unit 121 and past plot data (past frames) in chronological order stored in a storage device by the plot data storage unit 122 (step ST14). The track estimation unit 123 acquires from the storage device the number of past frames (n) to be used for clustering in chronological order from the current frame. After acquiring the current frame and the n past frames, the track estimation unit 123 arranges the detection points of the current frame and the detection points of the past frames in a single coordinate system.

[0064] The track estimation unit 123 sets an estimated position range for each of n past frames, starting from the detection point in the current frame (step ST15). The track estimation unit 123 sets a lower limit and an upper limit of the target's assumed speed according to a speed change relative to the assumed speed of the target, and sets an estimated position range based on the lower limit and upper limit of the target's assumed speed. For example, the track estimation unit 123 estimates the distance from the starting point for the Nth past frame in chronological order from the current frame as the assumed speed (lower limit and upper limit)×N of the target. Therefore, the track estimation unit 123 sets the estimated position range for the Nth past frame as a range in which the distance from the starting point is from the lower limit×N to the upper limit×N of the assumed speed.

[0065] After setting the estimated position range for each past frame, the track estimation unit 123 extracts detection points to be targeted for track estimation using the estimated position range for each past frame, and selects multiple detection points to be candidates for the track using the extracted detection points (step ST16).

[0066] The track estimation unit 123 determines whether each detection point in the past N frames is present within an estimated position range corresponding to the past N frames. The track estimation unit 123 targets detection points within the estimated position range for the past N frames for track estimation. When the track estimation unit 123 extracts detection points to be the target of track estimation, the track estimation unit 123 selects multiple detection points that are candidates for the track by grouping the extracted detection points in chronological order. For example, the track estimation unit 123 identifies the target position and selects multiple detection point groups that are candidates for the track moving toward the target position by comparing the distance and relative distance between the detection point of the current frame and each detection point for each of the past N frames.

[0067] Furthermore, the track estimation unit 123 acquires information necessary for estimating a track from the information management unit 124 (step S17). The track estimation unit 123 acquires position information of the target position, assumed target information, etc., as information necessary for estimating a track. The track estimation unit 123 identifies the assumed track of the target when the target moves toward the target position, based on the assumed target information acquired from the information management unit 124.

[0068] The track estimation unit 123 estimates a track based on the track of the assumed target identified from the information from the information management unit 124 and multiple detection points selected as track candidates (step ST19). The track estimation unit 123 creates a trajectory that connects multiple detection points selected as track candidates in a time series. The track estimation unit 123 compares the trajectory that connects multiple detection points in a time series with the track of the assumed target based on the target position and the assumed target information. The track estimation unit 123 estimates, as a track, multiple detection points among the multiple candidate detection points whose trajectory connected in a time series is a trajectory that follows the track of the assumed target. The track estimation unit 123 supplies the estimated track result to the track learning unit 125.

[0069] The track learning unit 125 selects the track of the target from the track estimation result supplied from the track estimation unit 123 (step ST19). The track learning unit 125 learns the track of the target in advance based on the target detection result and the like, and holds the learning result. The track learning unit 125 selects the track of the target from the track estimation result by the track estimation unit 123 based on the learning result. The track learning unit 125 supplies the track of the target selected based on the learning result to the track determination unit 126. When the track determination unit 126 of the track establishment device 12 obtains the track of the target selected by the track learning unit 125, it executes a track establishment process (target detection process) to determine whether or not to detect the detection point selected as the track of the target as a target (step ST20-22).

[0070] The track determination unit 126 calculates a proximity for determining whether or not the detection point that is the track of the target selected by the track learning unit 125 is detected as a target (step ST20). Here, the track determination unit 126 outputs that the target has been detected when the track of the target is approaching the target position. For example, it is assumed that the track determination unit 126 detects that a moving object (target) such as an aircraft or unmanned aircraft is approaching a facility at the target position. In this case, the track determination unit 126 calculates the degree of approach to the target position when the target moves along the selected trajectory as the proximity (threat level).

[0071] The track determination unit 126 determines whether or not to detect a target based on the approach calculated from the target's trajectory (step ST21). For example, the track determination unit 126 determines whether or not to detect a target based on whether or not the approach calculated from the target's trajectory exceeds a threshold for target detection. The track determination unit 126 detects a target when the approach exceeds the threshold for target detection, and does not detect a target when the approach does not reach the threshold for target detection.

[0072] If the track determination unit 126 does not detect it as a target (step ST21, NO), the process returns to step ST11 and repeats the above-mentioned processing. When the track determination unit 126 detects the track of a target as a target (step S21, YES), it outputs that the target has been detected (step ST22). For example, the track establishment device 12 displays information indicating that the target has been detected on a display device when a target is detected. The track establishment device 12 may also output information indicating the detection points detected as the target as the position of the target present within the scan range. The track establishment device 12 may also output a track consisting of a group of detection points determined to be a target as the track of the detected target.

[0073] As described above, the track establishment device of the embodiment creates plot data indicating detection points to be detected as target candidates from radio waves (received signals) received by an antenna, stores the created plot data in memory, selects multiple candidate detection points from the detection points indicated by the created plot data and detection points from past plot data, estimates, as a track, the multiple detection points whose trajectory connected in time series follows the track of an assumed target, and outputs the fact that the target has been detected if it is determined that the detection point estimated as the track is a target.

[0074] As a result, according to the track establishment device of the embodiment, even if a large number of detection point groups that are candidates for the track are selected from a large number of detection points indicated by time-series plot data created from received signals obtained by scanning the scan range multiple times by an antenna, a detection point group that is a trajectory assumed to be the track of the target can be obtained as a track estimation result. Also, according to the track establishment device of the embodiment, even if a detection point that is a candidate for the target is detected with low SN, a detection point group that is a trajectory estimated as the track of the target can be obtained as a track estimation result, so that even if the target is a moving object moving at high speed, it becomes possible to detect it from a distance.

[0075] (Modification) The target moving objects to be detected by the track establishment device 12 are assumed to be various moving objects such as flying objects, drones, or aircraft. The speed at which moving objects can move and the tracks they follow are considered to differ depending on the type of aircraft. For this reason, the radar device 1 including the track establishment device 12 may be configured to detect multiple types of targets. As a modified example of the track establishment device 12, an example will be described in which an estimated position range is set for multiple types of targets according to the assumed speed, etc., for each type of target.

[0076] A track establishment device 12 according to such a modified example can be realized by having an information management unit 124 manage target assumption information for each of multiple types of targets with a similar configuration to that described above. When multiple types of targets are to be detected, the track establishment device 12 sets the assumed target track for each of the multiple types of targets, and executes a track estimation process for each target according to the assumed target track.

[0077] Furthermore, when the type of the detected target is identified from a plurality of types of targets, the track establishment device 12 may output information indicating what type of target the detected target is. For example, when the track establishment device 12 detects an airborne object as a target, it may output information indicating that the airborne object has been detected, and when the track establishment device 12 detects an aircraft as a target, it may output information indicating that the aircraft has been detected.

[0078] As described above, the track establishment device according to the modified embodiment sets the anticipated target track for each of multiple types of targets, and estimates, as the track, a group of detection points that form a trajectory along the anticipated target track set for each of the multiple types of targets. As a result, the track establishment device described as the modified embodiment can detect various targets based on the anticipated tracks for each of the multiple types of targets.

[0079] Each of the above processes can be executed by several pieces of software. Therefore, the above processes can be realized by installing and executing several programs that execute the procedures of the above processes in a computer serving as a track establishment device through a computer-readable storage medium that stores these programs. For example, the computer that constitutes the track establishment device may install the program by downloading the program via a network and storing the downloaded program. Also, the computer serving as the track establishment device may install the program by reading the program from various information storage media and storing the read program.

[0080] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0081] 1...Radar device, 11…Antenna, 12...Wake establishment device, 120...Interface section, 121...plot data creation unit, 122...plot data storage unit (storage unit), 123...Wake estimation section, 123a...Setting storage section, 124...Information Management Department, 125…Track learning section, 126...Track determination unit (target detection unit), P(P0, P11, ..., P43) ... detection point, R…radar position, G(G1, ..., G4)...Estimated location range.

Claims

1. a plot data generating unit that generates plot data indicating detection points detected as target candidates from a signal received by the antenna; a storage unit that stores the plot data created by the plot data creation unit in a storage device; a track estimation unit that selects a plurality of candidate detection points from the detection points of the plot data created by the plot data creation unit and the detection points of the past plot data stored in the storage device, and estimates, as a track, a plurality of detection points whose track, when connected in time series, is a track along an assumed track of a target, among the selected plurality of candidate detection points; a target detection unit that outputs a signal indicating that a target has been detected when a plurality of detection points estimated as the wake by the wake estimation unit satisfy a criterion for detecting a target; A wake establishing device having:

2. The plot data creation unit determines a point in the received signal where the amplitude exceeds a threshold for plot detection as a detection point.

2. A track establishing apparatus according to claim 1.

3. The battle trajectory estimation unit specifies an assumed trajectory of the target based on assumed target information indicating an assumed trajectory when the target moves.

2. A track establishing apparatus according to claim 1.

4. the trajectory estimation unit specifies an assumed trajectory of a target when the target moves toward the target position based on target position information indicating the target position; A track establishing apparatus according to claim 3.

5. a track learning unit that selects a track of a target from a track estimation result by the track estimation unit based on a learning result regarding the track of the target, and supplies the selected track of the target to the target detection unit; 2. A track establishing apparatus according to claim 1.

6. the track estimation unit selects a plurality of candidate detection points from detection points indicated by past plot data based on a time series correlation with a detection point serving as a starting point; 2. A track establishing apparatus according to claim 1.

7. the track estimation unit sets an estimated position range for each past plot data from a detection point serving as a starting point, and selects the detection point serving as the starting point and past detection points within the estimated position range as a plurality of detection points; 7. A track establishing apparatus according to claim 6.

8. the track estimation unit sets an assumed target track for each of a plurality of types of targets, estimates a track using the assumed target track for each of the plurality of types of targets, the target detection unit outputs the type of the detected target when the detection point of the estimated trail for each of the plurality of types of targets is detected as a target; A track establishing apparatus according to any preceding claim.

9. an antenna for receiving radio waves in a predetermined scanning range; a plot data generating unit that generates plot data indicating detection points detected as target candidates from a signal received by the antenna; a storage unit that stores the plot data created by the plot data creation unit in a storage device; a track estimation unit that selects a plurality of candidate detection points from the detection points of the plot data created by the plot data creation unit and the detection points of the past plot data stored in the storage device, and estimates, as a track, a plurality of detection points whose track, when connected in time series, is a track along an assumed track of a target, among the selected plurality of candidate detection points; a target detection unit that outputs a signal indicating that a target has been detected when a plurality of detection points estimated as the wake by the wake estimation unit satisfy a criterion for detecting a target; A radar device having the above structure.

10. On the computer, A process of generating plot data indicating detection points detected as target candidates from the signal received by the antenna; A process of storing the created plot data in a storage device; a process of selecting a plurality of candidate detection points from the detection points of the created plot data and the detection points of the past plot data stored in the storage device, and estimating, as a track, a plurality of detection points whose trajectory, when connected in time series, among the selected plurality of candidate detection points, is a trajectory that follows the track of an assumed target; a process of outputting a detection result of a target when the plurality of detection points estimated as the wake satisfy a criterion for detecting the target; A target detection program that executes the following:

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