Target tracking device, target tracking method, and target tracking program

Abstract

To track targets more accurately. [Solution] The target tracking device is a target tracking device that performs tracking processing to track a target in a detection target area, and comprises: an acquisition unit that acquires echo data showing the correspondence between a position in the detection target area and the level of reflected waves reflected at the position from electromagnetic waves transmitted via an antenna; a detection unit that detects a plurality of reflectors whose level of reflected waves is equal to or greater than a predetermined value based on the echo data; an area setting unit that sets an area including the predicted position of the target, in which the target to be tracked is likely to exist; a selection unit that selects a target to be tracked from one or more of the reflectors in the area; and a tracking unit that performs tracking processing to track the target to be tracked as the target.

Description

Technical Field

[0001] The present disclosure relates to an object tracking device, an object tracking method, and an object tracking program.

Background Art

[0002] Conventionally, in a radar device having a function of tracking an object based on echo data, techniques for suppressing clutter have been developed. For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-103197) describes the following moving target-corresponding scan correlation method. That is, the moving target-corresponding scan correlation method includes a reception video memory that sequentially stores video signals output from a signal reception unit of a radar, an ultrasonic wave, and an optical camera device for each scan, and a plurality of scan images stored in the reception video memory are divided into small area regions, and a moving vector calculation unit that calculates a moving vector of a target existing in the region, a target index calculation unit that calculates an index indicating the possibility of a target existing in the small area region, a clutter level calculation unit that calculates a clutter level in the small area region, a scan correlation processing unit that inputs outputs of the target index calculation unit, the moving vector calculation unit, and the clutter level calculation unit, and a display unit that displays an output of the scan correlation processing unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A technique capable of more accurately tracking an object beyond the technique described in Patent Document 1 is desired.

[0005] This disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a target tracking device, a target tracking method, and a target tracking program that can track targets more accurately. [Means for solving the problem]

[0006] (1) The target tracking device of the present disclosure is a target tracking device that performs tracking processing for tracking a target in a detection target area, and comprises: an acquisition unit that acquires echo data indicating a correspondence between a position in the detection target area and the level of reflected waves reflected at the position from electromagnetic waves transmitted via an antenna; a detection unit that detects a plurality of reflectors whose level of reflected waves is equal to or greater than a predetermined value based on the echo data; an area setting unit that sets an area including the predicted position of the target, in which the target to be tracked may exist; a selection unit that selects a target to be tracked from one or more of the reflectors in the area; and a tracking unit that performs tracking processing for tracking the target to be tracked as the target.

[0007] Thus, by defining an area where a target to be tracked may exist, selecting a target from among multiple reflectors in that area, and tracking that target, compared to a configuration that selects a target from all reflectors in the detection area, it is possible to select a target as the tracked object with simpler processing while suppressing false tracking caused by selecting the location of clutter as the tracked object. Therefore, targets can be tracked more accurately.

[0008] (2) In (1) above, the area setting unit may set the area based on an index value indicating the wobble of the target.

[0009] With this configuration, for example, it is possible to set a region corresponding to the magnitude of the target's wobble, so that the region containing the target can be set more reliably while narrowing down the number of reflective objects that can be tracked.

[0010] (3) In (1) above, the region setting unit may set the region based on an index value calculated based on the amount of change in the velocity vector of the target.

[0011] With this configuration, for example, it is possible to set a region corresponding to the change in the velocity vector of the target, so that the region in which the target is more reliably included can be set while narrowing down the reflectors that are candidates for tracking.

[0012] (4) In (1) above, the region setting unit may set the region based on an index value calculated based on the amount of change in the velocity of the target.

[0013] With this configuration, for example, it is possible to set a region corresponding to the amount of change in the target's velocity, so that the region in which the target is more reliably included can be set while narrowing down the number of reflective objects that can be tracked.

[0014] (5) In the above (1), the area setting unit may set the area based on an index value calculated based on the amount of change in the position of the target.

[0015] With this configuration, for example, it is possible to set a region that corresponds to the amount of change in the target's position, so that the region that more reliably includes the target can be set while narrowing down the number of reflective objects that can be tracked.

[0016] (6) In any of (1) to (5) above, the area setting unit may set the area based on the velocity of the target.

[0017] With this configuration, for example, it is possible to set a region of a size corresponding to the velocity of the target, so that the region containing the target can be set more reliably while narrowing down the number of reflective objects that can be tracked.

[0018] (7) In any of (1) to (6) above, the area setting unit may set the area based on the size of the target.

[0019] Since the observation position of a target fluctuates according to the size of the target, this configuration allows for setting a region that takes into account the fluctuations that may occur depending on the size of the target. This makes it possible to narrow down the list of potential reflectors to track and set a region that more reliably includes the target.

[0020] (8) In any of (1) to (7) above, the region setting unit may repeatedly set the region. The region setting unit may set the next region based on the position of the tracking target selected by the selection unit. If the tracking target is not selected in the region by the selection unit, the region setting unit may set the next region based on the predicted position in the region.

[0021] With this configuration, for example, if a target cannot be selected because the echo signal of the target cannot be detected, the observed position of the target can be interpolated using the predicted position of the target, and the next area can be set. Therefore, false tracking caused by the next area being set based on the location of clutter can be suppressed.

[0022] (9) In any of (1) to (8) above, the selection unit may select the tracking target based on an index value indicating the wobble of the target.

[0023] With this configuration, it is possible to distinguish between the target and the location where clutter occurs based on an index value indicating the target's wobble, and to select the target as the tracking target.

[0024] (10) The object tracking method of the present disclosure is an object tracking method in an object tracking device that performs a tracking process of tracking an object in a detection target area, including: obtaining echo data indicating a correspondence relationship between a position in the detection target area and a level of a reflected wave obtained by reflecting an electromagnetic wave transmitted via an antenna at the position; detecting a plurality of reflectors whose reflected wave levels are equal to or higher than a predetermined value based on the echo data; setting an area including a predicted position of the object, the area being an area where the object to be tracked may exist; selecting a tracking target from one or more of the reflectors in the area; and performing the tracking process of tracking the selected tracking target as the object.

[0025] Thus, compared with a method of selecting a tracking target from all reflectors in a detection target area, by setting an area where an object to be tracked may exist, selecting a tracking target from a plurality of reflectors in the area, and tracking the selected tracking target as the object, it is possible to select an object as a tracking target with a simple process while suppressing false tracking caused by selecting the occurrence position of clutter as the tracking target. Therefore, the object can be tracked more accurately.

[0026] (11) In the above (10), the area may be set based on an index value indicating the fluctuation of the object.

[0027] By such a method, for example, an area corresponding to the magnitude of the fluctuation of the object can be set, so that while narrowing down the reflector of the tracking candidate, an area where the object is more surely included can be set.

[0028] (12) In the above (10), the area may be set based on an index value calculated based on the amount of change in the velocity vector of the object.

[0029] By such a method, for example, an area corresponding to the amount of change in the velocity vector of the object can be set, so that while narrowing down the reflector of the tracking candidate, an area where the object is more surely included can be set.

[0030] (13) In (10) above, the region may be set based on an index value calculated based on the amount of change in the velocity of the target.

[0031] This method allows us to define a region that corresponds to the change in the target's velocity, thereby narrowing down the list of potential tracking reflectors and defining a region that more reliably includes the target.

[0032] (14) In (10) above, the region may be set based on an index value calculated based on the amount of change in the position of the target.

[0033] This method allows us to define a region that corresponds to the amount of change in the target's position, thereby narrowing down the list of potential reflective objects to track and defining a region that more reliably includes the target.

[0034] (15) The target tracking program of the present disclosure is a target tracking program used in a target tracking device that performs tracking processing for tracking a target in a detection target area, and is a program for causing a computer to perform the following: a process of acquiring echo data showing a correspondence between a position in the detection target area and the level of reflected waves reflected at the position from electromagnetic waves transmitted via an antenna; a process of detecting a plurality of reflectors whose level of reflected waves is equal to or greater than a predetermined value based on the echo data; a process of setting an area that includes the predicted position of the target and in which the target to be tracked may exist; a process of selecting a target to be tracked from one or more of the reflectors in the area; and a tracking process that tracks the target to be tracked as the target.

[0035] Thus, by defining an area where a target to be tracked may exist, selecting a target from among multiple reflectors in that area, and tracking that target, compared to a configuration that selects a target from all reflectors in the detection area, it is possible to select a target as the tracked object with simpler processing while suppressing false tracking caused by selecting the location of clutter as the tracked object. Therefore, targets can be tracked more accurately. [Effects of the Invention]

[0036] According to this disclosure, targets can be tracked more accurately. [Brief explanation of the drawing]

[0037] [Figure 1] Figure 1 is a diagram showing the configuration of a radar device according to an embodiment of the present disclosure. [Figure 2] Figure 2 shows an example of an echo image displayed by the processing unit in the radar device according to the embodiment of this disclosure. [Figure 3] Figure 3 shows an example of tracking processing in the processing unit of a radar device according to an embodiment of the present disclosure. [Figure 4] Figure 4 shows an example of tracking processing in the processing unit of a radar device according to an embodiment of the present disclosure. [Figure 5] Figure 5 shows an example of tracking processing in the processing unit of a radar device according to an embodiment of the present disclosure. [Figure 6] Figure 6 shows an example of tracking processing in the processing unit of a radar device according to an embodiment of the present disclosure. [Figure 7] Figure 7 shows an example of a method for calculating an index value by a processing unit in a radar device according to an embodiment of the present disclosure. [Figure 8] Figure 8 shows an example of a method for calculating an index value by a processing unit in a radar device according to an embodiment of the present disclosure. [Figure 9]Figure 9 shows an example of a region set by the processing unit in a radar device according to an embodiment of the present disclosure. [Figure 10] Figure 10 shows another example of a region set by a processing unit in a radar device according to an embodiment of the present disclosure. [Figure 11] Figure 11 is a flowchart showing an example of the operation of the target tracking unit in a radar device according to an embodiment of the present disclosure when generating concatenated echo data. [Figure 12] Figure 12 is a flowchart showing an example of the operation of the target tracking unit in the radar device according to the embodiment of this disclosure when performing tracking processing. [Modes for carrying out the invention]

[0038] Embodiments of this disclosure will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, at least some of the embodiments described below may be combined in any way.

[0039] [Configuration and Basic Operation] Figure 1 is a diagram showing the configuration of a radar device according to an embodiment of the present disclosure. Referring to Figure 1, the radar device 201 comprises a radar unit 20, a display device 30, and a target tracking unit 101. The target tracking unit 101 is an example of a target tracking device. The radar unit 20 includes an antenna 21, a transmitting / receiving unit 22, and a signal processing unit 23. The target tracking unit 101 comprises an acquisition unit 11, a processing unit 12, and a storage unit 13. The processing unit 12 is an example of a detection unit, an example of a region setting unit, an example of a selection unit, and an example of a tracking unit. Some or all of the transmitting / receiving unit 22, the signal processing unit 23, the acquisition unit 11, and the processing unit 12 are implemented by a processing circuit (Circuitry) including, for example, one or more processors. The storage unit 13 is, for example, a non-volatile memory included in the above processing circuit.

[0040] The radar system 201 is installed on the ship 1. The target tracking unit 101 performs tracking processing to track targets S, such as other ships, in the detection area Ta. The target tracking unit 101 displays an echo image on the display device 30 that shows the position of the tracked target S during the tracking process. For example, the detection area Ta is the area inside a circle of a predetermined size centered on the ship 1.

[0041] <Radar Section> The radar unit 20 generates segmented echo data EdD, which is echo data Ed indicating the correspondence between a position in the segmented area Da and the echo level at that position, based on the reflected waves from the electromagnetic waves transmitted via the antenna 21. The segmented area Da is a sector-shaped region obtained by dividing the detection area Ta into N sections along the azimuth direction. N is an integer of 2 or more. The echo level at each position in the segmented echo data EdD indicates the level of the reflected waves reflected at that position.

[0042] For example, the radar unit 20 generates segmented echo data EdD at a generation timing Gd that follows a predetermined generation period Cd.

[0043] More specifically, the transmitting / receiving unit 22 transmits electromagnetic waves via the antenna 21 during a sweep period T of a predetermined length, and receives reflected electromagnetic waves via the antenna 21. The transmitting / receiving unit 22 generates digital data Dd by digitally converting the echo signal indicating the received reflected wave. The transmitting / receiving unit 22 repeats the transmission of electromagnetic waves and the generation of digital data Dd while rotating the antenna 21 so that the azimuth angle of the electromagnetic wave transmission direction changes by a predetermined angle for each sweep period T. Each time digital data Dd is generated, the transmitting / receiving unit 22 outputs the generated digital data Dd to the signal processing unit 23.

[0044] The signal processing unit 23 generates segmented echo data EdD based on multiple digital data Dd received from the transmitting / receiving unit 22. For example, the signal processing unit 23 generates segmented echo data EdD in which the echo levels at multiple locations in the segmented area Da are binarized. More specifically, it generates segmented echo data EdD in which the echo level values ​​at locations in the segmented area Da where the echo level is above a predetermined threshold are converted to "1", and the echo level values ​​at locations where the echo level is below the threshold are converted to "zero". Each time the signal processing unit 23 generates segmented echo data EdD, it transmits the generated segmented echo data EdD to the target tracking unit 101.

[0045] <Target tracking unit> The acquisition unit 11 in the target tracking unit 101 acquires concatenated echo data EdC, which is echo data Ed indicating the correspondence between the position in the detection target area Ta and the echo level at that position.

[0046] For example, the acquisition unit 11 generates concatenated echo data EdC at a generation timing Gs that follows a scan period Cs which is N times the generation period Cd. More specifically, the acquisition unit 11 receives segmented echo data EdD from the signal processing unit 23 and stores the received segmented echo data EdD in the storage unit 13. Whenever the number of segmented echo data EdD stored in the storage unit 13 reaches N, the acquisition unit 11 acquires N segmented echo data EdD from the storage unit 13 and concatenates them to generate concatenated echo data EdC. The acquisition unit 11 stores the generated concatenated echo data EdC in the storage unit 13.

[0047] The processing unit 12 performs tracking processing to track the target S based on the echo data Ed. More specifically, each time the acquisition unit 11 stores concatenated echo data EdC in the storage unit 13, the processing unit 12 identifies the coordinates indicating the current position of the target S based on the concatenated echo data EdC. Then, the processing unit 12 calculates the velocity vector Vc of the target S based on the coordinates of the target S identified based on the concatenated echo data EdC, the coordinates of the target S identified based on the concatenated echo data EdC at past generation timing Gs, and the scan period Cs.

[0048] Figure 2 shows an example of an echo image displayed by the processing unit in a radar device according to an embodiment of the present disclosure. In Figure 2, solid circles indicate the most recent observation position P of the target S, and dashed circles indicate past observation positions P of the target S. Also in Figure 2, solid arrows indicate the most recent velocity vector Vc of the target S, and dashed arrows indicate past velocity vector Vc of the target S.

[0049] Referring to Figure 2, the processing unit 12 performs a process to display the tracking result of the target S. More specifically, the processing unit 12 generates an echo image including the observed position P of the target S in the detection target area Ta and the velocity vector Vc of the target S, and displays the generated echo image on the display device 30. The processing unit 12 updates the echo image displayed on the display device 30 each time the acquisition unit 11 saves the concatenated echo data EdC to the storage unit 13.

[0050] Figures 3 to 6 show an example of tracking processing in the processing unit of a radar device according to an embodiment of the present disclosure. Figures 3 to 6 show (1) detection processing, (2) gating processing, (3) selection processing, and (4) update processing, respectively. Referring to Figures 3 to 6, the processing unit 12 performs, in tracking processing, a detection process to detect a reflector R, a gating process to set an area Ar in which a target S to be tracked may exist, a selection process to select a target Tt to be tracked, and an update process to update the echo image based on the selection result of the target Tt to be tracked.

[0051] (1) Detection process Referring to Figure 3, in the detection process, the processing unit 12 detects multiple reflectors R whose reflected wave level is above a predetermined value based on the concatenated echo data EdC. For example, in the detection target area Ta, the processing unit 12 detects reflectors R1, R2, R3, and R4 as tracking candidates in the tracking process. Reflector R4 is land. In addition, the processing unit 12 may be configured to detect reflectors R with an area less than a predetermined value as tracking candidates, while excluding reflectors R such as land with an area greater than or equal to the predetermined value from the tracking candidates.

[0052] (2) Gating process Referring to Figure 4, in the gating process, the processing unit 12 sets a region Ar that includes the predicted position Pe of the target S, and is a region Ar where the target S to be tracked may exist. More specifically, the processing unit 12 calculates the predicted position Pe of the target S at the next generation timing Gs of the concatenated echo data EdC based on the latest observed position P and latest velocity vector Vc of the target S. Then, the processing unit 12 sets a rectangular region Ar centered on the calculated predicted position Pe. Note that the shape of region Ar is not limited to a rectangle, but may be a polygon other than a rectangle, or it may be a circle, an ellipse, or a sector. In Figure 4, for illustrative purposes, all reflectors R are represented by triangles of the same size.

[0053] (3) Selection process Referring to Figure 5, the processing unit 12 selects a target Tt to be tracked from one or more reflectors R in region Ar during the selection process. For example, the processing unit 12 selects reflector R2 from reflectors R1, R2, and R3 in region Ar as the target Tt to be tracked. In Figure 5, reflectors R1, R3, and R4 that were not selected as the target Tt to be tracked are shown as dashed triangles.

[0054] (4) Update process Referring to Figure 6, the processing unit 12 performs tracking processing to track the target Tt as the object S. More specifically, in the update process, the processing unit 12 generates an echo image including the latest observation position P and the latest velocity vector Vc, and updates the echo image displayed on the display device 30 with the generated echo image.

[0055] The processing unit 12 repeatedly performs the detection process, gating process, selection process, and update process in this order. Note that the order of the gating process and the detection process is not limited to the above and may be changed.

[0056] (Details of gating and selection processes) Referring again to Figure 5, for example, the processing unit 12 sets the region Ar based on an index value IN indicating the wobble of the target S, the velocity of the target S, and the size of the target S. The index value IN is a statistical value calculated based on the change in the velocity vector Vc of the target S. Specific examples of the gating process and selection process are described below.

[0057] (Specific example 1) In the gating process, the processing unit 12 excludes the reflector R4, which is outside the region Ar, from the selection candidates among the reflectors R1, R2, R3, and R4.

[0058] Next, the processing unit 12 calculates an index value IN indicating the wobble of the target S when each reflector R1, R2, and R3 (excluding reflector R4 which was excluded from the selection candidates in the selection process) is selected as the target Tt. Based on the calculated index value IN, the processing unit 12 selects the target Tt.

[0059] Figures 7 and 8 show an example of a method for calculating index values ​​by a processing unit in a radar device according to an embodiment of the present disclosure. In Figures 7 and 8, the X direction is the east-west direction, and the Y direction is the north-south direction.

[0060] Referring to Figure 7, the processing unit 12 calculates the velocity vector Vr2, which is the velocity vector Vc of the target S when the reflector R2 is selected as the tracking target Tt, i.e., the target S.

[0061] Then, the processing unit 12 calculates Va, the absolute value of the difference between the maximum and minimum values ​​of the five most recent velocity vectors Vc, including velocity vector Vr2, as an index value IN when reflector R2 is selected as the target Tt to be tracked. More specifically, the processing unit 12 calculates VaX, the absolute value of the difference between the maximum and minimum values ​​of the five velocity vectors Vc in the X direction, and VaY, the absolute value of the difference between the maximum and minimum values ​​of the five velocity vectors Vc in the Y direction, as absolute values ​​Va.

[0062] Referring to Figure 8, the processing unit 12 calculates the velocity vector Vr3, which is the velocity vector Vc of the target S when the reflector R3 is selected as the tracking target Tt, i.e., the target S.

[0063] Then, the processing unit 12 calculates Va, the absolute value of the difference between the maximum and minimum values ​​of the five most recent velocity vectors Vc, including velocity vector Vr3, as an index value IN when reflector R3 is selected as the tracking target Tt. More specifically, the processing unit 12 calculates VaX, the absolute value of the difference between the maximum and minimum values ​​of the five velocity vectors Vc in the X direction, and VaY, the absolute value of the difference between the maximum and minimum values ​​of the five velocity vectors Vc in the Y direction, as absolute values ​​Va.

[0064] Similarly, the processing unit 12 calculates the absolute values ​​VaX and VaY when the reflector R1 is selected as the target Tt to be tracked. The processing unit 12 may also be configured to calculate the absolute values ​​VaX and VaY using two, three, four, or six or more velocity vectors Vc.

[0065] Next, the processing unit 12 compares the calculated absolute values ​​VaX and VaY with the threshold Th1. For example, the threshold Th1 is set to a value based on the size of the target S. If the processing unit 12 selects the reflector R as the target Tt, and at least one of the absolute values ​​VaX and VaY is greater than the threshold Th1, the processing unit 12 excludes the reflector R from the tracking candidates. Alternatively, the processing unit 12 may be configured to exclude the reflector R from the tracking candidates if either of the absolute values ​​VaX or VaY is less than or equal to the threshold Th1, while excluding the reflector R from the tracking candidates if both absolute values ​​VaX and VaY are greater than the threshold Th1. Alternatively, the absolute values ​​VaX and VaY may be compared with two different thresholds.

[0066] For example, if the processing unit 12 selects reflector R3 as the target Tt to be tracked, its absolute values ​​VaX and VaY are greater than the threshold Th1, so it excludes reflector R3 from the tracking candidates. On the other hand, if the processing unit 12 selects reflector R1 as the target Tt to be tracked, its absolute values ​​VaX and VaY are less than or equal to the threshold Th1, so it keeps reflector R1 as a tracking candidate. Also, if the processing unit 12 selects reflector R2 as the target Tt to be tracked, its absolute values ​​VaX and VaY are less than or equal to the threshold Th1, so it keeps reflector R2 as a tracking candidate.

[0067] Referring again to Figure 5, the processing unit 12 then selects the target to be tracked Tt based on the distance Ds between the candidate reflector R and the predicted position Pe. More specifically, the processing unit 12 selects the reflector R2, which has the smallest distance from the predicted position Pe, as the target to be tracked Tt among the remaining candidate reflectors R1 and R2.

[0068] Alternatively, the processing unit 12 may select the target Tt to be tracked based on the absolute values ​​VaX and VaY, which are the wobble index values ​​IN, instead of selecting the target Tt based on the distance Ds. In this case, the processing unit 12 selects the reflector R2, which has the smallest absolute values ​​VaX and VaY when selected as the target Tt among the remaining tracking candidates R1 and R2, as the target Tt to be tracked.

[0069] Figure 9 shows an example of a region set by the processing unit in a radar device according to an embodiment of the present disclosure. Figure 9 shows regions Ar1 and Ar2, which are regions Ar. Referring to Figure 9, the processing unit 12 repeatedly sets regions Ar. For example, when the processing unit 12 selects a target Tt to be tracked in region Ar1, it sets the next region Ar2 based on the position of the reflector R selected as the target Tt to be tracked.

[0070] More specifically, the processing unit 12 determines that the reflector R2 is the target S and calculates the velocity vector Vc of the target S. Based on the observed position P of the target S and the calculated velocity vector Vc, the processing unit 12 calculates the predicted position Pe of the target S at the next generation timing Gs of the concatenated echo data EdC. The observed position P may be the position of the reflector R2, or it may be a position obtained by performing a predetermined calculation process to smooth the observed position P with respect to the position of the reflector R2.

[0071] Furthermore, the processing unit 12 sets the area Sar of region Ar based on the size of the target S, the velocity of the target S, and the sway index value IN. For example, the processing unit 12 sets a larger area Sar for region Ar the larger the size of the target S, the larger the velocity of the target S, and the larger the index value IN. As an example, the processing unit 12 obtains the area Sar corresponding to the parameters by substituting the parameters such as the size of the target S, the velocity of the target S, and the index value IN into a predetermined calculation formula.

[0072] The processing unit 12 sets a region Ar2 centered on the calculated predicted position Pe and having a set area Sar. The processing unit 12 may set the area Sar without using the size of the target S, the velocity of the target S, or some of the index value IN. Furthermore, the area Sar may be a pre-set fixed value.

[0073] Figure 10 shows another example of a region set by the processing unit in a radar device according to an embodiment of the present disclosure. Figure 10 shows regions Ar1 and Ar2, which are regions Ar. Referring to Figure 10, if no tracking target Tt is selected in region Ar1, the processing unit 12 sets the next region Ar2 based on the predicted position Pe in region Ar1.

[0074] More specifically, the processing unit 12 excludes reflectors R1, R2, and R3 from the tracking candidates if the absolute values ​​VaX and VaY when reflector R1 is selected as the tracking target Tt are greater than the threshold Th1, the absolute values ​​VaX and VaY when reflector R2 is selected as the tracking target Tt are greater than the threshold Th1, and the absolute values ​​VaX and VaY when reflector R3 is selected as the tracking target Tt are greater than the threshold Th1.

[0075] Based on the comparison result between the absolute values ​​VaX and VaY and the threshold Th1, the processing unit 12 determines that if all reflectors R in region Ar1 are excluded from the tracking candidates, tracking becomes impossible. Therefore, it performs interpolation processing to interpolate the tracking target using the predicted position Pe in region Ar1.

[0076] More specifically, the processing unit 12 assumes that the observed position P of the target S is the predicted position Pe, and calculates the velocity vector Vc of the target S. Based on the predicted position Pe in region Ar1 and the calculated velocity vector Vc, the processing unit 12 calculates the predicted position Pe of the target S at the next generation timing Gs of the concatenated echo data EdC. The processing unit 12 also sets the area Sar based on the size of the target S, the velocity of the target S, and the wobble index value IN. The processing unit 12 sets region Ar2 centered on the calculated predicted position Pe and having the set area Sar. The processing unit 12 may set the area Sar without using some of the size of the target S, the velocity of the target S, and the index value IN. The area Sar may also be a pre-set fixed value.

[0077] Furthermore, when the processing unit 12 performs interpolation, it may be configured to accumulate the tracking results of the target S in the background instead of updating the echo image showing the tracking results of the target S. Also, if tracking becomes impossible, the processing unit 12 may be configured to terminate the tracking process without performing interpolation.

[0078] (Specific example 2) Referring again to Figure 5, the processing unit 12, in the same manner as in Specific Example 1, excludes the reflector R4 outside the region Ar from the selection candidates in the gating process among the reflectors R1, R2, R3, and R4.

[0079] Next, the processing unit 12 selects the target to track Tt based on the distance Ds between the reflectors R1, R2, and R3 (excluding reflector R4 which was excluded from the selection candidates in the selection process) and the predicted position Pe. More specifically, the processing unit 12 selects reflector R2, which has the smallest distance from the predicted position Pe among reflectors R1, R2, and R3, as the target to track Tt.

[0080] Referring again to Figure 7, the processing unit 12 then calculates the velocity vector Vr2 of the target S when the reflector R2 is selected as the target Tt, i.e., the target S. Then, the processing unit 12 calculates the absolute values ​​VaX and VaY as index values ​​IN when the reflector R2 is selected as the target Tt. The processing unit 12 compares the calculated absolute values ​​VaX and VaY with the threshold Th1.

[0081] Referring again to Figure 9, the processing unit 12 determines that the reflector R2 is the target S if the absolute values ​​of VaX and VaY when the reflector R2 is selected as the target Tt are less than or equal to the threshold Th1, and calculates the velocity vector Vc of the target S. Then, the processing unit 12 sets the region Ar2 in the same manner as in Specific Example 1.

[0082] Referring again to Figure 10, the processing unit 12, on the other hand, if at least one of the absolute values ​​VaX and VaY when the reflector R2 is selected as the target Tt to be tracked is greater than the threshold Th1, discards the selected target Tt to be tracked and performs interpolation processing.

[0083] More specifically, the processing unit 12 calculates the velocity vector Vc assuming that the observed position P of the target S is the predicted position Pe, in the same manner as in Specific Example 1, and sets the region Ar2.

[0084] (Other examples of index values ​​IN) The processing unit 12 is configured to calculate absolute values ​​VaX and VaY as index values ​​IN, but it is not limited to this. The processing unit 12 may also be configured to calculate other statistical values ​​based on the change in the velocity vector Vc of the target S as index values ​​IN.

[0085] For example, the processing unit 12 extracts multiple X-direction components Ix and multiple Y-direction components Iy from multiple velocity vectors Vc.

[0086] The processing unit 12 may calculate the variance of multiple X-direction components Ix as the index value IN, instead of the absolute value VaX, or calculate the standard deviation of multiple X-direction components Ix, or calculate the mean deviation of multiple X-direction components Ix, or calculate the interquartile range of multiple X-direction components Ix, or calculate the interquartile deviation of multiple X-direction components Ix.

[0087] Furthermore, the processing unit 12 may calculate the variance of multiple Y-direction components Iy as the index value IN instead of the absolute value VaY, or it may calculate the standard deviation of multiple Y-direction components Iy, or it may calculate the mean deviation of multiple Y-direction components Iy, or it may calculate the interquartile range of multiple Y-direction components Iy, or it may calculate the interquartile deviation of multiple Y-direction components Iy.

[0088] Furthermore, the processing unit 12 may calculate a statistical value of the angle formed by multiple velocity vectors Vc, or a statistical value of the cosine distance between multiple velocity vectors Vc, instead of the absolute values ​​VaX and VaY, as the index value IN.

[0089] Furthermore, the processing unit 12 may calculate a value as the index value IN, which is a combination of the above-mentioned multiple statistical values.

[0090] Furthermore, while the index value IN is defined as a statistical value calculated based on the change in the velocity vector Vc of the target S, it is not limited to this. The index value IN may be a statistical value calculated based on the change in the velocity of the target S. More specifically, the processing unit 12 calculates multiple scalar velocities Sv corresponding to multiple velocity vectors Vc. A scalar velocity Sv is a scalar quantity of the velocity of the target S. The processing unit 12 may calculate the absolute value of the difference between the maximum and minimum values ​​of the calculated multiple scalar velocities Sv as the index value IN, or it may calculate the variance of the multiple scalar velocities Sv, or it may calculate the standard deviation of the multiple scalar velocities Sv, or it may calculate the mean deviation of the multiple scalar velocities Sv, or it may calculate the interquartile range of the multiple scalar velocities Sv, or it may calculate the interquartile deviation of the multiple scalar velocities Sv.

[0091] Furthermore, the index value IN may be a statistical value calculated based on the positional quantity of the target S. More specifically, the processing unit 12 calculates the positional change amount Vp of the target S for each scan period Cs using multiple recent observation positions P. The positional change amount Vp is a scalar quantity of the distance moved by the target S. The processing unit 12 may calculate the absolute value of the difference between the maximum and minimum values ​​of the multiple calculated positional change amounts Vp as the index value IN, or it may calculate the variance of the multiple positional change amounts Vp, or it may calculate the standard deviation of the multiple positional change amounts Vp, or it may calculate the mean deviation of the multiple positional change amounts Vp, or it may calculate the interquartile range of the multiple positional change amounts Vp, or it may calculate the interquartile deviation of the multiple positional change amounts Vp.

[0092] [Operation Flow] The radar device according to the embodiment of this disclosure includes a computer including memory, and a processor such as a CPU in the computer reads and executes a program from the memory that includes some or all of the steps in the following flowchart. The program for this device can be installed externally. The program for this device is distributed either stored on a recording medium or via a communication line.

[0093] Figure 11 is a flowchart showing an example of the operation of the target tracking unit in a radar device according to an embodiment of the present disclosure when generating concatenated echo data. The acquisition unit 11 in the target tracking unit 101 performs the processing shown in Figure 11 each time it receives divided echo data EdD from the radar unit 20.

[0094] Referring to Figure 11, first, the acquisition unit 11 in the target tracking unit 101 stores the segmented echo data EdD received from the radar unit 20 in the storage unit 13 (step S11).

[0095] Next, the acquisition unit 11 terminates processing if the number of divided echo data EdD stored in the storage unit 13 has not reached N (NO in step S12).

[0096] On the other hand, when the number of divided echo data EdD stored in the storage unit 13 reaches N (YES in step S12), the acquisition unit 11 generates concatenated echo data EdC by concatenating the N divided echo data EdD (step S12).

[0097] Figure 12 is a flowchart showing an example of the operation of the target tracking unit in a radar device according to an embodiment of the present disclosure when performing tracking processing. The processing unit 12 in the target tracking unit 101 executes the processing shown in Figure 12 each time concatenated echo data EdC is generated by the acquisition unit 11.

[0098] Referring to Figure 12, first, the processing unit 12 in the target tracking unit 101 performs detection processing to detect the reflector R in the target area Ta based on the concatenated echo data EdC generated by the acquisition unit 11 (step S21).

[0099] Next, the processing unit 12 performs a gating process to set up region Ar. More specifically, the processing unit 12 calculates the current predicted position Pe of the target S based on the past observed position P of the target S and the velocity vector Vc of the target S. The processing unit 12 also sets the area Sar based on the size of the target S, the velocity of the target S, and the wobble index value IN. Then, the processing unit 12 sets up region Ar centered on the calculated predicted position Pe and having the set area Sar (step S22).

[0100] Next, the processing unit 12 performs a selection process to select a target Tt to be tracked from one or more reflectors R in region Ar. For example, as in the specific example 1 described above, the processing unit 12 excludes from the tracking candidates any reflectors R in region Ar whose index value IN, which indicates fluctuation when selected as a target Tt, is greater than a predetermined value. Then, the processing unit 12 selects the reflector R in region Ar that has the smallest distance from the predicted position Pe as the target Tt to be tracked (step S23).

[0101] Next, the processing unit 12 performs tracking processing to track the selected target Tt as the object S. More specifically, the processing unit 12 generates an echo image including the observation position P of the object S and the velocity vector Vc of the object S, and performs update processing to update the echo image displayed on the display device 30 with the generated echo image (step S24).

[0102] Furthermore, in step S24, if all reflectors R in region Ar are excluded from the tracking candidates and tracking becomes impossible, the processing unit 12 performs interpolation processing to interpolate the tracking target at the predicted position Pe in region Ar. Then, in the subsequent step S23, the processing unit 12 sets region Ar based on the predicted position Pe. That is, instead of the observed position P, the processing unit 12 calculates the predicted position Pe of the current target S based on the predicted position Pe and the velocity vector Vc, and sets region Ar centered on the calculated predicted position Pe.

[0103] The embodiments described above should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0104] 1 ship 11 Acquisition Department 12 Processing Units 13 Storage section 20 Radar section 21 Antennas 22 Transceiver Unit 23 Signal Processing Unit 30 Display device 101 Target tracking unit Ta detection target area P Observation location Vc, Vr2, Vr3 velocity vectors R,R1,R2,R3,R4 Reflector Pe predicted position Ar,Ar1,Ar2 area VaX, VaY absolute value

Claims

1. A target tracking device that performs tracking processing to track a target in a detection target area, An acquisition unit that acquires echo data showing the correspondence between the position in the detection target area and the level of the reflected wave reflected at the position from the electromagnetic wave transmitted via the antenna, A detection unit that detects multiple reflectors whose reflected wave level is above a predetermined value based on the echo data, A region setting unit sets a region that includes the predicted position of the target, and which is a region in which the target to be tracked may exist. A selection unit for selecting a tracking target from one or more of the reflectors in the aforementioned region, A target tracking device comprising: a tracking unit that performs the tracking process for tracking the target object as the target object.

2. The target tracking device according to claim 1, wherein the area setting unit sets the area based on an index value indicating the wobble of the target.

3. The target tracking device according to claim 1, wherein the area setting unit sets the area based on an index value calculated based on the amount of change in the velocity vector of the target.

4. The target tracking device according to claim 1, wherein the area setting unit sets the area based on an index value calculated based on the amount of change in the velocity of the target.

5. The target tracking device according to claim 1, wherein the area setting unit sets the area based on an index value calculated based on the amount of change in the position of the target.

6. The target tracking device according to any one of claims 1 to 5, wherein the area setting unit sets the area based on the speed of the target.

7. The target tracking device according to any one of claims 1 to 5, wherein the area setting unit sets the area based on the size of the target.

8. The area setting unit repeatedly sets the area, The area setting unit sets the next area based on the position of the tracking target selected by the selection unit, The target tracking device according to any one of claims 1 to 5, wherein if the selection unit does not select the target to be tracked in the area, the area setting unit sets the next area based on the predicted position in the area.

9. The target tracking device according to any one of claims 1 to 5, wherein the selection unit selects the target to be tracked based on an index value indicating the wobble of the target.

10. A target tracking device that performs tracking processing to track a target in a detection target area, and a target tracking method in the device, Echo data is acquired that shows the correspondence between the position in the detection target area and the level of the reflected wave reflected at the position from the electromagnetic wave transmitted via the antenna. Based on the echo data, multiple reflectors whose reflected wave levels are above a predetermined value are detected. A region including the predicted position of the target is defined as a region where the target to be tracked may exist. A target for tracking is selected from one or more of the reflectors in the aforementioned region. A target tracking method that performs the tracking process of tracking the target object as the target object.

11. The target tracking method according to claim 10, wherein the region is set based on an index value indicating the wobble of the target.

12. The target tracking method according to claim 10, wherein the region is set based on an index value calculated based on the amount of change in the velocity vector of the target.

13. The target tracking method according to claim 10, wherein the region is set based on an index value calculated based on the amount of change in the velocity of the target.

14. The target tracking method according to claim 10, wherein the area is set based on an index value calculated based on the amount of change in the position of the target.

15. A target tracking program used in a target tracking device that performs tracking processing to track an object in a detection target area, A process for acquiring echo data that shows the correspondence between the position in the detection target area and the level of the reflected wave reflected at the position from the electromagnetic wave transmitted via the antenna, Based on the echo data, a process is performed to detect multiple reflectors whose reflected wave levels are above a predetermined value, A process of defining a region that includes the predicted position of the target, and in which the target to be tracked may exist. A process for selecting a tracking target from one or more of the reflectors in the aforementioned region, A target tracking program for causing a computer to perform the tracking process of tracking the aforementioned target object as the aforementioned target.

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