Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.
The main functions of the modern radar system are target finding and target tracking, and under a complex environment, various clutter and interference signals exist in the space, which brings greater difficulty to the multi-target tracking technology, and is undoubtedly a greater challenge to the multi-target data association technology.
The current data association methods mainly include a nearest neighbor data association method and a global nearest neighbor data association method. The nearest neighbor data association method is high in association speed, but the association error probability is high in complex environment; the global nearest neighbor data association method has high association accuracy, but under the condition of more measured traces, the association search time can be multiplied, so that the problem of poor real-time performance exists. Therefore, the existing data association method has the problems of poor real-time performance or high occurrence probability of false association.
In order to explain the technical means of the present application, the following description will be given by way of specific examples.
Fig. 1 shows a schematic flow chart of an implementation of a data association method provided in an embodiment of the present application, which is suitable for a situation that the real-time performance of data association needs to be improved and the occurrence probability of a false association needs to be effectively reduced. Specifically, in this embodiment of the present application, the data association method may include steps 101 to 102.
Step 101, multiple tracks obtained by radar measurement and multiple maintained tracks are obtained.
In the embodiment of the application, when the radar performs multi-target tracking, multiple tracks need to be maintained, each track corresponds to one target, multiple tracks can be measured, and each track wave gate may only contain one track or contain multiple tracks, so that after multiple tracks obtained by radar measurement and multiple tracks maintained are obtained, all tracks in the wave gate need to be traversed for each track, and thus one track is associated with each track. When the flight path is associated with a certain point path, the flight path and the point path associated with the flight path belong to the same target.
Step 102, traversing all point tracks in a wave gate of a current target track to obtain an associated point track of the current target track, and determining an associated point track for a next target track after obtaining the associated point track of the current target track until determining the associated point track of each track in the plurality of tracks; and the current target track and the next target track are the tracks of any undetermined associated point track in the plurality of tracks.
In some embodiments of the present application, before traversing all the point tracks within the current target track wave gate, the following may be included: and calculating the distance, the angle difference and the speed difference between each point track obtained by the radar measurement and the current target track, and taking the point track with the distance, the angle difference and the speed difference within the associated threshold as the point track within the wave gate of the current target track.
That is to say, before traversing all the point tracks in the current target track wave gate, the point tracks which are not in the current target track wave gate need to be removed from the multiple point tracks obtained by radar measurement, that is, the point tracks which are not in the associated threshold of the current target track are removed, and all the point tracks which are not traversed in the current target track wave gate are obtained.
Specifically, the distance, the angle difference and the speed difference between each point track obtained by radar measurement and the current target track can be calculated, whether the distance, the angle difference and the speed difference are all within the associated threshold is judged, and then the point tracks which are not within the associated threshold in the point tracks are removed, so that the data quantity of data association is reduced, and the occurrence probability of false association is further reduced. The specific value of the association threshold can be set according to the actual application scenario.
As shown in fig. 2, the traversing all the point tracks in the current target track wave gate to obtain the associated point track of the current target track may include: step 201 to step 207.
Step 201, calculating and storing the distance between the current target track and the first trace point to obtain the current minimum distance; the first point trace is a point trace which is not traversed in any point trace in the target track wave gate.
The distance between the current target track and the first trace point may be calculated by using an euclidean distance calculation formula, or may be calculated by using other methods that can obtain the distance between the current target track and the first trace point, which is not limited in the present application.
In the embodiment of the application, when the distance between the target track and the point track is smaller, the probability that the target track and the point track belong to the same target is higher, and the point track and the target track are matched more; therefore, the target track needs to be associated with the point track with the smallest distance to the target track, and when each track is associated with the point track with the smallest distance to the target track, the sum of the distances between each track and the associated point track is as small as possible, so that the proper point track is matched for each track, and the occurrence of error association is reduced.
It should be noted that, in practical applications, before calculating and storing the distance between the current target track and the first point track, an initial value of the current minimum distance may be set, and the initial value is greater than the distance between the current target track and any point track within the current target track wave gate. Therefore, after the distance between the current target track and the first track point is calculated and stored, and the distance between the current target track and the first track point is compared with the initial value of the current minimum distance, the distance between the current target track and the first track point can still be used as the current minimum distance.
Step 202, calculating and storing the distance between the current target track and the next track point, and judging whether the distance between the current target track and the next track point is greater than or equal to the current minimum distance.
Specifically, the distance between the current target track and the next trace point may refer to the description of step 201, and is not described herein again.
In the embodiment of the application, after the distance between the current target track and the first point track is obtained through calculation, the distance between the current target track and the first point track can be determined as the current minimum distance, then, traversal of the next point track in the current target track wave gate is performed, the distance between the current target track and the next point track is compared with the current minimum distance, and then the current minimum distance is updated until all the point tracks in the current target track wave gate are traversed, and the point track corresponding to the current minimum distance is used as the associated point track of the current target track. Specifically, refer to the description of step 203 to step 206.
Step 203, if the distance between the current target track and the next point track is greater than or equal to the current minimum distance, judging whether the next point track is the last point track in the current target track wave gate, and if the next point track is not the last point track in the current target track wave gate, re-traversing the next point track in the current target track wave gate until all the point tracks in the current target track wave gate are traversed.
In some embodiments of the present application, if the distance between the current target track and the next point track is greater than or equal to the current minimum distance, it indicates that the probability that the current target track and the next point track belong to the same target is less than the probability that the current target track and the point track corresponding to the current minimum distance belong to the same target, that is, compared with the next point track, the point track with the current target track distance being the current minimum distance and the current target track are more matched, at this time, the current minimum distance may not be updated, and it may be determined whether the next point track is the last point track within the current target track wave gate, if the next point track is not the last point track within the current target track wave gate, it indicates that the point track within the current target track wave gate is not completely traversed, and the traversal of the next point track within the current target track wave gate needs to be performed again, and continuously updating the current minimum distance until all the point tracks in the wave gate of the current target track are traversed, determining the point track with the distance to the current target track as small as possible (namely the point track with the distance to the current target track as the current minimum distance), and further determining the point track with the distance to the current target track as the current minimum distance as the point track which is most matched with the current target track.
Step 204, if the distance between the current target track and the next track point is smaller than the current minimum distance, judging whether the next track point is associated with other tracks; and if the next track point is associated with the other tracks, judging whether the distance between the next track point and the other tracks is greater than the current minimum distance.
In some embodiments of the present application, if the distance between the current target track and the next track is less than the current minimum distance, it is indicated that the probability that the current target track and the next track belong to the same target is greater than the probability that the current target track and the track at the current minimum distance belong to the same target, that is, the next track is more matched with the current target track than the track at the current minimum distance, at this time, it is required to determine whether the next track is associated with other tracks, if the next track is not associated with other tracks, the current minimum distance may be updated to the distance between the current target track and the next track, and it is determined whether the next track is the last track within the current target track, if the next track is not the last track within the current target track, and traversing the next point track in the current target track wave gate again, and continuously updating the current minimum distance until all the point tracks in the current target track wave gate are traversed.
Step 205, if the distance between the next track point and the other track points is greater than the current minimum distance, updating the current minimum distance to the distance between the current target track and the next track point, and determining whether the next track point is the last track point in the current target track wave gate, if the next track point is not the last track point in the current target track wave gate, re-traversing the next track point in the current target track wave gate until all the track points in the current target track wave gate have been traversed.
In some embodiments of the present application, if the distance between the next track point and the other track point is greater than the current minimum distance, it indicates that the probability that the next track point and the current target track point belong to the same target is greater than the probability that the next track point and the other track point belong to the same target, and at this time, the current minimum distance may be updated to the distance between the current target track point and the next track point; and then, judging whether the next point track is the last point track in the current target track wave gate or not, if the next point track is not the last point track in the current target track wave gate, traversing the next point track in the current target track wave gate again, namely, the step 202 to the step 206, and continuously updating the current minimum distance until all the point tracks in the current target track wave gate are traversed.
Step 206, if the distance between the next point track and the other track is less than or equal to the current minimum distance, directly judging whether the next point track is the last point track in the current target track wave gate, and if the next point track is not the last point track in the current target track wave gate, traversing the next point track in the current target track wave gate again; and completing the traversal of all the point tracks in the current target track wave gate.
In some embodiments of the present application, if the distance between the next point track and the other track is less than or equal to the current minimum distance, it indicates that the possibility that the next point track and the current target track belong to the same target is less than the possibility that the next point track and the other track belong to the same target, at this time, the current minimum distance does not need to be updated, and it is directly determined whether the next point track is the last point track in the current target track wave gate, and if the next point track is not the last point track in the current target track wave gate, the next point track in the current target track wave gate is traversed again, and the current minimum distance is continuously updated until all the point tracks in the current target track wave gate are traversed.
Step 207, after all the point tracks in the current target track wave gate are traversed, taking the point track corresponding to the current minimum distance as an associated point track of the current target track, judging whether the point track corresponding to the current minimum distance is associated with other tracks, and if the point track corresponding to the current minimum distance is associated with other tracks, marking the other tracks as the tracks of which the associated point tracks are not determined.
Correspondingly, the determination of the associated point track of the next target track may adopt the above determination manner of the current target track.
It should be noted that, in the above step 207, in the process of re-determining the associated point track of the flight path marked as the undetermined associated point track after marking the other flight path as the flight path of the undetermined associated point track, it is not necessary to re-calculate the distance between the flight path and the point track in the flight path gate.
Fig. 3 shows a schematic diagram of a first specific implementation of the data association method provided by the present application, where if a point track 301 and a point track 302 obtained by radar measurement and a track 303 and a track 304 maintained by radar are obtained, and a point track in a wave gate of a track 303 only includes the point track 301 and the track 302, and a point track in a wave gate of the track 304 does not include the point track 301 and the track 302, when a point track is associated with the track 303, if a first point track is the point track 301, a distance d between the track 303 and the point track 301 may be determined1Determined as the current minimum distance, and then traverse the trace of points 302 due to the distance d between the trace 303 and the trace of points 3022Is greater than the distance d between the flight path 303 and the point path 3011Thus, trace 301 may be associated with track 303, and trace 302 may then be associated with track 304 after traversing trace 301 and trace 302.
As can be seen from fig. 3, with the data association method provided in the present application, when there is no track-crossing competition between the tracks (i.e., each time a track-crossing associated with a current target track is a track-crossing associated with no other track), each track crosses one track-crossing, and the entire data association process can be completed, at this time, the time complexity of the data association method is o (n).
Fig. 4 shows a schematic diagram of a second specific implementation of the data association algorithm provided in the present application, where if a point track 401 and a point track 402 obtained by radar measurement and a track 403 and a track 404 maintained by radar are obtained, and the points in the gates of the track 403 and the track 404 both include only the point track 401 and the point track 402, and the track 404 is already associated with the point track 401, when the track 403 is associated with the point track, if a first point track is the point track 402, the point track 403 and the point track 402 can be located between the first point track and the second point track 402Distance d of4Determining the current minimum distance, then traversing the point track 401, and calculating to obtain the distance d between the flight path 403 and the point track 4013Is smaller than the distance d between the flight path 403 and the point path 4024At this time, it is necessary to determine whether the trace point 401 is associated with another track, and since the trace point 401 is associated with another track 404, it is necessary to determine the current minimum distance (d)3) Whether the distance d between the point track 401 and the track 404 is compared5Small, at the current minimum distance (d)3) Distance d between waypoint 401 and track 4045In hours, track 404 may be marked as a track for which no associated point track is determined, and point track 401 may be associated with track 403, and then the associated point track may be re-determined for track 404. Specifically, trace points 402 may be associated with track 404 after traversing trace points 401 and 402.
As can be seen from fig. 4, with the data association method provided by the present application, when there are competing traces between the track and the track, that is, each time the trace associated with the current target track is a trace already associated with another track, each time the trace associated with the current target track needs to reselect an associated trace for another track associated before the trace, at this time, the time frequency of the data association method is T (n + n-1+ … +1), and the time complexity is O (n +1)2)。
By combining the above fig. 3 and fig. 4, it can be seen that the time complexity of the data association method provided by the present application is between O (n) and O (n)2) The overall time complexity of the method is lower than that of the global nearest neighbor data association algorithm, so that the complexity of the algorithm is reduced, and the real-time performance is improved.
In the embodiment of the application, in the process of determining the associated point track of the current target track, the point track corresponding to the current minimum distance is used as the associated point track of the current target track, and when the point track corresponding to the current minimum distance is associated with other tracks, the other tracks are marked as tracks without the associated point track, so that when the associated point track is determined for a plurality of maintained tracks, the probability of occurrence of data mis-association can be reduced as much as possible, and meanwhile, by the data association mode, the time complexity of the association of the data of the plurality of tracks can be between O (n) andO(n2) The overall time complexity is lower than that of a global nearest neighbor data association algorithm, and the real-time performance of data association is improved, so that the method and the device can effectively reduce the occurrence probability of false association while improving the real-time performance of data association.
It should be noted that, for simplicity of description, the foregoing method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the present application is not limited by the order of acts, as some steps may, in accordance with the present application, occur in other orders.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.