KR-102964025-B1 - METHOD FOR ASSOCIATING DATA FOR TRACKING HIGH-MOBILITY TARGET AND RADAR SYSTEM USING THE SAME

KR102964025B1KR 102964025 B1KR102964025 B1KR 102964025B1KR-102964025-B1

Abstract

The present invention provides a data association method for stably tracking a rapidly maneuvering target in a radar system and a radar system using the same. The data association method tracks a highly maneuvering target in a radar system. The data association method comprises: i) providing a line-of-sight velocity estimate, a line-of-sight velocity prediction, and a velocity measurement according to a tracking filter for a plot of a target; ii) calculating a first error variance between the line-of-sight velocity estimate and the velocity measurement; iii) calculating a second error variance between the line-of-sight velocity prediction and the velocity measurement; iv) if the first error variance is less than the second error variance, calculating the Mahalanobis squared distance between the line-of-sight velocity estimate and the velocity measurement; and v) if the Mahalanobis squared distance is less than a threshold value, determining whether the plot is data association.

Inventors

서정직
최성희

Assignees

국방과학연구소

Dates

Publication Date: 20260511
Application Date: 20230809

Claims (16)

As a data association method for tracking highly maneuverable targets in a radar system, A step of providing line-of-sight velocity estimates, line-of-sight velocity predictions, and velocity measurements for a plot of the target by means of a tracking filter, A step of calculating a first error variance between the above-mentioned line-of-sight velocity estimate and the above-mentioned velocity measurement value, A step of calculating a second error variance between the above-mentioned line-of-sight velocity prediction value and the above-mentioned velocity measurement value, If the first error variance is less than the second error variance, the step of calculating the Mahalanobis squared distance between the estimated line-of-sight velocity and the measured velocity, A step of determining whether the data of the plot is correlated when the Mahalanobis squared distance between the estimated line-of-sight velocity and the measured velocity is less than a threshold value. If the first error variance is greater than or equal to the second error variance, the step of calculating the Mahalanobis squared distance between the predicted line-of-sight velocity value and the measured velocity value, and A step of determining whether the data of the plot is correlated when the Mahalanobis squared distance between the predicted line-of-sight velocity and the measured velocity is less than the threshold value. A data association method including
In paragraph 1, A data association method that does not associate the plot when the Mahalanobis squared distance between the above-mentioned line-of-sight velocity estimate and the above-mentioned velocity measurement is greater than or equal to the above threshold.
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In paragraph 1, A data association method that does not associate the plot when the Mahalanobis squared distance between the predicted line-of-sight velocity and the measured velocity is greater than or equal to the threshold value.
In any one of paragraphs 1, 2 and 4, The above threshold is a data association method in which the threshold is 4 to 9.
In paragraph 1, The step of providing the above-mentioned line-of-sight velocity estimate, line-of-sight velocity prediction, and velocity measurement is: A step of providing a first distance estimate and a first velocity estimate according to the tracking filter in a first scan of the target undergoing uniformly accelerated motion, and A step of providing a second distance measurement and a second speed measurement according to the tracking filter in a second scan following the first scan. A data association method including
In paragraph 6, A data association method in which, in the step of calculating the first error variance above, the first error variance is calculated by the following mathematical formula. Here, the above is the error variance of the above distance measurement value, above is the error variance of the above distance estimate, above is the line-of-sight velocity error variance of the estimated value according to the above tracking filter, the above is the error covariance between the distance estimate and the line-of-sight velocity according to the above tracking filter, the above is the variance of the line-of-sight velocity measurement error.
In Paragraph 7, A data association method in which, in the step of calculating the second error variance above, the second error variance is calculated by the following mathematical formula. Here, the above is the error variance of the predicted line-of-sight velocity value according to the tracking filter, the is the error variance of the above line-of-sight velocity measurement.
In paragraph 8, A data association method in which, in the step of calculating the Mahalanobis squared distance, the Mahalanobis squared distance is calculated by the following mathematical formula. Here, the above is the above-mentioned line-of-sight velocity estimate, and the above is the above speed measurement value, and the above is the error variance using the above-mentioned line-of-sight velocity estimate.
In paragraph 6, A data association method in the step of providing the first distance estimate and the first velocity estimate, wherein the range of acceleration change of the target trackable by the tracking filter is 20 m/ s² to 90 m/ s² .
In paragraph 1, A data association method in the step of providing the above-mentioned line-of-sight velocity estimate, line-of-sight velocity prediction value, and velocity measurement value, wherein the tracking filter is a Kalman filter.
A radar system using a data association method according to paragraph 1, Transmitter/receiver unit, A signal processing unit connected to the above-mentioned transmitting and receiving unit and extracting the above-mentioned line-of-sight velocity estimation value, the above-mentioned line-of-sight velocity prediction value, and the above-mentioned velocity measurement value from electromagnetic waves received from the above-mentioned transmitting and receiving unit, A computational unit connected to the signal processing unit and calculating the first error variance, the second error variance, and the Mahalanobis squared distance using the line-of-sight velocity estimate, the line-of-sight velocity prediction, and the velocity measurement value, and A control unit connected to the above operation unit that determines the data association of the above plot A radar system including
In Paragraph 12, The above computational unit calculates the Mahalanobis squared distance between the line-of-sight velocity estimate and the velocity measurement value when the first error variance is less than or equal to the second error variance, and A radar system in which the control unit determines whether there is data correlation of the target plot when the Mahalanobis squared distance between the line-of-sight velocity estimate and the velocity measurement is less than the threshold value.
In Paragraph 12, The above computational unit calculates the Mahalanobis squared distance between the line-of-sight velocity prediction value and the velocity measurement value when the above first error variance exceeds the above second error variance, and A radar system in which the control unit determines whether there is data correlation of the target plot when the Mahalanobis squared distance between the predicted line-of-sight velocity value and the measured velocity value is less than the threshold value.
In paragraph 13 or 14, The above threshold value is a radar system with 4 to 9.
In Paragraph 12, A radar system in which the signal processing unit includes a target filter, and the target filter provides the line-of-sight velocity estimate, the line-of-sight velocity prediction, and the velocity measurement.

Description

Method for Associated Data for Tracking High-Mobility Targets and Radar System Using the Same The present invention relates to a data association method for target tracking and a radar system using the same, and more specifically, to a data association method for stably tracking a rapidly maneuvering target in a radar system and a radar system using the same. A radar system identifies the location of a moving target. The radar system transmits electromagnetic waves reflected by targets in its path. Then, the radar system determines the range and speed of the detected target by measuring the time delay and Doppler shift of the returned signal. Data association is a critical step in which measurements received from the radar system are associated with the existing tracking path. During data association, the information detected by the radar (plots) is mutually associated with the track being tracked, and the track is updated using the associated plots. In this case, data association is performed when the positional difference between the track and the plots is minimal, utilizing positional information such as distance, velocity, elevation, and azimuth from the plots. However, if a target is not actually detected or a false target is detected, the quality of the track deteriorates. Figure 1 is a schematic illustration of the plot and track of a target being tracked in a radar system. Figure 2 is a diagram schematically showing the data correlation range when the target of Figure 1 starts a rapid maneuver. FIG. 3 is a schematic flowchart of a data association method according to one embodiment of the present invention. Figure 4 is a schematic flowchart of the mathematical formulas used in each step of Figure 3. Figure 5 is a schematic block diagram of a radar system using the data association method of Figure 1. Figure 6 is a schematic block diagram of the operation unit of Figure 5. The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. The meaning of "comprising" as used in the specification specifies a particular characteristic, area, integer, step, action, element, and/or component, and does not exclude the presence or addition of other particular characteristic, area, integer, step, action, element, component, and/or group. Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined. For example, the term “applied” described below is interpreted to include both the state in which it is appropriately used and the state prior to appropriate use. Expressions described in the singular in this specification may be interpreted as singular or plural unless explicit expressions such as "one" or "single" are used. In this specification, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be named the second component, and similarly, the second component may be named the first component. In the flowchart described with reference to the drawings in this specification, the order of operations may be changed, several operations may be merged or some operations may be divided, and certain operations may not be performed. Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Figure 1 schematically shows the plot (P) and track (T) of a target displayed in a radar system. A target is tracked using a radar system. Plot (P) is extracted from the position information of a target detected by a radar system, more specifically, a target filter. The position information includes distance information and velocity information. Track (T) structures and represents the information obtained through Plot (P). Track (T) is generated by associating multiple Plots (P). As illustrated in FIG. 1, the radar system reliably tracks a target through a tracking filter. However, if the target maneuvers rapidly, tracking may fail. This is explained in detail through FIG. 2. FIG. 2 schematically illustrates the data correlation range when the target of FIG. 1