Air traffic control primary radar full-automatic track initiating and tracking method in strong clutter environment

Abstract

According to the air traffic control primary radar full-automatic track initiating and tracking method in the strong clutter environment, the clutter folding interference problem under the atmospheric waveguide condition is solved through the technologies of abnormal clutter multiple suppression and the like, the track false alarm rate under the full-automatic recording condition is remarkably reduced, and the tracking accuracy is improved. And the detection probability of the air traffic control primary surveillance radar on pneumatic targets such as civil aircrafts is obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of radars, and in particular relates to a fully automatic track initiation and tracking method for an air traffic control primary radar in a strong clutter environment. Background Art

[0002] When the radar is working in coastal, humid or desert areas, atmospheric waveguide often occurs as the temperature changes between day and night. Atmospheric waveguide causes electromagnetic waves to deviate from the original orbital direction. The ground objects or sea clutter that can only appear in line of sight extend to 80 or even 150km. Short pulse groups will have serious clutter folding phenomenon, which is obviously characterized by poor stability and large Doppler spectrum broadening. In this clutter background, the target often cannot establish normal navigation.

[0003] In a strong clutter environment or when emphasis is placed on detecting small targets, especially in coastal areas and areas with dense buildings, there is too much residual clutter, making it difficult to manually distinguish targets, and there are many false tracks in automatic tracking, which reduces the quality of the air situation. Clutter suppression must be performed through a one-step filtering process.

[0004] With the rapid development of radar technology, the radar signal processing capability is constantly improving. At the same time, there are a lot of clutter and interference, which puts higher requirements on the radar data processing technology to adapt to it. The traditional manual method can no longer be used to process the target measurement data. Radar data processing technology must be used to refine the radar's target measurement data in real time. Summary of the invention

[0005] In order to overcome the deficiencies in the prior art, the present invention proposes a method for fully automatic track initiation and tracking of air traffic control primary radar in a strong clutter environment. Through technologies such as abnormal clutter multiple suppression, the problem of clutter folding interference under atmospheric waveguide conditions is solved, and the track false alarm rate under fully automatic recording conditions is significantly reduced, and the detection probability of air traffic control primary surveillance radar for aerodynamic targets such as civil aircraft is significantly improved. Specifically, the following steps are included:

[0006] Step 1: Enhance the anti-interference capability of the equipment through anti-folding waveform design according to mission requirements and selection criteria.

[0007] Step 2: Evaluate the quality of the point track based on the point track feature statistics and point track density calculation, eliminate the false point tracks condensed by false target echoes, reduce the track false alarm rate, and control the number of initial point tracks sent to track processing.

[0008] Step 3: According to the point quality and point density, dynamically adjust the N / M criteria in the track starting area. When the number of points exceeds the threshold and meets the target starting criteria between multiple laps, establish the initial track file.

[0009] The first step of anti-folding clutter waveform design is as follows:

[0010] a) Use a combination of long and short pulses to receive folded echoes to improve short-range detection effects.

[0011] b) The folded echo is judged as asynchronous interference and is cleared by anti-asynchronous means.

[0012] The second step specifically includes:

[0013] a) Dot quality assessment

[0014] First, the clutter distribution statistics are processed to determine the density environment level. Then, the radar signal characteristics are used to achieve lowered threshold detection of key security targets in key areas. Finally, a comprehensive weighted calculation is performed to obtain the quality score of the point trace.

[0015] b) Point trace filtering

[0016] Firstly, the risk coefficient is calculated according to the multi-attribute hypothesis test, and then the point trace comprehensive cost function is constructed through the multi-dimensional information of the point trace to control the point trace filtering process and realize the filtering of low-quality point traces.

[0017] The third step specifically includes:

[0018] The data processing adopts the normalized statistical distance algorithm, and the interactive multi-mode filter of the uniform velocity model unscented Kalman filter and the uniform acceleration model unscented Kalman filter. The adaptive setting of the detection parameters is used as the basis for the filter switching to improve the filtering accuracy of the target; the track tracking method of the main and auxiliary target tracking processing mechanism is adopted, and the maximum branch restriction law is used to realize the track stability tracking of the aerodynamic target.

[0019] The beneficial effects of the present invention are

[0020] (1) High reliability: It can effectively solve the problems of track association errors, mistracking in strong clutter environments, and mistracking when multiple targets intersect, which are very likely to occur in the fully automatic track initiation processing when the radar is unattended.

[0021] (2) Wide application scenarios: Different detection and processing criteria can be used for different interference environments in different combat scenarios. Different track initiation and track tracking criteria are called according to regional clutter characteristics, realizing the pre-configuration and rapid call of anti-interference measures for multiple interference environments.

[0022] (3) Easy to implement: The system uses methods such as anti-folding clutter waveform, point-track filtering, and track start control. The technology is highly mature and the engineering implementation is relatively simple, which reduces the track false alarm rate and improves the detection probability.

[0023] (4) Extendibility: This technology is proposed for air traffic control radar, but it can also be extended to other types of radar systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the flow chart of fully automatic track initiation and tracking of air traffic control primary radar in a strong clutter environment.

[0025] Figure 2 This is the flow chart of point trace processing.

[0026] Figure 3 Schematic diagram of the dot quality assessment results. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, the method for fully automatic track initiation and tracking of an air traffic control primary radar in a strong clutter environment of the present invention has the following process steps:

[0029] 10) Anti-folding clutter waveform design

[0030] a) Anti-folding waveform design

[0031] The folded echo exceeds the radar pulse interval, so the echo signal cannot be received in the current pulse, and can only be received in the next pulse or even later pulses. If different signal waveforms are transmitted in different pulse intervals, different matched filters are used in signal processing to eliminate the folded echo of the previous period.

[0032] The present invention adopts a combination of long and short pulses. Although the hardware equipment is slightly increased, it also brings the following benefits:

[0033] ·Simultaneous reception of long and short pulses saves time resources.

[0034] Improved close-range detection.

[0035] b) Anti-asynchronous technology

[0036] From the perspective of anti-interference, the folded echo can be determined as asynchronous interference and can be eliminated through anti-asynchronous means.

[0037] 20) Point trace filtering processing technology, point trace filtering and related processing procedures such as Figure 2 shown.

[0038] a) Dot quality assessment

[0039] The present invention mainly adopts dot trace feature statistics and dot trace density calculation to evaluate dot trace quality.

[0040] ·Point feature statistics

[0041] In addition to system operating parameters, data processing extracts and integrates various types of information data contained in the EP package.

[0042] ·Point density calculation

[0043] The radar performs clutter data identification, statistical clutter distribution, and division of clutter areas.

[0044] Static area point data statistics accumulate echo points for each area unit in real time to determine the area level (severe clutter area, clutter area, clean area).

[0045] Dynamic area point trace data statistics traverse the point trace archive and determine the density environment level based on the dynamic point trace data.

[0046] ·Point quality scoring

[0047] The various characteristic information data of the statistical traces are comprehensively weighted to obtain the quality score of the traces, which is then applied to the track processing process to improve radar clutter suppression, target automatic tracking capabilities, and target tracking accuracy. The effect of evaluating the distance characteristic score and signal characteristic score of the condensed traces is shown in the figure below. Figure 3 shown.

[0048] b) Point trace filtering

[0049] The main purpose of point track filtering is to remove the points with the worst quality. On the one hand, it can reduce the false alarm rate of the track, and on the other hand, it can control the number of initial points sent to track processing.

[0050] The point trace filtering process is mainly controlled by the point trace quality risk coefficient (Risk), which is calculated by multi-attribute (azimuth spread, distance spread, amplitude information, etc.) binary (paired between attributes) hypothesis test.

[0051] 30) Track start control technology

[0052] The present invention dynamically adjusts the N / M criterion in the track start area according to the track quality and track density, accumulates the threshold track, and establishes the initial track file when the target start criterion is met between multiple laps.

[0053] a) Statistical distance intelligent association

[0054] The normalized statistical distance algorithm is used to perform normalized weighted processing on the distance and direction of the target according to its information covariance.

[0055] b) IMM filter based on AGX filter model

[0056] Based on the original maneuvering acceleration mutation (AGX) model filtering, the data processing adds an interactive multi-mode (IMM) filter using a uniform velocity model unscented Kalman filter (UKF+CV) and a uniform acceleration model unscented Kalman filter (UKF+CA). The filtering accuracy of the target is improved by adaptively setting the detection parameters and using them as the basis for switching between AGX and multi-mode.

[0057] c) Multi-Hypothesis Tracking (MHT) Processing

[0058] Multi-hypothesis tracking processing technology is used to establish the main and auxiliary target tracking processing mechanism.

[0059] The present invention is not limited to the above specific implementations, and the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the above implementations based on the technical essence of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for fully automatic track initiation and tracking of air traffic control primary radar in a strong clutter environment, characterized by: The following steps are involved: Step 1: Enhance the anti-interference capability of the equipment through anti-folding waveform design according to mission requirements and selection criteria; Step 2: Evaluate the quality of the track based on the track feature statistics and track density calculation, remove the false track condensed by the false target echo, reduce the track false alarm rate, and control the number of initial track sent to track processing; Step 3: According to the point quality and point density, dynamically adjust the N / M criteria in the track starting area. When the number of points exceeds the threshold and meets the target starting criteria between multiple laps, establish the initial track file.

2. The method for fully automatic track initiation and tracking of air traffic control primary radar in a strong clutter environment according to claim 1, characterized in that: The anti-folding clutter waveform design of the first step is specifically as follows: a) Use a combination of long and short pulses to receive folded echoes to improve short-range detection effects; b) The folded echo is judged as asynchronous interference and is cleared by anti-asynchronous means.

3. The method for fully automatic track initiation and tracking of air traffic control primary radar in a strong clutter environment according to claim 1, characterized in that: The second step specifically includes: a) Dot quality assessment First, the clutter distribution statistics are processed to determine the density environment level. Then, the radar signal characteristics are used to achieve the lowered threshold detection of key security targets in key areas. Finally, a comprehensive weighted calculation is performed to obtain the quality score of the point trace. b) Point trace filtering Firstly, the risk coefficient is calculated according to the multi-attribute hypothesis test, and then the point trace comprehensive cost function is constructed through the multi-dimensional information of the point trace to control the point trace filtering process and realize the filtering of low-quality point traces.

4. The method for fully automatic track initiation and tracking of air traffic control primary radar in a strong clutter environment according to claim 1, characterized in that: The third step specifically includes: The data processing adopts the normalized statistical distance algorithm, and the interactive multi-mode filter of the uniform velocity model unscented Kalman filter and the uniform acceleration model unscented Kalman filter. The adaptive setting of the detection parameters is used as the basis for the filter switching to improve the filtering accuracy of the target; the track tracking method of the main and auxiliary target tracking processing mechanism is adopted, and the maximum branch restriction law is used to realize the track stability tracking of the aerodynamic target.

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