A tracking processing method for low-altitude maneuvering flight targets

Abstract

This invention discloses a method for tracking and processing low-altitude maneuvering targets. Based on target indication information, the antenna direction is adjusted, a range acquisition gate is set, and target acquisition is initiated. Once the signal crosses a threshold, target tracking begins. The intermediate frequency received signal is sampled and processed to generate an angular error signal, which is then split into two channels. A multipath suppression channel uses a multipath error compensation fitting curve to cancel multipath reflection errors, followed by large time constant filtering to suppress the influence of long-period residual errors from multiple paths, achieving detection and closed-loop position tracking of low-altitude flying targets. A maneuvering target response processing channel uses abnormally large error signal rejection processing to suppress interference, followed by error signal differentiation processing to extract error variation components, achieving detection of maneuvering target signals and rapid maneuvering target response. Through error synthesis from the two channels, the antenna is driven by a servo system to achieve timely, accurate, and stable tracking of low-altitude maneuvering targets. This invention achieves accurate and stable tracking of rapidly maneuvering low-flying targets, meeting the performance requirements for low-angle tracking.

Description

Technical Field

[0001] This invention relates to radar target detection and tracking technology, specifically to a method for tracking and processing low-altitude maneuvering targets. Background Technology

[0002] When radar detects and tracks targets flying over the sea surface, the beam hits the sea surface, resulting in multiple paths of reflection from aerial targets and mirror targets, generating multipath error. This is a periodically changing, slowly varying error. Without intervention, this can cause target tracking to deviate from the axis, or even diverge, making stable tracking impossible. Simultaneously, the target tracking process also involves line-of-sight (LOS) error signals caused by the target deviating from the antenna's electrical axis—a rapidly changing error that changes with target movement. This LOS error is the closed-loop error required for target tracking. Therefore, during target tracking, measures must be taken to reduce the impact of multipath effects while maintaining a rapid response to errors caused by target movement to ensure stable, accurate, and effective target tracking. Commonly used low-angle tracking methods in engineering include narrow-beam radar, off-axis tracking, broadband frequency agility, and heavy filtering with compensation. However, each method has limitations. Narrow-beam radar increases system cost and has unsatisfactory results; off-axis tracking has larger errors and limited applicability; broadband frequency agility increases system complexity; and heavy filtering with compensation affects real-time performance, causing significant tracking lag. Therefore, a low-altitude target tracking method that better meets practical engineering needs is needed to improve target tracking capabilities. Summary of the Invention

[0003] The purpose of this invention is to provide a method for tracking and processing low-altitude maneuvering targets.

[0004] The technical solution for achieving the objective of this invention is: a method for tracking and processing low-altitude maneuvering targets, the method comprising:

[0005] Step 1: Adjust the antenna direction according to the target indication information, set the range acquisition gate, acquire the target, and switch to target tracking after the signal crosses the threshold;

[0006] Step 2: Sample and process the intermediate frequency received signal to form an angle error signal. Divide the angle error signal into two paths: one path is sent to the multipath suppression processing channel, and the other path is sent to the maneuvering target response processing channel.

[0007] The third step is the multipath suppression channel. The multipath error compensation fitting curve is used to cancel the multipath reflection error, and then the influence of the long-period residual error of the multipath is suppressed by the large time constant filter, so as to realize the detection and position closed-loop tracking of the low-altitude flying target.

[0008] Step 4: The maneuvering target response processing channel uses abnormally large error signal elimination processing to suppress interference, and then performs error signal differentiation processing to extract the error change component, thereby realizing the detection of maneuvering target signals and rapid maneuvering target response;

[0009] Step 5: Perform error synthesis on the signals sent from the multipath suppression processing channel and the maneuvering target response processing channel. That is, the multipath suppression processing channel eliminates the influence of multipath periodic error signals and realizes closed-loop tracking of the target's position. The maneuvering target response processing channel detects rapid changes in maneuvering target errors and realizes timely tracking of fast-moving targets. Finally, through error synthesis of the two channels, the antenna is driven by the servo system to achieve timely, accurate and stable tracking of low-altitude maneuvering targets.

[0010] Furthermore, in the second step, the sampling and processing of the intermediate frequency received signal specifically includes: sampling, accumulating, and sum-difference normalization of the intermediate frequency received signal to finally form an angular error signal.

[0011] Furthermore, in the third step, the method of using a multipath error compensation fitting curve to cancel multipath reflection errors specifically includes: retrieving the multipath error compensation fitting curve based on the target height estimate; the multipath error compensation fitting curve is determined by multipath reflection model simulation based on radar antenna height, target flight altitude, and electromagnetic reflection parameters of the marine environment.

[0012] Furthermore, in the third step, the filtering process with a large time constant suppresses the influence of long-period residual errors in multipath paths. The filtering time constant is determined by the multipath period and the target speed, and is taken as 2 to 3 times the multipath period.

[0013] Furthermore, in the fourth step, the abnormally large error signal elimination process specifically includes: eliminating errors exceeding half the beamwidth as interference signals.

[0014] Furthermore, in the fourth step, the error signal differential processing adopts differential processing, and after filtering, the error change component is extracted and added to the servo system speed loop. The selection of its filtering parameters reflects its maneuverability and is related to the limitations of dynamic characteristics and the completion of the mission. The typical overload value is generally no more than 20g.

[0015] Furthermore, in the fifth step, the error synthesis specifically involves: adding the output of the multipath suppression processing channel to the position loop of the servo system, and adding the output of the maneuvering target response processing channel to the velocity loop of the servo system, thereby driving the antenna to move via the servo system.

[0016] A tracking and processing system for low-altitude maneuvering targets, used to implement the aforementioned tracking and processing method for low-altitude maneuvering targets, includes: a transmitter, a transceiver switch, an antenna, a receiver, a signal processing sub-unit, and a servo control processing sub-unit, wherein:

[0017] In the signal processing unit:

[0018] The intermediate frequency signal output by the receiver is sampled, accumulated, and normalized to form an angle error signal. The angle error signal is then divided into two paths: one path is sent to the multipath suppression processing channel of the servo control processing unit, and the other path is sent to the maneuvering target response processing channel of the servo control processing unit.

[0019] And, responsible for target detection, acquisition, and distance tracking;

[0020] In the servo control processing unit:

[0021] In the multipath suppression processing channel, the multipath error compensation fitting curve is used to cancel the multipath reflection error, and then the large time constant filter is used to suppress the influence of the long-period residual error of the multipath, and the filtered error signal is output.

[0022] In the maneuvering target response processing channel, abnormal large error signal elimination processing is adopted to suppress interference. Then, after error signal differentiation processing, error change components are extracted and the error change rate signal is output.

[0023] Furthermore, error synthesis is performed on the filtered error signal and the error rate of change signal. The filtered error signal is added to the position loop of the servo system, and the error rate of change signal is added to the speed loop of the servo system to generate antenna drive commands.

[0024] The antenna moves according to the drive command to track low-altitude maneuvering targets.

[0025] Furthermore, it also includes a display console, used to monitor the target tracking process and display the target trajectory and status.

[0026] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the aforementioned method for tracking and processing low-altitude maneuvering targets.

[0027] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the aforementioned method for tracking and processing low-altitude maneuvering targets.

[0028] Compared with existing technologies, the significant advantages of this invention are as follows: In the context of low-altitude target tracking, this invention achieves accurate and stable tracking of fast-moving, low-flying targets through joint detection and error synthesis of multipath suppression channels and maneuvering target rapid response channels during target detection, acquisition, and tracking, thus meeting the performance requirements for low-angle tracking. This method is simple, practical, robust, and reliable, requiring no additional hardware resources. Improvements can be achieved simply by modifying the software on the existing tracking equipment, making it universally significant for enhancing radar's low-angle tracking capabilities and expanding its application scope. Attached Figure Description

[0029] Figure 1 This is an overall flowchart of the tracking and processing method for low-altitude maneuvering targets according to the present invention.

[0030] Figure 2 This is a block diagram showing the relationship between signal processing and servo control in this invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] Combination Figure 1 , Figure 2 The system components for implementing the tracking and processing method for low-altitude maneuvering targets according to the present invention include: a transmitter, a transceiver switch, an antenna, a receiver, a signal processing unit, a servo control processing unit, and a display and control console, wherein:

[0033] The transmitter radiates electromagnetic waves into space through a transceiver switch and an antenna. When the electromagnetic waves encounter a target, they are backscattered, forming a target echo, which is then transmitted to the receiver through the antenna and transceiver switch.

[0034] The receiver down-converts the target echo received by the antenna to an intermediate frequency signal and transmits it to the signal processing unit.

[0035] The signal processing unit samples, accumulates, and performs sum-difference normalization on the intermediate frequency signal from the receiver to form an angular error signal; it is also responsible for target detection, acquisition, and range tracking (setting the range acquisition gate and signal threshold decision).

[0036] The servo control processing unit performs multipath error suppression and rapid response processing for maneuvering targets based on the angular error signal, performs error synthesis, generates antenna drive commands to drive the antenna to move, and realizes closed-loop target tracking.

[0037] The control console monitors the target tracking process and displays the target trajectory and status.

[0038] The present invention provides a method for tracking and processing low-altitude maneuvering targets, comprising the following five parts:

[0039] Step 1: Based on external target indication information, including azimuth and distance, the system uses a servo control unit to drive the antenna to adjust its direction and sets a range acquisition gate in the signal processing unit. The echo received by the antenna is sent to the signal processing unit via a transceiver switch and receiver. The signal processing unit detects the echo signal, and when the signal strength exceeds a preset threshold, it determines that the target has been successfully acquired, and the system automatically enters the target tracking state.

[0040] Step 2: The intermediate frequency (IF) signal output from the receiver is sent to the signal processing unit. The signal processing unit samples, accumulates, and performs sum-difference normalization on the IF signal to form an angle error signal. This angle error signal simultaneously includes the slowly varying periodic error caused by multipath reflection and the rapidly varying line-of-sight angle error caused by the target deviating from the antenna's electrical axis. The signal processing unit copies the angle error signal into two paths: one is sent to the multipath suppression processing channel of the servo control processing unit, and the other is sent to the maneuvering target response processing channel of the servo control processing unit.

[0041] Step 3: After the servo control processes the multipath suppression signal of the receiving angle error signal of the extension unit, it performs the following operations:

[0042] Multipath error compensation cancellation: Based on the current target distance and altitude estimates, the compensation value is obtained from a pre-stored multipath error compensation fitting curve table, and then subtracted from the angular error signal. This fitting curve is determined by multipath reflection model simulation based on radar antenna height, target flight altitude, and marine environment electromagnetic reflection parameters (mainly sea state).

[0043] Large time constant filtering: The compensated error signal is low-pass filtered. The filtering time constant is determined by the multipath period and the target speed, and is taken as 2 to 3 times the multipath period to suppress the long-period residual error of the multipath.

[0044] Step 4: After receiving the angular error signal from the servo control processing sub-unit's maneuvering target response processing channel, perform the following operations:

[0045] Large abnormal error removal: Determine whether the absolute value of the angular error exceeds the threshold (e.g., half beamwidth). If it does, it is considered interference and removed.

[0046] Error signal differentiation processing: The differential operation is performed on the eliminated angular error sequence to extract the error change component, i.e., the error change rate, and the differentiation result is smoothed and filtered. The selection of its filtering parameters reflects its maneuverability and is related to the limitations imposed by its dynamic characteristics and the completion of its mission. The typical overload value generally does not exceed 20g.

[0047] Step 5: The servo control processing unit performs error synthesis on the output signals from steps 3 and 4.

[0048] The filtered error signal output from the third step is added to the position loop of the servo system as the given input for the position closed loop, in order to eliminate the influence of the multipath periodic error signal and realize the position closed loop tracking of the target.

[0049] The error change rate signal output from the fourth step is added to the speed loop of the servo system to detect rapid changes in the error of the maneuvering target, thereby enabling timely tracking of the maneuvering target.

[0050] After the position and velocity loops are cascaded, an antenna drive command is generated, which is then amplified to drive the antenna movement, ensuring that the antenna's electrical axis is always aligned with the target. The display and control console shows the tracking error and antenna pointing in real time, achieving timely, accurate, and stable tracking of low-altitude maneuvering targets.

[0051] Example

[0052] To verify the effectiveness of the present invention, the following experimental design was conducted.

[0053] Step 1: The target indication information is azimuth 80° and distance 10km. The system rotates the antenna to 80°, sets the distance acquisition gate center to 10km and the width to 1km. The target echo signal strength is 300, exceeding the threshold of 100, and enters tracking mode.

[0054] The second step is to sample, accumulate, and normalize the sum and difference of the intermediate frequency received signal to form an angle error signal of 0.5º. This angle error signal is then split into two paths: one path is sent to the multipath suppression processing channel, and the other path is sent to the maneuvering target response processing channel.

[0055] Step 3: The current target tracking distance is 10km, and the estimated target height is 20m. The multipath error compensation fitting curve at 20m height has a value of 0.35º at 10km. After using the multipath error compensation fitting curve to cancel out the multipath reflection error, 0.15º remains. After filtering with a large time constant of 10s, the filtered error value is 0.05º. This value is then used in the servo system position loop to achieve closed-loop tracking of the target position.

[0056] Step 4: An angular error signal of 0.5º enters the maneuver response channel. The half-beamwidth is 1.2º, and 0.5º does not exceed the threshold, so it is retained. Assuming the error values ​​for two frames 10km apart are 0.5º and 0.52º respectively, with a frame period of 20ms, after error signal differentiation processing, the error change component is extracted, with a difference of 1º / s. After smoothing and filtering, the value is taken as 0.9º / s, and this value is added to the servo system speed loop to achieve rapid response to maneuvering targets.

[0057] Step 5: The servo control processing unit sends 0.05º into the position loop and 0.9º / s into the speed loop, cascading to drive the antenna, thereby achieving stable and accurate tracking of low-altitude maneuvering targets.

[0058] In summary, this invention utilizes dual-channel error classification and joint error detection, combined with multi-path periodic error signal suppression and rapid response for maneuvering targets. Compared to existing low-angle target tracking methods, this presents a more rational and resource-efficient tracking method for low-altitude maneuvering targets, effectively improving low-angle target tracking capabilities in low-altitude target tracking scenarios. It is particularly suitable for single-frequency or narrow-band radar applications for low-altitude target detection and tracking. Furthermore, this method is simple and reliable, and can be widely used in low-altitude target tracking processes for radar equipment, demonstrating promising application prospects and comprehensive benefits.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A tracking process method for a low-altitude maneuvering flight target, characterized by, The method includes: Step 1: Adjust the antenna direction according to the target indication information, set the range acquisition gate, acquire the target, and switch to target tracking after the signal crosses the threshold; Step 2: Sample and process the intermediate frequency received signal to form an angle error signal. Divide the angle error signal into two paths: one path is sent to the multipath suppression processing channel, and the other path is sent to the maneuvering target response processing channel. The third step is the multipath suppression channel. The multipath error compensation fitting curve is used to cancel the multipath reflection error, and then the influence of the long-period residual error of the multipath is suppressed by the large time constant filter, so as to realize the detection and position closed-loop tracking of the low-altitude flying target. Step 4: The maneuvering target response processing channel uses abnormally large error signal elimination processing to suppress interference, and then performs error signal differentiation processing to extract the error change component, thereby realizing the detection of maneuvering target signals and rapid maneuvering target response; Step 5: Perform error synthesis on the signals sent from the multipath suppression processing channel and the maneuvering target response processing channel. That is, the multipath suppression processing channel eliminates the influence of multipath periodic error signals and realizes closed-loop tracking of the target's position. The maneuvering target response processing channel detects rapid changes in maneuvering target errors and realizes timely tracking of fast-moving targets. Finally, through error synthesis of the two channels, the antenna is driven by the servo system to achieve timely, accurate and stable tracking of low-altitude maneuvering targets.

2. The tracking process method for a low-altitude maneuvering flight target according to Claim 1, wherein In the second step, the sampling and processing of the intermediate frequency received signal specifically includes: sampling, accumulating, and sum-difference normalization of the intermediate frequency received signal to finally form an angular error signal.

3. The tracking process method for a low altitude maneuvering flight target according to claim 1, wherein In the third step, the method of using a multipath error compensation fitting curve to cancel multipath reflection error specifically includes: retrieving the multipath error compensation fitting curve based on the target height estimate; the multipath error compensation fitting curve is determined by multipath reflection model simulation based on radar antenna height, target flight altitude, and electromagnetic reflection parameters of the marine environment.

4. The method for tracking and processing low-altitude maneuvering targets as described in claim 1, characterized in that, In the third step, the effect of the long-period residual error of the multipath is suppressed by filtering with a large time constant. The filtering time constant is determined by the multipath period and the target speed, and is taken as 2 to 3 times the multipath period.

5. The method for tracking and processing low-altitude maneuvering targets as described in claim 1, characterized in that, In the fourth step, the abnormally large error signal elimination process specifically includes: eliminating errors exceeding half the beamwidth as interference signals.

6. The method for tracking and processing low-altitude maneuvering targets as described in claim 1, characterized in that, In the fourth step, the error signal differential processing adopts differential processing, and after filtering, the error change component is extracted and added to the servo system speed loop. The selection of its filtering parameters reflects its maneuverability and is related to the limitations of dynamic characteristics and the completion of the mission. The typical overload value does not exceed 20g.

7. The method for tracking and processing low-altitude maneuvering targets as described in claim 1, characterized in that, In the fifth step, the error synthesis specifically involves adding the output of the multipath suppression processing channel to the position loop of the servo system, adding the output of the maneuvering target response processing channel to the velocity loop of the servo system, and then driving the antenna to move via the servo system.

8. A tracking and processing system for low-altitude maneuvering targets, used to implement the tracking and processing method for low-altitude maneuvering targets as described in any one of claims 1-7, characterized in that, include: Transmitter, transceiver switch, antenna, receiver, signal processing unit, and servo control processing unit, among which: In the signal processing unit: The intermediate frequency signal output by the receiver is sampled, accumulated, and normalized to form an angle error signal. The angle error signal is then divided into two paths: one path is sent to the multipath suppression processing channel of the servo control processing unit, and the other path is sent to the maneuvering target response processing channel of the servo control processing unit. And, responsible for target detection, acquisition, and distance tracking; In the servo control processing unit: In the multipath suppression processing channel, the multipath error compensation fitting curve is used to cancel the multipath reflection error, and then the large time constant filter is used to suppress the influence of the long-period residual error of the multipath, and the filtered error signal is output. In the maneuvering target response processing channel, abnormal large error signal elimination processing is adopted to suppress interference. Then, after error signal differentiation processing, error change components are extracted and the error change rate signal is output. Furthermore, error synthesis is performed on the filtered error signal and the error rate of change signal. The filtered error signal is added to the position loop of the servo system, and the error rate of change signal is added to the speed loop of the servo system to generate antenna drive commands. The antenna moves according to the drive command to track low-altitude maneuvering targets.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the tracking and processing method for low-altitude maneuvering targets as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, wherein when executed by a processor, the computer program implements the tracking and processing method for low-altitude maneuvering targets as described in any one of claims 1-7.

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