A method of radar noise source detection tracking

Abstract

The application discloses a radar noise source detection and tracking method, and aims at the problem that self-defense jamming increases the difficulty of target detection and tracking, and creatively proposes detecting and tracking the jamming source of the self-defense jamming, and then realizes the detection and tracking of the target, so as to provide an effective detection means for the tracking and detection of the target.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radar technology, in particular to a radar noise source detection and tracking method. BACKGROUND

[0002] The tracking illumination radar is used to provide battlefield alert for weapon systems, and uses radar to search and track the incoming target autonomously or under the guidance of external aiming information, so as to provide target indication and target tracking data for the weapon system. In the past, the radar was seriously interfered by external and internal noise, which would drown the useful signal and increase the difficulty of target detection and tracking.

[0003] In order to improve the radar air defense combat and self-defense capability, the effective means for ground penetration. As an important way of air defense, the self-defense jamming can effectively reduce the interception and tracking probability by the enemy's terminal defense system when the attack side completes the fire penetration, air support and suppression of the enemy's air defense weapon system.

[0004] The tracking illumination radar is an important air defense equipment, and has the function of anti-self-defense jamming. Since the target and the jamming source are together, the jamming signal will enter the main lobe of the radar, resulting in the enhancement of the jamming signal, so that the radar cannot normally track the target. In this case, how to track the target becomes a problem to be solved urgently. SUMMARY

[0005] The present application provides a radar noise source detection and tracking method, which solves the problem that the target with a self-defense jamming source cannot be tracked well in the prior art.

[0006] The present application provides a radar noise source detection and tracking method, which comprises:

[0007] In the process of detecting and tracking the target, when it is determined that the strength of the jamming signal is greater than a preset threshold, the sum channel echo IQ data in the obtained radar echo signal is stored according to distance units;

[0008] The stored sum channel echo IQ data is subjected to pulse Doppler MTD processing;

[0009] The sum channel echo IQ data in the 0 subband and the non-0 subband is extracted by using the result of the MTD processing, the noise mean value and the maximum signal-to-noise ratio are calculated respectively, and whether there is noise interference is determined based on the calculated noise mean value and maximum signal-to-noise ratio;

[0010] When it is determined that there is noise interference, noise interference filtering is performed, and the noise source is tracked by calculating the distance error of the noise source, so as to realize tracking of the target.

[0011] Optionally, the method further comprises: when it is determined that the interference signal entering the main lobe of the radar causes the target to be unable to be normally tracked, triggering storage of the sum channel echo IQ data in the acquired radar echo signal according to distance units.

[0012] Optionally, after the storage of the sum channel echo IQ data in the acquired radar echo signal according to distance units, and before the pulse Doppler MTD processing of the stored sum channel echo IQ data, the method further comprises: obtaining an AGC normalization coefficient according to a current AGC value.

[0013] Optionally, the pulse Doppler MTD processing of the stored sum channel echo IQ data comprises: performing MTD operation on the sum channel echo IQ data of each period under the same distance unit, performing modulus operation on the FFT results of the sum channel echo IQ data of different periods, and then multiplying the calculated AGC normalization coefficient to obtain a normalized modulus value under each distance unit.

[0014] Optionally, the use of the result of the MTD processing to extract the sum channel echo IQ data in the 0 sub-band and the non-0 sub-band, to calculate the noise mean value and the maximum signal-to-noise ratio respectively, and to determine whether there is noise interference based on the calculated noise mean value and the maximum signal-to-noise ratio, comprises:

[0015] For the 0 sub-band data in the modulus value obtained after the MTD processing, the maximum modulus value and the distance gate number thereof are found, and the modulus values of a preset number of distance unit data around the maximum modulus value distance gate and all distance units of the previous and subsequent three distance gates are divided by the maximum modulus value to calculate the noise mean value, and then the maximum signal-to-noise ratio is calculated according to the calculated maximum modulus value and the noise mean value to obtain an SNR1.

[0016] For the 0 non-sub-band data in the FFT result modulus value of the sum channel, the maximum modulus value and the distance gate number and the velocity gate number thereof are found; in all distance unit data of the maximum modulus value velocity gate, the modulus values of a preset number of distance unit data around the maximum modulus value distance gate and all distance units of the previous and subsequent three distance gates are divided by the maximum modulus value to calculate the noise mean value; and the maximum signal-to-noise ratio is calculated according to the calculated maximum modulus value and the noise mean value to obtain an SNR2.

[0017] If MAX(SNR1, SNR2) ≥ a preset value, it is determined that there is no interference, otherwise, when the 0 sub-band noise mean value is greater than a first preset multiple of a prior value or the non-0 sub-band noise mean value is greater than a second preset multiple of a preset prior value, it is determined that there is noise interference, otherwise, there is no noise interference.

[0018] Optionally, the preset number is inversely proportional to the sampling rate of the radar echo signal.

[0019] Optionally, after determining that there is noise interference, the method further comprises: sequentially sliding the noise mean value and the maximum signal-to-noise ratio of the sum channel echo IQ data of the 0 sub-band and the non-0 sub-band of the next sliding period to determine whether the sum channel echo IQ data of the next sliding period has interference, and if the ratio of the number of periods determined to have interference to the total number of sliding periods in the plurality of sliding periods is greater than a preset proportion threshold, it is determined that there is interference.

[0020] Optionally, when it is determined that there is noise interference, noise interference filtering is performed, comprising

[0021] With the specified tracking noise source target distance, that is, the center of the corresponding distance unit, as the center distance gate, find the leading distance gate number of the maximum modulus value waveform in all data of the speed gate number corresponding to the maximum modulus value; calculate the distance deviation with the leading distance gate number and the center distance gate number; extract the modulus values of the front and back two distance wave gates in the distance dimension, and the distance error calculated by the modulus value of the leading distance gate number; and synthesize the noise distance measurement change amount according to the calculated distance deviation and distance error;

[0022] For the first time tracking, the distance change rate is directly calculated with the distance change amount and the frame interval, and then the predicted distance is extrapolated; for non-first-time tracking, the distance is processed by alpha-beta filtering according to the distance measurement change amount to obtain the filtered distance and the predicted distance of the current noise interference.

[0023] Optionally, after storing the sum channel echo IQ data in the acquired radar echo signal according to the distance unit, the method further comprises:

[0024] The elevation difference channel echo IQ data of different repetition periods is stored in a continuous arrangement form according to the distance unit, and the azimuth difference channel echo IQ data of different repetition periods is also sequentially arranged and stored according to the distance unit, for subsequent positioning and tracking of the target.

[0025] Optionally, in the process of detecting and tracking the interference source, when it is determined that the strength of the interference signal is less than a preset threshold, the target is detected and tracked again.

[0026] The present application has the following advantages:

[0027] In view of the problem that the current self-defense type interference increases the difficulty of target detection and tracking, the present application innovatively proposes to detect and track the interference source of the self-defense type interference, and then realize the detection and tracking of the target, thereby providing an effective detection means for the tracking and detection of the target.

[0028] The above description is only a summary of the technical solutions of the present application. In order to enable one skilled in the art to better understand the technical means of the present application, the contents of the specification can be implemented, and in order to enable the above and other purposes, features and advantages of the present application to be more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Moreover, the same reference numerals in the attached drawings indicate the same or similar components. In the drawings:

[0030] Figure 1 is a flowchart of a radar noise source detection and tracking method provided by an embodiment of the present application;

[0031] Figure 2 is a flowchart of another radar noise source detection and tracking method provided by an embodiment of the present application;

[0032] Figure 3 is a flowchart of a noise interference detection method provided by an embodiment of the present application;

[0033] Figure 4 is a flowchart of a noise interference filtering method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0034] The embodiments of the present application are aimed at the problem that existing radar cannot well track targets with self-defense jamming sources. The embodiments of the present application detect and track the jamming sources of self-defense jamming, and then realize detection and tracking of targets. The present application will be further described in detail in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0035] An embodiment of the present application provides a radar noise source detection and tracking method, referring to Figure 1 The method comprises the following steps.

[0036] S101, in the process of detecting and tracking the target, when it is determined that the intensity of the jamming signal is greater than a preset threshold, the range echo IQ data in the obtained radar echo signal is stored according to distance units;

[0037] Specifically, in the process of radar checking and tracking a target, if the intensity of the interference signal is greater than a preset threshold, the preset threshold can be set according to the requirement that the interference cannot effectively track the target, and it can be understood that when the interference signal entering the main lobe of the radar causes the target to be unable to be normally tracked, the radar echo signal and road echo IQ data obtained are stored according to distance units.

[0038] In a specific embodiment, while storing the radar echo signal and road echo IQ data according to distance units, the elevation difference road echo IQ data of different repetition periods is also stored in the form of continuous arrangement according to distance units, and the azimuth difference road echo IQ data of different repetition periods is also sequentially arranged and stored according to distance units, for subsequent direct positioning and tracking of the target.

[0039] In the process of detecting and tracking the interference source, when it is determined that the intensity of the interference signal is less than the preset threshold, the target is re-detected and tracked.

[0040] That is, when the radar cannot effectively track the target, the radar echo signal and road echo IQ data, the elevation difference road echo IQ data and the azimuth difference road echo IQ data are all stored according to distance units, and then a series of processing is performed based on the radar echo signal and road echo IQ data, so as to realize detection and tracking of the interference source, and when the interference signal is weakened, the elevation difference road echo IQ data and the azimuth difference road echo IQ data are directly used to realize detection and tracking of the target.

[0041] In addition, after the radar echo signal and road echo IQ data are stored according to distance units, an AGC normalization coefficient is obtained according to a current automatic gain control AGC value.

[0042] S102, pulse Doppler MTD processing is performed on the stored radar echo signal and road echo IQ data;

[0043] Specifically, the MTD operation is performed on the radar echo signal and road echo IQ data of each period under the same distance unit, the FFT results of the radar echo signal and road echo IQ data of different periods are modulated, and then multiplied by the calculated AGC normalization coefficient to obtain the normalized modulus value under each distance unit.

[0044] S103, using the result of the MTD processing, extracting the radar echo signal and road echo IQ data in the 0 sub-band and the non-0 sub-band, respectively calculating the noise mean value and the maximum signal-to-noise ratio, and determining whether there is noise interference based on the calculated noise mean value and the maximum signal-to-noise ratio.

[0045] In a specific implementation, the 0 sub-band data in the modulus value obtained after MTD processing is searched for a maximum modulus value and a distance gate number, and the modulus values of all distance cells except the maximum modulus value and the preset number of distance cells around the maximum modulus value distance gate are divided by the modulus values of all distance cells of the three distance gates before and after the maximum modulus value to calculate a noise mean value. Then, a maximum signal-to-noise ratio is calculated according to the calculated maximum modulus value and noise mean value to obtain an SNR1.

[0046] The 0 non-sub-band data in the modulus value of the sum channel FFT result is searched for a maximum modulus value and a distance gate number and a velocity gate number. In all distance cell data of the maximum modulus value velocity gate number, the modulus values of all distance cells except the maximum modulus value and the preset number of distance cells around the maximum modulus value distance gate are divided by the modulus values of all distance cells of the three distance gates before and after the maximum modulus value to calculate a noise mean value. Then, a maximum signal-to-noise ratio is calculated according to the calculated maximum modulus value and noise mean value to obtain an SNR2.

[0047] If MAX(SNR1, SNR2) is greater than or equal to a preset value, it is determined that there is no interference, otherwise, if the 0 sub-band noise mean value is greater than a first preset multiple of a prior value or the non-0 sub-band noise mean value is greater than a second preset multiple of a preset prior value, it is determined that there is noise interference, otherwise, there is no noise interference.

[0048] It should be noted that the preset number in the embodiment of the application is inversely proportional to the sampling rate of the radar echo signal. Specifically, a person skilled in the art can set it arbitrarily according to actual needs.

[0049] In order to further ensure the accuracy of the judgment of the noise source (that is, the interference noise source), the method described in the embodiment of the application further comprises:

[0050] The noise mean value and the maximum signal-to-noise ratio of the sum channel echo IQ data of the 0 sub-band and the non-0 sub-band of the next sliding period are sequentially slid to determine whether there is interference in the sum channel echo IQ data of the next sliding period. If the ratio of the number of periods determined to have interference to the total number of sliding periods is greater than a preset proportion threshold, it is determined that there is interference.

[0051] That is, the embodiment of the application determines whether there is interference by detecting and judging the data of multiple sliding periods, and then determines whether there is interference according to the ratio of the number of sliding periods determined to have interference to the total number of periods determined.

[0052] For example, when the number of sliding periods determined to have interference is 6 according to the above method, the total number of sliding periods detected and judged is 10, and the proportion threshold is 50%, then 6 / 10>50%, it is determined that there is interference, and the filtering process can be continued.

[0053] S104, when it is determined that there is noise interference, noise interference filtering is performed, and the noise source is tracked through the distance error of the calculated noise source, and tracking of the target is further realized.

[0054] Specifically, the embodiment of the present application is to find the leading distance gate number of the maximum modulus waveform in all data of the velocity gate number corresponding to the maximum modulus value, while taking the distance of the designated tracked noise source as the center distance gate, and taking the center of the corresponding distance unit as the center at the same time; the distance deviation is calculated according to the leading distance gate number and the center distance gate number; the modulus values of the two distance wave gates before and after the distance gate are extracted in the distance dimension, and the distance error is calculated according to the modulus value of the leading distance gate number; the noise distance measurement change is synthesized according to the calculated distance deviation and distance error.

[0055] For the first time tracking, the distance change rate is directly calculated according to the distance change and the frame interval, and then the predicted distance is extrapolated; for the non-first time tracking, the distance is processed by using the alpha-beta filter according to the distance measurement change, so as to obtain the filtered distance and the predicted distance of the current noise interference.

[0056] Overall, the embodiment of the present application is to solve the problem that the target detection and tracking are difficult due to the increase of the self-defense type interference, and the detection and tracking of the interference source of the self-defense type interference are innovatively proposed, so as to realize the detection and tracking of the target, and thus an effective detection means is provided for the target tracking detection.

[0057] The method of the embodiment of the present application will be explained and described in detail through a specific example as follows. Figures 2-4 The method of the embodiment of the present application will be explained and described in detail through a specific example as follows.

[0058] Referring to Figure 2 The method of the embodiment of the present application includes the following steps:

[0059] 1) Data preprocessing:

[0060] The IQ data and radar working words after pulse pressure of FPGA are obtained from the DDR3, and the 3-way data of the range, azimuth and elevation difference are stored in sequence according to the distance unit and the repetition period, and the AGC normalization coefficient is obtained according to the current AGC value.

[0061] The and-way echo IQ and and-way modulus value data are extracted in the DDR3, and are stored in the form of continuous arrangement of the data of different repetition periods of each distance unit, to obtain the and-way echo IQ array and the and-way echo modulus value array; the elevation difference way echo data are stored in the form of continuous arrangement of all period data of each distance unit, to obtain the elevation difference way echo IQ array; the azimuth difference way echo data are stored in the form of sequence arrangement of period sequence data of each distance unit, to obtain the azimuth difference way echo IQ array; and the AGC normalization coefficient is obtained according to the current AGC value.

[0062] 2) MTD processing:

[0063] That is, MTD is performed on the same distance unit number in a repetition period, the modulus of each IQ data of the sum channel FFT result is calculated, multiplied by the AGC normalization coefficient, and stored.

[0064] Specifically, the embodiment of the present application performs MTD operation on the same distance unit number in each period, calculates the modulus of each IQ data of the FFT result of the sum channel data of different periods, multiplies the AGC normalization coefficient calculated in step one, and stores.

[0065] 3) Noise interference detection;

[0066] The noise mean and maximum signal-to-noise ratio are calculated from the 0 sub-band and non-0 sub-band data in the MTD processing result, and it is determined whether there is interference by comparison;

[0067] Referring to Figure 3 , the noise interference detection of the embodiment of the present application specifically includes:

[0068] a) In the 0 sub-band data of the modulus value of the sum channel FFT result obtained in step two, the maximum modulus value and its distance gate number are found;

[0069] b) The modulus values of all distance units of the maximum modulus value and the three distance gates before and after are divided by the 21 distance unit data around the maximum modulus value distance gate to calculate the noise mean;

[0070] d) In the 0 non-sub-band data of the modulus value of the sum channel FFT result obtained in step two, the maximum value and its distance gate number and speed gate number are found;

[0071] e) In all distance unit data of the maximum modulus value speed gate, the modulus values of all distance units of the maximum modulus value and the three distance gates before and after are divided by the 21 distance unit data around the maximum modulus value distance gate to calculate the noise mean;

[0072] f) The maximum signal-to-noise ratio is calculated using the data of d) and e), and an SNR2 is obtained;

[0073] g) If MAX(SNR1, SNR2) ≥ 4, there is no interference, otherwise, if the noise mean of the 0 sub-band is greater than 8 times the prior value or the noise mean of the non-0 sub-band is greater than 4 times the prior value, it is determined that there is interference, otherwise, there is no interference;

[0074] h) The five most recent interference states are stored in a sliding manner, and if there is interference in three of the five consecutive taps, it is considered that there is interference.

[0075] 4) Noise interference filtering;

[0076] The tracking is started by calculating the distance error of the noise source, and the alpha-beta filter is used to obtain the filter extrapolation value of the tracking target.

[0077] Referring to Figure 4 The noise source interference filtering flowchart for the embodiment of the present application is as follows.

[0078] a) the distance of the noise source to be tracked is taken as the center distance, and the center distance gate is taken as the center distance gate;

[0079] b) the leading distance gate number of the maximum modulus value waveform is found in all data of the maximum modulus value corresponding to the speed gate number;

[0080] c) the distance deviation is calculated by using the leading distance gate number and the center distance gate number;

[0081] d) the modulus values of the two distance wave gates before and after the distance gate are extracted in the distance dimension, and the distance error is calculated by using the modulus value of the leading distance gate number;

[0082] e) the noise distance measurement change is synthesized by using the results of c) and d);

[0083] f) the distance change rate is directly calculated by using the distance change and the frame interval for the first tracking, and then the predicted distance is extrapolated;

[0084] g) for the non-first tracking, the distance is processed by using the alpha-beta filter according to the distance measurement change, so that the filtered distance and the predicted distance of the current noise interference are obtained.

[0085] In general, the embodiment of the present application proposes a noise source detection and tracking method, and the target can be tracked by tracking the interference source by using the method, so that the target detection performance is effectively improved. In the specific embodiment, the hardware of the embodiment of the present application is realized by using the FT6678 platform of the domestic product.

[0086] Although the preferred embodiments of the present application have been disclosed for the purpose of example, those skilled in the art will realize that various improvements, additions and substitutions are also possible, therefore, the scope of the present application should not be limited to the above-mentioned embodiments.

Claims

1. A method for detecting and tracking radar noise sources, characterized in that, include: During the target detection and tracking process, when the strength of the interference signal is determined to be greater than the preset threshold, the sum-path echo IQ data in the acquired radar echo signal is stored according to the range cell. The stored sum-echo IQ data is processed using pulse Doppler MTD. Using the results of MTD processing, the sum-path echo IQ data in the 0 subband and non-0 subband are extracted, and the noise mean and maximum signal-to-noise ratio are calculated respectively. Based on the calculated noise mean and maximum signal-to-noise ratio, it is determined whether there is noise interference. When noise interference is detected, noise interference filtering is performed, and the noise source is tracked by calculating the distance error of the noise source, thereby achieving target tracking.

2. The method according to claim 1, characterized in that, The method further includes: When it is determined that the interference signal entering the radar main lobe causes the target to be unable to be tracked normally, the acquisition of the radar echo signal and the sum-path echo IQ data are stored according to the range cell.

3. The method according to claim 1, characterized in that, After storing the sum-path echo IQ data from the acquired radar echo signal according to range cells, and before performing pulse Doppler MTD processing on the stored sum-path echo IQ data, the method further includes: The AGC normalization coefficient is obtained based on the current automatic gain control (AGC) value.

4. The method according to claim 3, characterized in that, The pulse Doppler MTD processing of the stored sum-echo IQ data includes: MTD calculation is performed on the sum-path echo IQ data of each period under the same distance cell. The FFT results of the sum-path echo IQ data of different periods are used to calculate the modulus. Then, the result is multiplied by the calculated AGC normalization coefficient to obtain the normalized modulus value under each distance cell.

5. The method according to any one of claims 1-4, characterized in that, The method utilizes the results of MTD processing to extract the sum-path echo IQ data in both the 0 and non-0 subbands, calculates the noise mean and maximum signal-to-noise ratio (SNR) for each, and determines the presence of noise interference based on the calculated noise mean and maximum SNR, including: For the 0 subband data in the magnitude value obtained after MTD processing, find its maximum magnitude value and its distance gate number, and calculate the noise mean by dividing the maximum magnitude value and the magnitude values ​​of all distance cells of the three distance gates in front and behind the maximum magnitude value by a preset number of distance cell data around the distance gate. Then, calculate the maximum signal-to-noise ratio based on the calculated maximum magnitude value and the noise mean value to obtain an SNR1. For the non-zero subband data in the FFT result of the path, find the maximum magnitude and its distance gate number and velocity gate number; among all distance cell data of the maximum magnitude velocity gate, calculate the noise mean by taking the magnitude of all distance cells around the maximum magnitude distance gate, excluding the maximum magnitude and the magnitudes of the three distance gates before and after it; calculate the maximum signal-to-noise ratio (SNR) based on the calculated maximum magnitude and noise mean, and obtain an SNR2; If MAX(SNR1, SNR2) ≥ preset value, then there is no interference. Otherwise, if the mean noise of the 0 subband is greater than the first preset multiple of the prior value or the mean noise of the non-0 subband is greater than the second preset multiple of the preset prior value, then there is noise interference. Otherwise, there is no noise interference.

6. The method according to claim 5, characterized in that, The preset quantity is inversely proportional to the sampling rate of the radar echo signal.

7. The method according to claim 5, characterized in that, After determining that noise interference exists, the method further includes: The noise mean and maximum signal-to-noise ratio of the sum-path echo IQ data of the 0 subband and non-0 subband in the next sliding cycle are judged sequentially to determine whether there is interference in the sum-path echo IQ data of the next sliding cycle. If the ratio of the number of cycles in which interference is determined to exist to the total number of sliding cycles is greater than a preset ratio threshold, then interference is determined to exist.

8. The method according to any one of claims 1-4, characterized in that, When noise interference is determined to exist, noise interference filtering is performed, including... Using the target distance of the noise source being tracked, which corresponds to the center of the corresponding distance cell, as the center distance gate, the leading edge distance gate number of the maximum magnitude waveform is found in all data corresponding to the velocity gate number of the maximum magnitude. The distance deviation is calculated using the leading edge distance gate number and the center distance gate number. The magnitudes of the two preceding and following distance gates are extracted in the distance dimension, and the distance error is calculated using the magnitude of the leading edge distance gate number. The noise distance measurement change is synthesized based on the calculated distance deviation and distance error. For the first tracking, the distance change rate is directly calculated based on the distance change and frame interval, and then the predicted distance is extrapolated. For subsequent tracking, the distance is processed using α-β filtering based on the distance measurement change to obtain the filtered distance and predicted distance for the current noise interference.

9. The method according to any one of claims 1-4, characterized in that, After storing the sum-path echo IQ data from the acquired radar echo signal according to range cells, the method further includes: The pitch difference path echo (IQ) data with different repetition periods are transferred and stored in a continuous arrangement according to the range unit, and the azimuth difference path echo (IQ) data with different repetition periods are also transferred and stored in a sequential arrangement according to the range unit, so as to be used for subsequent direct positioning and tracking of the target.

10. The method according to any one of claims 1-4, characterized in that, During the detection and tracking of interference sources, if the strength of the interference signal is determined to be less than a preset threshold, the target will be detected and tracked again.

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