Method, device, medium and system for improving target detection probability under clutter suppression

Abstract

The invention discloses a method, a device, a medium and a system for improving target detection probability under clutter suppression, and belongs to the field of radar signal processing, and the method comprises the steps: in an MTI radar system, carrying out the statistics of the response of Gaussian noise in a speed dimension after passing through an MTI filter, carrying out the averaging of the response in each speed dimension, recording a mean value to form a compensation coefficient table, and carrying out the calculation of the compensation coefficient table; compensation is performed after completion of coherent accumulation to reduce target energy loss in a non-clutter spectrum region. According to the method, the radar target detection probability is improved under clutter suppression, the target energy loss in a non-clutter spectrum region is reduced, and the system sensitivity is improved.

Description

Technical Field

[0001] The present invention relates to the field of radar signal processing, and more specifically, to a method, device, medium, and system for improving the target detection probability under clutter suppression. Background Art

[0002] Today's radars usually operate in a very complex environment. The echo signals received by the radar will include signals reflected by various static targets such as mountains, buildings, and trees, which brings certain difficulties to the identification of moving targets. Many radars use the MTI technology, that is, the moving target indication technology, to extract moving targets from the complex environment. Even when the signals returned by fixed targets are of a larger order of magnitude than those of moving targets, the MTI radar can still identify moving targets using the Doppler frequency shift. Although the returned data includes both the echo data of fixed targets and other clutter, the signals returned from fixed targets do not have frequency shifts. Any target moving at a relative speed greater than zero will generate a certain amount of frequency shift. In an MTI radar system, the data part of static targets does not have Doppler frequency modulation, and the phase in each echo pulse is the same. The echo of static targets can be eliminated through the MTI radar filter to achieve the purpose of clutter suppression. A typical MTI radar filter is a delay line canceller, which can extract the Doppler frequency shift and filter out the clutter echoes, thereby improving the detection ability of the radar.

[0003] The principle block diagram of target detection in an MTI radar system is as Figure 1 shown. The MTI radar filter can achieve clutter suppression, but the target energy loss is relatively large in the non-clutter frequency spectrum area, the target point amplitude decreases, and it cannot exceed the fixed threshold during detection, thereby reducing the target detection probability and losing the system sensitivity. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method, device, medium, and system for improving the target detection probability under clutter suppression, which improves the radar target detection probability under clutter suppression, reduces the target energy loss in the non-clutter frequency spectrum area, and thus improves the system sensitivity.

[0005] The purpose of the present invention is achieved through the following solutions:

[0006] A method for improving the target detection probability under clutter suppression includes the following steps:

[0007] In an MTI radar system, the response of Gaussian noise in the velocity dimension after passing through the MTI filter is statistically analyzed, the responses in each velocity dimension are averaged, and the mean value is recorded to form a compensation coefficient table, and compensation is performed after coherent integration to reduce the target energy loss in the non-clutter frequency spectrum area.

[0008] Further, in the MTI radar system, the response of the statistical Gaussian noise in the velocity dimension after passing through the MTI filter is statistically analyzed, the responses in each velocity dimension are averaged, and the mean values are recorded to form a compensation coefficient table, which is compensated after coherent integration. Specifically, it includes the following sub-steps:

[0009] S1. Determine the MTI radar filter. Let its filtering coefficient be Coeff, filter the input wideband noise x to obtain the signal y as shown in Equation (1), and then perform a transformation on y. The transformation includes an N-point FFT transformation; through the N-point FFT transformation, the amplitude response Y in each velocity dimension is obtained, as shown in Equation (2);

[0010] y = filter(Coeff, x) (1);

[0011] Y = FFT(y) (2);

[0012] S2. Perform Monte Carlo simulation on the velocity dimension amplitude response in Step S1. The number of simulation times is L, and the average of the L results is obtained as shown in Equation (3), and the reciprocal is taken to form the compensation coefficient Wopt, as shown in Equation (4);

[0013]

[0014] Y j is the amplitude response of the jth time;

[0015] S3. Insert the compensation coefficient Wopt after coherent integration, multiply S by the compensation coefficient Wopt to obtain S', as shown in Equation (5), and then perform target detection;

[0016] S' = S * Wopt (5).

[0017] Further, in Step S1, it further includes the following sub-steps: the velocity amplitude responses of the wideband noise after passing through the single delay line and the double delay line filters. Let the single delay line filtering coefficient be [1 -1], and the double delay line filtering coefficient be [1 -21].

[0018] A device for improving the target detection probability under clutter suppression includes a processor and a memory. A computer program is stored in the memory, and when the computer program is loaded by the processor, it executes the method described in any one of the above.

[0019] A computer-readable storage medium stores a computer program, and when the computer program is loaded by a processor, it executes the method described in any one of the above.

[0020] An electronic system includes the device for improving the target detection probability under clutter suppression described above.

[0021] The beneficial effects of the present invention include:

[0022] The present invention fully studies the target energy loss characteristics of the MTI filter in the non-clutter spectrum area, statistically analyzes the responses of a large amount of Gaussian noise in the velocity dimension after passing through the MTI filter, averages the responses in each velocity dimension, records the mean values to form a compensation coefficient table, and performs compensation after coherent integration. In view of the characteristics of the MTI filter's target energy loss in the non-clutter spectrum area under a strong clutter background, it reduces the target energy loss in the non-clutter spectrum area, can improve the target detection probability, and enhances the system sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 is the principle block diagram of target detection for the MTI radar system;

[0025] Figure 2 is the velocity amplitude response of the single-delay line / double-delay line filter;

[0026] Figure 3 is the velocity amplitude statistical average response of the single-delay line / double-delay line filter;

[0027] Figure 4 is the coefficient compensation value of the single-delay line / double-delay line filter;

[0028] Figure 5 is the post-processing flowchart of the inserted coefficient compensation;

[0029] Figure 6 is the comparison diagram of the noise floor before and after compensation;

[0030] Figure 7 is the comparison diagram of the target before and after compensation. DETAILED DESCRIPTION OF THE INVENTION

[0031] All the features disclosed in all the embodiments in this specification, or all the steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined and / or extended, replaced in any way.

[0032] The specific implementation process of the present invention is as follows:

[0033] In a preferred embodiment, a method for improving the target detection probability under clutter suppression is provided. Specifically, it includes the following steps:

[0034] 1), After the system determines the MTI radar filter, with the filter coefficient being Coeff, the input broadband noise x is filtered to obtain the signal y as shown in Equation (1), and then the N-point FFT transform is performed on y to obtain the amplitude response Y in each velocity dimension as shown in Equation (2).

[0035] y = filter(Coeff, x) (1);

[0036] Y = FFT(y) (2);

[0037] The velocity amplitude responses of the broadband noise after passing through the single-delay line and double-delay line filters are shown in Figure 2 , the filter coefficient of the single-delay line is [1 -1], and the filter coefficient of the double-delay line is [1 -2 1].

[0038] 2), Perform Monte Carlo simulation on the velocity dimension amplitude response in step 1), with the number of simulation times being L, and average the results of L times to obtain as shown in Equation (3), and its amplitude curve is as shown in Figure 3 , after taking the reciprocal, the compensation coefficient Wopt is formed as shown in Equation (4), and its amplitude curve is as shown in Figure 4 .

[0039]

[0040] Y j is the amplitude response of the jth time.

[0041] 3) The traditional processing is to directly perform target detection on the signal S after coherent integration. Now, the compensation coefficient Wopt is inserted after coherent integration, and S is multiplied by the compensation coefficient Wopt to obtain S' as shown in Equation (5), and then target detection is performed. The processing flow is as shown in Figure 5 .

[0042] S' = S * Wopt (5);

[0043] In summary, the present invention proposes a coefficient compensation method after using the MTI radar filter, which can reduce the target energy loss in the non-clutter spectrum area by the MTI filter. The comparison of the noise floors before and after coefficient compensation is shown in Figure 6 .

[0044] When the target velocity falls in the area with severe noise modulation, the target amplitude can be increased to exceed the fixed threshold. The targets before and after compensation are shown in Figure 7 , it can be seen that after filtering, although the signal-to-noise ratio of the target is high, the amplitude does not exceed the set fixed threshold, resulting in detection loss. However, after coefficient compensation, the target can be correctly detected.

[0045] Assume that the radar operating pulse repetition period is 700 μs. For different frequency band radar scenarios, the improvement effect of the present invention on the target amplitude loss is shown in Table 1 and Table 2. Its maximum gain improvement exceeds 30 dB, greatly reducing the system sensitivity loss.

[0046] Table 1 Statistical table of target amplitude gain at different speeds when the radar operating frequency band is 500M

[0047]

[0048]

[0049] Table 2 Statistical table of target amplitude gain at different speeds when the radar operating frequency band is 1200M

[0050] Target speed m / s 1200M 5～15 21.1 dB 15～30 5.8 dB 30～45 0.8 dB 45～60 0.9 dB 60～75 6.3 dB 75～90 20.7 dB 90～105 19.8 dB 105～120 5.4 dB

[0051] The technical effect verification of the present invention is as follows:

[0052] Based on the above method of the present invention, when a certain radar is tested, the beam range covers the airport and civil aviation aircraft can be observed. The flight speed of civil aviation aircraft is about 200 m / s. By selecting different flight paths, targets with different flight speeds can be observed, and the traces reported by radar processing are stored synchronously.

[0053] Scenario 1: The target detection distance is 55 Km to 180 Km, and the radial velocity range is -10 m / s to 85 m / s. The trace data of the traditional method and the present invention are recorded respectively, and the fixed threshold and the Cfar detection threshold are kept consistent.

[0054] Scenario 2: The target detection distance is 50 Km to 192 Km, and the radial velocity range is -5 m / s to 110 m / s. The trace data of the traditional method and the present invention are recorded respectively, and the fixed threshold and the Cfar detection threshold are kept consistent.

[0055] Scenario 3: The target detection distance is 75 Km to 210 Km, and the radial velocity range is 170 m / s to 200 m / s. The trace data of the traditional method and the present invention are recorded respectively, and the fixed threshold and the Cfar detection threshold are kept consistent.

[0056] Export the trace data in the three scenarios, and compare the proportion of the number of frames in which the target is correctly detected by the traditional method and the present invention. The results are shown in Table 3. It can be found that in Scenarios 1 and 2 with lower target radial velocity, the proportion of the number of detected frames has increased by more than 20%, which is consistent with the previous analysis. In Scenario 3 with higher speed, at this time, the improvement of the target amplitude loss after coefficient compensation is very small, so it is similar to the detection ratio of the traditional method.

[0057] Table 3 Summary table of the effects of implementation examples

[0058] Radial velocity range Detection ratio of traditional method Detection ratio of the present invention Improvement -10 m / s to 85 m / s 61.3％ 85.4％ 24.1％ -5 m / s to 110 m / s 65.4％ 85.6％ 20.2％ 170 m / s to 200 m / s 95.0％ 95.5％ 0.5％

[0059] It should be noted that within the scope of protection defined in the claims of the present invention, the following embodiments can be combined and / or extended, or replaced in any logical manner from the above specific implementation manners, such as the disclosed technical principles, disclosed technical features, or implicitly disclosed technical features.

[0060] Embodiment 1

[0061] A method for improving the target detection probability under clutter suppression, comprising the following steps:

[0062] In an MTI radar system, the responses of Gaussian noise in the velocity dimension after passing through the MTI filter are statistically analyzed, the responses in each velocity dimension are averaged, and the mean values are recorded to form a compensation coefficient table, and compensation is performed after coherent integration to reduce the target energy loss in the non-clutter spectrum region.

[0063] Embodiment 2

[0064] On the basis of Embodiment 1, in the MTI radar system, the responses of Gaussian noise in the velocity dimension after passing through the MTI filter are statistically analyzed, the responses in each velocity dimension are averaged, and the mean values are recorded to form a compensation coefficient table, and compensation is performed after coherent integration, which specifically includes the following sub-steps:

[0065] S1. Determine the MTI radar filter, assume its filtering coefficient is Coeff, filter the input wideband noise x to obtain the signal y, as shown in Equation (1), and then perform a transformation on y, where the transformation includes an N-point FFT transformation; through the N-point FFT transformation, the amplitude responses Y in each velocity dimension are obtained; as shown in Equation (2);

[0066] y = filter(Coeff, x) (1);

[0067] Y = FFT(y) (2);

[0068] S2. Perform Monte Carlo simulation on the velocity dimension amplitude responses in Step S1, the number of simulation times is L, and the average of the L results is obtained as shown in Equation (3), and the reciprocal is obtained to form the compensation coefficient Wopt, as shown in Equation (4);

[0069]

[0070] Y j is the amplitude response of the jth time;

[0071] S3. Insert the compensation coefficient Wopt after coherent integration, multiply S by the compensation coefficient Wopt to obtain S′, as shown in Equation (5), and then perform target detection;

[0072] S′ = S * Wopt (5).

[0073] Embodiment 3

[0074] Based on Embodiment 2, in step 1), the following sub - steps are further included: for the velocity magnitude responses of the broadband noise after passing through the single - delay - line and double - delay - line filters, the single - delay - line filtering coefficient is set to [1 -1], and the double - delay - line filtering coefficient is set to [1 -2 1].

[0075] Embodiment 4

[0076] An apparatus for improving the target detection probability under clutter suppression includes a processor and a memory. A computer program is stored in the memory, and when the computer program is loaded by the processor, it executes the method described in any one of Embodiments 1 to 3.

[0077] Embodiment 5

[0078] A computer - readable storage medium stores a computer program. When the computer program is loaded by a processor, it executes the method described in any one of Embodiments 1 to 3.

[0079] Embodiment 6

[0080] An electronic system includes the apparatus for improving the target detection probability under clutter suppression described in Embodiment 4.

[0081] The units involved in the embodiments of the present invention can be implemented in software or in hardware. The described units can also be set in a processor. Among them, the names of these units do not constitute a limitation to the unit itself in some cases.

[0082] According to one aspect of the embodiments of the present invention, a computer program product or a computer program is provided. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer - readable storage medium. The processor of a computer device reads the computer instructions from the computer - readable storage medium, and the processor executes the computer instructions, so that the computer device executes the methods provided in the above various alternative implementation manners.

[0083] As another aspect, the embodiments of the present invention further provide a computer - readable medium. The computer - readable medium can be included in the electronic device described in the above embodiments; or it can exist alone without being assembled into the electronic device. The above computer - readable medium carries one or more programs. When the one or more programs are executed by an electronic device, the electronic device implements the methods described in the above embodiments.

Claims

1. A method for improving target detection probability under clutter suppression, characterized in that: The following steps are involved: In the MTI radar system, the response of Gaussian noise in the velocity dimension after passing through the MTI filter is statistically analyzed, the responses in each velocity dimension are averaged, and the mean is recorded to form a compensation coefficient table. After completing the coherent accumulation, compensation is performed to reduce the target energy loss in the non-clutter spectrum area.

2. The method for improving target detection probability under clutter suppression according to claim 1, characterized in that: In the MTI radar system, the response of Gaussian noise in the velocity dimension after passing through the MTI filter is statistically analyzed, the responses in each velocity dimension are averaged, the average is recorded to form a compensation coefficient table, and compensation is performed after completing the coherent accumulation, specifically including the following sub-steps: S1, determine the MTI radar filter, set its filter coefficient as Coeff, filter the input broadband noise x to obtain the signal y, see formula (1), and then transform y, the transformation includes N-point FFT transformation; through the N-point FFT transformation, the amplitude response Y of each velocity dimension is obtained; see formula (2); y = filter(Coeff,x) (1); Y = FFT(y) (2); S2, perform Monte Carlo simulation on the velocity dimension amplitude response in step S1, the number of simulations is L, and the average of the results of L times is obtained See formula (3), and the compensation coefficient Wopt is formed after the inverse is calculated, see formula (4); Y j is the jth magnitude response; S3, insert the compensation coefficient Wopt into the coherent accumulation, multiply S by the compensation coefficient Wopt to get S′, see formula (5), and then perform target detection; S′=S*Wopt (5).

3. The method for improving target detection probability under clutter suppression according to claim 2, characterized in that: In step S1, the following sub-steps are also included: the speed amplitude response of the broadband noise after passing through the single delay line and double delay line filters, the single delay line filter coefficient is set to [1-1], and the double delay line filter coefficient is set to [1-2 1] respectively.

4. A device for improving target detection probability under clutter suppression, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is loaded by the processor, the method according to any one of claims 1 to 3 is executed.

5. A computer-readable storage medium, characterized in that: A computer program is stored in a readable storage medium, and the computer program is loaded by a processor to execute the method according to any one of claims 1 to 3.

6. An electronic system, characterized in that: It includes the device for improving the target detection probability under clutter suppression as described in claim 4.

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