A false target elimination method based on distance dimension characteristic

Abstract

The application discloses a false target elimination method based on distance dimension characteristics, which comprises the following steps: after the signal of main channel pulse compression is moduled and logarithmized, the signal is divided into two paths, one path extracts maximum value points, and the minimum value of the difference between the extracted maximum value points and left and right maximum value points is taken as the distance dimension signal characteristic quantity of the maximum value points, the other path is detected by constant false alarm, and the detection points are matched with the other maximum value points; the distance dimension signal characteristic quantity of the maximum value points of the matched detection points is compared with a threshold value, whether the detection points are false targets is judged, if the detection points are false targets, the detection points are eliminated, otherwise, the detection points are real targets, and the detection points are reserved. The application does not depend on the shadow channel, only depends on the main channel signal, dense false target interference is eliminated by judging the main channel distance dimension signal characteristics, the remaining real target signal is obtained, and the application can make up for the loophole of the shadow channel method and serve as a complementary / alternative solution.

Description

TECHNICAL FIELD

[0001] The present application relates to the problem of false target decision rejection in the field of radar electronic countermeasures, and in particular to a false target rejection method based on distance dimension characteristics. BACKGROUND

[0002] With the continuous development of electronic information technology, the survival environment of radar in electronic warfare is becoming more and more complex. Among them, the dense false target jamming is an important form of jamming in electronic warfare. It is a multiple false target echo signal generated by the jammer according to a certain track. They are mixed with real targets, making it difficult to distinguish true and false targets.

[0003] The conventional sidelobe shadowing method judges whether the false target jamming is a signal entering from the main lobe or the sidelobe of the main channel by introducing a shadowing channel, thereby suppressing the sidelobe false target jamming. However, this method also has defects, for example, when the target and the jamming direction coincide, it cannot be distinguished, resulting in failure.

[0004] The present application is not dependent on the shadowing channel, but only on the main channel signal. By judging the distance dimension signal characteristics of the main channel, the dense false target jamming is rejected, and the remaining real target signal is left. SUMMARY

[0005] The purpose of the present application is to provide a false target rejection method based on distance dimension characteristics, aiming to realize false target decision by distinguishing the characteristics of true and false targets in the main channel.

[0006] To this end, the present application provides a false target rejection method based on the difference value characteristics of the maximum value points, comprising the following steps: after the signal of the main channel after pulse compression is modulated and logarithmized, it is divided into two paths, one path extracts the maximum value points of the signal and calculates the small value of the difference value between the extracted maximum value points and the left and right maximum value points as the distance dimension signal characteristic quantity of the maximum value points, the other path performs constant false alarm detection to obtain a detection result, and each over-detection point in the detection result is matched with another maximum value point; for the matched over-detection point, the distance dimension signal characteristic quantity of the maximum value point is compared with a threshold value, and whether the detection point is a false target is judged according to the comparison result, if it is judged as a false target, the over-detection point is rejected, otherwise it is judged as a real target, and the over-detection point is retained.

[0007] The present application extracts distance dimension characteristics, does not depend on the shadowing channel, and only depends on the main channel signal. By judging the distance dimension signal characteristics of the main channel, the dense false target jamming is rejected, and the remaining real target signal is left. Thus, the vulnerability of the shadowing channel method can be compensated for, and the shadowing channel method can be supplemented or replaced.

[0008] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0009] The accompanying drawings, which form a part of the specification, are included to provide a further understanding of the application and are incorporated herein in conjunction with the description of the application. The drawings are as follows:

[0010] Figure 1 is a flow chart of the false target elimination method based on the maximum point difference characteristic;

[0011] Figure 2 is a maximum point extraction flow chart;

[0012] Figure 3 is a maximum point extraction schematic diagram;

[0013] Figure 4 is a real echo data result diagram;

[0014] Figure 5 shows the difference value result corresponding to the left and right maximum points;

[0015] Figure 6 shows the difference value result corresponding to the maximum points matched by the detection points;

[0016] Figure 7 shows the true and false target judgment result;

[0017] Figure 8 is a local enlarged view of the true and false target judgment result. DETAILED DESCRIPTION

[0018] The application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0019] The application belongs to the field of false target judgment elimination in radar electronic countermeasure, and aims to realize false target judgment by relying on the feature difference between true and false targets in the main channel. The main function is to provide an engineering implementation method for false target elimination based on distance dimension characteristics.

[0020] The working mechanism of the method is as follows: after the signal after pulse compression of the main channel is logarithmically processed, it is processed in two ways. One way is to extract the maximum points and calculate the distance dimension signal characteristic quantity (the small value of the difference between the maximum point and the left and right maximum points) of the extracted maximum points, and the other way is to perform constant false alarm detection. The detection points that pass the detection are matched with the maximum points of the other way (the matching method takes distance error as the threshold), and the detection points that pass the matching are compared with the threshold value by judging the characteristic quantity of the maximum point to determine whether the detection point is a false target.

[0021] Among them, the maximum point corresponds to a wave peak on the signal. The detection with constant false alarm probability (CFAR) property is called constant false alarm detection.

[0022] The application provides a false target elimination method based on distance dimension characteristics, as shown in the figure, and the flow is as follows: Figure 1

[0023] Step one: extract the maximum value point of the data sequence D, and obtain the result sequence M.

[0024] Step two: the absolute value of the difference between the maximum value point and the left and right maximum value points is selected to obtain the result sequence X.

[0025] Step three: match the detection point with the maximum value point, and compare the difference of the matched maximum value point with the threshold.

[0026] Step four: according to the comparison result, judge whether the detection result is a false target.

[0027] Step five: if the judgment is a false target, eliminate the detection result, otherwise, judge it as a true target and keep it.

[0028] The application extracts distance dimension characteristics, does not depend on the shadow channel, only depends on the main channel signal, eliminates dense false target interference through judging the main channel distance dimension signal characteristics, and leaves the real target signal. Further, the shortcomings / vulnerabilities of the shadow channel method can be compensated.

[0029] As shown in Figure 2 and Figure 3 , the maximum value point extraction process of the data sequence D is as follows:

[0030] Step one: difference (i.e. adjacent data right data minus adjacent left data) is performed on the data sequence D (the sequence number is from 1 to N), and the data difference sequence R (the sequence number is from 2 to N) is obtained.

[0031] Step two: symbol judgment (i.e. the difference sequence is greater than zero to obtain the result 1, and less than or equal to zero to obtain the result 0) is performed on the data difference sequence R, and the symbol judgment result sequence S (the sequence number is from 2 to N) is obtained.

[0032] Step three: the result sequence SN of the sequence S is inverted and left shifted by one bit.

[0033] Step four: the sequence S and SN are added to obtain the result sequence G.

[0034] Step five: judge the sequence G value, the value is 2, and the corresponding data sequence D position is the maximum value point, and the value is-2, and the corresponding data sequence D position is the minimum value point.

[0035] As shown in Figure 3 , the method for obtaining the result sequence X of the absolute value of the difference between the maximum value point and the left and right maximum value points is as follows:

[0036] ​If G4, G(N-3) equals 2, the D4, D(N-3) of the corresponding data sequence is the maximum point, then the absolute value of the difference between the maximum point D4, D(N-3) and the left and right maximum points is selected as the result sequence X4 and X(N-3) of the smaller result sequence X, and the operation is as follows:

[0037] X4 = min(abs(D4-D3), abs(D4-D5)), X(N-3) = min(abs(D(N-3)-D(N-4)), abs(D(N-3)-D(N-2)))

[0038] Where abs represents taking the absolute value, and min represents selecting the smaller value between the two.

[0039] As shown in Figure 3 , the method of comparing the difference between the over-detection result and the maximum value point with the threshold is as follows:

[0040] If the over-detection results are over-detection points D3, D(N-3) respectively, and the maximum value points are D4, D20, D(N-3), the matching method is to subtract the positions 4, 20, N-3 corresponding to the maximum values D4, D20, D(N-3) from the positions 3 corresponding to the over-detection results D3 respectively, and take the absolute value, to obtain the difference results 1, 17, N-6, take the minimum value 1, and compare it with the matching threshold MT (for example, MT equals 2), if it is less than or equal to MT, it is matched, that is, the over-detection result D3 matches the maximum value point D4, and by analogy, the over-detection result D(N-3) matches the maximum value point D(N-3).

[0041] The false target point judgment method is as follows:

[0042] Suppose the over-detection result D3 matches the maximum value point D4, judge whether X4 corresponding to the maximum value point D4 is between the threshold intervals FT1 (for example, FT1 = 1) and FT2 (for example, FT2 = 15), that is, whether X4 > FT1 and X4 < FT2, if the above conditions are met, the over-detection result D3 is judged as a false target point, and is rejected, otherwise it is judged as a true target, and is retained.

[0043] The processing process and results of the actual radar echo data interfered by dense false targets are shown in Figures 5 to 8 .

[0044] Figure 4 The blue color is the echo signal received by the stealth channel, the red color is the echo data received by the main channel, the black asterisk is the extracted maximum value point of the main channel, and the red circle is the over-detection point of the main channel, wherein the true target over-detection point is at the 11060 distance unit, and the other over-detection points are false target points.

[0045] Figure 5 is the minimum value of the difference between all maximum value points and the left and right adjacent maximum value points.Figure 6 The maximum point corresponding difference result is matched for the detection point.

[0046] Figure 7 The result is judged whether in the threshold interval FT1 (for example, FT1=1) and FT2 (for example, FT2=15) by judging the maximum point corresponding difference result matched for the detection point, from Figure 7 It can be seen from the figure that the false target is eliminated and the real target is reserved. Figure 8 A local enlarged view of the real target.

[0047] The above merely describes the embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A false target elimination method based on distance dimension characteristics, characterized in that: It includes the following steps: After taking the modulus and logarithm of the signal after main channel pulse compression, it is divided into two paths for processing: In the first path, the maximum value points of the signal are extracted, and the smaller value of the difference between the extracted maximum value point and the left and right maximum value points is calculated as the distance dimension signal feature quantity of this maximum value point. In the second path, a constant false alarm rate detection is performed to obtain the over-detection result; Match each over-detection point in the over-detection result with the maximum value points in the first path. For the matched over-detection points, compare the distance dimension signal feature quantity of its maximum value point with the threshold value; Judge whether this detection point is a false target according to the comparison result. If it is judged as a false target, then eliminate this over-detection point. Otherwise, it is judged as a real target and this over-detection point is retained.

2. The false target elimination method based on distance dimension characteristics according to claim 1 is characterized in that: The method for extracting the maximum value points is as follows: Step 1: Differentiate the data sequence D, that is, subtract the left data from the right data of adjacent data, to obtain the data difference sequence R, where the data sequence number of the data sequence D ranges from 1 to N, and the data sequence number of the data difference sequence R ranges from 2 to N; Step 2: Perform a sign judgment on the sequence number difference sequence R, that is, if the differential data is greater than zero, the result is 1, and if it is less than or equal to 0, the result is 0, to obtain the sequence number judgment result sequence S, where the data sequence number of the result sequence S ranges from 2 to N; Step 3: The result sequence SN after taking the inverse of the sequence S and shifting it one bit to the left; Step 4: Add the sequence S and SN correspondingly to obtain the result sequence G; Step 5: Judge the value of the sequence G. The position corresponding to the data sequence D at the position where the value is 2 is the maximum value point, and the position corresponding to the data sequence D at the position where the data is -2 is the minimum value point.

3. The false target elimination method based on distance dimension characteristics according to claim 2 is characterized in that: The calculation method for selecting the smaller absolute value of the difference between the maximum value point and the left and right maximum value points to obtain the result sequence X is as follows: Let the maximum value point be D(N - 3), then the operation of X(N - 3) of the result sequence X obtained by selecting the smaller absolute value of the difference between the maximum value point D(N - 3) and the left and right maximum value points is as follows: X(N - 3)=min(abs(D(N - 3)-D(N - 4)), abs(D(N - 3)-D(N - 2))) Where abs represents taking the absolute value, and min represents selecting the smaller value between the two.

4. The false target elimination method based on distance dimension characteristics according to claim 1 is characterized in that: The over-detection points and the maximum value points in the first path are matched according to the distance error as the threshold.

5. The false target elimination method based on distance dimension characteristics according to claim 4 is characterized in that: The matching method for the over-detection points and the maximum value points in the first path is as follows: For each over-detection point, subtract the position corresponding to each over-detection point from the position corresponding to each maximum value point, and take the absolute value of the difference, and compare it with the matching threshold. If it is less than the matching threshold, the maximum value point corresponding to the absolute value of the difference less than the matching threshold is the maximum value point matched by this over-detection point.

6. The false target elimination method based on distance dimension characteristics according to claim 1 is characterized in that: Assume that the distance dimension feature Xj of the matching maximum value point Dj of the over-detection point Di. Judge whether the Xj corresponding to the maximum value point Dj is between the threshold intervals FT1 and FT2, that is, whether Xj > FT1 and Xj < FT2. If the above conditions are met, then judge the over-detection result Dj as a false target point and eliminate it. Otherwise, judge it as a real target and retain it.

Images