Time domain cancellation and fine processing cascaded clutter cancellation method, device, medium and system

Abstract

The invention discloses a time domain cancellation and fine processing cascaded clutter cancellation method, device, medium and system, and belongs to the field of passive detection based on an external radiation source, and the method comprises the steps: processing data through employing the time domain cancellation and fine processing cascaded clutter cancellation method; the clutter cancellation capability of the cancellation method is improved, so that the adaptive capacity of a passive detection system based on an external radiation source to a complex environment is improved, and the final effect is that the detection signal-to-noise ratio of weak target detection is improved.

Description

Technical Field

[0001] The present invention relates to the field of passive detection based on external radiation sources, and more specifically, to a clutter cancellation method, device, medium and system of cascaded time domain cancellation and refined processing. Background Art

[0002] Passive detection technology based on external radiation sources is to receive the direct wave signal of the non-cooperative external radiation source and the scattered echo signal of the target from the external radiation source. The receiving station performs cross-correlation processing on the direct wave signal and the target echo signal to detect the parameters such as the target dual-base time delay and Doppler frequency shift, and then use the direction finding results to realize passive positioning and tracking of the target. The principle diagram of passive detection positioning based on external radiation sources is shown in the figure below. Figure 1 As shown, the external radiation source detection and positioning system uses a time difference ellipse and a lateral line to intersect to obtain the target position information.

[0003] In typical scenarios of external radiation source detection, it is easy to calculate that the received direct wave and clutter power are usually much greater than the target's scattered echo power. Therefore, canceling strong direct and clutter signals becomes a necessary way to detect external radiation sources. Among them, the traditional extended cancellation method clutter cancellation method (also known as ECA-B method) is widely used and has good results. The mathematical description of the traditional time domain cancellation method is shown in the following formula:

[0004]

[0005] Among them, s tar is the signal received by the target channel, s ref is the signal received by the direct channel, s ECA-B is the result after cancellation, N is the number of sampling points of the entire data segment, N B is the length of each segment, then Indicates the number of segments, is the cancellation coefficient of each segment. For detailed definition, please refer to relevant public literature.

[0006] Based on the actual data collected by the receiving device, the above traditional clutter cancellation method is used for processing, where Figure 2 It is the time-frequency diagram of the signal before traditional time-domain cancellation. Figure 3 This is the signal time-frequency diagram after traditional time-domain cancellation. It can be seen that for the field test data of the equipment, the traditional time-domain fire-fighting method has cancelled most of the clutter, and the cancellation capability is as follows: Figure 4 The relevant processing results are shown in Figure 5 shown.

[0007] In the external radiation source detection system used in the actual environment, under complex electromagnetic environment conditions, there are usually other interference signals in the same frequency range of the external radiation used by the system. The traditional external radiation source detection system clutter cancellation method can cancel the strong multipath and ground clutter signals of the external radiation source used, but when faced with a complex environment with unknown multiple interference signals, especially when facing unknown weak interference signals hidden under the strong multipath and clutter signals of the external radiation source used, the traditional clutter cancellation method increases the clutter residue, thereby reducing the target detection signal-to-noise ratio, and even failing to detect the target. This is a technical problem that urgently needs to be optimized and solved in the detection of external radiation sources. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a clutter cancellation method, device, medium and system of cascaded time domain cancellation and refined processing. In view of the new phenomena and new problems in the complex electromagnetic environment faced by passive detection systems based on civilian external radiation sources such as FM broadcasting and digital television in actual applications, the clutter cancellation ability of traditional time domain cancellation methods of external radiation source detection systems is limited. By utilizing the prior that external radiation source signals are generally constant modulus signals, a clutter cancellation method of cascaded time domain cancellation and refined processing is proposed, thereby improving the target detection performance of the entire system.

[0009] The object of the present invention is achieved through the following solutions:

[0010] A clutter cancellation method of cascading time domain cancellation and refined processing comprises the following steps:

[0011] S1: The data received by the target channel of the passive detection device based on the external radiation source and the data received by the direct channel are cancelled using the time domain cancellation method to obtain data s ECA-B , the data length is the total number of data sampling points is N;

[0012] S2: For the data s after cancellation of length N ECA-B ,pass Calculate the average power E;

[0013] S3: Set the threshold δ so that the weak echo signal scattered by the external radiation source irradiating the target meets |s ECA-B [n]| 2 ≤δ·E, where δ is an adjustable parameter;

[0014] S4: For s ECA-B Satisfied in |s ECA-B [n]| 2 The sampling point of >δ·E is judged as unknown interference, and the zeroing operation is performed. The cancellation data s obtained by fine processing new [n] is as follows;

[0015]

[0016] S5: For the result s obtained after cancellation new [n], according to the two-dimensional correlation processing, and complete the detection of target distance and Doppler parameters in the two-dimensional correlation plane;

[0017] S6: The multi-channel target echo data completes the operations of step S1 to step S5, and the target azimuth information is measured using the data after multi-channel cancellation, and finally the target position information is acquired.

[0018] Furthermore, in step S3, the selection of the δ value is determined by adjusting the processing effect of the multi-shot data.

[0019] Furthermore, the value range of δ includes 2, 4, 6, and 8.

[0020] A clutter cancellation device with cascaded time domain cancellation and refined processing includes 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 described in any one of the above items is executed.

[0021] A computer-readable storage medium stores a computer program, wherein the computer program executes any of the above methods when loaded by a processor.

[0022] A clutter cancellation system with time domain cancellation and refined processing cascaded includes the clutter cancellation device with time domain cancellation and refined processing cascaded as described above.

[0023] The beneficial effects of the present invention include:

[0024] The present invention aims at the problem of unknown interference signals faced by passive detection systems based on external radiation sources in practical applications, and proposes a clutter cancellation method using a cascade of time domain cancellation and refined processing, thereby improving the clutter cancellation capability of the cancellation method, thereby improving the adaptability of the passive detection system based on external radiation sources to complex environments, and ultimately improving the detection signal-to-noise ratio of weak target detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 This is a schematic diagram of the positioning principle;

[0027] Figure 2This is the time-frequency domain diagram before traditional time-domain cancellation;

[0028] Figure 3 This is the time-frequency domain diagram after traditional time-domain cancellation;

[0029] Figure 4 It is the traditional cancellation method and capability diagram;

[0030] Figure 5 This is a diagram showing the results of the traditional cancellation method.

[0031] Figure 6 is a flow chart of the method steps of the present invention;

[0032] Figure 7 This is the time-frequency diagram after cancellation processing by the proposed method;

[0033] Figure 8 It is the proposed cancellation method and capability diagram;

[0034] Fig. 9 This is a graph showing the processing results of the traditional cancellation method. DETAILED DESCRIPTION

[0035] All features disclosed in all embodiments in this specification, or steps in all methods or processes implicitly disclosed, except for mutually exclusive features and / or steps, can be combined and / or expanded or replaced in any manner.

[0036] In view of the current situation in the background, the inventor of this application found the following technical problem: Specifically, regarding the technical problem to be solved by the present invention, the external radiation source detection system based on civilian external radiation sources such as FM broadcasting and digital TV signals, the external radiation source signal itself is a constant mode signal. The time-frequency diagram after analyzing the actual external field data after traditional time domain cancellation, that is, analyzing Figure 3 It can be seen that the residual signal after traditional time domain cancellation contains multiple narrow pulse signals at regular positions. The source of the signal is unknown, but the signal will affect the detection of weak echo signals. Providing a weak target detection signal-to-noise ratio by eliminating the influence of the unknown interference is the technical problem to be solved by the present invention.

[0037] The specific implementation process of the present invention is as follows: In a preferred embodiment, the present invention provides a clutter fire prevention method of cascading time domain cancellation and refined processing, comprising the following steps:

[0038] Step 1: The data received by the target channel of the passive detection device based on the external radiation source is s tar , and the data received by the direct channel is s ref , using the traditional time domain cancellation method of formula (1) to obtain the data s after cancellation by the traditional time domain cancellation method ECA-B , where the data length, i.e. the total number of data sampling points, is N;

[0039] Step 2: For the traditional time-domain cancelled data s with length N ECA-B , calculate the average power E through .

[0040] Step 3: According to the characteristic that the external radiation source signal is a constant modulus signal, it can be known that the weak target echo data s obtained through the operation of formula (1) ECA-B should be a constant modulus signal. In theory, the amplitude of each point of s ECA-B is constant, that is, the power of each point is constant. Considering the actual situation, a threshold δ can be set. The weak echo signal scattered by the external radiation source irradiating the target should satisfy |s ECA-B [n]| 2 ≤δ·E, where δ can take values such as 2, 4, 6, 8, etc. as an adjustable parameter. The selection of the δ value can be adjusted and determined through the processing effect of multiple beats of data, and then used for the subsequent data processing;

[0041] Step 4: For the sampling points in s ECA-B where |s ECA-B [n]| 2 >δ·E, it is judged as unknown interference and a zeroing operation is performed. The refined cancelled data s new [n] is as shown in the following formula;

[0042]

[0043] Step 5: For the obtained cancelled result s new [n], perform traditional two-dimensional correlation processing and detect the target distance and Doppler parameters on the two-dimensional correlation plane;

[0044] Step 6: The multi-channel target echo data completes the operations from Step 1 to Step 5, uses the multi-channel cancelled data to complete the measurement of the target azimuth information, and finally completes the acquisition of the target position information. The algorithm flow of a clutter cancellation method with cascaded time-domain cancellation and refinement processing is as Figure 6 shown.

[0045] Comparison Figure 7 with Figure 3 , the method of the present invention effectively suppresses the clutter residue of the traditional cancellation method in a multi-interference environment. Comparison Figure 8 with Figure 4 , the method of the present invention reduces the cancelled clutter-to-noise ratio by 2.484 dB, significantly improving the cancellation ability.

[0046] Figure 5 is the relevant processing result of the traditional cancellation method, Fig. 9 is the relevant processing result after the proposed cascaded time-domain cancellation and refinement processing. It can be seen from the comparison that Figure 5The traditional cancellation method has successfully achieved clutter suppression. At this time, the correlation floor is 283.41dB, and a suspected target detection point appears. However, due to the weak target signal and low target signal-to-noise ratio, it is difficult to detect. Fig. 9 The proposed cancellation method further optimizes the clutter cancellation capability. At this time, the correlation floor is 279.58dB, the target signal-to-noise ratio of the suspected target detection point is significantly improved, and the target is clearly visible.

[0047] The units involved in the embodiments of the present invention may be implemented by software or hardware, and the units described may also be arranged in a processor. The names of these units do not, in some cases, limit the units themselves.

[0048] According to one aspect of an embodiment of the present invention, a computer program product or a computer program is provided, the computer program product or the computer program includes a computer instruction, and the computer instruction is stored in a computer-readable storage medium. A processor of a computer device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device executes the method provided in the above various optional implementations.

[0049] As another aspect, an embodiment of the present invention further provides a computer-readable medium, which may be included in the electronic device described in the above embodiment; or may exist independently without being assembled into the electronic device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by an electronic device, the electronic device implements the method described in the above embodiment.

Claims

1. A clutter cancellation method of cascading time domain cancellation and refinement processing, characterized in that: The following steps are involved: S1: The data received by the target channel of the passive detection device based on the external radiation source and the data received by the direct channel are cancelled using the time domain cancellation method to obtain data s ECA-B , the data length is the total number of data sampling points is N; S2: For the data s after cancellation of length N ECA-B ,pass Calculate the average power E; S3: Set the threshold δ so that the weak echo signal scattered by the external radiation source irradiating the target meets s ECA-B [n] 2 ≤δ·E, where δ is an adjustable parameter; S4: For s ECA-B Satisfied | s ECA-B[ n ] 2 The sampling point of >δ·E is judged as unknown interference, and the zeroing operation is performed. The cancellation data s obtained by fine processing new [n] is as follows; S5: For the result s obtained after cancellation new [n], according to the two-dimensional correlation processing, the target distance and Doppler parameters are detected in the two-dimensional correlation plane; S6: The multi-channel target echo data completes the operations of step S1 to step S5, and the target azimuth information is measured using the data after multi-channel cancellation, and finally the target position information is acquired.

2. The clutter cancellation method of cascaded time domain cancellation and refined processing according to claim 1, characterized in that: In step S3, the selection of the δ value is determined by adjusting the processing effect of the multi-shot data.

3. The clutter cancellation method of cascaded time domain cancellation and refined processing according to claim 4, characterized in that: The value range of δ includes 2, 4, 6, and 8.

4. A clutter cancellation device with cascaded time domain cancellation and refined processing, 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 when the computer program is loaded by a processor, the method according to any one of claims 1 to 3 is executed.

6. A clutter cancellation system with cascaded time domain cancellation and refined processing, characterized in that: A clutter cancellation device comprising the cascaded time domain cancellation and refined processing as described in claim 4.

Images