Clutter cancellation method, device, medium and system of time domain cancellation and fine processing cascade

Abstract

The application discloses a clutter cancellation method and device based on time-domain cancellation and fine processing cascade, a medium and a system, and belongs to the field of passive detection based on external radiation sources, and comprises the following steps: data is processed by using the clutter cancellation method based on time-domain cancellation and fine processing cascade. The application improves 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 finally improves the detection signal-to-noise ratio of weak target detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of passive detection based on external radiation sources, and more particularly, to a clutter cancellation method and device based on time domain cancellation and fine processing, a medium and a system. BACKGROUND

[0002] Passive detection based on external radiation sources is a technology that receives direct wave signals of non-cooperative external radiation sources and target scattering echo signals of external radiation source illumination signals, and a receiving station performs cross-correlation processing on the direct wave signals and target echo signals to detect target bistatic time delay, Doppler shift and other parameters, and then uses the direction finding results to achieve passive positioning and tracking of the target. As shown in Figure 1 , the external radiation source detection and positioning system uses a time difference ellipse intersecting a lateral line to achieve acquisition of target position information.

[0003] In a typical external radiation source detection scenario, the received direct wave and clutter power is usually much larger than the target scattering echo power. Therefore, canceling strong direct waves and clutter signals is a necessary way for external radiation source detection. The traditional extended cancellation method clutter cancellation method (also known as ECA-B method) is widely used and has good effect. The mathematical description of the traditional time domain cancellation method is as follows:

[0004] (1)

[0005] wherein, is the signal received by the target channel, is the signal received by the direct channel, is the result after cancellation, N is the number of sampling points of the entire data, is the length of each segment, and represents the number of segments, is the cancellation coefficient of each segment, and detailed definitions can be found in related public documents.

[0006] Based on the actual data collected by the receiving device, the above traditional clutter cancellation method is used for processing, wherein Figure 2 is the signal time-frequency graph before traditional time domain cancellation, Figure 3 is the signal time-frequency graph after traditional time domain cancellation. It can be seen that for device real-time field test data, the remaining 2.895dB can be cancelled by the traditional time domain cancellation method. It can be seen that the traditional time domain cancellation method has cancelled most of the clutter, and the cancellation ability is shown in FIG. 4, and the related processing results are shown in FIG. 5.

[0007] The external radiation source detection system applied to the actual environment has other interference signals in the same frequency range of the external radiation used by the system under the condition of complex electromagnetic environment. The clutter cancellation method of the traditional external radiation source detection system can cancel the strong multipath and ground clutter signals of the used external radiation source, but when facing the complex environment of unknown multi-interference signals, especially the unknown weak interference signals hidden in the strong multipath and clutter signals of the used external radiation source, the traditional clutter cancellation method increases the residual clutter, thereby reducing the signal-to-noise ratio of target detection, and even cannot realize the detection of the target, which is a technical problem to be optimized and solved for the external radiation source detection. SUMMARY

[0008] The present application aims to overcome the deficiencies of the prior art, and provides a clutter cancellation method, device, medium and system of time-domain cancellation and fine processing cascade, which aims at the new phenomena and problems of complex electromagnetic environment in the practical application of the passive detection system based on the civilian external radiation source such as frequency modulation broadcast and digital television, and improves the target detection performance of the whole system by using the priori that the external radiation source signal is generally a constant modulus signal.

[0009] The purpose of the present application is realized by the following scheme:

[0010] A clutter cancellation method of time-domain cancellation and fine processing cascade, comprising the following steps:

[0011] S1: based on the data received by the target channel of the passive detection equipment of the external radiation source and the data received by the direct channel, using a time-domain cancellation method to cancel the data , the data length is the total sampling point number N;

[0012] S2: for the canceled data with a length of N, the average power E is calculated by ;

[0013] S3: set the threshold value , so that the weak echo signal scattered by the external radiation source irradiation target satisfies , wherein is an adjustable parameter;

[0014] S4: for the sampling points in that satisfy , judge as unknown interference, and perform zero operation, and the canceled data obtained by fine processing is as follows:

[0015] ;

[0016] S5: for the obtained post-cancellation result , according to two-dimensional correlation processing, and the detection of target distance and Doppler parameters is completed in a two-dimensional correlation plane;

[0017] S6: the multi-channel target echo data complete the operation of steps S1 to S5, the multi-channel post-cancellation data is used to complete the target azimuth information measurement, and finally the target position information is obtained.

[0018] Further, in step S3, The selection of the value is determined by the processing effect adjustment of multiple shots of data.

[0019] Further, The value range of includes 2, 4, 6 and 8.

[0020] A clutter cancellation device of time domain cancellation and fine processing cascade, comprising a processor and a memory, the memory stores a computer program, when the computer program is loaded by the processor and executes the method as claimed in any one of the above.

[0021] A computer readable storage medium, the computer readable storage medium stores a computer program, the computer program is loaded by a processor and executes the method as claimed in any one of the above.

[0022] A clutter cancellation system of time domain cancellation and fine processing cascade, comprising the clutter cancellation device of time domain cancellation and fine processing cascade as claimed in the above.

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

[0024] The present application aims at the unknown interference signal problem faced by the passive detection system based on external radiation source in actual application, proposes a clutter cancellation method of time domain cancellation and fine processing cascade, improves the clutter cancellation ability of the cancellation method, thereby improving the adaptability of the passive detection system based on external radiation source to complex environment, and finally improves the detection signal-to-noise ratio of weak target detection. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

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

[0027] Figure 2 It is a time-frequency domain graph before traditional time domain cancellation;

[0028] Figure 3 Time-frequency domain diagram for traditional time-domain cancellation;

[0029] Figure 4 Capability diagram for traditional cancellation method;

[0030] Figure 5 Result diagram related to traditional cancellation method;

[0031] Figure 6 Flowchart of method steps of the present application;

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

[0033] Figure 8 Capability diagram for the proposed cancellation method;

[0034] Figure 9 Result diagram related to traditional cancellation method. DETAILED DESCRIPTION

[0035] All features disclosed in the specification or all steps of methods or processes disclosed in the specification disclosed by all examples in the specification can be combined and / or extended, replaced, unless mutually exclusive.

[0036] In view of the status in the background, the inventors of the present application found the following technical problems: Specifically, the technical problems to be solved by the present application, based on the external radiation source detection system of the civilian external radiation source such as frequency modulation broadcast and digital television signal, the external radiation source signal itself is a constant modulus signal. The time-frequency diagram after analyzing the actual data of the external field by traditional time-domain cancellation, that is, analyzing Figure 3 It can be seen that the residual signal after traditional time-domain cancellation has 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, and the provision of 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 application.

[0037] The specific implementation process of the present application is as follows: In a preferred embodiment, the present application provides a clutter cancellation method for cascading time-domain cancellation and fine processing, comprising the following steps:

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

[0039] Step 2: for the conventional time domain after cancellation data of length N , by calculating the average power E;

[0040] Step 3: according to the characteristics of the external radiation source signal being a constant modulus signal, the weak target echo data obtained by operation of formula (1) should be a constant modulus signal, and in theory the amplitude of each point is constant, that is, the power of each point is constant; considering the actual situation, a threshold value can be set, and the weak echo signal scattered by the external radiation source irradiated target should satisfy , wherein as an adjustable parameter, can take values of 2, 4, 6, 8 and the like, the selection of the value can be determined by the processing effect of multiple shots of data, and then used for subsequent data processing;

[0041] Step 4: for the sampling points in , it is judged as unknown interference, and a zero operation is performed, and the fine processing of the after-cancellation data is as follows:

[0042] (2)

[0043] Step 5: for the obtained after-cancellation result , according to the conventional two-dimensional correlation processing, and the detection of target distance and Doppler parameter is completed in the two-dimensional correlation plane;

[0044] Step 6: the multi-channel target echo data completes the operations of steps 1 to 5, and the multi-channel after-cancellation data is used to complete the measurement of target azimuth information, and finally the target position information is obtained. The algorithm flow of the clutter cancellation method of the cascade of time domain cancellation and fine processing is as shown in Figure 6 .

[0045] Compared with Figure 7 and Figure 3 , the method effectively suppresses the clutter remaining of the conventional cancellation method in a multi-interference environment. Compared with Figure 8 and Figure 4 , the method makes the clutter-to-noise ratio after cancellation reduce by 2.484dB, and significantly improves the cancellation ability.

[0046] Figure 5 is the correlation processing result of the conventional cancellation method, Figure 9 is the correlation processing result after the cascade cancellation of the time domain cancellation and fine processing. It can be seen from the comparison that Figure 5 ​The traditional cancellation method has successfully realized clutter suppression, and the correlation base is 283.41 dB at this time, and a suspected target detection point appears, but the target signal is weak, the target signal-to-noise ratio is not high, and it is difficult to detect; Figure 9 The proposed cancellation method further optimizes the clutter cancellation capability, and the correlation base is 279.58 dB at this time, the target signal-to-noise ratio of the suspected target detection point is significantly improved, and the target is clear and visible.

[0047] The units described in the embodiments of the present application can be implemented in the form of software, or can be implemented in the form of hardware, and the described units can also be arranged in a processor. In some cases, the name of the unit does not constitute a limitation on the unit itself.

[0048] According to an aspect of an embodiment of the present application, a computer program product or computer program is provided, which includes computer instructions stored in a computer readable storage medium. The processor of the 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 method provided in the various optional implementation manners described above.

[0049] As another aspect, the embodiments of the present application also provide a computer readable medium, which can be included in the electronic device described in the above embodiments, or can exist separately without being assembled into the electronic device. The above computer readable medium carries one or more programs, which, when executed by the electronic device, enable the electronic device to implement the method described in the above embodiments.

Claims

1. A clutter cancellation method cascaded with time-domain cancellation and fine-tuning processing, characterized in that, Includes the following steps: S1: The data received by the target channel and the data received by the direct channel of the passive detection device based on the external radiation source are canceled using the time-domain cancellation method to obtain the final data. The data length is N, and the total number of sampling points is N. S2: For the canceled data of length N ,pass Calculate the average power E; S3: Set threshold The weak echo signal scattered by the target after being illuminated by an external radiation source satisfies ,in As an adjustable parameter; S4: For China satisfies The sampling points were identified as having unknown interference, and a zeroing operation was performed. The resulting data was then refined and cancelled. As shown in the following formula; ； S5: Regarding the obtained cancellation result The target distance and Doppler parameters are detected in the two-dimensional correlation plane according to the two-dimensional correlation processing. S6: Multi-channel target echo data completes the operations from steps S1 to S5. The target azimuth information is measured using the multi-channel canceled data, and finally the target position information is acquired.

2. The clutter cancellation method cascaded with time-domain cancellation and fine-tuning processing according to claim 1, characterized in that, In step S3, The selected values ​​were determined through adjustments based on the processing effects of multiple data shots.

3. The clutter cancellation method cascaded with time-domain cancellation and fine-tuning processing according to claim 2, characterized in that, The value range includes 2, 4, 6, and 8.

4. A clutter cancellation device that cascades time-domain cancellation and fine-tuning processing, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program that, when loaded by the processor, executes the method as described in any one of claims 1 to 3.

5. A computer-readable storage medium, characterized in that, A computer program is stored in a readable storage medium, which, when loaded by a processor, executes the method as described in any one of claims 1 to 3.

6. A clutter cancellation system cascaded with time-domain cancellation and fine-tuning processing, characterized in that, The clutter cancellation device includes the time-domain cancellation and fine-tuning cascaded clutter cancellation device as described in claim 4.

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