A short-time matching method to resist spectrum dispersion interference

Abstract

The present invention provides a short-time matching method for resisting spectral dispersion interference, which is used to overcome the problem of improving signal performance in the case of multi-spectral dispersion interference in the prior art. The present invention utilizes the digital channel data of the radar to suppress one or more spectral dispersion interferences through positioning, parameter estimation, filtering, interception, reconstruction and cancellation, and then estimates the parameters of the target through filtering and detection technology; uses reconstruction technology to achieve inverse transformation of the interference data to obtain estimated interference time domain data; suppresses interference through cancellation, and then uses the original filter to filter the signal, and finally outputs the parameters of the target through the detector. Since the present invention only involves the digital receiving channel of the radar and only uses time domain and frequency domain information, the algorithm does not need to change the system structure, only needs to adjust the signal processing algorithm, which is convenient for engineering implementation.

Description

Technical Field

[0001] The invention relates to the technical field of radar and electronic countermeasures, and in particular to a short-time matching method for resisting spectrum dispersion interference. Background Art

[0002] Since linear frequency modulation signals can effectively solve the contradiction between radar range and resolution, this signal form is widely used in the radar field. Therefore, many interference styles for linear frequency modulation signals have emerged in the field of electronic countermeasures, among which spectrum dispersion interference is one of the most efficient interferences. At present, there are two main ways for radars using linear frequency modulation signals to resist such interference: one is to transform the waveform; the other is to estimate the parameters of spectrum dispersion interference, and then achieve the de-slant of interference parameters through transformation, and then reconstruct the interference through signal processing methods to achieve the purpose of removing interference detection targets. Since the first method does not use linear frequency modulation signals, its range or resolution will be reduced, thereby affecting the overall performance of the radar, so this solution is generally not used in actual processes. The second method can usually only be performed for one spectrum dispersion interference. Since part of the signal will be lost in the process of suppressing interference, resulting in a loss of signal-to-noise ratio, this method will fail when there are two or more spectrum dispersion interferences. Summary of the invention

[0003] To this end, the present invention provides a short-time matching method for resisting spectrum dispersion interference, so as to overcome the problem of improving signal performance during multi-spectrum dispersion interference in the prior art.

[0004] To achieve the above object, the present invention provides a short-time matching method for resisting spectrum dispersion interference, comprising:

[0005] Step s1, the digital receiving channel of the radar obtains channel data;

[0006] Step s2, using envelope difference technology to obtain the location parameters of the interference;

[0007] Step s3, using a time-frequency analysis tool to estimate the data and obtain the linear frequency modulation slope parameter of the interference;

[0008] Step s4, filtering the data using various filters to obtain data after the interference pulse is compressed;

[0009] Step s5, reconstructing the interfered time domain data;

[0010] Step s6, suppressing interference through cancellation to obtain interference suppressed data.

[0011] Furthermore, in the step s1, the signal is passed through the digital receiving channel of the radar to obtain channel data A, whose dimension is 1×L, where L is the number of range gates.

[0012] Furthermore, the interference location parameter B is obtained based on the channel data and using the envelope difference technology. The processing formula is as follows:

[0013] B=|A1|-|A2|,

[0014] Among them, A1 is the last L-1 rows of A, and A2 is the first L-1 rows of A;

[0015] B is detected. When the first peak appears, its position is the starting position L1 of the interference. The position where the second peak first appears is the interference position L2. The interference data C is extracted through L1 and L2, and its dimension is 1×(L2-L1+1).

[0016] Furthermore, in step s3, the data C is estimated using a time-frequency analysis tool to obtain n interfering linear frequency modulation slope parameters, including k1, k2, ... and k n , using n interfering linear frequency modulation slope parameters to construct the corresponding linear frequency modulation signal filters in turn, including h k1 、h k2 , ... and h kn , and calculate the corresponding frequency response filter, including H k1 (f) H k2 (f), ... and H kn (f).

[0017] Furthermore, the data C are filtered by the linear frequency modulation signal filter to obtain the data D1, D2, ..., D after the interference pulse is compressed. n ; Use different thresholds to intercept the data, and get the corresponding threshold size data as |D1|, |D2|, ... |D n |, when processing, the data values ​​greater than the threshold data are retained, and the data values ​​less than or equal to the threshold data are set to zero, and the intercepted data are E1, E2, ..., E n .

[0018] Further, according to step s5, the time domain data of interference is reconstructed to obtain n time domain data of interference, and the formula is as follows:

[0019] F i =I FFT{FFT{Ei}. / HKi},

[0020] In the formula, i=1,2,3,...n, FFT{Ei} represents fast Fourier transform, I FFT{} represents inverse fast Fourier transform and . / represents the division of corresponding elements of two vectors.

[0021] Furthermore, interference suppression is achieved through cancellation, and the data after interference suppression is obtained, and the formula is as follows:

[0022]

[0023] The original radar transmission signal is used to construct a filter to filter the data to obtain pulse compressed data, which is then detected using conventional detection technology, and the target parameters are output based on the starting position of the interference.

[0024] Furthermore, the time-frequency analysis tool in step s3 includes short-time Fourier transform, wavelet analysis and fractional Fourier transform.

[0025] Furthermore, the selection of the threshold data in step s4 includes a fixed value and an adaptive threshold according to the strength of the interference.

[0026] Furthermore, the detection technology in step s6 includes using a unit average CFAR detector or using a large selection, small selection, and sorting CFAR algorithm for calculation.

[0027] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention utilizes the digital channel data of the radar to suppress one or more spectral dispersion interferences through positioning, parameter estimation, filtering, interception, reconstruction and cancellation, and then estimates the parameters of the target through filtering and detection technology; first, obtain channel data through the digital receiving channel of the radar; estimate the location parameters of the interference using envelope information, and extract the interference data segment; calculate the parameters of the interference using the interference data, and calculate the frequency domain response filter of the interference; filter the interference data, and intercept the interference data; use reconstruction technology to achieve the inverse transformation of the interference data to obtain the estimated interference time domain data; suppress the interference through cancellation, and then use the original filter to filter the signal, and finally output the parameters of the target through the detector. Since the present invention only involves the digital receiving channel of the radar, and only uses the time domain and frequency domain information, the algorithm does not need to change the system structure, only needs to adjust the signal processing algorithm, which is convenient for engineering implementation;

[0028] Furthermore, the method of the present invention belongs to a time domain processing algorithm, and only the data of the interference segment can be processed, and does not involve multi-channel data, so its calculation amount is small;

[0029] Furthermore, the method of the present invention only requires single-channel data of the radar, so it has wide applicability;

[0030] Furthermore, the method of the present invention only involves the signal processing flow, and only requires upgrading the processing system and software without changing other system structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a flowchart of the short-time matching method for resisting spectrum dispersion interference. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0033] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0034] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] See also Figure 1 As shown, it is a flow chart of a short-time matching method for resisting spectrum dispersion interference;

[0036] Step s1, the digital receiving channel of the radar obtains channel data;

[0037] Step s2, using envelope difference technology to obtain the location parameters of the interference;

[0038] Step s3, using a time-frequency analysis tool to estimate the data and obtain the linear frequency modulation slope parameter of the interference;

[0039] Step s4, filtering the data using various filters to obtain data after the interference pulse is compressed;

[0040] Step s5, reconstructing the interfered time domain data;

[0041] Step s6, suppressing interference through cancellation to obtain interference suppressed data.

[0042] The present invention utilizes the digital channel data of the radar to suppress one or more spectral dispersion interferences through positioning, parameter estimation, filtering, interception, reconstruction and cancellation, and then estimates the parameters of the target through filtering and detection technology; first, obtain channel data through the digital receiving channel of the radar; use envelope information to estimate the location parameters of the interference, and extract the interference data segment; use the interference data to calculate the parameters of the interference, and calculate the frequency domain response filter of the interference; filter the interference data and intercept the interference data; use reconstruction technology to achieve the inverse transformation of the interference data to obtain the estimated interference time domain data; suppress the interference through cancellation, and then use the original filter to filter the signal, and finally output the parameters of the target through the detector. Since the present invention only involves the digital receiving channel of the radar and only uses time domain and frequency domain information, the algorithm does not need to change the system structure, only the signal processing algorithm needs to be adjusted, which is convenient for engineering implementation;

[0043] Specifically, in step s1, the signal is received through the digital receiving channel of the radar and channel data A is obtained, whose dimension is 1×L, where L is the number of range gates.

[0044] Specifically, the interference location parameter B is obtained based on the channel data and using the envelope difference technology. The processing formula is as follows:

[0045] B=|A1|-|A2|,

[0046] Among them, A1 is the last L-1 rows of A, and A2 is the first L-1 rows of A;

[0047] B is detected. When the first peak appears, its position is the starting position L1 of the interference. The position where the second peak first appears is the interference position L2. The interference data C is extracted through L1 and L2, and its dimension is 1×(L2-L1+1).

[0048] Specifically, in step s3, the data C is estimated using a time-frequency analysis tool to obtain n interfering linear frequency modulation slope parameters, including k1, k2, ... and k n , using the n interfering linear frequency modulation slope parameters to construct the corresponding linear frequency modulation signal filters in turn, including h k1 、h k2 , ... and h kn , and calculate the corresponding frequency response filter, including H k1 (f) H k2 (f), ... and H kn (f).

[0049] Specifically, the data C is filtered by the linear frequency modulation signal filter to obtain the data D1, D2, ..., D after the interference pulse is compressed.n ; Use different thresholds to intercept the data, and get the corresponding threshold size data as |D1|, |D2|, ... |D n |, when processing, the data values ​​greater than the threshold data are retained, and the data values ​​less than or equal to the threshold data are set to zero, and the intercepted data are E1, E2, ..., E n .

[0050] Specifically, according to step s5, the time domain data of interference is reconstructed to obtain n time domain data of interference, and the formula is as follows:

[0051] F i =I FFT{FFT{Ei}. / HKi},

[0052] In the formula, i=1,2,3,...n, FFT{Ei} represents fast Fourier transform, I FFT{} represents inverse fast Fourier transform and . / represents the division of corresponding elements of two vectors.

[0053] Specifically, interference is suppressed by cancellation, and the data after interference suppression is obtained, and the formula is as follows:

[0054]

[0055] The original radar transmission signal is used to construct a filter to filter the data to obtain pulse compressed data, which is then detected using conventional detection technology, and the target parameters are output based on the starting position of the interference.

[0056] Specifically, the time-frequency analysis tools in step s3 include short-time Fourier transform, wavelet analysis and fractional Fourier transform.

[0057] Specifically, the selection of the threshold data in step s4 includes a fixed value and an adaptive threshold according to the strength of the interference.

[0058] Specifically, the detection technology in step s6 includes using a unit average CFAR detector or using a large selection, small selection, and sorting CFAR algorithm for calculation.

[0059] Specifically, the method of the present invention belongs to a time domain processing algorithm, and only the data of the interference segment can be processed, and does not involve multi-channel data, so its calculation amount is small;

[0060] Specifically, the method of the present invention only requires single-channel data of the radar, so it has wide applicability;

[0061] Specifically, the method of the present invention only involves the signal processing flow, and only requires upgrading the processing system and software without changing other system structures.

[0062] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0063] Example:

[0064] Step s1, the data vector length is 5000, the interference start position is 1001, the end position is 2000, the original linear frequency modulation signal slope is k0, there are two spectral dispersion interferences, and the interference frequency modulation slopes are k 1＝ 4k 0， k 2＝ 8k0, then the dimension of data A is 1×5000;

[0065] Step s2, A1 is the last 4999 data of A, A2 is the first 4999 data of A, L1=1001, L2=2000, the interfering data C is a vector composed of the 1001th to 2000th data in data A, and the dimension is 1×2000;

[0066] Step s3, estimate the interference data C. Since the interference energy is much greater than the signal, only two interference slope parameters k1 and k2 can be obtained. The expression of linear frequency modulation signal is used to calculate h k1和 h k2 , and the Fourier transform is performed to obtain the corresponding frequency response filter H of the two interferences k1 (f) and H k2 (f);

[0067] Step s4, according to the filter H k1 (f) and H k2 (f) filtering the data C to obtain data D1 and D2, constructing two threshold data for interception, and obtaining data E1 and E2;

[0068] Step s5, obtaining the interfered time domain data F1 and F2 respectively according to the formula for obtaining n interfered time domain data;

[0069] Step s6, filtering G according to the formula for obtaining the data after interference suppression, at this time, filtering the signal with the slope of the original linear frequency modulation signal k0 and then detecting it, and outputting the parameters of the target comprehensively at the comprehensive starting position.

[0070] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A short-time matching method for resisting spectrum dispersion interference, characterized in that: include: Step s1, the digital receiving channel of the radar obtains channel data; Step s2, using envelope difference technology to obtain the location parameters of the interference; Step s3, using a time-frequency analysis tool to estimate the data and obtain the linear frequency modulation slope parameter of the interference; Step s4, filtering the data using various filters to obtain data after the interference pulse is compressed; Step s5, reconstructing the interfered time domain data; Step s6, suppressing interference by cancellation to obtain interference suppressed data; In the step s1, the signal is passed through the digital receiving channel of the radar to obtain channel data A, whose dimension is 1×L, where L is the number of range gates; According to the channel data and using the envelope difference technology, the interference location parameter B is obtained, and the processing formula is as follows: B=|A1|-|A2|, Among them, A1 is the last L-1 rows of A, and A2 is the first L-1 rows of A; Detect B. When the first peak appears, its position is the starting position L1 of the interference. The position where the second peak first appears is the interference position L2. The interference data C is extracted through L1 and L2, and its dimension is 1×(L2-L1+1); In step s3, the data C is estimated using a time-frequency analysis tool to obtain n interfering linear frequency modulation slope parameters, including k1, k2, ... and k n , using the n interfering linear frequency modulation slope parameters to construct the corresponding linear frequency modulation signal filters in turn, including h k1 、h k2 , ... and h kn , and calculate the corresponding frequency response filter, including H k1 (f) H k2 (f), ... and H kn (f); The data C are filtered by the linear frequency modulation signal filter to obtain the interference pulse compressed data D1, D2, ..., D n ; Use different thresholds to intercept the data, and get the corresponding threshold size data as |D1|, |D2|, ... |D n |, when processing, the data values ​​greater than the threshold data are retained, and the data values ​​less than or equal to the threshold data are set to zero, and the intercepted data are E1, E2, ..., E n； According to step s5, the time domain data of interference is reconstructed to obtain n time domain data of interference, and the formula is as follows: F i =IFFT{FFT{Ei}. / HKi}, In the formula, i = 1, 2, 3, ... n, FFT {Ei} represents fast Fourier transform, IFFT {} represents inverse fast Fourier transform, and . / represents the division of corresponding elements of two vectors; The interference is suppressed by cancellation, and the data after interference suppression is obtained. The formula is as follows: The original radar transmission signal is used to construct a filter to filter the data to obtain pulse compressed data, which is then detected using conventional detection technology, and the target parameters are output based on the starting position of the interference.

2. The short-time matching method for resisting spectrum dispersion interference according to claim 1 is characterized in that: The time-frequency analysis tools in step s3 include short-time Fourier transform, wavelet analysis and fractional Fourier transform.

3. The short-time matching method for resisting spectrum dispersion interference according to claim 2 is characterized in that: The selection of the threshold data in step s4 includes a fixed value and an adaptive threshold according to the strength of the interference.

4. The short-time matching method for resisting spectrum dispersion interference according to claim 3 is characterized in that: The detection technology in step s6 includes using a unit average CFAR detector or using a large selection, small selection, and sorting CFAR algorithm for calculation.

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