CN116299205B - Time domain sliding window subspace projection SAR broadband interference suppression method - Google Patents
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Abstract
The invention discloses a method for inhibiting SAR broadband interference by projection of a time domain sliding window subspace, which comprises the following steps: acquiring an interfered SAR echo signal; the SAR echo signal comprises a plurality of pulse echo signals; for each pulse echo signal, intercepting a sub echo signal of the pulse echo signal through a preset sliding window to obtain a plurality of sub echo signals of the pulse echo signal; for each sub-echo signal, constructing an echo matrix of the sub-echo signal by adopting a preset space dimension; determining an interference subspace matrix of the sub-echo signals according to the echo matrix of the sub-echo signals; according to the echo matrix and the interference subspace matrix of the sub-echo signals, carrying out interference suppression on the sub-echo signals to obtain a plurality of interference suppressed sub-echo signals of each pulse echo signal; rearranging the plurality of interference-suppressed sub-echo signals of each pulse echo signal to obtain each interference-suppressed pulse echo signal, thereby obtaining an SAR echo signal after interference suppression.
Description
Technical Field
The invention belongs to the technical field of radar signal anti-interference, and particularly relates to a time domain sliding window subspace projection SAR broadband interference suppression method.
Background
Under the background of increasingly complex current electromagnetic environments, interference means aiming at the research of the synthetic aperture radar are increasingly diversified, the interference forms are increasingly flexible, and the imaging effect of the synthetic aperture radar (Synthetic Aperture Radar, SAR) is seriously affected. From the viewpoint of signal bandwidth, the interference signal may be classified into a narrowband interference signal and a wideband interference signal. Compared with the narrow-band interference signal, the broadband interference signal occupies a larger bandwidth, so that the SAR working frequency band is more easily affected, and the countermeasure is difficult. The Eigensubspace-based filtering with application in narrow-band interference suppression for SAR published by ZHOU Feng et al proposes an interference suppression method based on subspace projection, wherein interference is regarded as main components of radar echo signals, mutually orthogonal interference subspaces and signal subspaces are constructed by utilizing main component analysis, and then the echo signals are projected in the interference subspaces, so that interference signals in the echo signals are extracted, interference suppression is realized by interference cancellation, and narrowband interference can be counteracted. Based on the aggregation of wideband interference signals in the time-frequency domain, TAO Mingliang et al (Wideband interference mitigation in high-resolution airborne synthetic aperture radardata) propose that a short-time Fourier transform is performed on the signals to obtain a time spectrum containing a series of signal transient spectrums, and subspace projection is performed on each transient spectrum in sequence to realize wideband interference suppression.
However, the transient spectrum of the broadband interference signal is not stable, so that the existing method is difficult to construct an effective interference subspace, and the problem of insufficient algorithm interference suppression is caused; in addition, the existing method needs to perform processing in a signal time-frequency domain, so that short-time Fourier transform and inverse short-time Fourier transform are needed to be performed on the received SAR echo signal, and the problems of high algorithm calculation amount and low efficiency are caused.
Disclosure of Invention
In order to solve the problems in the related art, the invention provides a method for suppressing broadband interference of a time domain sliding window subspace projection SAR. The technical problems to be solved by the invention are realized by the following technical scheme:
the invention provides a method for inhibiting SAR broadband interference by projection of a time domain sliding window subspace, which comprises the following steps:
s1, acquiring an interfered SAR echo signal; the SAR echo signal comprises a plurality of pulse echo signals;
s2, intercepting sub-echo signals of each pulse echo signal through a preset sliding window to obtain a plurality of sub-echo signals of the pulse echo signal;
s3, for each sub-echo signal, constructing an echo matrix of the sub-echo signal by adopting a preset space dimension;
s4, determining an interference subspace matrix of the sub-echo signals according to the echo matrix of the sub-echo signals;
s5, carrying out interference suppression on the sub-echo signals according to the echo matrix and the interference subspace matrix of the sub-echo signals to obtain a plurality of interference suppressed sub-echo signals of each pulse echo signal;
s6, rearranging the plurality of interference-suppressed sub-echo signals of each pulse echo signal to obtain each interference-suppressed pulse echo signal, thereby obtaining an SAR echo signal after interference suppression.
In some embodiments, the preset sliding window has a preset window length and a preset sliding step length, and step S2 specifically includes: and for each pulse echo signal, adopting a preset sliding window with the preset window length and the preset sliding step length to carry out sliding interception on the pulse echo signal, so as to obtain a plurality of sub echo signals of the pulse echo signal.
In some embodiments, each pulse echo signal is represented as:the method comprises the steps of carrying out a first treatment on the surface of the The plurality of sub-echo signals of each pulse-echo signal are represented as: />And->The method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>For each pulse echo signal,/a.c.)>For the length of each pulse echo signal, +.>For a preset window length of said preset sliding window,/-or->For a preset sliding step length of said preset sliding window, < > there is>For echo signal from each pulse>The number of sub-echo signals cut out in the middle, < +.>Is->Sub-echo signals>，/>Is->The%>And sampling points.
In some embodiments, the echo matrix for each sub-echo signal is represented as:and->The method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>For the echo matrix of each sub-echo signal, < +.>For the preset spatial dimension, +.>Is->Matrix of dimensions->Is->The%>Element(s)>，/>To transpose the symbols.
In some embodiments, step S4 comprises:
s41, calculating a covariance matrix of an echo matrix of the sub echo signals;
s42, carrying out eigenvalue decomposition on the covariance matrix to obtain eigenvalue vectors and eigenvector matrixes;
s43, dividing the eigenvector matrix based on the eigenvalue vector to obtain an interference subspace matrix of the sub-echo signals.
In some embodiments, the eigenvalue vector comprises a plurality of eigenvalues, the eigenvector matrix comprises a plurality of eigenvectors corresponding one-to-one to the plurality of eigenvalues; step S43 includes:
s431, determining the number of elements in the interference subspace matrix according to the plurality of characteristic values and the preset coefficient；
S432, preceding among the plurality of feature vectorsAnd taking the eigenvectors as elements in the interference subspace matrix to obtain the interference subspace matrix.
In some embodiments, the eigenvalue vector is expressed as:the method comprises the steps of carrying out a first treatment on the surface of the The eigenvector matrix is expressed as: />The method comprises the steps of carrying out a first treatment on the surface of the The interference subspace matrix is expressed as: />The method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>For the eigenvalue vector,/->For the plurality of characteristic values, +.>The preset space dimension is set;for the eigenvector matrix,/a>Is->The plurality of feature vectors are in one-to-one correspondence; />For the interference subspace matrix; />To meet->Minimum value->For the preset coefficient, < >>To transpose the symbols.
In some embodiments, step S5 comprises:
s51, projecting an echo matrix of the sub-echo signal to an interference subspace matrix of the sub-echo signal to obtain an interference matrix of the sub-echo signal;
s52, subtracting the interference matrix of the sub echo signals from the echo matrix of the sub echo signals to obtain an echo matrix after interference cancellation of the sub echo signals;
s53, rearranging elements in the echo matrix after interference cancellation of the sub echo signals to serve as sub echo signals after interference suppression of the sub echo signals;
s54, obtaining a plurality of interference suppressed sub-echo signals of each pulse echo signal for each pulse echo signal with the plurality of sub-echo signals.
The invention has the following beneficial technical effects:
the pulse echo signal is intercepted by constructing the time domain sliding window, so that the broadband interference signal is approximately stable in the sub-signal in the time domain sliding window, and the interference subspace and the signal subspace can be effectively separated in the sub-signal, so that the interference extraction and cancellation in the sub-signal are realized, the problem of insufficient interference suppression performance caused by the construction of the interference subspace in the time domain by the traditional method is solved, and the anti-interference effect is improved; and the broadband interference suppression processing is carried out in the time domain of the radar echo signal, so compared with the prior art, the method does not need to carry out short-time Fourier transform and inverse short-time Fourier transform on the echo signal, thereby remarkably reducing the calculated amount and effectively improving the suppression efficiency.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Drawings
Fig. 1 is a flowchart of a method for suppressing wideband interference of a time domain sliding window subspace projection SAR according to an embodiment of the present invention;
FIG. 2A is an exemplary interfered SAR imaging result provided in accordance with an embodiment of the present subject matter;
fig. 2B is an exemplary SAR imaging result after interference suppression provided by an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but embodiments of the present invention are not limited thereto.
In the description of the present invention, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.
Although the invention is described herein in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
Fig. 1 is a flowchart of a method for suppressing wideband interference of a time domain sliding window subspace projection SAR according to an embodiment of the present invention, as shown in fig. 1, the method includes the following steps:
s1, acquiring an interfered SAR echo signal; the SAR echo signal comprises a plurality of pulse echo signals.
Here, the SAR echo signal subject to the disturbance is a two-dimensional SAR echo signal, and the two-dimensional SAR echo signal includes a plurality of pulse echo signals each of whichCan be expressed as formula (1): />(1) The method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>For each pulse echo signal +.>Length of->For pulse echo signals->Is a sampling point of (a).
S2, intercepting sub-echo signals of each pulse echo signal through a preset sliding window to obtain a plurality of sub-echo signals of the pulse echo signal.
Specifically, the predetermined sliding window has a predetermined window lengthAnd preset sliding step +.>Based on this, step S2 specifically includes: for each pulse echo signal +.>Adopts a window with a preset length +.>And preset sliding step +.>Is set to be the pulse echo signal +.>Performing sliding interception to obtain the pulse echo signal +.>Is a pulse echo signal +.>The plurality of sub-echo signals of (a) are expressed as formula (2): />(2) Wherein->，For echo signal from each pulse>The number of sub-echo signals cut out in the middle, < +.>Is->Sub-echo signals>，/>Is->The%>And sampling points.
S3, for each sub-echo signal, constructing an echo matrix of the sub-echo signal by adopting a preset space dimension.
Specifically, each sub echo signalIs>Expressed as formula (3):(3) The method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>，/>For the preset space dimension->Is->Matrix of dimensions->Is->The%>The number of elements to be added to the composition,，/>to transpose the symbols.
S4, determining an interference subspace matrix of the sub-echo signals according to the echo matrix of the sub-echo signals.
Specifically, step S4 includes:
s41, calculating an echo matrix of the sub echo signalsCovariance matrix>。
Here, the echo matrix can be calculated using equation (4)Covariance matrix>：/>（4）。
S42, opposite covariance matrixDecomposing the characteristic value to obtain a characteristic value vector +.>And feature vector matrix>。
Here, the eigenvalue vectorExpressed by formula (5): />(5) The method comprises the steps of carrying out a first treatment on the surface of the Feature vector matrixExpressed by formula (6): />（6）；/>Is->A plurality of characteristic values contained in (a) and +.>Ordering from small to large, < >>Is->The plurality of feature vectors included in the set, and,and->One-to-one correspondence.
S43, dividing the eigenvector matrix based on the eigenvalue vector to obtain an interference subspace matrix of the sub-echo signals.
Here, step S43 includes:
s431 according to the valueAnd preset coefficients, determining an interference subspace matrix +.>Element number +.>。
Here the number of the elements is the number,to meet->Minimum value->Is a preset coefficient.
S432, willFront middle>The feature vector is used as interference subspace matrix +.>The elements in (1) to obtain an interference subspace matrix +.>。
Here, the interference subspace matrixExpressed by the formula (7): />（7）。
S5, according to the echo matrix and the interference subspace matrix of the sub-echo signals, the sub-echo signals are subjected to interference suppression, and a plurality of interference suppressed sub-echo signals of each pulse echo signal are obtained.
Specifically, step S5 includes:
s51, echo matrix of the sub echo signalsInterference subspace matrix for the sub-echo signals>Projecting to obtain interference matrix of the sub echo signal>。
Here, the interference matrixExpressed by formula (8): />（8）。
S52, echo matrix of the sub echo signalsSubtracting the interference matrix of the sub-echo signal +.>Obtaining echo matrix after interference cancellation of the sub-echo signals>。
Here, the echo matrix after interference cancellationExpressed by formula (9):
(9) Wherein, the method comprises the steps of, wherein,，/>，/>is->A dimension matrix.
S53, rearranging elements in the echo matrix after interference cancellation of the sub echo signals to be used as sub echo signals after interference suppression of the sub echo signals.
Here, for each echo matrixCan be according to->The size of the subscript of each element contained in (e.g.,is->Is one element of (a) and the subscript of the element is +.>) In order from small to large, for +.>The elements in the inner are rearranged to obtain rearranged +.>Rearranged +.>Namely sub echo signal->Is suppressed by the interference-suppressed sub-echo signal +.>。
Specifically, the sub echo signal after interference suppressionCan be expressed by the formula (10):
（10）。
s54, obtaining a plurality of interference suppressed sub-echo signals of each pulse echo signal for each pulse echo signal with a plurality of sub-echo signals.
Here, when each pulse echo signalHaving multiple sub-echo signals, i.e. +.>The pulse echo signal +.>Is a sub-echo signal after interference suppression, i.e. +.>。
S6, rearranging the plurality of suppressed sub-echo signals of each pulse echo signal to obtain each suppressed pulse echo signal, and thus obtaining the suppressed SAR echo signal.
Here, for each pulse echo signalIs a plurality of interference suppressed sub-echo signalsAccording to the size of the subscript of each interference-suppressed sub-echo signal (e.g., interference-suppressed sub-echo signal +)>The subscript of (1) are reordered in order from small to large to obtain a corresponding pulse echo signal after interference suppression, and thus, the SAR echo signal after interference suppression can be obtained.
According to the invention, the pulse echo signal is intercepted by constructing the time domain sliding window, so that the broadband interference signal is approximately stable in the sub-signal in the time domain sliding window, and the interference subspace and the signal subspace can be effectively separated in the sub-signal, so that the interference extraction and cancellation in the sub-signal are realized, the problem of insufficient interference suppression performance caused by constructing the interference subspace in the time-frequency domain in the conventional method is solved, and the anti-interference effect is improved; and the broadband interference suppression processing is carried out in the time domain of the radar echo signal, so compared with the prior art, the method does not need to carry out short-time Fourier transform and inverse short-time Fourier transform on the echo signal, thereby remarkably reducing the calculated amount and effectively improving the suppression efficiency.
The above method of the invention is further illustrated by the following example:
and step 1, taking out one pulse echo signal in the interfered two-dimensional SAR echo.
Step 2, sliding interception sub echo signals:
2.1 Setting the length of the sliding windowSlide step +.>；
2.2 For pulse echoPerforming sliding cutting to obtain->Sub-echo signalsFirst, theiThe sub-echo signals may be denoted +.>；
Step 3, constructing sub echo signalsInterference subspace matrix->：
3.1 Space dimension is set；
3.2 Construction of sub-echo signalsIs>；
3.3 Calculating an echo matrixCovariance matrix>；
3.4 For covariance matrixDecomposing the characteristic value to obtain a characteristic value vector +.>And feature vector matrix>；
3.5 Instruction) commandnTo meet the requirements ofIs used for constructing an interference subspace matrix；
Step 4, subspace projection is carried out on the sub-echo signals, and interference cancellation is carried out:
4.1 Matrix of echoesTo subspace matrix->Projecting to obtain interference matrix->；
4.2 Matrix of echoesSubtracting interference matrix->Obtaining an echo matrix after interference cancellation>；
4.3 Matrix of echoesRearranging to obtain sub-echo signals after interference suppression；
Step 5, rearranging the sub echo signals after interference suppression to obtain pulse echo signals after interference suppression:
5.1 For all intercepted sub echo signals in step 2)Processing in step 3 and step 4 to obtain all interference suppressed sub echo signals +.>；
5.2 Sub-echo signals after interference suppression)Rearranging to obtain pulse echo signal +.>；
And 6, performing the processing from the step 1 to the step 5 on each pulse echo in the interfered two-dimensional SAR echo, namely finishing the interference suppression processing on the two-dimensional SAR echo.
The technical effects achieved by the method provided by the invention are further described below through simulation experiment data.
1. Simulation conditions:
the hardware platform of the simulation experiment of the invention is: intel (R) Core (TM) i7-10700 CPU,2.90GHz, memory 64G.
The software platform of the simulation experiment of the invention is: matlab2021.
2. Simulation content and result analysis:
under the simulation condition, the SAR echo data subjected to broadband interference is subjected to interference suppression processing by using the method disclosed by the invention, and the result is shown in fig. 2A and 2B. Fig. 2A and fig. 2B are both results of remote sensing imaging of airborne synthetic aperture radar on the earth, and an imaging scene includes islands and lakes. Specifically, fig. 2A is an imaging result of the radar after the radar is subjected to the composite interference, and an image of the island in fig. 2A is covered by the interference suppression; fig. 2B is an image result after the interference suppression processing using the present invention, and it can be seen that the interference has been removed in fig. 2B, and islands (regions constituted by black lines in fig. 2B) have been developed.
In summary, the invention provides a method for suppressing broadband interference of a time domain sliding window subspace projection SAR, which is used for extracting and canceling broadband interference signals in radar echo by projecting the sliding window subspace of the echo signals, so that effective broadband interference suppression can be realized in a signal time domain, the calculated amount is reduced, and the suppression efficiency is improved.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (5)
1. The method for suppressing the broadband interference of the SAR by the time domain sliding window subspace projection is characterized by comprising the following steps of:
s1, acquiring an interfered SAR echo signal; the SAR echo signal comprises a plurality of pulse echo signals;
s2, intercepting sub-echo signals of each pulse echo signal through a preset sliding window to obtain a plurality of sub-echo signals of the pulse echo signal;
s3, for each sub-echo signal, constructing an echo matrix of the sub-echo signal by adopting a preset space dimension;
s4, calculating a covariance matrix of an echo matrix of the sub echo signals; performing eigenvalue decomposition on the covariance matrix to obtain eigenvalue vectors and eigenvector matrixes; the eigenvalue vector comprises a plurality of eigenvalues, and the eigenvector matrix comprises a plurality of eigenvectors corresponding to the eigenvalues one by one; determining the number n of elements in an interference subspace matrix of the sub-echo signals according to the characteristic values and the preset coefficient; taking the first n eigenvectors in the eigenvectors as elements in the interference subspace matrix to obtain an interference subspace matrix of the sub-echo signal; the eigenvalue vector is expressed as: lambda= [ lambda ] 1 ,λ 2 ,...,λ d ]The method comprises the steps of carrying out a first treatment on the surface of the The eigenvector matrix is expressed as: u= [ U ] 1 ,u 2 ,...,u d ] T The method comprises the steps of carrying out a first treatment on the surface of the The interference subspace matrix is expressed as: v= [ u ] 1 ,u 2 ,...,u n ] T The method comprises the steps of carrying out a first treatment on the surface of the Wherein lambda is the eigenvalue vector, lambda 1 ,λ 2 ,...,λ d D is the preset space dimension for the plurality of characteristic values; u is the eigenvector matrix, U 1 ,u 2 ,...,u d Is lambda and lambda 1 ,λ 2 ,...,λ d The plurality of feature vectors are in one-to-one correspondence; v is the interference subspace matrix; n is as follows0.8 is the preset coefficient, and T is the transposed symbol;
s5, carrying out interference suppression on the sub-echo signals according to the echo matrix and the interference subspace matrix of the sub-echo signals to obtain a plurality of interference suppressed sub-echo signals of each pulse echo signal;
s6, rearranging the plurality of interference-suppressed sub-echo signals of each pulse echo signal to obtain each interference-suppressed pulse echo signal, thereby obtaining an SAR echo signal after interference suppression.
2. The method for suppressing wideband interference of a time-domain sliding window subspace projection SAR according to claim 1, wherein said preset sliding window has a preset window length and a preset sliding step length, and step S2 specifically comprises: and for each pulse echo signal, adopting a preset sliding window with the preset window length and the preset sliding step length to carry out sliding interception on the pulse echo signal, so as to obtain a plurality of sub echo signals of the pulse echo signal.
3. The time domain sliding window subspace projection SAR wideband interference suppression method of claim 1, wherein each pulse echo signal is represented as: s= [ s ] 1 ,s 2 ,...,s l ]The method comprises the steps of carrying out a first treatment on the surface of the The plurality of sub-echo signals of each pulse-echo signal are represented as: s is(s) 1 ,s 2 ,...,s (l-w+1)/t And s i ＝[s i ,s i+1 ,...,s i+w-1 ]The method comprises the steps of carrying out a first treatment on the surface of the Wherein s is the pulse echo signal, l is the length of the pulse echo signal, w is the preset window length of the preset sliding window, t is the preset sliding step length of the preset sliding window, and (l-w+1)/t is the number of sub-echo signals cut from the pulse echo signal s, s i For the i < th > sub-echo signal, i=1, 2, (l-w+1)/t, s i Is the i-th sample point in s.
4. A time domain sliding window subspace projection SAR wideband interference suppression method according to claim 3, wherein the echo matrix of each sub-echo signal is expressed as:and z j ＝[s i+j-1 ,s i+j ,...,s i+j+d-2 ] T The method comprises the steps of carrying out a first treatment on the surface of the Wherein Z is each sub-echo signalEcho matrix d is the preset spatial dimension, < > and>matrix of d× (d-w) dimension, z j J=1, 2 for the j-th element in Z.
5. The method for suppressing wideband interference of a time-domain sliding window subspace projection SAR according to claim 1, wherein step S5 comprises:
s51, projecting an echo matrix of the sub-echo signal to an interference subspace matrix of the sub-echo signal to obtain an interference matrix of the sub-echo signal;
s52, subtracting the interference matrix of the sub echo signals from the echo matrix of the sub echo signals to obtain an echo matrix after interference cancellation of the sub echo signals;
s53, rearranging elements in the echo matrix after interference cancellation of the sub echo signals to serve as sub echo signals after interference suppression of the sub echo signals;
s54, obtaining a plurality of interference suppressed sub-echo signals of each pulse echo signal for each pulse echo signal with the plurality of sub-echo signals.
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| CN103675768A (en) * | 2013-12-17 | 2014-03-26 | 中国人民解放军国防科学技术大学 | Suppression method for satellite-borne SAR radio-frequency interference |
| CN111965612A (en) * | 2020-07-08 | 2020-11-20 | 西安电子科技大学 | Clutter suppression method based on subspace projection |
| CN113176543A (en) * | 2021-03-26 | 2021-07-27 | 上海卫星工程研究所 | Radio frequency interference suppression method and system based on multi-dimensional information combination |
| CN113655443A (en) * | 2021-08-26 | 2021-11-16 | 北京理工大学 | Low-frequency band SAR radio frequency interference suppression method for broadband digital television signal |
| CN114895261A (en) * | 2022-04-07 | 2022-08-12 | 西安电子科技大学 | Clutter suppression method based on multi-frequency sub-pulse coding array |
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| CN111965612A (en) * | 2020-07-08 | 2020-11-20 | 西安电子科技大学 | Clutter suppression method based on subspace projection |
| CN113176543A (en) * | 2021-03-26 | 2021-07-27 | 上海卫星工程研究所 | Radio frequency interference suppression method and system based on multi-dimensional information combination |
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