Method and apparatus for airborne radar anti-tow jamming

Abstract

The application relates to the field of radar technology and provides a method and device for resisting towed interference of an airborne radar. The method comprises the following steps: constructing sum channel data, azimuth difference channel data and elevation difference azimuth data of echo signals; constructing sum-difference three-channel data of each pulse according to the sum channel data, the azimuth difference channel data and the elevation difference azimuth data; processing the sum-difference three-channel data by using a blind source separation algorithm to obtain target echo channel data and a separation matrix; pulse compressing the target echo channel data to obtain a target distance estimation value; determining an azimuth angle and an elevation angle of a target according to the target echo channel data and the separation matrix; and constructing a target echo matrix by using target echo channel data of each pulse, and performing Doppler processing on the target echo matrix to obtain a target speed estimation value. The application can resist towed interference, determine the distance, the azimuth angle, the elevation angle and the speed of the target, and realize effective detection of the target.

Description

Technical Field

[0001] This invention relates to the field of radar technology, and in particular to a method and apparatus for resisting dragged interference in airborne radar. Background Technology

[0002] In some existing technologies, when a friendly target equipped with airborne radar intercepts an opposing target, the opposing target may release a towed decoy. The energy of the towed decoy is often higher than the target's echo energy, causing the friendly target to track the energy center between the opposing target and the decoy. Ultimately, the friendly target passes between the opposing target and the decoy, making accurate interception impossible. For example, when monitoring whether a drone has entered a no-fly zone and intercepting it, the violating drone may release signal decoys to interfere with radar tracking, making accurate interception impossible. Therefore, to enable friendly targets to accurately intercept opposing targets, a method for airborne radar to resist towed interference is urgently needed.

[0003] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and apparatus for airborne radar to resist dragged interference.

[0005] The present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for airborne radar to resist dragged interference, comprising:

[0007] Construct echo signal sum channel data, azimuth difference channel data, and elevation difference azimuth data;

[0008] Based on the sum channel data, azimuth difference channel data, and pitch difference azimuth data, construct the sum and difference three-channel data for each pulse;

[0009] The sum and difference three-channel data are processed using a blind source separation algorithm to obtain the target echo channel data and the separation matrix;

[0010] The target echo channel data is pulse-compressed to obtain a target range estimate; the target azimuth and elevation angles are determined based on the target echo channel data and the separation matrix.

[0011] The target echo matrix is ​​constructed using the target echo channel data of each pulse, and the target echo matrix is ​​subjected to Doppler processing to obtain the target velocity estimate.

[0012] Preferably, the channel data is ;

[0013] in, The weights representing the formation and channel data are appropriate. , This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates azimuth beam direction And the pitch beam direction Spatial guidance vector, Describes an N×N identity matrix. For the echo data of N pulses, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

[0014] Preferably, the azimuth difference channel data is ;

[0015] in, This represents the appropriate weights used to form the azimuth difference channel data. , Indicates that all elements are 1 Column vectors Indicates that all elements are 1 Column vectors Indicates that all elements are -1 Column vectors This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates the direction of the pitch angle. The spatial guiding vector in the z-axis direction, For the echo data of N pulses, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

[0016] Preferably, the pitch difference azimuth data is ;

[0017] in, This represents the appropriate weights used to form the azimuth difference channel data. , Indicates that all elements are 1 Column vectors Indicates that all elements are -1 Column vectors Indicates that all elements are 1 Column vectors This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates the direction of the pitch angle. The spatial guiding vector in the z-axis direction, Indicates the direction of the azimuth. And the pitch angle is The x-axis spatial guiding vector, For the echo data of N pulses, This represents the conjugate transpose operation. Let N represent the complex field, where N is the total number of pulses and L is the number of snapshots.

[0018] Preferably, the step of constructing the sum and difference three-channel data for each pulse based on the sum channel data, azimuth difference channel data, and pitch difference azimuth data specifically includes:

[0019] Construct a sum-difference three-channel matrix ;in, For channel data, This is azimuth difference channel data. This is pitch difference azimuth data;

[0020] Construct the sum and difference three-channel data of the nth pulse ;in, , Representative selection of sum and difference three-channel matrix The data in rows n, n+N, and n+2N, where n = 1, 2, ..., N, and N is the total number of pulses. Let L represent the complex field, and L be the number of snapshots.

[0021] Preferably, the step of pulse compression of the target echo channel data to obtain the target distance estimate specifically includes:

[0022] For target echo channel data Each row of data is subjected to matched filtering to obtain the filtered result. ; For target echo channel data The p-th row of data in The original signal transmitted by the radar;

[0023] Based on the filtered results The column index corresponding to the maximum value in The calculated target distance estimate is ;in, Indicates the sampling time interval. Represents the speed of light. Let N represent the complex field, where N is the total number of pulses and L is the number of snapshots.

[0024] Preferably, determining the azimuth and elevation angles of the target based on the target echo channel data and the separation matrix specifically includes:

[0025] Calculate the separation matrix The pseudoinverse yields the manifold matrix. ;

[0026] Find the filtered result The row index h corresponding to the maximum value in the matrix is ​​used to construct new data using the row index h and the manifold matrix. ;in, For manifold matrix The first in Column data; For target echo channel data The first in Row data;

[0027] According to the new data Determine the target's azimuth and elevation angles. ;

[0028] in, , , for The covariance matrix, , It is a spatial steering vector that traverses the range [-90°, 90°] for both azimuth and elevation angles. This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots. This indicates finding the trace of a matrix.

[0029] Preferably, the step of constructing a target echo matrix using target echo channel data from each pulse, and performing Doppler processing on the target echo matrix to obtain a target velocity estimate, specifically includes:

[0030] Construct the target echo matrix ;

[0031] For the target echo matrix Each row of data is subjected to matched filtering to obtain the filtered matrix. ;in, For the first The target echo channel data of the first pulse The nth row of data in the filtered matrix is ​​where n is a positive integer greater than or equal to 1 and less than or equal to N, and N is the total number of pulses. ; For the target echo matrix The nth row of data, The original signal transmitted by the radar;

[0032] For the filtered matrix Perform a Fast Fourier Transform on each column of data to obtain the transformed matrix. ; where, the transformed matrix The data in column l , ,in, The first one used for speed measurement A preset Doppler frequency value, , The filtered matrix The first in Column data;

[0033] Find the transformed matrix The row index corresponding to the maximum value in ,by The corresponding preset Doppler frequency value As a reference frequency ;

[0034] When radial Doppler velocity At that time, the estimated target velocity was calculated to be... Otherwise, the calculated target velocity estimate is... ;in, Indicates the pulse repetition frequency. The prior velocity of the target For a preset integer, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

[0035] In a second aspect, the present invention also provides an apparatus for resisting dragged interference of airborne radar, used to implement the method for resisting dragged interference of airborne radar as described in the first aspect, the apparatus comprising:

[0036] At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor for performing the airborne radar anti-towed jamming method described in the first aspect.

[0037] Thirdly, the present invention also provides a non-volatile computer storage medium storing computer-executable instructions that are executed by one or more processors to perform the method described in the first aspect.

[0038] Fourthly, a chip is provided, comprising: a processor and an interface for calling and running a computer program stored in a memory, performing the method as described in any of the first aspects.

[0039] Fifthly, a computer program product comprising instructions is provided, which, when executed on a computer or processor, cause the computer or processor to perform the method as described in any of the first aspects.

[0040] This invention first constructs the sum and difference three-channel data for each pulse, then uses a blind source separation algorithm to obtain the target echo channel data, and obtains the target range estimate after pulse compression; then uses the maximum likelihood algorithm to estimate the target's azimuth and elevation angles; and obtains the target's velocity estimate through Doppler processing, thereby resisting drag interference and determining the target's range, azimuth, elevation angles and velocity, achieving effective target detection. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0042] Figure 1 This is a schematic diagram of a method for airborne radar to resist dragged interference provided in an embodiment of the present invention;

[0043] Figure 2 This is a flowchart illustrating a method for airborne radar to resist dragged interference provided in an embodiment of the present invention;

[0044] Figure 3 This is a flowchart illustrating a method for airborne radar to resist dragged interference provided in an embodiment of the present invention;

[0045] Figure 4 This is a flowchart illustrating a method for airborne radar to resist dragged interference provided in an embodiment of the present invention;

[0046] Figure 5 This is a flowchart illustrating a method for airborne radar to resist dragged interference provided in an embodiment of the present invention;

[0047] Figure 6 This is a flowchart illustrating a method for airborne radar to resist dragged interference provided in an embodiment of the present invention;

[0048] Figure 7 This is a schematic diagram of a method for airborne radar to resist dragged interference provided in an embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram of a method for airborne radar to resist dragged interference provided in an embodiment of the present invention;

[0050] Figure 9This is a schematic diagram of the architecture of an airborne radar anti-drag jamming device provided in an embodiment of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as openly inclusive, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples; that is, although they may be incorporated into embodiments or examples using the above terms for reasons such as order and position, it does not limit them to be incorporated in combination by a single embodiment or example.

[0053] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, for example, the description may use the prefix "A" or "B" to describe the same type of nouns as two independent entities. In this case, the corresponding features defined with "A" and "B" are used only to distinguish between similar entities and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0054] In the description of this invention, the expression “A and / or B” (where A and B are used to formally represent specific features) will be used. The corresponding expression includes the following three combinations: only A, only B, and a combination of A and B.

[0055] As used in this invention, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from a particular value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0056] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] Example 1:

[0058] When a friendly target equipped with airborne radar intercepts an enemy target, a confrontation process occurs. This involves the friendly target attempting to intercept the enemy target, while the enemy target releases towed decoys to interfere with the friendly target. Analysis reveals the following characteristics of this confrontation process:

[0059] (1) As the distance between our target and the enemy target continues to decrease, the angle between the enemy target and the decoy relative to our target becomes larger and larger, such as Figure 1 The diagram shows the relationship between the angle between our target and the enemy target as distance changes.

[0060] (2) No matter how many interferences the decoy releases in the time or frequency domain, from the perspective of the spatial domain, our target only faces one main lobe interference.

[0061] (3) The interference released by the decoy is generally to sample the signal transmitted by our target and add noise modulation, and there is a minimum limit to the sampling width of the jammer.

[0062] (4) In the final stage, the distance between our target and the other target is very close. Our target needs to measure the distance of the other target in order to ensure accurate interception of the other target. At this time, the pulse width of our target is very narrow.

[0063] Because in the final stage, the width of the target's transmitted signal will be smaller than the jammer's sampling width, the signal relayed by the jammer at this time is a combination of the target's transmitted signal and the noise signal in the time domain. This will lead to a decrease in the correlation between the jammed signal and the real echo signal, and there will only be one main lobe of interference in the airspace. Based on these characteristics, in order to counter the towed interference of the aforementioned towed decoy, Embodiment 1 of this invention provides a method for airborne radar to resist towed interference, such as... Figure 2 As shown, it includes:

[0064] In step 201, the echo signal sum channel data, azimuth difference channel data, and pitch difference azimuth data are constructed.

[0065] In step 202, the sum and difference three-channel data of each pulse are constructed based on the sum channel data, azimuth difference channel data, and pitch difference azimuth data.

[0066] In step 203, the sum and difference three-channel data are processed using a blind source separation algorithm to obtain the target echo channel data and the separation matrix.

[0067] In step 204, pulse compression is performed on the target echo channel data to obtain the target range estimate; based on the target echo channel data and the separation matrix, the azimuth and elevation angles of the target are determined.

[0068] In step 205, a target echo matrix is ​​constructed using the target echo channel data of each pulse. Doppler processing is then performed on the target echo matrix to obtain an estimated target velocity. The azimuth and elevation angles of the target are estimated using a maximum likelihood algorithm.

[0069] Steps 202 to 204 are executed for each pulse, thereby calculating an estimated target distance, azimuth, and elevation angle for each pulse. This single-pulse parameter measurement method effectively improves the measurement speed. Step 205 is executed once for multiple pulses.

[0070] This implementation first constructs the sum and difference three-channel data for each pulse, then uses the blind source separation algorithm to obtain the target echo channel data, and obtains the target range estimate after pulse compression; then uses the maximum likelihood algorithm to estimate the target's azimuth and elevation angles; and obtains the target's velocity estimate through Doppler processing, thereby resisting drag interference and determining the target's range, azimuth, elevation angles and velocity, achieving effective target detection.

[0071] It should be noted that in this embodiment, the method is described with our own target as the execution subject. Correspondingly, for the sake of brevity, "target" is used as an alternative description of "opponent's target". Unless otherwise specified, "target" in this embodiment refers to "opponent's target".

[0072] In one optional implementation, the channel data is ;in, The weights representing the formation and channel data are appropriate. , This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates azimuth beam direction And the pitch beam direction Spatial guidance vector, Describes an N×N identity matrix. For the echo data of N pulses, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

[0073] The azimuth difference channel data is ;in, This represents the appropriate weights used to form the azimuth difference channel data. , Indicates that all elements are 1 Column vectors Indicates that all elements are 1 Column vectors Indicates that all elements are -1 Column vectors This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates the direction of the pitch angle. The spatial guiding vector in the z-axis direction, For the echo data of N pulses, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

[0074] The pitch difference azimuth data is ;in, This represents the appropriate weights used to form the azimuth difference channel data. , Indicates that all elements are 1 Column vectors Indicates that all elements are -1 Column vectors Indicates that all elements are 1 Column vectors This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates the direction of the pitch angle. The spatial guiding vector in the z-axis direction, Indicates the direction of the azimuth. And the pitch angle is The x-axis spatial guiding vector, For the echo data of N pulses, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

[0075] In practical use, the construction of sum-difference three-channel data for each pulse based on the sum-channel data, azimuth difference channel data, and pitch difference azimuth data specifically includes: constructing a sum-difference three-channel matrix. ;in, For channel data, This is azimuth difference channel data. For pitch difference azimuth data; construct the sum and difference three-channel data of the nth pulse. ;in, , Representative selection of sum and difference three-channel matrix The data in rows n, n+N, and n+2N, where n = 1, 2, ..., N, and N is the total number of pulses. Let L represent the complex field, and L be the number of snapshots.

[0076] In step 203, a blind source separation algorithm is used to process the sum and difference three-channel data to obtain the target echo channel data and the separation matrix, which is: using a blind source separation algorithm to process the sum and difference three-channel data. The data is processed to obtain the target echo channel data. and separation matrix .

[0077] In a practical application scenario, pulse compression is performed on the target echo channel data to obtain a target distance estimate, such as... Figure 3 As shown, it specifically includes:

[0078] In step 301, the target echo channel data is processed. Each row of data is subjected to matched filtering to obtain the filtered result. ; For target echo channel data The p-th row of data in This represents the raw signal transmitted by the radar. Where p is a positive integer, p = 1, 2, ..., P, and P represents the target echo channel data. Total number of rows.

[0079] In step 302, based on the filtered result The column index corresponding to the maximum value in The calculated target distance estimate is ;in, Indicates the sampling time interval. Represents the speed of light. Let L represent the complex field, and L be the snapshot number. Filtered result. The column index corresponding to the maximum value in This represents the distance gate cell to the target location. In practical applications, the target echo channel data... The filtered result corresponding to each row of data in the data. The maximum values ​​in the table have the same column index and row index.

[0080] The target's azimuth and elevation angles are determined based on the target echo channel data and the separation matrix, such as... Figure 4 As shown, it specifically includes:

[0081] In step 401, the separation matrix is ​​calculated. The pseudoinverse yields the manifold matrix. .

[0082] In step 402, the filtered result is found. The row index h corresponding to the maximum value in the matrix is ​​used to construct new data using the row index h and the manifold matrix. ;in, For manifold matrix The first in Column data; For target echo channel data The first in Row data. The row index h can take values ​​of 1, 2, or 3.

[0083] In step 403, based on the new data Determine the target's azimuth and elevation angles. The target's azimuth and elevation angles were obtained by searching the 3D map.

[0084] in, , , for The covariance matrix, , It is a spatial steering vector that traverses the range [-90°, 90°] for both azimuth and elevation angles. This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots. This indicates finding the trace of a matrix.

[0085] It should be noted that, in this embodiment, the target echo channel data This actually refers to the target echo channel data of the nth pulse. For ease of description, this embodiment uses... This target echo channel data represents the common processing process of the target echo channel data of other pulses. For example, assuming there are N pulses, the above steps 301~302 and 401~403 are performed on each pulse, thereby calculating a target distance estimate, azimuth angle and elevation angle for each pulse.

[0086] The target echo data is subjected to Doppler processing to obtain an estimated target velocity value, such as... Figure 5 As shown, it specifically includes:

[0087] In step 501, the target echo matrix is ​​constructed. .

[0088] In step 502, the target echo matrix is... Each row of data is subjected to matched filtering to obtain the filtered matrix. ;in, For the first The target echo channel data of the first pulse The row data represents the target echo channel data of the nth pulse in the h-th channel data, where n is a positive integer greater than or equal to 1 and less than or equal to N, and N is the total number of pulses. The nth row data in the filtered matrix... ; For the target echo matrix The nth row of data, This is the original signal emitted by the radar.

[0089] In step 503, the filtered matrix is... Perform a Fast Fourier Transform on each column of data to obtain the transformed matrix. ; where, the transformed matrix The data in column l , ,in, The first one used for speed measurement A preset Doppler frequency value, , The filtered matrix The first in Column data.

[0090] In step 504, the transformed matrix is ​​found. The row index corresponding to the maximum value in Indexed by this row The corresponding preset Doppler frequency value As a reference frequency According to the reference frequency The target velocity estimate is calculated, specifically: when the radial Doppler velocity... At that time, the estimated target velocity was calculated to be... Otherwise, the calculated target velocity estimate is... ;in, Indicates the pulse repetition frequency. The prior velocity of the target The integer is a preset value, obtained by those skilled in the art based on experience. This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

[0091] Example 2:

[0092] Based on the method described in Embodiment 1, this invention combines specific application scenarios and uses technical descriptions in relevant scenarios to illustrate the implementation process of the features of this invention in those scenarios.

[0093] This embodiment provides a method for airborne radar to resist dragged interference, such as... Figure 6 As shown, it specifically includes:

[0094] In step 601, a signal model is constructed.

[0095] In step 602, sum and difference three-channel data are generated.

[0096] In step 603, target distance and angle are estimated.

[0097] In step 604, target velocity estimation is performed.

[0098] The construction of the signal model specifically includes:

[0099] like Figure 7 As shown, assume that the radar antenna array of our target is a Uniform array, with all array elements arranged in a uniform area. In the array, the element spacing is d, and the azimuth angle of the source relative to the array is denoted as . The elevation angle relative to the array is denoted as The spatial steering vector of this array can be expressed as:

[0100] (1)

[0101] (2)

[0102] (3)

[0103] in, Indicates Kronecker product operation, superscript The transpose operation is represented by the symbol. This indicates the wavelength of the signal transmitted by our target. and are the spatial steering vectors for the z-axis and x-axis, respectively; e is the natural constant, approximately equal to 2.71828. It is the imaginary unit.

[0104] Assuming our target transmits a pulse width of... The linear frequency modulated signal has the following expression:

[0105] (4)

[0106] In the formula: , For frequency modulation slope, For the center frequency, For frequency modulation bandwidth, center frequency With wavelength The relationship is c = 3 × 10 8 m / s represents the speed of light. The echo signal from the target can be represented as:

[0107] (5)

[0108] Equation (5) represents the expression from the first The range gate cell begins to receive the echo signal from the enemy target, where L represents the number of snapshots. Assume the azimuth angle of the enemy target relative to our target is... The pitch angle is Then, the echo data of the target from our target's receiving array for one pulse repetition period can be represented as:

[0109] (6)

[0110] When our target transmits a signal pulse width When the width is particularly short, interference sampling width will occur. In cases such as Figure 8 The diagram shows the width of the relay interference signal and the target echo signal. The dashed line represents the interference sampling width. The black rectangle represents the echo signal from the enemy target, and the white rectangle represents the noise signal. At this time, the jamming will forward both the signal transmitted by our target and the noise signal.

[0111] (7)

[0112] In the formula This represents a noise signal with a width of , This indicates the starting distance gate for relay jamming. Assume the azimuth angle of the towed decoy relative to our target is... The pitch angle is Then, the interference echo data relayed by the receiving array of our target for one pulse repetition cycle can be expressed as:

[0113] (8)

[0114] The receiver array data for one pulse repetition cycle of our target can be represented as:

[0115] (9)

[0116] In the formula This represents a noise matrix for one repetition period. .

[0117] Consider that our target emits N coherent pulse trains, with a pulse repetition period of... , If the pulse repetition frequency is given, then the slow time-domain steering vector can be expressed as:

[0118] (10)

[0119] In the formula Let represent the radial Doppler velocity. Then, the echo data of the N pulses received by our target can be expressed as:

[0120] (11)

[0121] In the formula , This represents a noise matrix with N repetition periods. and These represent the radial Doppler velocity of the enemy target relative to our target and the Doppler velocity of the jamming signal, respectively.

[0122] Based on the signal model of equation (11), the generation of the sum and difference three-channel data specifically includes: generating sum, azimuth difference, and elevation difference data from the spatial domain, specifically: constructing three corresponding channel weight vectors. Assuming the radar spatial beam pointing is... Then the channel weight vector is , The N×N identity matrix and channel data can be represented as:

[0123] (12)

[0124] In the formula This indicates the conjugate transpose operation.

[0125] The azimuth difference channel weight vector is:

[0126] (13)

[0127] In the formula Indicates that all elements are 1 Column vectors Indicates that all elements are 1 Column vectors Indicates that all elements are -1 If the column vector is used, then the azimuth difference channel data can be represented as:

[0128] (14)

[0129] The pitch difference channel weight vector is:

[0130] (15)

[0131] In the formula Indicates that all elements are 1 Column vectors Indicates that all elements are -1 Column vectors Indicates that all elements are 1 If the column vector is used, then the pitch difference channel data can be represented as:

[0132] (16)

[0133] The three channel data from equations (12), (14), and (16) are reassembled into the following new matrix:

[0134] (17)

[0135] From the equation (17) The sum and difference data of the nth (n=1, 2, … , N) pulse are extracted. The specific method for extracting the data is as follows:

[0136] (18)

[0137] (19)

[0138] Equation (19) represents the matrix The three row index values, equation (18) represents taking the matrix Data in rows n, n+N, and n+2N.

[0139] After obtaining the data from the three channels of azimuth, pitch difference, and sigma difference, the target signal is then separated using a blind source separation algorithm to achieve anti-interference. The target distance is estimated by pulse compression of the target channel data, and then the target angle is estimated using the maximum likelihood algorithm.

[0140] The target distance and angle estimation specifically includes:

[0141] The blind source separation algorithm is used to process equation (18) to obtain the target echo channel data and the separation matrix, which are denoted as follows: and Find the separation matrix. The pseudo-inverse yields the manifold matrix of the sum and difference 3-channel data. .

[0142] right Each row of data is subjected to matched filtering (the implementation principle is shown in equation (25)), specifically as follows: , For target echo channel data The p-th row of data in The original signal transmitted by the radar. The filtered result is a matrix. The row index of the maximum value in the matrix is ​​found and denoted as h; the column index of the maximum value is denoted as l, where l represents the distance gate cell containing the target. The data is then reconstructed as follows:

[0143] (20)

[0144] For the data in equation (20), the maximum likelihood algorithm is used to estimate the azimuth and elevation angles of the target. That is, the angle corresponding to the maximum value of the following equation is recorded as the estimated azimuth and elevation angles of the target:

[0145] (twenty one)

[0146] In the formula This indicates finding the trace of a matrix.

[0147] (twenty two)

[0148] (twenty three)

[0149] In the formula It is the airspace steering vector that traverses the range of azimuth and elevation angles near the beam pointing.

[0150] The target velocity estimation specifically includes:

[0151] The target velocity estimate is mainly obtained through Doppler processing. The target echo channel data of all pulses shown in equation (20) are reassembled into the following matrix:

[0152] (twenty four)

[0153] Perform matched filtering on each row of the matrix S above (corresponding to each pulse). Taking the matched filtering on the nth row of data as an example:

[0154] (25)

[0155] In the formula This represents the convolution operation.

[0156] For the above matrix Perform a Fast Fourier Transform on each column (corresponding to each distance gate unit), and denote the matrix. The data in column l is Taking the fast Fourier transform of the data in the l-th column as an example, that is, for the N-point sequence... Performing an N-point discrete Fourier transform yields:

[0157] (26)

[0158] In the formula

[0159] (27)

[0160] The matrix in equation (26) That is, after the data has undergone matched filtering and Doppler processing, find the matrix. The maximum value of and the corresponding Doppler velocity are denoted as . The target speed is:

[0161] (28)

[0162] because When our target operates at a high repetition rate, that is... If the velocity is relatively small, the velocity measured by equation (28) will exhibit velocity ambiguity, requiring resolution of the velocity ambiguity. Resolution of velocity ambiguity requires a general understanding of the prior velocity range of the opposing target. Assume the prior velocity of a certain opposing target is approximately... Then the estimated speed of the target is:

[0163] (29)

[0164] In the formula, u is an integer.

[0165] The above method is designed according to the software flow as follows:

[0166] The input to this software process is: Where M is the number of array elements, N is the number of pulses, and L is the number of snapshots. The software flow is as follows:

[0167] 1. Generate channel data using equations (12), (14), and (16) respectively. Azimuth difference channel data Pitch difference channel data .

[0168] 2. After processing each pulse data, the target distance and angle information are obtained; that is, for each pulse, the following methods (1) to (5) are executed:

[0169] (1) Construct the sum and difference 3-channel data of the nth pulse according to formula (18). .

[0170] (2) Using blind source separation algorithm for After processing, three channels of data were obtained. and separation matrix This yields the manifold matrix of the sum and difference 3-channel data. .

[0171] (3) To Each row of data is subjected to matched filtering (the implementation principle is shown in equation (25)). The row index of the maximum value of the matrix is ​​found and denoted as h; the column index of the maximum value is denoted as l, which represents the distance gate cell where the target is located.

[0172] (4) Construct the sum and difference 3-channel echo data containing the target according to formula (20).

[0173] (5) According to Equation (21), the maximum likelihood algorithm is used to estimate the azimuth and elevation angles of the target.

[0174] 3. Perform matched filtering and Doppler processing on the data shown in equation (24) to obtain the target velocity information.

[0175] 4. If our target operates at a high repetition rate and velocity ambiguity exists, use equation (29) to resolve the velocity ambiguity. Finally, output the estimated values ​​of target range, azimuth, pitch angle and velocity.

[0176] Example 3:

[0177] like Figure 9 The diagram shown is a schematic representation of the architecture of an airborne radar anti-drag jamming device according to an embodiment of the present invention. The airborne radar anti-drag jamming device of this embodiment includes one or more processors 21 and a memory 22. Wherein, Figure 9 Take a processor 21 as an example.

[0178] Processor 21 and memory 22 can be connected via a bus or other means. Figure 9 Taking the example of a connection between China and Israel via a bus.

[0179] The memory 22, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs and non-volatile computer-executable programs, such as the airborne radar anti-drag jamming method in Embodiment 1. The processor 21 executes the airborne radar anti-drag jamming method by running the non-volatile software programs and instructions stored in the memory 22.

[0180] Memory 22 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 22 may optionally include memory remotely located relative to processor 21, which can be connected to processor 21 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0181] The program instructions / modules are stored in the memory 22 and, when executed by one or more processors 21, perform the airborne radar anti-drag jamming method described in Embodiment 1 above.

[0182] It is worth noting that the information interaction and execution process between the modules and units in the above-mentioned device and system are based on the same concept as the processing method embodiment of the present invention. For details, please refer to the description in the method embodiment of the present invention, and will not be repeated here.

[0183] Those skilled in the art will understand that all or part of the steps in the various methods of the embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc.

[0184] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for resisting dragged interference by airborne radar, characterized in that, include: Construct echo signal sum channel data, azimuth difference channel data, and elevation difference azimuth data; Based on the sum channel data, azimuth difference channel data, and pitch difference azimuth data, construct the sum and difference three-channel data for each pulse; The sum and difference three-channel data are processed using a blind source separation algorithm to obtain the target echo channel data and the separation matrix; The target echo channel data is pulse-compressed to obtain the target distance estimate; Based on the target echo channel data and the separation matrix, determine the target's azimuth and elevation angles; including: calculating the separation matrix. The pseudoinverse yields the manifold matrix. Find the filtered result The row index corresponding to the maximum value in Using the row index Construct new data with the manifold matrix ;in, For manifold matrix The first in Column data; For target echo channel data The first in Row data; based on the new data Determine the target's azimuth and elevation angles. ;in, , , for The covariance matrix, , It is a spatial steering vector that traverses the range [-90°, 90°] for both azimuth and elevation angles. This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots. This indicates finding the trace of a matrix; The target echo matrix is ​​constructed using the target echo channel data of each pulse, and the target echo matrix is ​​subjected to Doppler processing to obtain the target velocity estimate.

2. The method for airborne radar to resist dragged interference according to claim 1, characterized in that, The channel data is ; in, The weights representing the formation and channel data are appropriate. , This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates azimuth beam direction And the pitch beam direction Spatial guidance vector, Describes an N×N identity matrix. For the echo data of N pulses, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

3. The method for resisting dragged interference of airborne radar according to claim 1, characterized in that, The azimuth difference channel data is ; in, This represents the appropriate weights used to form the azimuth difference channel data. , Indicates that all elements are 1 Column vectors Indicates that all elements are 1 Column vectors Indicates that all elements are -1 Column vectors This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates the direction of the pitch angle. The spatial guiding vector in the z-axis direction, For the echo data of N pulses, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

4. The method for resisting dragged interference of airborne radar according to claim 1, characterized in that, The pitch difference azimuth data is ; in, This represents the appropriate weights used to form the azimuth difference channel data. , Indicates that all elements are 1 Column vectors Indicates that all elements are -1 Column vectors Indicates that all elements are 1 Column vectors This refers to the azimuth angle of the radar airspace beam. The elevation angle of the radar airspace beam direction. Indicates the direction of the pitch angle. The spatial guiding vector in the z-axis direction, Indicates the direction of the azimuth. And the pitch angle is The x-axis spatial guiding vector, For the echo data of N pulses, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

5. The method for resisting dragged interference by airborne radar according to claim 1, characterized in that, The step of constructing sum-difference three-channel data for each pulse based on the sum-channel data, azimuth difference channel data, and pitch difference azimuth data specifically includes: Construct a sum-difference three-channel matrix ;in, For channel data, This is azimuth difference channel data. This is pitch difference azimuth data; Construct the sum and difference three-channel data of the nth pulse ;in, , Representative selection of sum and difference three-channel matrix The data in rows n, n+N, and n+2N, where n = 1, 2, ..., N, and N is the total number of pulses. Let L represent the complex field, and L be the number of snapshots.

6. The method for resisting dragged interference of airborne radar according to claim 1, characterized in that, The step of pulse compression of the target echo channel data to obtain the target distance estimate specifically includes: For target echo channel data Each row of data is subjected to matched filtering to obtain the filtered result. ; For target echo channel data The p-th row of data in The original signal transmitted by the radar; Based on the filtered results The column index corresponding to the maximum value in The calculated target distance estimate is ;in, Indicates the sampling time interval. Represents the speed of light. Let N represent the complex field, where N is the total number of pulses and L is the number of snapshots.

7. The method for airborne radar to resist dragged interference according to claim 1, characterized in that, The process of constructing a target echo matrix using target echo channel data from each pulse, and then performing Doppler processing on the target echo matrix to obtain a target velocity estimate, specifically includes: Construct the target echo matrix ; For the target echo matrix Each row of data is subjected to matched filtering to obtain the filtered matrix. ;in, For the first The target echo channel data of the first pulse The nth row of data in the filtered matrix is ​​where n is a positive integer greater than or equal to 1 and less than or equal to N, and N is the total number of pulses. ; For the target echo matrix The nth row of data, The original signal transmitted by the radar; For the filtered matrix Perform a Fast Fourier Transform on each column of data to obtain the transformed matrix. ; where, the transformed matrix The data in column l , ,in, The first one used for speed measurement A preset Doppler frequency value, , The filtered matrix The first in Column data; Find the transformed matrix The row index corresponding to the maximum value in ,by The corresponding preset Doppler frequency value As a reference frequency ; When radial Doppler velocity At that time, the estimated target velocity was calculated to be... Otherwise, the calculated target velocity estimate is... ;in, Indicates the pulse repetition frequency. The prior velocity of the target For a preset integer, This represents the conjugate transpose operation. Let L represent the complex field, and L be the number of snapshots.

8. A device for resisting dragged interference of airborne radar, characterized in that, include: At least one processor; And a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the processor for performing the airborne radar anti-drag jamming method according to any one of claims 1 to 7.

9. A non-volatile computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, which are executed by one or more processors to perform the airborne radar anti-drag jamming method according to any one of claims 1 to 7.

Images