Radar clutter suppression method and device, storage medium and product

Abstract

The invention discloses a radar clutter suppression method and device, a storage medium and a product, and relates to the technical field of radars. The method comprises the following steps: respectively carrying out pulse compression processing on radar echo signals collected by each channel to obtain a one-dimensional pulse compression result; performing digital beam forming processing on the one-dimensional pulse compression result to obtain one-dimensional distance dimension results in different directions; performing fast Fourier transform on the one-dimensional distance dimension result to obtain an original distance Doppler map; estimating a clutter spectrum center and a clutter spectrum width according to the original distance Doppler map; designing a filter according to the clutter spectrum center and the clutter spectrum width; performing convolution calculation on the one-dimensional distance dimension matrix and a filter to obtain a primary clutter suppression processing result; and performing fast Fourier transform on the primary clutter suppression processing result along the row direction to obtain a distance Doppler map after primary clutter suppression processing. According to the invention, a good clutter suppression effect can be realized, and the problem of reduction of radar clutter suppression efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the field of radar technology, and in particular relates to a radar clutter suppression method, device, storage medium and product based on a moving platform. Background Art

[0002] Through-the-wall radar is a device that emits electromagnetic waves of a specific frequency and can penetrate opaque non-metallic obstacles such as walls and ruins to detect, locate and track hidden life objects behind obstacles. It is mainly used in emergency rescue, life detection, security and other fields. UAV platforms have many advantages such as flexibility, compactness and high maneuverability. Therefore, installing the through-the-wall radar system on the UAV platform can greatly improve the range and efficiency of through-the-wall radar target detection and search.

[0003] However, the position changes of the UAV platform, such as jitter and drift during hovering, lead to a decrease in the clutter suppression ratio of the radar system, which poses a huge challenge to through-wall radar target detection.

[0004] The existing through-wall radar clutter suppression algorithm is mainly implemented through multi-order cancellation processing with fixed coefficients, which cannot adapt to the clutter spectrum expansion and clutter spectrum center drift caused by the shaking and drift of the airborne platform. Summary of the invention

[0005] The purpose of the present invention is to provide a radar clutter suppression method, device, storage medium and product to solve the problem that the shaking and drift of the airborne platform lead to the expansion of the clutter spectrum of the through-wall radar and the drift of the clutter spectrum center, which in turn leads to the decrease of the clutter suppression efficiency of the through-wall radar and the poor target detection performance.

[0006] The present invention solves the above technical problems through the following technical solutions: A radar clutter suppression method, comprising:

[0007] Perform pulse compression processing on the radar echo signals collected from each channel to obtain a one-dimensional pulse compression result for each channel;

[0008] Perform digital beamforming processing on the one-dimensional pulse compression results of each channel to obtain one-dimensional distance results in different directions;

[0009] Perform fast Fourier transform on the one-dimensional distance dimension results in each direction to obtain the original range Doppler map in each direction;

[0010] Estimate the clutter spectrum center and clutter spectrum width in each direction according to the original range Doppler map in each direction;

[0011] Design filters in each direction according to the center and width of the clutter spectrum in each direction;

[0012] The one-dimensional distance matrix in each direction is convolved with the filter to obtain a clutter suppression processing result;

[0013] The result of the primary clutter suppression processing is subjected to a fast Fourier transform along its row direction to obtain a range Doppler map after the primary clutter suppression processing.

[0014] Furthermore, the one-dimensional distance dimension results in each direction are respectively subjected to fast Fourier transform, specifically including:

[0015] A one-dimensional distance matrix in each direction is obtained according to the one-dimensional distance result in each direction; wherein the one-dimensional distance matrix in each direction is expressed as:

[0016]

[0017] in, Represents θ k The one-dimensional distance matrix of the direction, θ k represents the kth direction that the radar beam is pointing to,

[0018] Indicates that at the lth moment θ k The one-dimensional distance dimension result of the direction, L represents the number of time points, and N represents the one-dimensional distance dimension result Length;

[0019] The one-dimensional distance matrix in each direction is subjected to fast Fourier transform along its row direction to obtain the original range Doppler map in each direction.

[0020] Furthermore, the clutter spectrum center and clutter spectrum width in each direction are estimated according to the original range Doppler map in each direction, specifically including:

[0021] The row elements of the original range Doppler map are compressed and normalized to obtain a first normalized result; wherein the compression and normalization formula is:

[0022]

[0023] Among them, D 1×L′ Represents θ k The row element compression result of the original range-Doppler map in the direction, RD N×L′ Represents θ k The original range-Doppler map of the direction, RD N×L′ (n,:) represents θ k All elements in the nth row of the original range Doppler map of the direction, N represents θ k The number of rows of the original range-Doppler map in the direction, L′ represents the number of spectrum indices, represents the first normalization result;

[0024] The clutter spectrum center and clutter spectrum width in the corresponding direction are estimated according to the first normalization result. The specific estimation formula is:

[0025]

[0026] Among them, d cen and d wid Respectively represent θ k The clutter spectrum center and clutter spectrum width in the direction, Represents the first normalization result a i elements, a i Represents the i-th element in set A, where A satisfies The set of all frequency indices l′, D max represents the intermediate quantity, max(A) and min(A) represent the maximum and minimum elements in set A respectively, T 3dB Indicates the 3dB threshold.

[0027] Furthermore, filters in each direction are designed according to the clutter spectrum center and clutter spectrum width in each direction, specifically including:

[0028] Taking the center of the clutter spectrum as the frequency response center of the filter, and taking the spectral width of the clutter spectrum as the suppression zone width of the frequency response of the filter;

[0029] The cost function is designed according to the frequency response of the filter; wherein the expression of the cost function is:

[0030]

[0031] Among them, J WLS represents the cost function, w(ω) represents the weight coefficient, ω represents the angular frequency, and h represents θ k Directional filter coefficients, N O Represents the filter order, H d (ω) represents the frequency response of the filter;

[0032] The filter coefficient h is calculated when the cost function takes the minimum value, and the filter is determined according to the filter coefficient h.

[0033] Furthermore, the suppression method also includes secondary clutter suppression processing, specifically including:

[0034] Estimate the clutter range-dimensional position set in each direction according to the original range-Doppler map in each direction;

[0035] The residual clutter spectrum structure diagram is constructed according to the clutter range-dimensional position set in each direction and the range Doppler diagram after a clutter suppression process;

[0036] A secondary clutter suppression process is performed on the range Doppler map after the primary clutter suppression process according to the residual clutter spectrum structure map to obtain the range Doppler map after the secondary clutter suppression process.

[0037] Furthermore, the clutter range-dimensional position set in each direction is estimated according to the original range Doppler map in each direction, specifically including:

[0038] The column elements of the original range-Doppler image are compressed and normalized to obtain a second normalized result; wherein the compression and normalization formula is:

[0039]

[0040] R N×1 =R N×1 / max(R N×1 );

[0041] Among them, R N×1 Represents θ k The column element compression result of the original range-Doppler map of the direction, RD N×L′ (:,l′) represents θ k All elements in the l′th column of the original range Doppler map of the direction, represents the second normalization result;

[0042] The second normalized result is subjected to constant false alarm rate detection and clustering to obtain a distance dimension position set of each clutter.

[0043] Furthermore, a residual clutter spectrum structure diagram is constructed according to the clutter range-dimensional position set in each direction and the range Doppler diagram after a clutter suppression process, specifically including:

[0044] The residual clutter spectrum is constructed based on the clutter range-dimensional position set in each direction and the range Doppler map after a clutter suppression process; the specific construction formula is:

[0045]

[0046] Among them, C_RD N′×L′ represents the residual clutter spectrum, It represents the range Doppler map after a clutter suppression process. Represents the range Doppler map All elements in row B of P e represents the distance dimension position set of the e-th clutter, and n represents the distance dimension position set P e The distance unit index in , B represents the set consisting of all distance unit indices, and N′ represents the number of elements in the set B;

[0047] The residual clutter spectrum is subjected to singular value decomposition, and the specific decomposition formula is:

[0048]

[0049] Among them, U N′×N′ and are all orthogonal matrices of singular value decomposition, S N′×L′ is the diagonal matrix of the singular value decomposition;

[0050] Take the orthogonal matrix The first column v L′×1 As the residual clutter spectrum structure diagram.

[0051] Further, performing secondary clutter suppression processing on the range Doppler image after the primary clutter suppression processing according to the residual clutter spectrum structure diagram specifically includes:

[0052] Calculate the similarity between each range unit of the range Doppler map after the primary clutter suppression process and the residual clutter spectrum structure map. The specific calculation formula is:

[0053]

[0054] Where P(n') represents the similarity between the spectrum structure in the n'th range unit of the range Doppler map after the first clutter suppression process and the residual clutter spectrum structure map, T scale Indicates setting threshold, vv n' Indicates the intermediate quantity, represents all elements in the n'th row of the range-Doppler map after a clutter suppression process. represents the element in the n'th row and l'th column of the range Doppler map after a clutter suppression process, and v(l') represents the residual clutter spectrum structure diagram v L′×1 The l′th element of , L′ represents the number of spectrum indices;

[0055] According to the similarity, a secondary clutter suppression process is performed on the range Doppler map after the primary clutter suppression process to obtain the range Doppler map after the secondary clutter suppression process. The specific processing formula is:

[0056]

[0057] in, The range Doppler map after secondary clutter suppression processing All elements in the n'th row,

[0058] represents the range Doppler map after a clutter suppression process, Pu represents the intermediate value, P u(n') represents the n'th element in Pu, and N represents the number of rows of the range-Doppler map after one clutter suppression process.

[0059] Based on the same concept, the present application also provides an electronic device, including a memory, a processor, and a computer program / instruction stored in the memory, wherein the processor executes the computer program / instruction to implement the radar clutter suppression method as described above.

[0060] Based on the same concept, the present application also provides a computer-readable storage medium on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the radar clutter suppression method as described above is implemented.

[0061] Based on the same concept, the present application also provides a computer program product, including a computer program / instruction, which implements the radar clutter suppression method as described above when executed by a processor.

[0062] Beneficial Effects

[0063] Compared with the prior art, the advantages of the present invention are:

[0064] The present invention extracts echo data in various directions (i.e., one-dimensional distance dimension results) through digital beamforming, estimates the center and spectral width of clutter spectrum in various directions on this basis, designs an FIR filter for clutter suppression according to the center and spectral width of the clutter spectrum, and realizes primary clutter suppression through the designed FIR filter; the present invention can realize better clutter suppression effect by adaptively adjusting the correlation coefficient of the filter through the estimated center and spectral width of the clutter spectrum, and improves the problem of decreased radar clutter suppression efficiency caused by shaking or drifting of the airborne platform.

[0065] In order to further suppress residual clutter, the present invention designs an image domain clutter suppression method based on spectral structure similarity, which realizes secondary suppression of clutter, further improves the clutter suppression effect, and effectively improves the effectiveness and stability of radar clutter suppression under moving platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0067] Figure 1 is a flow chart of a radar clutter suppression method according to an embodiment of the present invention;

[0068] Figure 2is a schematic diagram of estimating the center and width of a clutter spectrum in an embodiment of the present invention;

[0069] Figure 3 1 is a schematic diagram of estimating the position coordinates of each clutter in the distance dimension in an embodiment of the present invention;

[0070] Figure 4 It is a schematic diagram of the processing results of different steps in the embodiment of the present invention. DETAILED DESCRIPTION

[0071] The following is a clear and complete description of the technical solutions in the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0072] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0073] Figure 1 Figure 2 shows a schematic diagram of radar clutter suppression method. Figure 1 As shown, the radar clutter suppression method comprises the following steps:

[0074] Step 1: Perform pulse compression processing on the radar echo signals collected by each channel to obtain the one-dimensional pulse compression results of each channel.

[0075] The radar echo signal collected by each channel is pulse compressed to obtain the one-dimensional pulse compression result of the channel. in, Represents the one-dimensional pulse compression result of the mth channel and length N, m∈(1,M), and M represents the number of channels.

[0076] Step 2: Perform digital beamforming processing on the one-dimensional pulse compression results of each channel to obtain one-dimensional distance results in different directions.

[0077] Taking the mth channel as an example, the specific formula for performing digital beamforming processing on the one-dimensional pulse compression results of each channel is:

[0078]

[0079] in, Represents θ k The one-dimensional distance dimension result of the direction, θ k represents the kth direction pointed by the radar beamforming, k∈[1,K], where K represents the number of directions; X N×M Represents the one-dimensional pulse compression results of M channels; Represents θ k Extraction coefficient of direction, coefficient It can be obtained through digital beam forming method.

[0080] Step 3: Perform fast Fourier transform on the one-dimensional range dimension results in each direction to obtain the original range Doppler map in each direction.

[0081] In a specific implementation of the present invention, the one-dimensional distance dimension results in each direction are respectively subjected to fast Fourier transform, specifically including:

[0082] Step 3.1: Obtain a one-dimensional distance matrix in each direction based on the one-dimensional distance results in each direction.

[0083] By independently and continuously accumulating L one-dimensional distance results in each direction, we can get the one-dimensional distance matrix in the corresponding direction. k direction as an example, θ k The one-dimensional distance matrix of the direction can be expressed as:

[0084]

[0085] in, Represents θ k One-dimensional distance matrix of directions; Indicates that at the lth moment θ k The one-dimensional distance dimension result of the direction; L represents the number of time points or the number of one-dimensional distance dimension results; N represents the one-dimensional distance dimension result The length of the one-dimensional distance dimension result The length of is equal to the length of the one-dimensional pulse compression result of each channel, so both are represented by the character N.

[0086] Step 3.2: Convert the one-dimensional distance matrix in each direction Perform fast Fourier transform along the row direction to obtain the original range Doppler map RD in each direction N×L′ , L′ represents θ k The original distance Doppler map of the direction RD N×L′ The number of spectrum indices, θ k The original distance Doppler map of the direction RD N×L′ The number of rows and θ k The number of rows of the one-dimensional distance matrix of the direction is equal and is N.

[0087] Step 4: Estimate the clutter spectrum center and clutter spectrum width (or broadening) in each direction based on the original range Doppler map in each direction.

[0088] In a specific embodiment of the present invention, Figure 2 As shown, the clutter spectrum center and clutter spectrum width in each direction are estimated based on the original range Doppler map in each direction, including:

[0089] Step 4.1: Take θ k Taking the direction as an example, the row elements of the original range Doppler map are compressed and normalized to obtain the first normalized result; wherein the compression and normalization formula is:

[0090]

[0091] Among them, D 1×L′ Represents θ k The original distance Doppler map of the direction RD N×L′ The row element compression result, RD N×L′ (n,:) represents θ k The original distance Doppler map of the direction RD N×L′ All elements in the nth row of Represents the first normalized result, max(D 1×L′ ) means taking D 1×L′ The largest element in .

[0092] Step 4.2: Estimate the clutter spectrum center and clutter spectrum width in the corresponding direction based on the first normalization result. The specific estimation formula is:

[0093]

[0094] Among them, d cen and d wid Respectively represent θ k The clutter spectrum center and clutter spectrum width in the direction; Represents the first normalization result a i elements, a i Represents the i-th element in set A, where A satisfies The set of all frequency indices l′ of max represents the intermediate quantity, max(A) and min(A) represent the maximum and minimum elements in the set A respectively; T 3dB Indicates the 3dB threshold, which refers to the frequency point when the gain drops to half of the maximum gain.

[0095] Through steps 1 to 4, the estimation of the clutter spectrum center and the clutter spectrum width is realized. Clutter suppression is performed based on the estimated clutter spectrum characteristics, which is more targeted and has a better suppression effect.

[0096] Step 5: Design filters in each direction according to the center and width of the clutter spectrum in each direction.

[0097] In a specific implementation of the present invention, filters in each direction are designed according to the clutter spectrum center and clutter spectrum width in each direction, specifically including:

[0098] Step 5.1: Take θ k direction as an example, taking the center of the clutter spectrum d cen As the frequency response center of the filter, the clutter spectrum width d wid The width of the suppression zone as the frequency response of the filter;

[0099] Step 5.2: Design a cost function based on the frequency response of the filter; the expression of the cost function is:

[0100]

[0101] Among them, J WLS represents the cost function, w(ω) represents the weight coefficient, ω represents the angular frequency, and h represents θ k Directional filter coefficients, N O Represents the filter order, H d (ω) represents the frequency response of the filter;

[0102] Step 5.3: Find the filter coefficient h when the cost function takes the minimum value, and determine the filter based on the filter coefficient h.

[0103] Convert the filter design into the optimization solution process of the cost function, and use the common optimization algorithm to solve the following formula to get θ k Directional filter coefficients:

[0104]

[0105] Based on the clutter spectrum characteristics estimated in step 4, the correlation coefficient h of the filter is adaptively adjusted to achieve a better clutter suppression effect.

[0106] Step 6: Perform convolution calculation on the one-dimensional distance dimension result in each direction and the filter in the corresponding direction to obtain the result of the first clutter suppression processing. The specific formula is:

[0107]

[0108] in, Represents θ k The result of the first clutter suppression process in the direction, ⊙ represents the convolution symbol.

[0109] Step 7: Submit the result of the first clutter suppression process Perform fast Fourier transform along the row direction to obtain the range Doppler map after the first clutter suppression process.

[0110] The present invention adaptively adjusts the correlation coefficient of the filter by estimating the center of the clutter spectrum and the spectrum width, and then performs a clutter suppression using the correlation coefficient of the filter, thereby achieving a better clutter suppression effect and improving the problem of decreased radar clutter suppression efficiency caused by shaking or drifting of the airborne platform.

[0111] In order to further eliminate strong clutter residues, the present invention also designs an image domain clutter suppression method based on spectral structure similarity, and uses the image domain clutter suppression method to perform a range Doppler image after a clutter suppression process. Perform secondary clutter suppression, including:

[0112] Step 8: Estimate the clutter range-dimensional position set in each direction based on the original range-Doppler map in each direction.

[0113] In a specific embodiment of the present invention, Figure 3 As shown, the clutter range-dimensional position set in each direction is estimated based on the original range Doppler map in each direction, specifically including:

[0114] Step 8.1: Take θ k Direction as an example, the original distance Doppler map RD N×L′ The column elements of are compressed and normalized to obtain the second normalized result; wherein the compression and normalization formula is:

[0115]

[0116] Among them, R N×1 Represents θ k The original distance Doppler map of the direction RD N×L′ The column element compression result, RD N×L′ (:,l′) represents θ k The original distance Doppler map of the direction RD N×L′ All elements in the l′th column of Represents the second normalization result, max(R N×1 ) means taking R N×1 The largest element in .

[0117] Step 8.2: Normalize the second result Perform constant false alarm rate detection and clustering to obtain the distance dimension position set P1, P2, ..., P of each clutter. e ,...,P E , where P e represents the distance dimension position set of the e-th clutter, E represents the number of clutter, and the distance dimension position set P e Contains N distance units, n is the distance dimension position set P eThe distance unit index in .

[0118] Step 9: Construct a residual clutter spectrum structure diagram based on the clutter range-dimensional position set in each direction and the range Doppler map after a clutter suppression process.

[0119] In a specific embodiment of the present invention, a residual clutter spectrum structure diagram is constructed according to a clutter range-dimensional position set in each direction and a range Doppler diagram after a clutter suppression process, specifically including:

[0120] Step 9.1: Take θ k direction as an example, according to the clutter distance dimension position set P1, P2, ..., P e ,...,P E And the range Doppler map after the first clutter suppression process Construct the residual clutter spectrum; the specific construction formula is:

[0121]

[0122] Among them, C_RD N′×L′ represents the residual clutter spectrum, Represents the range Doppler map All elements in the Bth row of , B represents the set consisting of all distance unit indices, N′ represents the number of elements in set B, that is, the number of distance units in set B;

[0123] Step 9.2: Residual clutter spectrum C_RD N′×L′ Perform singular value decomposition, the specific decomposition formula is:

[0124]

[0125] Among them, U N′×N′ and are all orthogonal matrices of singular value decomposition, S N′×L′ is the diagonal matrix of the singular value decomposition;

[0126] Step 9.3: Get the orthogonal matrix The first column v L′×1 As the residual clutter spectrum structure diagram.

[0127] Step 10: Perform secondary clutter suppression processing on the range-Doppler map after the primary clutter suppression processing according to the residual clutter spectrum structure diagram to obtain the range-Doppler map after the secondary clutter suppression processing.

[0128] In a specific embodiment of the present invention, a secondary clutter suppression process is performed on the range Doppler image after the primary clutter suppression process according to the residual clutter spectrum structure diagram, specifically including:

[0129] Step 10.1: Calculate the range Doppler map after the clutter suppression process The structure diagram of each distance unit and residual clutter spectrum The specific calculation formula is:

[0130]

[0131] Where P(n') represents the range Doppler map after a clutter suppression process. The spectrum structure and residual clutter spectrum structure in the n'th distance unit The similarity of T scale represents the set threshold (set to 0.6 in this embodiment), vv n' Indicates the intermediate quantity, represents all elements in the n'th row of the range-Doppler map after a clutter suppression process. represents the element in the n'th row and l'th column of the range Doppler map after a clutter suppression process, and v(l') represents the residual clutter spectrum structure diagram v L′×1 The l′th element of .

[0132] Step 10.2: Perform secondary clutter suppression processing on the range Doppler map after the primary clutter suppression processing according to the similarity P(n) to obtain the range Doppler map after the secondary clutter suppression processing. The specific processing formula is:

[0133]

[0134] in, The range Doppler map after secondary clutter suppression processing All elements in the n'th row, P u Indicates the intermediate quantity, P u (n') represents the n'th element in Pu.

[0135] In another specific implementation of the present invention, an image domain clutter suppression method based on spectral structure similarity may also be used to perform clutter suppression processing on the original range Doppler image, specifically including:

[0136] Estimate the clutter range-dimensional position set in each direction according to the original range-Doppler map in each direction;

[0137] The residual clutter spectrum structure diagram is constructed according to the clutter range-dimensional position set in each direction and the original range-Doppler diagram;

[0138] The original range Doppler image is subjected to clutter suppression processing according to the residual clutter spectrum structure diagram to obtain the range Doppler image after clutter suppression processing.

[0139] Figure 4The processing results of different steps are shown in Figure θ k The original range Doppler map of the direction, the range Doppler map after the first clutter suppression process, the clutter spectrum map, and the range Doppler map after the second clutter suppression process. It can be seen from the range Doppler map after the first clutter suppression process that compared with the original range Doppler map, the clutter has been significantly weakened, and the target at the position of the dotted circle has been highlighted, but there is still clutter residual near the zero frequency; it can be seen from the range Doppler map after the second clutter suppression process that the target is obvious and there is no other clutter. Figure 4 It can be seen that the method of the present invention has better clutter suppression performance under the premise of retaining the target echo energy.

[0140] Example 2

[0141] An embodiment of the present application further provides an electronic device, which includes: a memory, a processor, and a computer program / instructions stored in the memory, and the processor executes the computer program / instructions to implement the radar clutter suppression method in the embodiment of the present application.

[0142] Although not shown, the electronic device includes a processor, which can perform various appropriate operations and processes according to the program and / or data stored in the read-only memory (ROM) or the program and / or data loaded from the storage portion into the random access memory (RAM). The processor can be a multi-core processor, or it can include multiple processors. In some embodiments, the processor can include a general main processor and one or more special coprocessors, such as a central processing unit, a graphics processing unit (GPU), a neural network processor (NPU), a digital signal processor (DSP), etc. In RAM, various programs and data required for device operation are also stored. The processor, ROM and RAM are connected to each other via a bus. The input / output (I / O) interface is also connected to the bus.

[0143] The processor and memory are used together to execute the program / instructions stored in the memory. When the program / instructions are executed by the computer, the methods, steps or functions described in the above embodiments can be implemented.

[0144] Although not shown, the embodiment of the present application further provides a computer-readable storage medium on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the radar clutter suppression method in the embodiment of the present application is implemented.

[0145] Readable storage media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0146] Although not shown, the embodiment of the present application further provides a computer program product, including: a computer program / instruction, which implements the radar clutter suppression method in the embodiment of the present application when the computer program / instruction is executed by a processor.

[0147] What is disclosed above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention, which should be covered within the protection scope of the present invention.

Claims

1. A radar clutter suppression method, characterized in that: The inhibition method comprises: Perform pulse compression processing on the radar echo signals collected from each channel to obtain a one-dimensional pulse compression result for each channel; Perform digital beamforming processing on the one-dimensional pulse compression results of each channel to obtain one-dimensional distance results in different directions; Perform fast Fourier transform on the one-dimensional distance dimension results in each direction to obtain the original range Doppler map in each direction; Estimate the clutter spectrum center and clutter spectrum width in each direction according to the original range Doppler map in each direction; Design filters in each direction according to the center and width of the clutter spectrum in each direction; The one-dimensional distance matrix in each direction is convolved with the filter to obtain a clutter suppression processing result; The result of the primary clutter suppression processing is subjected to a fast Fourier transform along its row direction to obtain a range Doppler map after the primary clutter suppression processing.

2. The radar clutter suppression method according to claim 1, characterized in that: The one-dimensional distance dimension results in each direction are respectively subjected to fast Fourier transform, including: A one-dimensional distance matrix in each direction is obtained according to the one-dimensional distance result in each direction; wherein the one-dimensional distance matrix in each direction is expressed as: in, Represents θ k The one-dimensional distance matrix of the direction, θ k represents the kth direction that the radar beam is pointing to, Indicates that at the lth moment θ k The one-dimensional distance dimension result of the direction, L represents the number of time points, and N represents the one-dimensional distance dimension result Length; The one-dimensional distance matrix in each direction is subjected to fast Fourier transform along its row direction to obtain the original range Doppler map in each direction.

3. The radar clutter suppression method according to claim 1, characterized in that: The clutter spectrum center and clutter spectrum width in each direction are estimated based on the original range Doppler map in each direction, including: The row elements of the original range Doppler map are compressed and normalized to obtain a first normalized result; wherein the compression and normalization formula is: Among them, D 1×L′ Represents θ k The row element compression result of the original range-Doppler map in the direction, RD N×L′ Represents θ k The original range-Doppler map of the direction, RD N×L′ (n,:) represents θ k All elements in the nth row of the original range Doppler map of the direction, N represents θ k The number of rows of the original range-Doppler map in the direction, L′ represents the number of spectrum indices, represents the first normalization result; The clutter spectrum center and clutter spectrum width in the corresponding direction are estimated according to the first normalization result. The specific estimation formula is: Among them, d cen and d wid Respectively represent θ k The clutter spectrum center and clutter spectrum width in the direction, Represents the first normalization result a i elements, a i Represents the i-th element in set A, where A satisfies The set of all frequency indices l′, D max represents the intermediate quantity, max(A) and min(A) represent the maximum and minimum elements in set A respectively, T 3dB Indicates the 3dB threshold.

4. The radar clutter suppression method according to claim 1, characterized in that: According to the clutter spectrum center and clutter spectrum width in each direction, filters in each direction are designed respectively, including: Taking the center of the clutter spectrum as the frequency response center of the filter, and taking the spectral width of the clutter spectrum as the suppression zone width of the frequency response of the filter; The cost function is designed according to the frequency response of the filter; wherein the expression of the cost function is: Among them, J WLS represents the cost function, w(ω) represents the weight coefficient, ω represents the angular frequency, and h represents θ k Directional filter coefficients, N O Represents the filter order, H d (ω) represents the frequency response of the filter; The filter coefficient h is calculated when the cost function takes the minimum value, and the filter is determined according to the filter coefficient h.

5. The radar clutter suppression method according to any one of claims 1 to 4, characterized in that: The suppression method also includes secondary clutter suppression processing, specifically including: Estimate the clutter range-dimensional position set in each direction according to the original range-Doppler map in each direction; The residual clutter spectrum structure diagram is constructed according to the clutter range-dimensional position set in each direction and the range Doppler diagram after a clutter suppression process; A secondary clutter suppression process is performed on the range Doppler map after the primary clutter suppression process according to the residual clutter spectrum structure map to obtain the range Doppler map after the secondary clutter suppression process.

6. The radar clutter suppression method according to claim 5, characterized in that: The clutter range-dimensional position set in each direction is estimated based on the original range Doppler map in each direction, specifically including: The column elements of the original range Doppler map are compressed and normalized to obtain a second normalized result; wherein the compression and normalization formula is: Among them, R N×1 Represents θ k The column element compression result of the original range-Doppler map of the direction, RD N×L′ (:,l′) represents θ k All elements in the l′th column of the original range Doppler map of the direction, represents the second normalization result; The second normalized result is subjected to constant false alarm rate detection and clustering to obtain a distance dimension position set of each clutter.

7. The radar clutter suppression method according to claim 5, characterized in that: The residual clutter spectrum structure diagram is constructed based on the clutter range-dimensional position set in each direction and the range Doppler map after a clutter suppression process, specifically including: The residual clutter spectrum is constructed based on the clutter range-dimensional position set in each direction and the range Doppler map after a clutter suppression process; the specific construction formula is: Among them, C_RD N′×L′ represents the residual clutter spectrum, It represents the range Doppler map after a clutter suppression process. Represents the range Doppler map All elements in row B of P e represents the distance dimension position set of the e-th clutter, and n represents the distance dimension position set P e The distance unit index in , B represents the set consisting of all distance unit indices, and N′ represents the number of elements in the set B; The residual clutter spectrum is subjected to singular value decomposition, and the specific decomposition formula is: Among them, U N′×N′ and are all orthogonal matrices of singular value decomposition, S N′×L′ is the diagonal matrix of the singular value decomposition; Take the orthogonal matrix The first column v L′×1 As the residual clutter spectrum structure diagram.

8. The radar clutter suppression method according to claim 5, characterized in that: According to the residual clutter spectrum structure diagram, a secondary clutter suppression process is performed on the range Doppler image after the primary clutter suppression process, specifically comprising: Calculate the similarity between each range unit of the range Doppler map after the primary clutter suppression process and the residual clutter spectrum structure map. The specific calculation formula is: Where P(n') represents the similarity between the spectrum structure in the n'th range unit of the range Doppler map after the first clutter suppression process and the residual clutter spectrum structure map, T scale Indicates setting threshold, vv n' Indicates the intermediate quantity, represents all elements in the n'th row of the range-Doppler map after a clutter suppression process. represents the element in the n'th row and l'th column of the range Doppler map after a clutter suppression process, and v(l') represents the residual clutter spectrum structure diagram v L′×1 The l′th element of , L′ represents the number of spectrum indices; According to the similarity, a secondary clutter suppression process is performed on the range Doppler map after the primary clutter suppression process to obtain the range Doppler map after the secondary clutter suppression process. The specific processing formula is: in, The range Doppler map after secondary clutter suppression processing All elements in the n'th row, represents the range Doppler map after a clutter suppression process, Pu represents the intermediate value, P u (n') represents the n'th element in Pu, and N represents the number of rows of the range-Doppler map after one clutter suppression process.

9. An electronic device comprising a memory, a processor, and a computer program / instruction stored in the memory, characterized in that: The processor executes the computer program / instructions to implement the radar clutter suppression method according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instructions are executed by a processor, the radar clutter suppression method according to any one of claims 1 to 8 is implemented.

11. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the radar clutter suppression method according to any one of claims 1 to 8 is implemented.

Images