STAP method for dimension reduction in element-pulse domain with pulse-dependent dimension reduction structure

Abstract

The present invention discloses an element-pulse domain dimensionality reduction STAP method in which the dimensionality reduction structure varies with pulses, which relates to the field of radar signal processing technology. The method comprises the following steps: setting antenna array elements of a radar, wherein M pulses are reflected in each antenna array element, and each pulse corresponds to a different subaperture; obtaining the subaperture translation n and the number of array elements N of the subaperture according to radar parameters and generalized DPCA conditions; and x and the number of pulses of the subaperture M x ; Based on the sub-aperture translation n and the number of sub-aperture elements N x and the number of pulses of the subaperture M x , selecting a subaperture for the pulse, obtaining corresponding data slices, and forming a data cube; performing the same subarray division processing on the array elements within each subaperture to reduce dimensionality and obtain the target space-time steering vector; obtaining the optimal weight based on the target space-time steering vector, further obtaining the filter output formula, and obtaining the filtering result based on the filter output formula. This application can improve the radar's anti-interference capability.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar signal processing, and in particular relates to an array element-pulse domain dimensionality reduction STAP method in which the dimensionality reduction structure varies with pulses. Background Art

[0002] Ultra-high-speed platform radars and airborne radars have a large field of view and receive a large area of ​​clutter, which has a serious impact on moving target detection. Therefore, reliable clutter suppression methods have become one of the difficulties to be faced.

[0003] In related technologies, based on the space-time coupling characteristics of radar clutter, space-time adaptive processing (STAP) can be used to suppress clutter. Whether it is an airborne radar or an ultra-high-speed platform radar, its clutter is non-stationary and non-uniform. When using the STAP method to suppress its clutter, the number of samples that meet the independent and identical distribution when constructing the covariance matrix is ​​small, and the clutter suppression effect is poor.

[0004] Therefore, it is urgent to improve the above problems to ensure the effective operation of airborne radar and ultra-high-speed radar. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention provides a STAP method for element-pulse domain dimensionality reduction in which the dimensionality reduction structure varies with the pulse. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present application provides a STAP method for element-pulse domain dimensionality reduction in which the dimensionality reduction structure varies with the pulse, comprising:

[0007] Set up the radar antenna array elements, and reflect M pulses in each antenna array element, each pulse corresponding to a different sub-aperture;

[0008] According to the radar parameters and the generalized DPCA condition, the sub-aperture translation n and the number of sub-aperture elements N are obtained. x and the number of pulses of the subaperture M x ;

[0009] Based on the sub-aperture translation n and the number of sub-aperture elements N x and the number of pulses of the subaperture M x , select subapertures for all used pulses, obtain corresponding data slices, and form a data cube;

[0010] Perform the same sub-array division processing on the array elements in each sub-aperture to reduce the dimension and obtain the target space-time steering vector;

[0011] Based on the target spatiotemporal steering vector, an optimal weight is obtained, and an output formula of a filter is further obtained. According to the output formula of the filter, a filtering result is obtained.

[0012] Beneficial effects of the present invention:

[0013] The present invention provides an element-pulse domain dimensionality reduction STAP method in which the dimensionality reduction structure varies with the pulse. The method adjusts the receiving aperture of each pulse data, that is, full-aperture transmission is used when transmitting signals, and sub-aperture reception is used when receiving signals (the receiving sub-aperture varies with the pulse). It can also be understood that during pulse 1, only sub-aperture 1 is used to receive echo data, and non-uniform sub-array division processing is performed within the sub-aperture; similarly, for pulse M, only sub-aperture M is used to receive echo data, and non-uniform sub-array division processing is performed within the sub-aperture, ensuring that there is a large amount of overlap of array elements in different pulses and different sub-apertures, thereby improving the radar's anti-interference capability. In addition, the sub-array division form within each sub-aperture is the same. In this way, it can be ensured that while reducing the dimensionality in the element domain, each sub-aperture of each pulse has corresponding sub-arrays that are as close to static as possible with other pulses.

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 1 is a flow chart of a STAP method for element-pulse domain dimensionality reduction in which the dimensionality reduction structure varies with the pulse, provided by an embodiment of the present invention;

[0016] Figure 2 is another flow chart of the element-pulse domain dimensionality reduction STAP method in which the dimensionality reduction structure varies with the pulse, provided by an embodiment of the present invention;

[0017] Figure 3 Schematic diagram of a structure of sub-aperture selection provided by an embodiment of the present invention;

[0018] Figure 4 is another structural schematic diagram of subaperture selection provided by an embodiment of the present invention;

[0019] Figure 5 This is a simulation result diagram provided by an embodiment of the present invention;

[0020] Figure 6 This is an existing simulation result diagram provided by an embodiment of the present invention;

[0021] Figure 7 1 is a comparison diagram of the clutter residual of the two methods provided by the embodiment of the present invention;

[0022] Figure 8 This is a diagram showing the effect of clutter suppression using the existing STAP method when some pulses can reach the sub-aperture, as provided by an embodiment of the present invention;

[0023] Figure 91 is a diagram showing the clutter suppression effect of the method proposed in the present invention when only part of the pulses can reach the sub-aperture according to an embodiment of the present invention;

[0024] Figure 10 This is a diagram showing the effect of clutter suppression using the existing STAP method when all pulses provided by the embodiment of the present invention can reach the sub-aperture;

[0025] Figure 11 This is a diagram showing the effect of clutter suppression using the existing STAP method when all pulses provided by the embodiment of the present invention can reach the sub-aperture;

[0026] Figure 12 1 is a diagram showing the clutter suppression effect of the method proposed in the present invention when all pulses provided in the embodiment of the present invention can reach the sub-aperture;

[0027] Figure 13 This is a comparison diagram of the residual clutter of the two methods when all pulses provided by the embodiment of the present invention can be obtained within the sub-aperture;

[0028] Figure 14 This is a diagram showing the effect of clutter suppression using the existing STAP method when only part of the pulses can reach the sub-aperture, as provided by an embodiment of the present invention;

[0029] Figure 15 1 is a diagram showing the clutter suppression effect of the method proposed in the present invention when only part of the pulses can reach the sub-aperture according to an embodiment of the present invention;

[0030] Figure 16 This is a comparison diagram of the residual clutter of two methods provided by an embodiment of the present invention when only part of the pulses can reach the sub-aperture. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0032] See Figure 1 , Figure 1 This is a flow chart of a STAP method for dimension reduction in the element-pulse domain, wherein the dimension reduction structure varies with the pulse, provided in an embodiment of the present invention. The STAP method for dimension reduction in the element-pulse domain, wherein the dimension reduction structure varies with the pulse, provided in this application, includes:

[0033] S101. Setting antenna elements of a radar, wherein M pulses are reflected in each antenna element, each pulse corresponding to a different sub-aperture;

[0034] S102. Obtain the subaperture translation n and the number of subaperture elements N according to radar parameters and generalized DPCA conditions. x and the number of pulses of the subaperture M x ;

[0035] S103: Sub-aperture-based translation n and sub-aperture element number N x and the number of pulses of the subaperture M x , selecting the subaperture for all used pulses, obtaining corresponding data slices, and forming a data cube;

[0036] S104, performing the same sub-array division process on the array elements in each sub-aperture, performing dimensionality reduction, and obtaining the target spatiotemporal steering vector;

[0037] S105 , based on the target spatiotemporal steering vector, obtaining an optimal weight, further obtaining an output formula of a filter, and obtaining a filtering result according to the output formula of the filter.

[0038] Specifically, this embodiment proposes an array element-pulse domain dimensionality reduction method in which the dimensionality reduction structure changes with the pulse, in order to solve the problems of constructing a covariance matrix when using the STAP method to suppress clutter, a small number of samples satisfying independent and identical distribution, poor clutter suppression effect, and insufficient computational complexity of the adaptive dimensionality reduction method.

[0039] In the related technology, the existing methods, such as adaptive dimensionality reduction methods, require echo data, covariance matrix or eigendecomposition. It is impossible to fix the dimensionality reduction method in the radar design stage, and the amount of calculation is large.

[0040] In view of this, see Figure 2 , Figure 2 This is another flow chart of the array element-pulse domain dimensionality reduction STAP method in which the dimensionality reduction structure varies with the pulse provided in an embodiment of the present invention. The array element-pulse domain dimensionality reduction STAP method in which the dimensionality reduction structure varies with the pulse provided in this embodiment is implemented by the following steps.

[0041] S101. Setting antenna elements of a radar, wherein M pulses are reflected in each antenna element, each pulse corresponding to a different sub-aperture;

[0042] S102. Obtain the subaperture translation n and the number of subaperture elements N according to radar parameters and generalized DPCA (does it have a Chinese name) conditions. x and the number of pulses of the subaperture M x ;

[0043] S103: Sub-aperture-based translation n and sub-aperture element number N x and the number of pulses of the subaperture M x , selecting the subaperture for all used pulses, obtaining corresponding data slices, and forming a data cube;

[0044] S104, performing the same sub-array division process on the array elements in each sub-aperture, performing dimensionality reduction, and obtaining the target spatiotemporal steering vector;

[0045] S105 , based on the target spatiotemporal steering vector, obtaining an optimal weight, further obtaining an output formula of a filter, and obtaining a filtering result according to the output formula of the filter.

[0046] The above process uses element-pulse domain dimensionality reduction to adjust the receiving aperture of each pulse data, that is, full-aperture transmission is used when transmitting signals, and sub-aperture reception is used when receiving signals (the receiving sub-aperture changes with the change of pulses); it can also be understood that during pulse 1, only sub-aperture 1 is used to receive echo data, and non-uniform sub-array division processing is performed within the sub-aperture; similarly, for pulse M, only sub-aperture M is used to receive echo data, and non-uniform sub-array division processing is performed within the sub-aperture, ensuring that there is a large amount of element overlap in different pulses and different sub-apertures, thereby improving the radar's anti-interference capability; in addition, the sub-array division form within each sub-aperture is the same. In this way, it can be ensured that while reducing the element domain dimensionality, each sub-aperture of each pulse has a corresponding sub-array that is as close to static as possible with other pulses.

[0047] In an optional embodiment of the present application, based on the sub-aperture translation n, the number of sub-aperture elements N x and the number of pulses of the subaperture M x The specific process of selecting subapertures for all used pulses, obtaining corresponding data slices, and forming a data cube includes:

[0048] The radar adopts phased array form, and the number of azimuth array elements is N L , the number of pitch and elevation array elements is N C , the radar transmits M pulses in one array element, and the maximum number of unambiguous range gates is L;

[0049] Get the space-time snapshot data received by the mth pulse of the lth range gate as N C ×N L dimensional matrix x l,m , where N L is the number of antenna array elements in azimuth, N C is the number of antenna array elements in the elevation direction, and L is the maximum number of unambiguous range gates;

[0050]

[0051] Based on the subaperture translation n and the number of subaperture elements N x It is understandable that as the pulse changes, the sub-aperture used to receive the echo signal will also change; the dimension of the m-th pulse data of the l-th range gate is reduced to obtain the dimension reduction matrix T m,s ;

[0052]

[0053] Where s is the subscript, T m,s The dimension is N x ×N L ; It should be noted that the dimensionality reduction matrix T m,s Changes with the pulse;

[0054] Based on the matrix x l,m and the dimension reduction matrix T m,s , get the echo data received by the mth pulse of the lth range gate as The dimension of the echo data received by the mth pulse of the lth range gate after dimensionality reduction is N C ×N x ;

[0055] The number of pulses M based on the subaperture x , get data slices; where the number of data slices is M x ×L, the dimension of the data slice is N C ×N x ;0 <M x ≤M, and M x is an integer;

[0056] Rearrange and integrate all the range gates and all the pulse data to form a dimension of N C N x ×M x ×L data cube.

[0057] In an optional embodiment of the present application, the specific process of obtaining the filtering result includes:

[0058] Get the space-time snapshot data x% received by the lth range gate after dimensionality reduction l ;

[0059]

[0060] Get the pulse data x received by the array element in the mth row and nth column k (m,n),x k (m,n)=[x mn1 ,…,x mnk ] T ; where x mnk is the space-time snapshot data received by the array element in the mth row and nth column at the kth pulse, m=1,…,N c ,n=1,…,N x ;

[0061] Perform the same sub-array division process on the array elements in each sub-aperture to reduce the dimension and obtain the space-time two-dimensional sampling data in the lth range gate.

[0062] After dimensionality reduction processing, the target time domain steering vector S after dimensionality reduction is obtained t0 , S t0 =T t T S t , where T t M×M x dimensional pulse domain dimensionality reduction matrix, S t is the target time domain steering vector;

[0063] After dimensionality reduction processing, the target spatial guidance vector S after dimensionality reduction is obtained s0 ,m,S s0 ,m=T m,s T S s , where T m,s is the spatial dimension reduction matrix of the m-th pulse data, S s is the target airspace guidance vector;

[0064] Based on the target time-domain steering vector and the target space-domain steering vector, the target space-time steering vector S0 is obtained by a preset first formula; wherein the preset first formula is:

[0065]

[0066] Obtain the optimal weights according to the linear constrained minimum variance (LCMV) criterion;

[0067] The expression of the linear constrained minimum variance criterion is:

[0068]

[0069] The optimal weight expression is:

[0070]

[0071] in, is the covariance matrix of clutter plus noise, and by making maximum likelihood estimation on the data after dimensionality reduction, we can get

[0072] Based on the optimal weights, the output formula of the filter is obtained to obtain the filtering result; wherein, the expression of the output of the filter is:

[0073] Where H is the transpose.

[0074] See Figure 3 , Figure 3 is a schematic diagram of a structure of subaperture selection provided by an embodiment of the present invention. In an optional embodiment of the present application, the constraints for selecting subapertures for all used pulses include:

[0075] When the distance the radar array moves within the mT time is less than 0.5d, it is considered that the radar array position does not move; at this time, the sub-apertures corresponding to the pulses within the mT time are the same;

[0076] Where d is the array element spacing.

[0077] It should be noted that when When b = 1, 2, 3…;

[0078] In the above case, if the distance moved by the radar within the repetition period of the first b pulses is less than d / 2, it is considered that the radar has not moved. In order to ensure that the equivalent phase center of transmission and reception remains unchanged, the sub-aperture selected for b pulses is the same; for the b+1th pulse, the array moves forward by d / 2. At this time, the transmitting phase center moves forward by d / 2. In order to ensure that the equivalent phase center of transmission and reception remains unchanged, the receiving phase center should move in the opposite direction by d / 2, that is, the position of the receiving subaperture should be moved backward by 1 array element spacing compared with the position of the receiving subaperture of the previous pulse, and the subaperture length remains unchanged; in addition, similarly, starting from the b+1th pulse, the subaperture corresponding to the 2bth pulse is the same, and so on. The subaperture changes once every b pulses until the entire array is taken.

[0079] See Figure 4 , Figure 4 is another structural diagram of subaperture selection provided by an embodiment of the present invention. In an optional embodiment of the present application, the constraints for selecting subapertures for all used pulses further include:

[0080] When the radar array moves b×d / 2 along the heading direction, the position of the sub-aperture corresponding to the corresponding pulse moves in the opposite direction by b array element spacings compared with the position of the sub-aperture corresponding to the previous pulse.

[0081] It should be noted that when When b = 1, 2, 3…;

[0082] In the above case, by comparing the relationship between the distance the array moves and the distance between the phase centers of the two array elements, it is found that the array moves forward b×d / 2 in each pulse, that is, the transmitting phase center moves forward b×d / 2, and the receiving phase center should move backward b×d / 2, that is, the receiving subaperture should move backward by b array element spacings compared with the receiving subaperture of the previous pulse, and the subaperture length remains unchanged.

[0083] In an optional embodiment of the present application, the rules for selecting subapertures for all used pulses include:

[0084] When vT=md / 2, the subapertures corresponding to different pulses are different, and the subaperture shifts corresponding to adjacent pulses are Nm =b; at this time, the sub-aperture selection rule satisfies the following formula:

[0085] N=N x +(M x -1)N m ;

[0086] Among them, M x ≤M, N is the number of array elements in the radar array, M is the pulse emitted by the array element, v is the radar speed, T is the pulse repetition period, and b is a variable used to determine the sub-aperture selection rule.

[0087] In an optional embodiment of the present application, the rule for selecting subapertures for all used pulses further includes:

[0088] When vT = d / 2b, with the first pulse as the reference, the position of the subaperture changes once every b pulses. Compared with the previous subaperture position, the current subaperture position shifts backward by one array element spacing. When the subaperture changes, the subaperture shift amount is N m =1; at this time, the sub-aperture selection rule satisfies the following formula:

[0089]

[0090] Among them, M x ≤M, N is the number of array elements in the radar array, M is the pulse emitted by the array element, v is the radar speed, T is the pulse repetition period, b variable is used to determine the sub-aperture selection rule, The value is rounded to the nearest integer.

[0091] In an optional embodiment of the present application, the method further includes: obtaining a clutter rank;

[0092] When vT = md / 2, according to the Brennan criterion, the clutter rank is obtained, and its expression is:

[0093]

[0094] The variable b is used to determine the subaperture selection rule, b = 1, 2, 3, ..., β = 2νT / d.

[0095] It should be noted that the above embodiment is applicable when all pulses can obtain sub-apertures.

[0096] In an optional embodiment of the present application, the method further includes: obtaining a clutter rank;

[0097] When vT = d / 2b, according to the Brennan criterion, the clutter rank is obtained, and its expression is:

[0098]

[0099] The variable b is used to determine the sub-aperture selection rule, b=1, 2, 3...

[0100] It should be noted that the above embodiment is applicable to the case where some pulses are taken into a sub-aperture.

[0101] In an optional embodiment of the present application, see Figures 5 to 7 , Figure 5 This is a simulation result diagram provided by an embodiment of the present invention. Figure 6 This is an existing simulation result diagram provided by an embodiment of the present invention. Figure 7 This is a comparison of the residual clutter using two methods provided by an embodiment of the present invention. The radar speed is 7500 m / s, the satellite altitude is 698.19 km, the array size is 2 m × 50 m, the number of array elements is 13 × 333, the carrier frequency is 1 GHz, the wavelength is 0.3 m, the bandwidth is 5 GHz, the pulse repetition frequency is 10,000 Hz, the number of pulses is 100, the range resolution is 30 m, the orbital inclination is 85°, and only 500 range gates near the main lobe are considered. The number of pulses used is 91, the number of array elements in each subaperture is 243, and after the non-uniform sub-array division within the subaperture, the number of subarrays is 50.

[0102] See Figures 8 to 13 , Figure 8 This is a diagram showing the effect of clutter suppression using the existing STAP method when some pulses can reach the sub-aperture, as provided by an embodiment of the present invention. Figure 9 : is a diagram showing the clutter suppression effect of the method proposed by the present invention when only part of the pulses can reach the sub-aperture, provided by an embodiment of the present invention. Figure 10 This is a diagram showing the effect of clutter suppression using the existing STAP method when all pulses provided by the embodiment of the present invention can reach the sub-aperture. Figure 11 FIG12 is a diagram showing the effect of clutter suppression using the STAP method when all pulses provided by the embodiment of the present invention can reach the sub-aperture. FIG13 is a diagram showing the effect of clutter suppression using the method proposed by the present invention when all pulses provided by the embodiment of the present invention can reach the sub-aperture. Figure 13 This is a comparison diagram of the residual clutter of the two methods provided by the embodiment of the present invention when all pulses can be obtained in the sub-aperture; taking a uniformly arranged linear array as an example, the antenna array surface is distributed along the heading, the number of array elements is 39, the number of pulses emitted by the radar within one CPI is 10, the carrier speed is 75m / s, the pulse repetition frequency is 1000Hz, the carrier altitude is 8000km, the carrier frequency is 1GHz, and the wavelength is 0.3m. When all pulse data can be used, according to the sub-aperture selection rule, the number of sub-aperture array elements can be determined to be 30. When only part of the pulse data can be used, assuming that the number of pulses that can be obtained in the sub-aperture is 7, then according to the sub-aperture selection rule, the number of sub-aperture array elements can be determined to be 33. The sub-aperture is divided into 7 sub-arrays using the non-uniform sub-array division method.

[0103] See Figures 14 to 16 , Figure 14 This is a diagram showing the effect of clutter suppression using the existing STAP method when only part of the pulses can reach the sub-aperture, provided by an embodiment of the present invention. Figure 15 : is a diagram showing the clutter suppression effect of the method proposed by the present invention when only part of the pulses can reach the sub-aperture, provided by an embodiment of the present invention. Figure 16 This is a comparison diagram of the residual clutter of two methods provided by an embodiment of the present invention when only part of the pulses can obtain the sub-aperture; taking a uniformly arranged linear array as an example, the antenna array surface is distributed along the heading, the number of array elements is 64, the number of pulses emitted by the radar within one CPI is 20, the pulse repetition frequency is 1000 Hz, the carrier altitude is 8000 km, the carrier frequency is 1 GHz, and the wavelength is 0.03 m. According to the sub-aperture selection rule, the number of sub-aperture array elements can be determined to be 30. At this time, all pulse data can be used. When only part of the pulse data can be utilized, assuming that the number of pulses that can obtain the sub-aperture is 10, then according to the sub-aperture selection rule, the number of sub-aperture array elements can be determined to be 46. The sub-aperture is divided into 7 sub-arrays using the non-uniform sub-array division method.

[0104] The present invention provides an element-pulse domain dimensionality reduction STAP method in which the dimensionality reduction structure varies with the pulse. The method adjusts the receiving aperture of each pulse data, that is, full-aperture transmission is used when transmitting signals, and sub-aperture reception is used when receiving signals (the receiving sub-aperture varies with the pulse). It can also be understood that during pulse 1, only sub-aperture 1 is used to receive echo data, and non-uniform sub-array division processing is performed within the sub-aperture; similarly, for pulse M, only sub-aperture M is used to receive echo data, and non-uniform sub-array division processing is performed within the sub-aperture, ensuring that there is a large amount of overlap of array elements in different pulses and different sub-apertures, thereby improving the radar's anti-interference capability. In addition, the sub-array division form within each sub-aperture is the same. In this way, it can be ensured that while reducing the dimensionality in the element domain, each sub-aperture of each pulse has corresponding sub-arrays that are as close to static as possible with other pulses.

[0105] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A STAP method for dimension reduction in the element-pulse domain, wherein the dimension reduction structure varies with the pulse, characterized in that: include: The antenna array element of the radar is set, and each of the antenna array elements has an internal reflection M pulses, each of the pulses corresponding to a different subaperture; Obtain the subaperture translation according to radar parameters and generalized DPCA conditions N m , the number of elements of the sub-aperture N x and the number of pulses of the subaperture M x ; The translation amount based on the subaperture N m , the number of elements of the sub-aperture N x and the number of pulses of the subaperture M x , selecting the sub-aperture for all the pulses used, obtaining corresponding data slices, and forming a data cube; Performing the same sub-array division processing on the array elements within each sub-aperture to reduce the dimension and obtain the target spatiotemporal steering vector; Based on the target spatiotemporal steering vector, an optimal weight is obtained, and an output formula of a filter is further obtained. Then, a filtering result is obtained according to the output formula of the filter.

2. The element-pulse domain dimensionality reduction STAP method with pulse-dependent dimensionality reduction structure according to claim 1, characterized in that: The translation amount based on the sub-aperture N m , the number of elements of the sub-aperture N x and the number of pulses of the subaperture M x The specific process of selecting the sub-aperture for all the pulses used, obtaining corresponding data slices, and forming a data cube includes: Get the l Distance door m The space-time snapshot data received by the pulse is dimensional matrix ,in, N L is the number of azimuth array elements of the antenna array element, N C is the number of elevation elements of the antenna array element, L is the maximum number of unambiguous range gates; ； The translation amount based on the subaperture N m and the number of elements of the subaperture N x , for l Distance door m The pulse data is reduced in dimension to obtain the reduced dimension matrix ; ； in, s is the subscript, The dimension is N L × N x ; Matrix-based and the reduced dimension matrix , get the l Distance door m The echo data received by the pulse is , ; After dimensionality reduction l Distance door m The dimension of the echo data received by each pulse is ; The number of pulses based on the subaperture M x , get the data slices; wherein the number of the data slices is M x × L , the dimension of the data slice is ; Rearrange and integrate all the range gates and all the pulse data to form a dimension of N C N x × M x × L data cube.

3. The element-pulse domain dimensionality reduction STAP method with pulse-dependent dimensionality reduction structure according to claim 2, characterized in that: The specific process of obtaining the filtering result includes: Get the first l Space-time snapshot data received by the range gate ; ； Get the m Rank n Pulse data received by the array element , ;in, For the m Rank n The array element is in the k The space-time snapshot data received by each pulse, ; Perform the same sub-array division process on the array elements in each sub-aperture to reduce the dimension and obtain the l The space-time two-dimensional sampling data within the range gate , ; After dimensionality reduction processing, the target time domain steering vector after dimensionality reduction is obtained , ,in, for dimensional pulse domain dimensionality reduction matrix, is the target time domain steering vector; After dimensionality reduction processing, the target spatial guidance vector after dimensionality reduction is obtained , ,in, For the m The spatial dimension reduction matrix of the pulse data is is the target airspace guidance vector; Based on the target time-domain steering vector and the target space-domain steering vector, the target space-time steering vector is obtained by a preset first formula. ; Among them, the preset first formula is: ； Obtain the optimal weights according to the linear constrained minimum variance criterion; The expression of the linear constrained minimum variance criterion is: ； The optimal weight expression is: ； in, is the covariance matrix of clutter plus noise, and by making maximum likelihood estimation on the data after dimensionality reduction, we can get ; Based on the optimal weights, the output formula of the filter is obtained to obtain the filtering result; wherein, the expression of the output of the filter is: , where H is the transpose.

4. The STAP method for dimension reduction in the element-pulse domain with pulse-dependent dimension reduction structure according to claim 1, characterized in that: The constraints for selecting the sub-aperture for all the pulses used include: When the radar array mT The distance moved within the time is less than 0.5 d When , it is considered that the radar array position does not move; at this time, mT The subapertures corresponding to the pulses within a time are the same; in, d is the array element spacing, m For the m A pulse.

5. The STAP method for dimension reduction in the element-pulse domain with pulse-dependent dimension reduction structure according to claim 1, characterized in that: The constraint condition for selecting the sub-aperture for all the pulses used also includes: When the radar array moves along the heading direction When the position of the sub-aperture corresponding to the corresponding pulse moves in the opposite direction compared with the position of the sub-aperture corresponding to the previous pulse b Array element spacing, d is the array element spacing, b is a variable used to determine the sub-aperture selection rule.

6. The element-pulse domain dimensionality reduction STAP method with pulse-dependent dimensionality reduction structure according to claim 1, characterized in that: The rule for selecting the sub-aperture for all the pulses used includes: when When the subapertures corresponding to different pulses are different, the subaperture shifts corresponding to adjacent pulses are N m =b ; At this time, the sub-aperture selection rule satisfies the following formula: ； in, , N is the number of radar array elements, M is the pulse emitted by the array element, v is the radar speed, T is the pulse repetition period, b is a variable used to determine the subaperture selection rule, d is the array element spacing.

7. The STAP method for dimension reduction in the element-pulse domain with pulse-dependent dimension reduction structure according to claim 1, characterized in that: The rule for selecting the sub-aperture for all the pulses used further includes: when When the first pulse is used as reference, b The position of the subaperture of each pulse changes once. Compared with the previous subaperture position, the current subaperture position shifts backward by one array element spacing. When the subaperture changes, the subaperture shift amount is N m =1; at this time, the sub-aperture selection rule satisfies the following formula: ； in, , N is the number of radar array elements, M is the pulse emitted by the array element, v is the radar speed, T is the pulse repetition period, b is a variable used to determine the subaperture selection rule, To round off, d is the array element spacing.

8. The STAP method for dimension reduction in the element-pulse domain with pulse-dependent dimension reduction structure according to claim 1, characterized in that: Also includes: Get the clutter rank size; when When , according to the Brennan criterion, the size of the clutter rank is obtained, and its expression is: ； in, b is a variable used to determine the subaperture selection rule, b=1, 2, 3…, β =2 vT / d , d is the array element spacing.

9. The STAP method for dimension reduction in the element-pulse domain with pulse-dependent dimension reduction structure according to claim 1, characterized in that: Also includes: Get the clutter rank size; when When , according to the Brennan criterion, the size of the clutter rank is obtained, and its expression is: ； in, b is a variable used to determine the subaperture selection rule, b =1, 2, 3…, d is the array element spacing.

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