CN-122017776-A - Space-based radar clutter suppression method based on multi-domain cascade processing

CN122017776ACN 122017776 ACN122017776 ACN 122017776ACN-122017776-A

Abstract

The invention discloses a space-based radar clutter suppression method based on multi-domain cascade processing, which comprises the steps of designing a linear frequency modulation signal and a phase coding signal, designing a first waveform signal based on pulse width frequency modulation polarity agility and linear frequency modulation by changing the frequency modulation polarity of the linear frequency modulation signal, designing a second waveform signal based on phase coding, pulse width frequency modulation polarity agility and linear frequency modulation according to the phase coding signal and the first waveform signal, designing a quadrature waveform signal group related to the second waveform signal by adopting an SQP algorithm based on a minimized peak sidelobe energy criterion, calculating clutter space-time snapshot data according to the quadrature waveform signal group, designing a matched filter according to the quadrature waveform signal group and filtering the clutter space-time snapshot data, adopting a 3DT-STAP algorithm, calculating a space-time two-dimensional filter weight coefficient according to the filtered clutter space-time snapshot data and a space-time two-dimensional filter weight coefficient, and calculating a clutter suppression result according to the filtered clutter space-time snapshot data and the space-time two-dimensional filter weight coefficient.

Inventors

LIAO GUISHENG
ZHENG LONGHAI
CHEN YUFENG
TIAN MIN
GAO DAWEI
Yue yaxing

Assignees

西安电子科技大学

Dates

Publication Date: 20260512
Application Date: 20260115

Claims (10)

1. The space-based radar clutter suppression method based on multi-domain cascade processing is characterized by comprising the following steps of: Establishing a planar array space-based early warning radar clutter signal model; designing linear frequency modulation signals and phase coding signals of waveforms with different pulse widths; Designing a first waveform signal based on pulse width frequency modulation polarity agility and linear frequency modulation by changing the frequency modulation polarity of the linear frequency modulation signal, and designing a second waveform signal based on phase encoding, pulse width frequency modulation polarity agility and linear frequency modulation according to the phase encoding signal and the first waveform signal; designing an orthogonal waveform signal group related to the second waveform signal based on the minimized peak sidelobe energy criterion and by adopting an SQP algorithm; based on a planar array space-based early warning radar clutter signal model, clutter space-time snapshot data are calculated according to orthogonal waveform signal groups; designing a matched filter according to the orthogonal waveform signal group, and filtering clutter space-time snapshot data according to the matched filter; and adopting a 3DT-STAP algorithm, adaptively calculating a space-time two-dimensional filter weight coefficient of the 3DT-STAP according to the filtered clutter space-time snapshot data, and calculating a clutter suppression result according to the filtered clutter space-time snapshot data and the space-time two-dimensional filter weight coefficient of the 3 DT-STAP.
2. The space-based radar clutter suppression method based on multi-domain cascade processing according to claim 1, wherein the designed chirp signal is expressed as: ; Wherein, the Representation of Time of day (time) A chirp signal corresponding to each waveform, Represent the first The pulse width corresponding to the waveform of each pulse, , The number of waveforms is represented and, The number of modulation phases is represented by, Representing a rectangular window function; the designed phase encoded signal is expressed as: ; Wherein, the Representation of Time of day (time) The phase encoded signals corresponding to the respective waveforms, Represent the first The phase modulation sequence corresponding to the waveform The phase modulation value of each symbol, , , Representing the number of symbols in the corresponding phase modulation sequence for each waveform, , Representation of Time of day (time) The waveform corresponds to the first phase modulation sequence An ideal rectangular pulse of one symbol, 。
3. The space-based radar clutter suppression method based on multi-domain cascade processing according to claim 1, wherein the first waveform signal based on pulse width modulation polarity agility and chirp is designed to be expressed as: ; Wherein, the Representation of Time of day (time) A first waveform signal corresponding to the respective waveform, , The number of waveforms is represented and, Represent the first The pulse width of the individual waveforms is such that, Represent the first A random non-negative integer corresponding to the waveform is used for changing the frequency modulation polarity, Representing bandwidth.
4. The space-based radar clutter suppression method based on multi-domain cascade processing of claim 1, wherein the method for designing different pulse widths comprises a pulse width sliding mode and a pulse width hopping mode, wherein the pulse width sliding mode comprises a pulse width reducing mode with equal intervals and a pulse width with larger middle and smaller middle.
5. The method for clutter suppression of space-based radar based on multi-domain cascade processing according to claim 1, wherein the second waveform signal based on phase encoding, pulse width modulation polarity agility and chirp is designed to be expressed as: ; Wherein, the Representation of Time of day (time) A second waveform signal corresponding to the respective waveform, , The number of waveforms is represented and, Representation of Time of day (time) A first waveform signal corresponding to the respective waveform, Representation of Time of day (time) The phase encoded signals corresponding to the respective waveforms, Represent the first The phase modulation sequence corresponding to the waveform The phase modulation value of each symbol, , , Representing the number of symbols in the corresponding phase modulation sequence for each waveform, , The number of modulation phases is represented by, Representation of Time of day (time) The waveform corresponds to the first phase modulation sequence An ideal rectangular pulse of one symbol, , A rectangular window function is represented and, Represent the first Pulse width corresponding to each waveform.
6. The method of claim 1, wherein designing the set of orthogonal waveform signals for the second waveform signal based on the minimized peak sidelobe energy criterion and using the SQP algorithm comprises: Designing an orthogonal waveform optimization model related to the second waveform signal, wherein the optimization target of the orthogonal waveform optimization model is to minimize peak sidelobe energy of the orthogonal waveform signal, and the peak sidelobe energy comprises autocorrelation peak sidelobe energy and peak cross correlation energy; and solving an orthogonal waveform optimization model by adopting an SQP algorithm to obtain an orthogonal echo signal group.
7. The method for space-based radar clutter suppression based on multi-domain cascade processing according to claim 6, wherein the designed orthogonal waveform optimization model for the second waveform signal is expressed as: ; Wherein, the Representing the autocorrelation peak side lobe energy of the orthogonal waveform signal, Representation adjustment And Is characterized by comprising a specific gravity of (2), , The number of waveforms is represented and, Representing the peak cross-correlation energy of the quadrature waveform signal, , Represent the first Corresponding to each waveform Is used as a function of the autocorrelation function of (c), The time delay is indicated as such, Representing the width of the main lobe of the device, Represent the first Corresponding to each waveform Is used as a cross-correlation function of (c), Representing a modulo operation.
8. The space-time snapshot data based on multi-domain cascade processing according to claim 1, wherein the clutter space-time snapshot data is calculated according to the orthogonal waveform signal group, and is expressed as: ; Wherein, the Represent the first Clutter space-time snapshot data for each range gate, Indicating the number of clutter blocks on a single range loop, Represents the number of orthogonal waveform signals in the orthogonal waveform signal group, Represent the first On the fuzzy distance ring The azimuth of each clutter block, Represent the first On the fuzzy distance ring Pitch angle of each clutter block, Represent the first On the fuzzy distance ring The echo amplitude of the individual clutter blocks, Representing the space-time steering vector corresponding to the clutter, Representing the first of the orthogonal waveform signal groups A second waveform signal is provided which is a waveform of the second signal, Represent the first On the distance gate The first clutter block The number of blur distances is a function of the number of blur distances, The speed of light is indicated as being the speed of light, Representing a noise signal.
9. The space-based radar clutter suppression method based on multi-domain cascade processing according to claim 1, wherein the adaptive calculation of the space-time two-dimensional filter weight coefficient of the 3DT-STAP according to the filtered clutter space-time snapshot data is performed by adopting a 3DT-STAP algorithm, and the method comprises the following steps: constructing a Doppler domain transformation matrix according to the Doppler channel number; Extracting three columns of data corresponding to a Doppler channel where a target is located and multiple common channels on two sides of the target in the Doppler domain transformation matrix to form a Doppler filter bank; According to the Doppler filter bank, a transformation matrix of the 3DT-STAP is designed; According to the transformation matrix of the 3DT-STAP, transforming the clutter space-time snapshot data after filtering to obtain transformed clutter space-time snapshot data; According to the transformation matrix of the 3DT-STAP, calculating the space-time steering vector of the 3DT-STAP of the target; Calculating a clutter covariance matrix of the 3DT-STAP according to the transformed clutter space-time snapshot data; and calculating the weight coefficient of the space-time two-dimensional filter of the 3DT-STAP according to the clutter covariance matrix of the 3DT-STAP and the space-time steering vector of the 3DT-STAP of the target.
10. The space-based radar clutter suppression method based on multi-domain cascade processing according to claim 1, wherein the space-time two-dimensional filter weight coefficient of the 3DT-STAP is calculated as: ; Wherein, the The space-time two-dimensional filter weight coefficients representing 3DT-STAP, Represents the clutter covariance matrix of 3DT-STAP, , Represent the first The transformed clutter space-time snapshot data for each range gate, Representing the conjugate-transpose operation, Indicating the number of distance gates and, Representation of Is used for the inversion operation of (a), , Representing the transformation matrix of 3DT-STAP, Representation of Is subjected to the conjugate-transpose operation, , A set of doppler filters is represented and, Data representing the doppler channel in which the target is located in the doppler domain transform matrix, Data representing multiple common channels on both sides of the target in the doppler domain transform matrix, , Indicating the operation of the transpose, The number of doppler channels is represented and, Representing the first of the Doppler domain transform matrices The data of the individual doppler channels, A doppler domain transform matrix is represented and, Representation of Is used for the matrix of units of (a), Represents Kronecker products between matrices, Represent the first The filtered clutter space-time snapshot data for each range gate, Respectively the azimuth angle and the pitch angle corresponding to the targets, Representing the space-time steering vector to which the target corresponds, Representation of Is a conjugate transpose operation of (a).

Description

Space-based radar clutter suppression method based on multi-domain cascade processing Technical Field The invention belongs to the technical field of radar signal processing, and particularly relates to a space-based radar clutter suppression method based on multi-domain cascade processing. Background The space-based early warning radar is core equipment for realizing all-day and all-weather rapid early warning on weak moving targets in wide area air and nearby space in the future, and has the strategic advantages of wide coverage, great power, anti-stealth and the like. However, as the platform runs in satellite orbit and the movement speed is extremely fast and is influenced by the rotation of the earth, the space-time coupling relation of clutter changes along with the distance unit, and the phenomenon is further aggravated by serious distance blurring, so that the clutter environment faced by the space-based radar in moving target detection presents extremely complex 'non-stable' characteristics, and the space-time self-adaptive processing performance of the direct transplanting airborne radar is rapidly deteriorated. As can be seen, clutter suppression is a central challenge in space-based radar systems. The prior space-based radar carrier suppression scheme mostly has the following key technical problems caused by non-stationarity clutter and serious distance blurring: 1) The problem of mismatch suppression caused by the fact that clutter space-time spectrum changes along with a distance unit is solved. The conventional classical space-time adaptive processing technology based on the stationarity assumption cannot adapt to the rapid change of the serious non-stationarity of the clutter spectrum, so that the estimated clutter covariance matrix is not matched with the real clutter covariance matrix, and the clutter suppression performance is obviously reduced. 2) The clutter suppression problem of the area with the most unsteady state, namely the area with the short-range severe distance blur, needs to be solved. The short-range region distance blurring effect compresses and superimposes clutter with different geographic incoherence and statistical properties into the same observation data. The superposition not only amplifies the nonlinear modulation effect caused by the yaw angle, but also brings the clutter environment with the most extreme non-stationarity, becomes a main area of failure of the existing algorithm, and severely restricts the detection capability of weak moving targets. 3) The system performance and reliability impact problems caused by clutter non-stationarity need to be solved. The complex strong fuzzy clutter seriously floods the weak moving target signal, and the detection capability of the radar under the strong clutter background is directly restricted. Meanwhile, mismatched clutter suppression can cause a large number of false alarms, so that radar output is unreliable, and decision efficiency is affected. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a space-based radar clutter suppression method based on multi-domain cascade processing. The technical problems to be solved by the invention are realized by the following technical scheme: the embodiment of the invention provides a space-based radar clutter suppression method based on multi-domain cascade processing, which comprises the following steps: Establishing a planar array space-based early warning radar clutter signal model; designing linear frequency modulation signals and phase coding signals of waveforms with different pulse widths; Designing a first waveform signal based on pulse width frequency modulation polarity agility and linear frequency modulation by changing the frequency modulation polarity of the linear frequency modulation signal, and designing a second waveform signal based on phase encoding, pulse width frequency modulation polarity agility and linear frequency modulation according to the phase encoding signal and the first waveform signal; designing an orthogonal waveform signal group related to the second waveform signal based on the minimized peak sidelobe energy criterion and by adopting an SQP algorithm; based on a planar array space-based early warning radar clutter signal model, clutter space-time snapshot data are calculated according to orthogonal waveform signal groups; designing a matched filter according to the orthogonal waveform signal group, and filtering clutter space-time snapshot data according to the matched filter; and adopting a 3DT-STAP algorithm, adaptively calculating a space-time two-dimensional filter weight coefficient of the 3DT-STAP according to the filtered clutter space-time snapshot data, and calculating a clutter suppression result according to the filtered clutter space-time snapshot data and the space-time two-dimensional filter weight coefficient of the 3 DT-STAP. The invention has the beneficial effects that: The inven