Research On Heterogeneous Clutter Suppression Technique In Space-time Processing

When airborne radar detects ground and low-altitude moving targets,it usually works in the low-visibility state.Therefore,the strong ground clutter has a serious impact on the detection performance of radar system.Space-time adaptive processing(STAP)can solve the clutter suppression problem of airborne radar.In the practical application,the construction of STAP algorithm with low computational complexity and low data volume,namely,dimensionality reduction and rank reduction,and new STAP algorithm adapted to Heterogeneous clutter environment,are the research focuses of STAP technology at present.The research object of this paper is the clutter suppression method of airborne phased array radar,which mainly studies clutter heterogeneity,clutter compensation algorithm,sparse recovery method and space-time adaptive processing algorithm.The main contents of this paper are as follows.1.Research on space-time adaptive processing method.First,the paper gives the principle of the full-space time adaptive processing algorithm,and introduces the expressions of the optimal full vector and output SCNR of the adaptive filter.Finally,the paper compares the clutter suppression performance of several dimension-reducing STAP algorithms by using the output SCNR as a measurement index,and studies the effect of channel error and training sample number on the performance of STAP methods.2.Research on heterogeneous clutter suppression method based on clutter compensation.First,the paper establishs the clutter echo model of the system and analyses the clutter heterogeneous characteristics of different distance units at different drift angles.Then,the principle of two clutter compensation algorithms:the Doppler Warping(DW)and the Angle-Doppler Compensation(ADC),which can be used in the scene of non-side-looking radar is introduced.The clutter suppression performance of the DW algorithm and the ADC algorithm after compensation is simulated and analyzed in terms of the power spectrum and the output SCNR.3.Research on clutter suppression based on sparse recovery.Firstly,the basic principle of sparse recovery technology applied in STAP is introduced.Sparseness of clutter spatial time spectrum is analyzed,and spatiotemporal adaptive processing is transformed into optimization problem.Then the reason why a training data sample may lose its statistical characteristics is discussed,and the properties of angle-Doppler plane clutter are analyzed.A SR-STAP method based on linear regression technique is proposed in the scenario where the number of aVirginiailable training samples is limited to one.The clutter suppression performance of the SR-STAP method is simulated.4.Research on clutter suppression of airborne bistatic radar.Firstly,for analyzing the clutter heterogeneous characteristics of different bistatic radar scenarios,based on the geometric configuration of the bistatic radar and the equation of the bistatic radar,the clutter signal model of the bistatic radar is established.Then,the paper introduces the principle of Adaptive Angle-Doppler Compensation(A~2DC),and analyzes the influence of the size of the smoothing window on the Doppler phase estimation in the center of the clutter spectrum.Finally,by taking the output SCNR as the measurement index,this paper simulates the clutter suppression performance of the STAP method compensated by the A~2DC algorithm.