The Study And Software Implementation Of MIMO Radar Target Fast Reconstruction Method Under Ill-posed Sensing Matrix

MIMO radar is a new radar system in recent years.The waveform diversity technology is utilized to improve significantly resolution of targets,and the parameter identification ability for radar system can be enhanced.Compared with traditional radar,MIMO radar has great advantages in parameter estimation,noise suppression and anti-jamming ability.Only very few signal sampling values are needed for Compressed Sensing to reconstruct the sparse signal accurately.The targets echo signal of MIMO radar is sparsely.Then compressed sensing can be applied to the reconstruction of MIMO radar target signal.However,the sensing matrix of MIMO radar is seriously ill-posed,which causes compressed sensing algorithms fails to reconstruct the target signal effectively.Aiming at the above-mentioned problems,the following research work is carried out in this paper.The main contents of paper is summarized as follow.(1)Because of the ill-posed sensing matrix,the smoothed l0norm(SLO)algorithm fails to estimate target parameter in multiple input multiple output(MIMO)radar.To solve this problem,the truncated modified smoothed l0norm algorithm for MIMO radar is proposed.Based on the truncated singular value decomposition algorithm(TSVD),the retained singular values of sensing matrix are divided into the larger and smaller by the selected truncated threshold.Then,the two groups of the singular values are modified by using different modified criterion.From the modified singular values and the corresponding left and right singular matrix,the SVD inverse transform is utilized to obtain a non ill-posed sensing matrix.Finally,the SLO algorithm can be used to reconstruct the target signals in the MIMO radar by take advantage of the obtained non ill-posed sensing matrix.Therefore,the target parameters can be fast estimated with high accuracy for MIMO radar.(2)In order to solve the poor approximation performance of Gauss functions and the problem of "jagged phenomenon" during the iterative process,a smoothed l0 norm algorithm based on modified approximate hyperbolic tangent function is proposed in this paper.Firstly,a modified approximate hyperbolic tangent function with better approximation performance is proposed to approximate the l0norm.Then,a sparse problem model for MIMO radar based on the function is established.And a Newton method is utilized to solve the extreme value problem.Therefore,the accurate reconstruction of MIMO radar target signal can be realized by the proposed algorithm.(3)The software development of MIMO radar target fast reconstruction is realized mainly by LabVIEW.The innovation of software development lies in the realization of the flexible combination for Lab VIEW and MATLAB.Their advantages in interface design and programming operation are fully realized.Then the 3D estimation map of the target is displayed on the LabVlIEW interface,and the development of test software is completed.