Research On Spatial Spectrum Estimation Technology Based On Sparse Array

Compared with uniform array,sparse array can effectively enlarge the aperture of array and improve the accuracy and resolution of DOA estimation under the same number of elements.Therefore,array optimization and sparse array spatial spectrum estimation technology have attracted increasing attention of researchers.In this paper,DOA estimation and genetic algorithm are analyzed.The sparse optimization of arrays using genetic algorithm is mainly studied.The DOA estimation of sparse arrays and the optimization algorithm of de-ambiguity and sidelobe level are proposed.The main work of this paper includes:1.The related knowledge of DOA theory and classical representative algorithms are studied,and the common spatial spectrum estimation array signal models based on uniform arrays are summarized.2.The principle and implementation of genetic algorithm(GA)are studied.The flow chart of GA is introduced.The function extremum is simulated by GA,which embodies the advantages of GA.3.The process steps to optimize the sparse structure of array antenna using genetic algorithm(GA)are proposed,and the fitness function with minimum relative sidelobe level is constructed.Through simulation,the aim of reducing antenna array elements,reducing cost,preventing grid lobes and obtaining low sidelobe pattern is achieved.When the sidelobe level of circular array is sparse,it is found that the sidelobe level of circular array does not decrease significantly.The sidelobe level of circular array is further reduced by combining genetic algorithm with other algorithms.The simulation results show that the combination of genetic algorithm and phase-amplitude method has the lowest sidelobe level and higher convergence efficiency under the same number of iterations.4.The related technologies of DOA estimation are studied,including the DOA estimation method based on l1_SVD sparse signal reconstruction.The simulation shows that it has the advantage of high accuracy in the case of low signal-to-noise ratio.In this paper,a MUSIC method based on semi-circular matrix is proposed to remove DOA ambiguity,which can effectively remove trivial and non-trivial ambiguities.The factors affecting the performance of DOA estimation are analyzed,and the correction method of element position error is proposed.