Research On DOA Estimation Of Coprime Matrix Based On High-order Statistics

In the field of array signal processing,DOA estimation has attracted much attention because of its wide applicability.With the continuous development of research and the improvement of technical standards,the performance of DOA estimation algorithm is increasingly required.Based on the in-depth study of the existing high-resolution DOA estimation algorithm and its improved algorithm,this paper focuses on the high-resolution DOA algorithm with low signal-to-noise ratio(SNR)and few samples.At the same time,a novel array structure based on mutual prime array is proposed.Finally,a feasible concept based on high-order statistical expansion is proposed for the non-uniform linear matrix model.The main work of this paper is as follows:1.To solve the problem of performance degradation of classical DOA estimation under low signal-to-noise ratio(SNR)environment,a new DOA estimation method is proposed by combining high-order statistics and expectation maximization(EM)algorithm.At low SNR,the proposed algorithm has excellent estimation performance,good stability and resolution,and is advantageous for estimating the direction of arrival of signals with high resolution.2.Based on the sparse linear array theory,a three-element co-prime array composed of three groups of uniform submatrices is proposed.Additionally,we generalize the methods of DECOM and music to ternary co-prime array.When the array length is the same,the new type of co-prime array can realize DOA estimation with higher resolution,less computational complexity and more degrees of freedom than the co-prime array and extended co-prime array.At the same time,the general structure of multi-element mutual-prime array is put forward and its rationality is verified.3.Consider introducing high-order statistics into non-uniform linear matrices,and briefly derive the DOA estimation algorithm of high-order statistics based on simple and extended co-prime array.For the simple co-prime array,the fourth-order cumulant expansion is introduced into the MUSIC algorithm of the uniform sub-array.For extended co-prime array,the virtualized covariance matrix is obtained by using the fourth-order cumulant extension,and then the subspace algorithm is used to estimate the direction of arrival.