Research On DOA Estimation Of Sparse Arrays

Direction of arrival(DOA)estimation is an important part of array signal processing.It is widely used in radar positioning,electronic reconnaissance and communication.Compared with uniform array,sparse array can make the whole system cost minimum on the basis of satisfying measurement accuracy,so it has important research significance.The purpose of this thesis is to improve the accuracy of sparse array DOA estimation,improve the speed of sparse array DOA estimation and reduce the complexity of the system.The main work of this thesis is as follows:Firstly,this thesis introduces the antenna array structure and signal reception model commonly used in DOA estimation of array signals,and simulates and analyzes two classical subspace decomposition MUSIC and TLS-ESPRIT algorithms.Secondly,this thesis applys MUSIC algorithm to sparse array DOA estimation,arranges array element according to the Sunzi theorem as an example of sparse array.In view of the MUSIC algorithm spectrum peak search has the problem of large amount of calculation,this thesis puts forward the sparse array DOA estimation method based on improved MUSIC.This thesis applies niche genetic algorithm to MUSIC spectrum peak search,which effectively reduces the computational amount of searching spectral peak.Simulation shows that the algorithm still has better estimation precision under low SNR.Then,based on the matrix completion theory,this thesis proposes a variable threshold fixed point continuation algorithm to solve the problem of long running time of fixed point continuation algorithm.By improving the threshold parameters of the algorithm,the operation speed of the algorithm is effectively improved.Finally,aiming at some array element have random loss of or damage in the sparse array,this thesis applies the theory of matrix completion to sparse array DOA estimation.The thesis analyses the two different methods: sparse array DOA estimation method based on the snapshot completion and based on the Toeplitz matrix completion,the simulation results show that through the matrix completion,the precision of sparse array DOA estimation can be effectively improved.