Research On DOA Estimation Algorithm Based On Short Snapshots

The research foundation of the traditional DOA estimation algorithm is the data from a large number of snapshots.In the field of practical application,however,it is very difficult to obtain ideal data from a large number of snapshots because of the need of real-time processing.Therefore,the research of the DOA estimation algorithm based on short snapshots even a single snapshot is very important and valuable.This paper mainly studies the DOA estimation algorithm of short snapshots.In order to solve the problem that the MUSIC algorithm can't be used in the case of single snapshot,an improved MUSIC algorithm for single snapshot which is called ISS-MUSIC is researched in this paper.This algorithm improves the performance of classical MUSIC algorithm,and it combines the method of constructing pseudo-covariance and the method of conjugate enhancement.The advantage of the ISS-MUSIC algorithm is that it can be used in the case of single snapshot.Meanwhile,its performance outperforms the method of single snapshot MUSIC algorithm based on pseudo-covariance without enhancing conjugate.To solve the problem of computational complexity,an algorithm called ISSPCM is researched in this paper.It improves the MUSIC algorithm and the pseudo covariance matrix algorithm in the field of computational complexity.This algorithm combines the method of constructing pseudo-covariance matrix and the method of Propagator.The advantage of the ISSPCM algorithm is that it can be used in the case of single snapshot.Meanwhile,the computation complexity of it is smaller than the improved MUSIC algorithm based on pseudo-covariance matrix without Propagator.To solve the problem of short snapshots in the case of wideband signal,a DOA estimation algorithm for frequency agile signal based on short snapshots which is called ISSFAS is firstly researched in this paper.This algorithm combines the method of constructing pseudo-covariance matrix and the method of frequency domain focusing,and it uses the pseudo covariance matrix which is newly built to replace the covariance matrix and uses the method of frequency domain focusing to deal with the problem of changing frequency.The research results show that the ISSFAS algorithm has good performance of DOA estimation,and it can super resolute in the case of short snapshots.Meanwhile,its performance outperforms the case without pseudo-covariance matrix.At the same time,to solve the problem of the array placement of wideband signal,a method called minimum redundant array based on several-levels is researched on the basis of minimum redundant array.This method can deal with the problem of the DOA estimation of wideband signal on the condition of fixed array number and fixed minimum element interval using the method of sparse representation,and it has good performance.