Research On Off-Grid Direction-of-Arrival Estimation Algorithm For Coprime Array

As an important part of array signal processing,direction-of-arrival(DOA)estimation has been widely applied in radar,wireless communications,biological detection and other areas.Among the array structures used by the DOA estimation,the coprime array has received extensive attention in recent years by researchers because it can break through the degree-of-freedom limited in uniform linear array.In this paper,based on the coprime array,several DOA estimation algorithms are proposed in an off-grid manner.The main contents of the paper are listed as follows:1.Firstly,the receive signal model of the uniform linear array and the coprime array are studied,and their performance comparison is carried out.At the same time,we also introduce two kinds of traditional super-resolution DOA estimation algorithms.2.Secondly,based on the equivalent received signals of the coprime virtual array,the degree-of-freedom can reach up to O(MN)with M+N-1 physical sensors.On this basis,two new DOA estimation algorithms in an off-grid manner based on Vandermonde decomposition and ESPRIT algorithm are proposed,respectively.The peak response in spatial spectra of the both algorithms can represent the power of each source in the meantime.The simulation results demonstrate that,both algorithms show the advantages in estimation accuracy and computational complexity.3.Finally,a DOA estimation algorithm based on the Toeplitz matrix reconstruction of interpolated coprime virtual Array is proposed for the shortcomings of the classic algorithms which can not use all the information provided by the coprime array received signals.The algorithm reconstructs the interpolated virtual array covariance matrix in the Toeplitz structure constraint of the non-uniform virtual array for using the degrees of freedom provided by the coprime array completely.On the basis of this,DOA estimation can be performed by the Vandermonde decomposition algorithm.