DOA Estimation for Coherent and Incoherent Sources Based on Co-prime Array

In this paper, a DOA estimation method based on co-prime array is proposed to resolve the coherent and incoherent hybrid sources. Firstly, with respect to the difference co-array of co-prime array, the desired units with corresponding contiguous intervals in the correlation matrix are extracted and rearranged into an augmented correlation matrix. Then we decorrelate the augmented correlation matrix by reconstructing matrix algorithm, forward spatial smoothing and forward-backward spatial smoothing algorithm. Finally, through MUSIC spatial spectrum searching on the basic of the decorrelated correlation matrix, DOA estimation towards sources is obtained. The simulation results show that the proposed method can achieve DOA estimation of the coherent and incoherent hybrid sources with more number than physical array. Through comparison, it can be concluded that the reconstructing matrix algorithm obtains a larger number of distinguishable sources and the error performance of which is better under low SNR. However, the spatial smoothing algorithms have a better estimation error performance in the case of low snapshot.