DOA estimation based on a modified spatial spectrum

A novel direction of arrivals (DOAs) estimation method based on a modified spatial spectrum is proposed in this paper, which can be used for the source number and DOAs estimation of the weak signals in the presence of the strong interferences. First, the eigenvectors of the spatial covariance matrix is sorted according to the descending order of the eigenvalues. Then, the modified spatial spectrum of each eigenvector is estimated in turn based on the projection features and orthogonal features. Finally, whether there is a signal source or not is judged by the ratio of the maximum value of the spatial spectrum to the mean value of the sidelobes, and the DOA of the signal is obtained by the angle corresponding to the maximum value. The method does not require the angle information of strong interferences. Simulation results demonstrate the effectiveness and the superiority of the proposed method.