Close direction of arrival estimation for multiple narrowband sources

In this paper, a simple method for the DOA estimation in the case of close angles is presented. By means of the spatial MUSIC, the problem of localizing multiple narrowband stationary signals impinging a uniform linear antenna array can be solved. Close direction finding based on such a noise subspace MUSIC estimator can however fail. The presented method resolve the close directions estimated initially from the spatial MUSIC. The refinement is done by examining the number of rising peaks with the rank of the Hankel matrix. Then, taking the inverse DFT and calculating the spectral MUSIC provide a better DOA estimate. Besides, a temporal-spatial frequency kernel is shown. Three simulation examples are given to demonstrate the improved DOA estimation in a situation of the source signals arriving so close.