DOA Estimation Method with the Distributed Nested Array

In this paper, we investigate the problem of direction of arrival (DOA) estimation in phased-array radar. The array consisting of two separated nested subarrays with dual baselines is used to form the DOA problem. And we present a new DOA estimation method, called weighting signal subspace MUSIC method (WSSMUSIC). By designing the separated nested array and using Khatri-Rao product processing, a large number of virtual array apertures are extended. With the redundancy removal and spatial smoothing, the rank of covariance matrix is restored. The short baseline within subarray yields non-ambiguous coarse DOA estimation by WSSMUSIC. Then the long baseline between subarray yields high accuracy and non-ambiguous DOA estimation by WSSMUSIC searching peak in search region which is determined by coarse DOA and main-lobe region. The virtual extension of aperture can be achieved for this array without increasing the number of sensors and computational complexity compared with traditional uniform linear array. And the proposed algorithm gives significant improvement in DOA estimation performance. The simulation results validate the theoretical algorithm.