Two-Dimensional DOA Estimation of Coherent Signal Exploiting the Motion of Parallel Array

Non-uniform arrays can achieve larger array apertures and estimation accuracy compared to uniform arrays with the same number of elements. However, the non-uniform spacing between array elements poses a challenge for applying classical spatial smoothing methods and similar techniques to achieve coherent signal angle estimation. In this paper, we leverage array motion to achieve signal decorrelation, facilitating accurate estimation of two-dimensional (2-D) angles for coherent signals. First, by exploiting the motion of a parallel coprime array, we construct a new cross-covariance matrix (CCM), which can be vectorized to obtain the difference coarray even with coherent signal, and can transform the 2-D angle estimation into one-dimensional (1-D) angle estimation at the same time. Second, with the vectorized CCM, an off-grid sparse representation approach, coupled with joint sparse recovery technology, is considered to obtain accurate angle estimation. In contrast to the existing approach, the proposed method can conduct 2-D angle estimation without requiring prior knowledge of the source count, which makes it more applicable in practice. The validity and superiority of the proposed method are confirmed through simulation.