Underdetermined DOA Estimation for Coherent Signals With Moving Sparse Circular Array

With a small number of array elements and the mutual coupling effect, direction of arrival (DOA) estimation for coherent signals will suffer from performance degradation, in underdetermined scenario. To solve the problem, this paper proposes a sparse uniform circular array (SUCA) on moving platform for mutual coupling reduction, and then employs a sparse signal reconstruction method for underdetermined DOA estimation of coherent signals with single snapshot. There is a systematic procedure to determine the inter-element spacing of the original SUCA and number of shifted SUCAs for the synthetic UCA, to achieve more degrees of freedom (DOF) than the number of elements. The construction of mutual coupling matrix is investigated to demonstrate the lower mutual coupling in the synthetic array. On the basis, the underdetermined DOA estimation of coherent signals is performed by using the sparse signal reconstruction method. Simulation results are given to illustrate the superiority of the proposed array in terms of DOF enhancement and mutual coupling reduction.