Improved two-dimensional DOA estima-tion of Non-circular Signals for Parallel Sparse Array

In this letter, an extended virtual array based on sum-difference co-array (SDC) of parallel sparse array (PSA) is derived, which have more Degrees-of-freedoms (DOFs) than the conventional virtual array only based on difference co-array (DC), for two-dimensional (2-D) direction of arrival (DOA) estimation of non-circular (NC) signal. Specifically, be placing two subarrays symmetrically with the coordinate axis, the com-plex joint three-dimensional (3-D) problem of 2-D DOA and one-dimensional (1-D) NC phase is simplified to two 1-D problems, which greatly reduces the computational complexity and improves the accuracy of results. At end, the effectiveness and superiority of the proposed algorithm are validated by numerical simulations.