2-D Wideband DOA Estimation with Circular Arrays Based on the Difference Co-Array Concept

Two-dimensional (2-D) direction of arrival (DOA) estimation with a circular array based on the difference co-array has attracted considerable attention in past years. In this paper, the difference co-array position set of a circular array with arbitrary sensor arrangement is derived, and condition under which the maximum number of virtual co-array sensors can be provided by a circular array is presented. Then, an augmented uniform circular array (AUCA) is proposed, providing the maximum number of DOFs for arbitrary number of physical sensors. Compressive sensing based focusing method for the one-dimensional case is extend to 2-D wideband DOA estimation, where focusing on the difference co-array is adopted for performance improvement. Simulations show that better performance can be achieved by our proposed AUCA.