Resolving ambiguities in DOA estimation by optimizing the element orientations

A method of resolving ambiguities in direction-of-arrival (DOA) estimation for sparse linear arrays with directional antennas is reported. The DOA estimation ambiguity comes from the linear dependence among the array manifold vectors of different DOAs. Optimizing the element orientations can break down the linearity. The element orientations are optimized by using particle swarm optimization (PSO) algorithm with the Weiss-Weinstein bound (WWB). This method is demonstrated through simulations of a 5-element collinear array of dipole antennas.