Ambiguity Resolution Technology for Direction of Arrival Estimation in UCAs

When the radius of the uniform circle array(UCA)is larger than half wavelength,the accuracy of direction finding(DF)will be reduced due to ambiguity.To solve the problem,a novel method is proposed,in which some element in UCA is modified as the small-radius element,for the purpose of breaking the balance achieved when the steering-vectors generated by the false and true angle in direction of arrival(DOA)estimation are completely equal.The method can restrain the false peak.With virtual array transformation applied,the method can be implemented without changing the actual UCA’s structure.The simulation result proves that the proposed method can effectively restrain the false peak and realize the accurate DOA estimation in the planar array with larger radius.