An Ambiguity-Solving Method for DOA Estimation with Unfolded Co-prime Arrays

Direction-of-arrival (DOA) estimation with unfolded co-prime linear arrays has been investigated thanks to the large aperture, excellent performance, and full degrees-of-freedom (DOFs). Besides, it has been admitted that the ambiguity problem can be suppressed thanks to the co-prime property. However, it is not always true. In some specific cases, ambiguities would still be found at the angles of which the corresponding directional vectors can be represented as linear combinations of the directional vectors of the true DOAs. In this paper, this ambiguity problem is discussed, and an ambiguity-solving method is proposed. Compared to the original method, the proposed method contains all the advantages of unfolded co-prime linear arrays, and can solve the ambiguity problem successfully and efficiently. Numerical simulations are given to show the reliability and robustness of the proposed ambiguity-solving method.