Partly-Filled Nonuniform Linear Arrays for DOA Estimation in Multipath Signals

The partly-filled nonuniform linear arrays (PFNLA) are presented and the DOA estimation problem for multipath signals is investigated. A new approach is proposed for DOA estimation in nonuniform linear arrays (NLA) based on array interpolation. A Wiener formulation is used to improve the condition number of the mapping matrix as well as the performance for noisy observations. An initial DOA estimate is obtained by using the uniform part of the PFNLA. This initial estimate is used in array interpolation and a new covariance matrix is found which improves the DOA estimation significantly. Noniterative and iterative algorithms are developed for the DOA estimation in multipath. The proposed approach overcomes some of the limitations of the conventional array interpolation. It is shown that the DOA performance is close to the CRB and the method is robust for a variety of source and DOA scenarios.