2-D DOA Estimation of Coherent Wideband Signals with Auxiliary-Vector Basis

We develop a two-dimensional (2-D) direction-of- arrival (DOA) estimation scheme for coherent wideband source signals using coherent signal subspace method based auxiliary-vector (CSSM-AV) basis. Computation of the basis is carried out by a modified version of the orthogonal CSSM-AV filtering algorithm. The proposed method reconstructs the signal subspace using a cross-correlation matrix after which the modified CSSM-AV algorithm is employed to estimate the azimuth and elevation angles. Then, successive orthogonal maximum cross- correlation auxiliary vectors are calculated to form a basis for the scanner-extended signal subspace. This technique is very efficient in reducing the algorithm complexity. Since it does not require that the eigenvectors be determined in order to find the signal subspace and yields a superior resolution performance for closely spaced sources even when the number of samples is low. Specifically, the complexity of the proposed 2-D DOA estimation algorithm compared to the CSSM algorithm is more favorable when the number of signals arriving on the antenna element is much less than the number of antenna elements. Performance evaluation shows that the proposed method outperforms competing methods such as CSSM, TOPS and WAVES algorithms in terms of estimation error, probability of resolution and number of sample support for a given SNR in scenarios in which many sources are present in the system, the array size is large, and the number of samples is small.