Two-dimensional DOA estimation with an improved spatially separated electromagnetic vector sensor array

Two problems exists in direction of arrival (DOA) estimation using the existing spatially separated electromagnetic vector sensor (SS-EMVS). One is that the existing algorithm for SS-EMVS is disabled when there is no temporal rotational invariance of the incident signals. The other one is that the existing SS-EMVS can not extend the two dimensional (2D) array apertures, which leads to poor 2D DOA estimation accuracy. Based on these reasons, an improved SS-EMVS array is proposed. Firstly, the 1D direction cosine-estimation can be obtained via the spatial rotational invariance offered by the proposed array instead of temporal rotational invariance. Secondly, the other dimensional direction-cosine can be obtained by the combination of the vector-cross product estimator and the conventional interferometry method. Finally, the 2D DOA can be obtained by the trigonometric operation on the obtained 2D direction-cosine. The proposed algorithm is independent of the incident signals forms and greatly improves the 2D DOA estimation accuracy because of the utilization of array apertures extension. Simulation results verify the effectiveness of the proposed algorithm.