Research on the wideband DOA estimation with test of orthogonality of subspace based on beamspace

The direction-of-arrival (DOA) can be estimated by measuring the orthogonal relation between the signal and the noise subspaces of multiple frequency components of the wideband signal with Test of Orthogonality of Projected Subspace (TOPS) algorithm. This algorithm largely depends on estimation of signal subspace of the reference frequency; therefore, it has some shortcomings such as more fake peaks, poor performance under low SNR and so on. To avoid these problems, a new direction of arrival (DOA) estimation method for wideband sources based on beamspace is proposed in this paper. In the proposed method, the array receiving data is firstly transformed to beamspace by beamspace transformation, and then the decision vector can be constructed by the orthogonal relation between the noise subspaces and steering vector of multiple frequency components of the wideband sources in beamspace, finally, the DOA can be estimated by searching the maxima of the pseudo spatial spectrum according to decision vector. The new method does not require initial focusing angles and avoid the fake peaks that often appear in TOPS algorithm. At the same time, the new method reduces not only the SNR resolution threshold but also the computational burden so that it has better performance than TOPS algorithm. Applying the method on a uniform linear array and circular array respectively, simulation results and sea-experiment demonstrate the effectiveness of the proposed method by comparing it with some wideband DOA estimation methods.