Multiple source location-the signal subspace approach

The multiple source location problem is solved for a general array geometry using the principal of least-squares modeling. The incident wavefields may be a mixture of coherent and noncoherent sources that are broadband and/or narrowband. Furthermore, the wavefields may be plane waves and/or spherical waves. An effective algorithmic approach is developed for solving the multiple source location problem in the signal and covariance domains. In each domain, it is necessary to represent a set of vectors as a linear combination of array steering vectors. Using this property, a generic descent algorithmic approach is developed for estimating the wavefield directions of arrival. The success of such iterative approaches is critically dependent on the generation of good estimates to initialize the algorithm. An effective initialization procedure is developed for this purpose. Direction-of-arrival estimates which arise from the proposed procedure are empirically found to be unbiased and low variance