Modal decomposition signal subspace algorithms

A new method of estimating the locations of multiple wide-band emitters arriving at an array of sensors is presented in this paper. The wide-band emitter location problem is treated as a separable multidimensional spectrum estimation problem by modal decomposition of the estimated spectral factor or spectral density matrix at the poles of the emitters. This modal decomposition method extends conventional sinusoidal separation approaches to wide-band emitters. Several methods of modal decomposition are presented and the signal subspace approach of Schmidt [2], and Su and Morf ([3], [4]), is extended and applied to the decomposed spectral residues for determination of emitter locations. The method is asymptotically exact and provides the capability to resolve correlated or even coherent emitters.