Coherent signal-subspace focusing to frequency dependent modeling for DOA estimation of wide-band sources

In this paper a new method of direction of arrival (DOA) estimation of wide-band sources by coherent signal-subspace focusing to frequency-dependent modeling (CSSFDM) is proposed. The coherent signal-subspace (CSS) was proposed by H. Wang and M. Kaveh in 1985. Its key point is the focusing which maps the signal subspaces of the narrow-band components of the wide band onto a single signal subspace. Y. Grenier set up a frequency-dependent model (FDM) by introducing the basis of frequency into array signals to directly process wide band signals in 1994. We present a new method that combines CSS and FDM, and construct its focusing matrix. Because of extending the order of the covariance matrix of array signals and presenting effectively noise subspace by FDM, the new method shows the better performance than CSS. By means of focusing, it reduces obviously computational complexity of the spatial spectrum of FDM. The effectiveness of the new method is confirmed by computer simulation.