Specific 2-D spectral estimation for wideband beamforming

The potential of a two-dimensional spectral estimation approach to the problem of DOA (direction of arrival) estimation in wideband array beamforming problems is presented. It is shown that the covariance or interspectral matrix does not provide an adequate starting point in order to coherently average the energy of a given source. Angle focusing is envisaged from a prior two-dimensional spectral density. From this prior estimate, basic DFT interpolation may be used to obtain an angle/frequency representation of the wavefield, where source focusing can be done without requiring ad-hoc transformations. The viewpoint of the wideband DOA estimation problem states more clearly the potential, objectives, and fundamental limitations of focusing methods which are carried out at the interspectral matrix level or at the two-dimensional spectral density level