Quadratic estimators of the frequency-wavenumber spectrum
M.P. Clark, Louis L. Scharf, C.T. Mullis · 1991
A general representation is presented for quadratic estimators of the far-field frequency-wavenumber spectrum. The quadratic estimators are constructed from linear transformations of the array data. These linear transformations contain the windows normally associated with multiple window spectral estimators and act as multidimensional baseband beamformers. It is the selection of these windows that is most important in the design of quadratic spectral estimators. A discussion is presented of the two dimensional periodogram and the two dimensional Thomson (1982) estimator as prototypical examples of quadratic estimators.>