A deterministic direct data domain approach to signal estimation utilizing nonuniform and uniform 2-D arrays

A direct data domain deterministic approach utilizing a nonuniform array to adaptively estimate the signal strength of an incoming signal in the presence of strong jammers, clutter, and thermal noise is presented. This method is based on choosing a weighted difference of neighboring antenna outputs, based on the direction of arrival of the signal of interest, in such a way that only the unwanted components remain. These unwanted signals are then nulled by adaptive weights. These weights are then used to estimate the signal strength for a set of sampling time instants. This approach is suited for a highly changing environment, particularly in the presence of blinking jammers and where clutter characteristics change rapidly, provided the signal of interest does not change significantly during the observation interval. Two main deterministic approaches are presented - one based on the solution of a generalized eigenvalue problem, the other based on the solution of a set of linear equations utilizing the conjugate gradient method. These methods are applied to nonuniform as well as uniform 2D arrays, and the results are compared.