Linear constraints in hot clutter cancellation

This paper addresses the use of adaptive array signal processing in airborne radar systems to remove terrain-scattered interference, or hot clutter. Mitigation of terrain scattered interference in airborne radar systems involves cancellation of reflections from a multiplicity of ground reflector locations each having potentially different directions of arrival, time delay, and Doppler. This paper presents a specific methodology for the use of a space-time adaptive processor in which successive time samples from each sensor output are combined adaptively. Multiple constraints are employed to ensure that the desired signal characteristics are maintained. The approach presented achieves effective elimination of hot clutter while simultaneously either maximizing the signal-to-noise ratio of the desired signal or to providing a distortionless time estimate of the signal. Examples are presented using recorded data from the Mountaintop Program to illustrate the effectiveness of the proposed approach and to show comparisons with previous approaches