Clutter Compensation for Space-Air Bistatic Radar Based on Unitary Subspace Transformation

Since the space-air bistatic radar (SABR) system works in down-looking mode, it encounters a severely broadened clutter spectrum and the clutter is range dependent. Thereby diminishing the performance of space-time adaptive processing (STAP) technology through covariance matrix estimation error. It is necessary to perform clutter compensation before STAP clutter suppression. Inspired by the thinking of coherent signal subspace method for estimating the directions of arrival of wideband signals, we propose the range dependence compensation method which transforms the clutter subspace of training samples into the clutter subspace of reference range bin by unitary matrix transformation. Simulation examples are conducted to validate the effectiveness of the proposed algorithm.