Comparison of Bistatic Clutter Mitigation Algorithms for Varying Geometries

Airborne bistatic radar systems require effective techniques to mitigate the impact of ground clutter returns on detection performance. Bistatic clutter generally appears more severe than in monostatic systems owing to increased two-way antenna gain over a broad set of angles and greater clutter spectral variation over range. Adaptive filtering seems like a natural response to combat both of these effects. However, the consequent clutter non-stationarity - variation of clutter angle-Doppler response with range - presents difficulty when implementing the adaptive filter, since such an effect leads to errors in the requisite clutter covariance matrix estimate. Approaches for coping with clutter non-stationarity are central to effective bistatic space-time adaptive processing STAP techniques. In this paper we consider the impact of sensor geometry on the performance of several recently proposed bistatic STAP techniques. Our findings suggest best performance for those methods providing pre-STAP compensation of the data in both angle and Doppler.