Reduced-rank terrain scattered interference mitigation

Radar systems are particularly vulnerable to the interference produced by jammer multipath reflections known as terrain scattered interference (TSI) or hot clutter. This interference is due to the diffuse scattering of jammer energy off large patches of terrain and consequently is present over large angular regions and large range intervals. Cancellation methods attempt to exploit the temporal correlation present in the TSI by using a large number of temporal taps. However, the adaptive degrees of freedom typically required for cancellation to the noise floor tend to be very large, motivating the investigation into various rank reduction strategies. In this paper we look at various methods of reducing the computational complexity of the canceller while maximizing the cancellation achieved. The canceller used is based on a beamspace transformation that is shown to yield certain advantages for rank reduction purposes. Results are demonstrated on experimental data collected as part of the Navy/ARPA Mountaintop program.