Tracking Swerling fluctuating targets at low altitude over the sea

Accurate tracking of targets flying at low altitudes above a smooth surface is difficult because of the surface reflection. The authors propose a solution based on deterministic physical modeling of the specular multipath and the maximum likelihood (ML) method. The techniques are described, the Cramer-Rao (CR) bounds derived, and the results of performance studies presented including comparison with classical Fourier beamforming. Experimental results obtained with two X-band experimental systems over sea conditions varying from sea state zero to sea state three are presented