Adaptive Space-Time Radar Techniques and Waveforms

The problem is to improve airborne maritime radar detection of small moving targets in clutter, where the clutter varies with time, range, azimuth, sea state, grazing angle, wind speed, and the look direction of the radar relative to the wind direction. A new version of space-time adaptive processing (STAP) is applied to the problem. The new technique provides improved covariance estimation for interference suppression (adaptive whitening) and for environmentally adaptive detection. Signal-filter design techniques are generalized to maximize signal-to-interference-plus-noise ratio (SINR) by adjusting the sidelobe levels of a generalized signal-filter ambiguity function that depends on range, Doppler, and azimuth. Differences between the target and clutter impulse response are used to enhance detection. Post detection processing is used to detect extended targets.