TABLE OF CONTENTS Peter G. Richardson
Since the early 1970s, STAP (space time adaptive processing) methods have been actively considered for look down airborne radar where target signals have to compete with strong ground clutter returns. Most previous STAP research has been devoted to SLAR (sideways looking airborne radar) applications where the plane of the receiving antenna is coaligned with the direction of travel. For this type of antenna configuration, a linear relationship between the angular location and Doppler frequency of the clutter can be exploited to allow clutter rejection and enhanced signal detectability via two-dimensional filtering in the spatial and temporal frequency domains. Appropriate filters can be realised via the sampling of a coherent pulse train with a phased array antenna. Non-adaptive filter weight solutions which theoretically achieve full clutter suppression in SLAR correspond to the well known DPCA (displaced phase centre antenna) technique, e.g. see References 1 and 16. STAP offers the advantage over DPCA that the filter weights are calculated adaptively. This leads to robustness in the presence of errors, e.g. amplitude and phase mismatch errors between channels, or drift in the platform velocity. STAP also offers the capability to simultaneously suppress jamming and clutter.
Over the last...
