Subband STAP in wideband radar systems

The detection of moving targets, both airborne and ground-based, is enabled by ground clutter mitigation using space-time adaptive processing (STAP). As technological advances make it possible to perform wide bandwidth processing and future systems require high resolution for target identification, the need has arisen for the effective implementation of wideband STAP. In order to prevent the deleterious effects of dispersion for wideband systems, STAP is performed in subbands, which is also computationally more efficient than full bandwidth STAP. The separate, independent adaptive processing in the individual subbands, however, introduces complications that must be addressed in order to maintain desired performance. These issues are unique to subband STAP, namely, target Doppler dispersion across subbands and range sidelobe levels following subband recombination. In each case, we identify the cause of the problem and propose an effective solution. Throughout this paper, we focus on practical solutions that are tractable and do not require an inordinate amount of computation.