Wide area surveillance concepts based on geosynchronous illumination and bistatic UAV or satellite reception

The authors describe and evaluate in this paper the performance of a space-based radar surveillance concept employing geosynchronous illumination and bistatic reception-with either unmanned airborne vehicles (UAVs) or low-orbit satellites as reception platforms. Two classes of surveillance are considered: that of aircraft targets (generically designated as "airborne moving target indication" or AMTI) and that of slow-moving ground targets (generically designated as "ground moving target indication" or GMTI). While the bistatic concepts are hardly new, it is our conclusion, based on design examples presented here, that the emergence of high-speed processing to support large-scale beamforming for AMTI, and MTI-SAR for GMTI, have made these approaches feasible with the result of substantial cost and performance advantages over more conventional monostatic approaches when only limited regions (i.e. one or two theater-sized areas) need to be covered at any one time. MTI-SAR represents moving target indication achieved by matching an ensemble of possible target phase histories using radar processing techniques similar to those employed in synthetic aperture radar (SAR) for fixed targets. Continuing improvements in processing and space component technology, beyond the assumed implementation date of 2010, may increase this advantage of bistatic system surveillance.