Airborne array aperture UWB UHF radar-motivation and system considerations

The paper discusses the necessity, feasibility and technology of FOPEN GMTI. It argues that this functionality may be one mode in a multi-function UWB UHF system, which jointly possesses the capabilities for air target MTI and high resolution FOPEN SAR. The radar platform may be a UAV or an aircraft, whereas it is proposed to use the push boom type of antenna mounting previously adopted with advantage for the CARABAS II UWB VHF SAR. Presently the push booms will hold a set of UWB UHF antenna elements. The paper relates GMTI to SAR, extended from imaging stationary ground to the 4-parameter set of targets in linear and uniform motion relative to ground. It is recognised that this extended imaging problem only depends on one new parameter viz. the SAR focusing velocity. The required signal processing may be tackled in an efficient manner by a hierarchical scheme based on iteratively merging subapertures and increasing the resolution. Rejection of stationary clutter and detection occurs on all the levels of increasing the resolution. The paper also provides a brief presentation of the Swedish FOA efforts to produce an experimental demonstrator of this multi-function radar system.