Dual Channel Adaptive Antenna Nulling with Auxiliary Selection for Spaceborne Radar

A doubly adaptive scheme is proposed for detection and jammer cancellation by spaceborne radar, characterized by a dual receiving channel scheme. Generally many auxiliary antenna elements are required to protect a radar with a high gain antenna without tapering, from a single jammer with generic direction of arrival. However, assuming a slowly changing jamming scenario, we show that it is possible to apply first an adaptive selection of the best auxiliary element, and then to apply an adaptive scheme for jammer cancellation and target detection using only two receiving channels, connected respectively to the main antenna beam, and to the best selected auxiliary antenna beam. This paper characterizes the performance of this approach, together with its limitations.