ADAPTIVE ATTENUATION OF CLUTTER AND JAMMING FOR ARRAY RADAR

Minimising clutter breakthrough while adaptively cancelling jamming is a recognised problem for radar, especially for airborne radar where g round clutter is distributed widely in direction and Doppler frequency . By adapting the angular gain of an array independently for each rang e bin and by adapting both the small and the large scale order of its weight function, it is shown that clutter can be reduced to levels wel l below what is possible for a conventional antenna and that the advan tage remains when jamming is cancelled at the same time. Separating th e spatial adaption into processes for different spatial scales enables the weights for an array of several thousand elements to be calculate d with a numerical workload similar to that for a sub-arrayed radar, b ut with improved clutter suppression ultimately deriving from access t o signals from individual array elements. The arguments are illustrate d by simulations for an airborne radar operating in a high pulse repet ition frequency mode.