AUTOFOCUSING OF SAR IMAGES BASED ON THE PRODUCT HIGH-ORDER AMBIGUITY FUNCTION

An autofocusing technique is proposed, based on the modelling of the i nstantaneous phase, induced by the relative radar/target motion, as a generic order polynomial and on the estimation of the polynomial coeff icients by the so-called product high-order ambiguity function. The pr oposed estimation method is able to deal with multicomponent signals a nd is robust against model order mismatching, provided that the select ed order is greater than the true order. The proposed method is compar ed with the phase gradient autofocusing method, and applications are p resented of focusing of extended scenes and detection and imaging of m oving targets.