New autofocusing technique for SAR images based on the Wigner-Ville distribution

High resolution images can be obtained with synthetic aperture radars, by exploiting the motion between the aircraft carrying the radar and the observed scene, if the relative motion parameters are known exactly. There exist some techniques for estimating these parameters from the collected data, but only for specific cases (linear and quadratic phase error). A technique for compensating phase errors whatever their time variation is proposed. The proposed technique is based on a joint time-frequency analysis of the received signal, carried out using the Wigner-Ville distribution.