Optimal processings design for synthetic aperture radar

摘要

Synthetic aperture radar (SAR) is a microwave imagery system capable ofproducingudhigh resolution images by processing properly data collected by a relativelyudsmall antenna.udIn this papet the bi-dimensionnal received signal, using spatial coordinates, isudformulated. The image is reconstructed by a two- dimensionnal filtering operationud. We propose a straightforward derivation for the coherent sommation methodud(or bock-projection of range responses) and the 2-D azimuth matched filtering .udThe image quality is determined by that of the ambiguity fonction. This latter isudanalyzed and optimized for two performance criteria. First, for a matched filterudreceiver (maximal signal-to-noise ratio receiver), the optimal waveform is shownudta be a non linear FM pulse which autocorrelationfunction is a Taylor . The optimaludazmiuth weighting fonction is related to that of Taylor by a Fourier transform .udSecond, for a Wiener filter (least mean-squares receiver), we show that the optimaludwaveform is the firstprolate spheroidal fonction . The single-hit measurementudof the scattering matrix by mean of two optimal orthogonal waves is discussed .udResolutions, SNR as well as ambiguities, are specified .