SYNTHETIC-APERTURE-RADAR IMAGING OF THE OCEAN SURFACE USING THE SLIGHTLY-ROUGH FACET MODEL AND A FULL SURFACE-WAVE SPECTRUM

A new technique to model synthetic-aperture-radar (SAR) imaging of ocean waves is developed using the slightly-rough-facet model of the surface. The facets are mapped into the image plane individually and their responses are added coherently to give the composite image. A windowing technique allows the orbital motions of all electromagnetically large-scalewaves to be included in the mapping function deterministically; no scene coherence time is used. Simulated images show that the image cut-of T of azimuthally propagating waves is due to smearing by wind-generated intermediate waves. The focus adjustment that gives the greatest image contrast when imaging azimuthally propagating waves is half the phase velocity of the dominant long wave. However, spatially offsetting the multiple looks in the image domain to compensate the propagation of the long wavesduring the integration time of the SAR appears to be the optimal processing technique. The imaging process is highly non-linear under most realistic conditions, so the surface wavespectral information cannot be extracted from the image using a linear transfer function. © 1990 Taylor & Francis Group, LLC.