ABSTRACT
Spaceborne imaging radar must employ a different strategy to achieve the required azimuth resolution. Collecting a sequence of echoes therefore allows the construction of a two dimensional radar image of the scene, normally with each echo contributing to a "slice" of measurements across a swath while the movement of the instrument allows a collection of echoes to be measured at different points along the swath. The two areas where imaging radar warrants greater use in the terrestrial context is soil moisture estimation and forest biomass mapping. Rainfall may also roughen the water surface, so that patterns of rainfall may also be observed in radar images. Before diving straight in at the deep end with a description of a Synthetic Aperture Radar system, it is customary, and useful, to first give a brief description of the original radar imaging system, Side-Looking Airborne Radar or Real Aperture Radar.
