SAR image data from a variety of spaceborne and airborne sensors will
be much more commonplace in the early 21st century. Why will SAR data
be used in some applications and what will it be used for? Part of the
answer lies in SAR's ability to provide high-resolution imagery, inde
pendent of cloud cover or sun illumination, and in the sensitivity of
radar measurements to certain physical characteristics of the area bei
ng imaged, such as surface roughness, structure, dielectric constant a
nd, to some extent, motion. Another part of the answer is provided by
the high-resolution topography and topographic change maps which can b
e generated using the technique of SAR interferometry.