The direction cosine method of scatterer location extended to spotlight-mode IFSAR

A particularly efficient and accurate method of creating digital elevation maps (DEMs) from interferometric SAR data was introduced by the stripmap SAR community. We show how to extend this approach, the direction cosine method, to the case of high-resolution spotlight-mode SAR. The method allows the computation of the three dimensional position of scatterers in absolute coordinates directly from the raw radar measurements of range, Doppler, and interferometric phase. Having so computed position triples, the data can then be interpolated onto any map projection desired. The technique is illustrated with actual high-resolution spotlight-mode imagery.