Development of a multiple adjustment processor for generation of DEMs over large areas using SAR data

During the last years orbital SAR data have been acquired for almost every place in the world. This fact can be used for generating large digital elevation models (DEM) of remote areas using SAR interferometry (InSAR). Nevertheless, the generation of large quality DEMs using this technique presents several problems, such as temporal decorrelation (even with a one-day temporal gap between acquisitions), baseline errors or SAR parameters calibration. These factors can dramatically degrade the quality of the final DEM and, therefore, advanced InSAR techniques are needed to minimize or compensate for these errors. In this paper the Institut Cartogra`fic de Catalunya (ICC) presents a robust method for generating very large, high quality DEMs using a set of SAR interferograms. The method is based on a simultaneous multiple adjustment of critical parameters for the SAR images using three types of phase-registered points: control points, known-height and corresponding points. Results for the area of Tierra del Fuego (Argentina) are also presented.