WIDE-AREA TERRAIN SURVEYING WITH INTERFEROMETRIC SAR

For many applications, extraction of useful data from synthetic apertu re radar (SAR) or other sensor imagery of the Earth's surface can be e xpedited by encoding terrain relief cues within the image. Shadowing m ay provide qualitative cues, but the most accurate relief information results from direct measurement of terrain elevation on a pixel-by-pix el basis. Airborne interferometric SAR (IFSAR) offers a method for the generation of digital elevation maps (DEMs) which has recently come o f age technologically. Before semiautomated IFSARE (IFSAR elevation) m apping becomes commercially practical, concerns in the areas of accura cy, reproducibility, throughput, and cost must be addressed. This arti cle considers these issues in the context of a study which was conduct ed with a production military SAR system flown in an experimental IFSA RE mode. Example IFSARE imagery from an associated Army/ARPA mapping p rogram is presented and analyzed for detail. Geopositioning accuracy a nd reproducibility are discussed; one standard was a set of high accur acy, high resolution DEMs which were produced from optical photo stere o pairs and controlled by a GPS-based ground survey. Computer throughp ut requirements are assessed from the standpoint of near real-time pro cessing and low cost.