Aspects of RADARSAT ScanSAR Interferometric Processing

Abstract

ScanSAR interferometry extends the choice of SAR modes by its ability to monitor and map very large areas. Radarsat is the first operational instrument offering wide swath interferometric data; however, in near future there will be two more missions, SRTM and Envisat, which will feature a ScanSAR mode. However, the lack of complex ScanSAR products has restricted the use and development of ScanSAR interferometry so far. In order to take advantage of repeat-pass ScanSAR interferometry new algorithms and processors have to be designed. Important aspects of interferometric ScanSAR processing will be discussed in this paper. Besides interferometric burst assembly and ScanSAR beam combination, co-registration will be an issue. Two possibilities to construct ScanSAR interferograms from the individual bursts will be discussed. Moreover, optimal combination of beams, preserving phase consistency, is also considered. With respect to co-registration Radarsat SAR images with their known high Doppler centroid values, co-registration is of special concern. Accuracies of well below one tenth of a pixel must be achieved. The success of the used techniques will be presented. In addition, a ScanSAR DEM will be shown; its quality will be assessed using a reference DEM from the test site in the vicinity of Las Vegas.