SAR Ground Control Point Identification with the Aid of High Resolution Optical Data

Abstract

Only until recently, it has been demonstrated that absolute localization with centimeter accuracy can be achieved for manually matched Persistent Scatterer (PS)s from TerraSAR-X images acquired from cross-heading geometries [1]. This paper describes an automatic algorithm for absolute localization of natural PSs in SAR images, where the detection of potential PSs is aided by high resolution optical data. As the focus of the study is on urban areas, the target detection part relies on identification of lamp posts using template matching. These targets are, most probably, the only ones visible in SAR images acquired from both ascending and descending orbits. Thus, the methodology includes identification of lamp posts from high resolution optical data and retrieves the precise absolute three-dimensional coordinates of the points from corrected TerraSAR-X timing measurements using the stereo SAR method [1]. Preliminary results for a test site in the city of Berlin acquired from TerraSAR-X high resolution spotlight mode are shown.