Havacılık ve Uzay Teknolojileri Dergisi (Jan 2013)
3D QUALITY ASSESSMENT OF HIGH RESOLUTION TERRASAR-X DATA: BARCELONA CASE STUDY
Abstract
In recent years, Synthetic Aperture Radar (SAR) data is being used intensely for scientific applications and many SAR missions have been accomplished. On the contrary of optical systems operating based on passive sensing principle, SAR technology is capable of providing data independent of weather conditions and time of acquisition under favour of active sensing ability and long wavelength. The most important problem of SAR data was decided upon the resolutuion. However, this problem is overcome with orbitting of TerraSAR-X (TSX) which is considered to be a revolution. TSX can provide high resolution data (up to 1m) covering large areas thanks to three different imaging modes. Today, many scientific studies are performed employing TSX data. ISPRS SAR Interferometry Working Group is also conducting a project that performs quality assessment of digital elevation models generated from TSX data. Within the scope of this project,several test sites are being studied from Turkey, Spain, Germany and Italy. In this research, many high resolution DEMs are generated using 3m azimuth resolution TSX StripMap (SM) mode images for Barcelona (Spain) and the most suitable one is chosen and quality asessment is performed on it in the context of the aforementioned project. For the study, quality assessment is performed taking into consideration accuracy and visuality components in Barcelona test site that has been partitioned in two sub-areas as a large area with steep and mountainous topography and an urban area. In the application, a photogrammetric reference model that has 10 cm horizontal and 10 cm – 1 m vertical accuracy was used for the verification. The results show that TSX DEM is compatible with all aspects of the topography with the accuracy between ±8-10m. As another application in the study, Barcelona city model available in Google Earth, which is known to be generated by very accurate LIDAR data, and PSI results of TSX are compared. As a result, it is observed that PSI products and reference data are quite compatible and RMSZ of elevations are around 2,5m.
