Abstract
Abstract. In recent years, Synthetic Aperture Radar (SAR) data have been widely used for scientific applications and several SAR missions were realized. The active sensor principle and the signal wavelength in the order of centimeters provide all-day and all-weather capabilities, respectively. The modern German TerraSAR-X (TSX) satellite provides high spatial resolution down to one meter. Based on such data SAR Interferometry may yield high quality digital surface models (DSMs), which includes points located on 3d objects such as vegetation, forest, and elevated man-made structures. By removing these points, digital elevation model (DEM) representing the bare ground of Earth is obtained. The primary objective of this paper is the validation of DEMs obtained from TSX SAR data covering Barcelona area, Spain, in the framework of a scientific project conducted by ISPRS Working Group VII/2 "SAR Interferometry" that aims the evaluation of DEM derived from data of modern SAR satellite sensors. Towards this purpose, a DSM was generated with 10 m grid spacing using TSX StripMap mode SAR data and converted to a DEM by filtering. The accuracy results have been presented referring the comparison with a more accurate (10 cm–1 m) digital terrain model (DTM) derived from large scale photogrammetry. The results showed that the TSX DEM is quite coherent with the topography and the accuracy is in between ±8–10 m. As another application, the persistent scatterer interferometry (PSI) was conducted using TSX data and the outcomes were compared with a 3d city model available in Google Earth, which is known to be very precise because it is based on LIDAR data. The results showed that PSI outcomes are quite coherent with reference data and the RMSZ of differences is around 2.5 m.
Highlights
Digital Surface Models (DSMs) are the basic components for three dimensional (3D) representation of the Earth surface comprising vegetation, forest and human made structures above bare topography
The validation of digital elevation models and persistent scatterer (PS) data derived from current Synthetic Aperture Radar (SAR) satellite TSX was targeted
StripMap mode spatial data of TSX, acquired with 3m resolution was employed and a digital surface model was generated in Barcelona, Spain, with 10m grid spacing applying complex interferometric processing steps and validated in two separate areas including different terrain formations
Summary
Digital Surface Models (DSMs) are the basic components for three dimensional (3D) representation of the Earth surface comprising vegetation, forest and human made structures above bare topography. DSMs can be generated by wide range of techniques from ground survey to space-borne remote sensing. Those DSMs feature different properties in terms of coverage, accuracy, and cost per area. If large land coverage is required and 0.5m-10m accuracy is enough, space-borne remote sensing may be the best technique (considering USGS standards). A DSM with 10m grid interval was generated from TerraSAR-X (TSX) StripMap mode (3m resolution) data at Barcelona test site applying standard InSAR processing. The groups apply different techniques for DEM generation (Radargrammetry, standard InSAR, multi-baseline InSAR etc.) and the results shall be validated against high quality ground truth. The DLR agreed to provide more than 100 TSX images of several urban areas for the project
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