Validation of Radargrammetric Digital Elevation Models (DEMs) Generated with TerraSAR-X Data

Due to weather and illumination independence of the TerrraSAR-X system, radar gives a great opportunity to collect data from all over the world within short time without any restrictions. Interferometric SAR (InSAR) is a common method for elevation modelling with radar data. Because of the time difference of interferometric pair collection (11 days for TerraSAR-X) and resulting coherence problems caused by changes in the nature (e.g. plant growth) a stereo approach is an alternative for digital elevation modelling with TerraSAR-X. The potential of digital elevation modelling with TerraSAR-X stereo pairs is under development and evaluation since the middle of 2008 at Infoterra GmbH. Acquisitions with different incidence angles are taken to simulate a stereo effect. This method, called radargrammetry, is taken to derive digital elevation models (DEMs) from radar imagery. Different approaches could be taken for the accuracy measurements of DEMs. Aside from visual inspection of a dataset statistics are calculated with the available reference data. The validation during the development phase of the radargrammetric derived TerraSAR-X Stereo DEM product and results from the DEM processing are discussed in this paper.