TanDEM-X IDEM precision and accuracy assessment based on a large assembly of differential GNSS measurements in Kruger National Park, South Africa

摘要

High resolution Digital Elevation Models (DEM) represent fundamental data for a wide range of Earth surface process studies. Over the past years, the German TanDEM-X mission acquired data for a new, truly global Digital Elevation Model with unprecedented geometric resolution, precision and accuracy. First TanDEM Intermediate Digital Elevation Models (i.e. IDEM) with a geometric resolution from 0.4 to 3 arc sec have been made available for scientific purposes in November 2014. This includes four 1 degrees x 1 degrees tiles covering the Kruger National Park in South Africa. Here, we document the results of a local scale IDEM height accuracy validation exercise utilizing over 10,000 RTK-GNSS-based ground survey points from fourteen sites characterized by mainly pristine Savanna vegetation. The vertical precision of the ground checkpoints is 0.02 m (1 sigma). Selected precursor data sets (SRTMGLI, SRTM41, ASTER-GDEM2) are included in the analysis to facilitate the comparison.