Evaluation of interferometric SAR DEMs generated using TanDEM-X data

Recently launched TanDEM-X SAR mission (June, 2010) aims to generate a consistent global DEM equaling HRTI-3 specification. In view of global DEM generation using TanDEM-X InSAR data, it is very important to evaluate their accuracy over various test areas. This paper presents the evaluation of DEM generated using interferometric technique from TanDEM-X data in and around Mumbai city in India. The DEM was also compared with the DEM generated using Cartosat-1 stereo optical data having equivalent resolution. On comparison of the results obtained from the two techniques with the accurate DGPS values, it is observed that TanDEM-X DEM has a RMSE value of 8 m and is superior to Cartosat DEM which gives 15 m RMSE value for this test site. The standard deviation of the uncertainty of the elevation value given by TanDEM-X DEM and Cartosat DEM is 7.9 m and 9.7m respectively. More data sets with varying elevation are needed for the evaluation of TanDEM-X data by combining ascending and descending passes.