Abstract: At present, many researchers have carried out a series of work about TanDEM-X/TerraSAR-X DEM generation. These research results showed the feasibility to generate high precision TDX/TSX DEM. In order to verify the question of whether TanDEM-X/TerraSAR-X DEM satisfy the requirement of topographic mapping, we need qualitatively and quantitatively analyze the TanDEM-X/TerraSAR-X DEM accuracy. Covariance function method was presented for accuracy analysis of TDX/TSX DEM. Covariance of each distance between pixels with height error was estimated by this method. Then covariance function was acquired by fitting covariance. When distance equal to zero, covariance represents TDX/TSX DEM mean square error (MSE), and covariance function value denoted TDX/TSX DEM estimation of MSE. Covariance function method avoided the effects of gross error on accuracy evaluation. A pair of TDX/TSX SAR images was used to generate high precision DEM by DInSAR technique. The results show that the TDX/TSX DEM accuracy assessed by the covariance function method is feasible, and TDX/TSX DEM accuracy is up to 1.46 m. TDX/TSX DEM can satisfy the requirement of 1:10 000 topographic mapping, and also provide advantageous condition for topographic mapping of void region in China.

Key words: TanDEM-X, DEM, InSAR, phase unwrapping, covariance function