The data are India IRS / P5 satellite optical stereo image pair data in 2008 and ESA TanDEM-X and TerraSAR-X sister radar satellite image pair data in 2013, respectively.

ERDAS software was used to preprocess the data, and combined with the field GPS ground control point survey results to extract DEM if image 2008. Gamma software was used for preprocessing and interferometry in image 2003. After the extraction, the software "multi-functional DEM corrector" is used to repeatedly register and correct it with reference to the 30 meter resolution SRTM data in 2000, so as to ensure that it has the unified elevation datum and the minimum coordinate deviation with other DEM data in this area. Finally, the accuracy of the extracted results is verified and evaluated by ICESat satellite laser altimetry data and field GPS survey results.

By using the platform equipped with TerraSAR-X and TanDEM-X sensors, the complex data (including amplitude and phase information) of the same ground object are obtained at the same time to form an interference pair. After accurate registration, complex interferograms can be obtained by conjugate multiplication of complex images. Based on the geometric relationship among flight platform, beam view and baseline, the phase information in complex interferogram is unwrapped to obtain the ground elevation information. The absolute accuracy in the vertical direction is better than 10 m, and the relative accuracy is 4 m at & gt; 20% and 2 m at & lt; 20%.