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DEM generation and analysis on rugged terrain using ENVISAT/ASAR ENVISAT/ASAR multi-angle insar data

The suitable incidence angle is one of the important parameters on DEM mapping precision when interferometric SAR used to generate DEM on mountainous terrain. In this paper, from real ENVISAT/ASAR multiple angle interferometric data, SRTM DEM with 90m horizontal resolution and 1:50000 digital topographic DEM, the concrete impact of incidence angle on DEM accuracy has been analysed and discussed from qualitative and quantitative views。 The result indicates: (1)For ASAR multi-incidence angle interferometric data, the effects of the layover and foreshortening on DEM precision are significantly at lower incidence angle, and difference of DEM accuracy is large, for example, the accuracy difference between IS2 and IS4 ASAR DEM is more than 6m. So, the incidence angle must be selected rigidly when InSAR are used for rugged terrain mapping. (2) Temporal decorrelation is serious with 35 days time interval, the overall evaluation of DEM precision are difficult. If the InSAR data that have wider incidence range and have not temporal decorrelation can be obtained, the further and overall evaluation and analysis that radar layover, shadow and foreshortening are how to affect the DEM precision can be investigated.