Comparing SAR and SRTM, Which data source can produce relatively accurate DEM?

Question

How much accuracy could we can expect from producing DEM from SAR using InSAR techniques as compare to available SRTM 1ArcSec data? Specifically in view of the available Sentinel-1 datasets?

Any thoughts?

Answer 1

First of all, SRTM and SAR should not be opposed, because SRTM was derived by interferometry (C-Band and 60 meter long baseline). Sentinel-1 is also C-Band and a relatively small baseline (50 m RMS orbital tube).

The big difference is that SRTM used a mast on the shuttle for systematic interferometry, while you lose a lot of coherence between two consecutive Sentinel-1 acquisitions (12 days with one satellite, 6 days with Sentinel-1a and Sentinel-1 B), therefore it is more difficult to extract DEM. The advantage of Sentinel-1 is however the length of its time series.