To generate DEM from 2 pairs of sentinel-1_VV polarization using SNAP you should apply the following steps:
- S1 TOPS ESD Coregistration
- Creating Interferogram
- Goldenstein Phase Filtering
- Exporting to Snaphu, unwrapping and importing back
- Phase to Elevation
- Range-Doppler Terrain Correction
When comparing generated DEM with SRTM_1-arcsecond the result was too close and gives more details as Sentinel generated DEM spatial resolution is about 14 meters.
InSAR DEM affected by low coherence, atmospheric disturbance and unwrapping errors so we found some areas showing clearly distortions, but after repeating unwrapping process this distorted areas are decreased.
The 2 pairs of sentinel-1 used in this example with the perpendicular baseline about 221 meter & temporal baseline 24 days: S1A_IW_SLC__1SDV_20191002T154701_20191002T154731_029282_0353D1_8841 S1A_IW_SLC__1SDV_20191026T154701_20191026T154731_029632_035FDD_798C
The following pictures some processing steps and final results
Find this useful tutorial showing how to create a DEM from Sentinel-1 data in SNAP.
By: Przemysław Slesiński