I am pre-processing a number of Sentinel-1 EW GRDM images over northeast Greenland and am running into issues with the terrain-flattening part of my pre-processing. My steps are as follows:
- Calibrate to beta0
- Terrain flatten
- Terrain correct
- Resample
For a number of the scenes the terrain-flattening works completely fine, however, for several, the output is almost entirely empty aside from a few artifacts.
Some troubleshooting attempted so far has included processing images individually as opposed to in a batch, terrain-flattening on non-subsetted images as opposed to subsetted ones, and using different DEMs (Copernicus Global DEM 30 and an external DEM - AW3D30). All to no avail.
A couple of scenes that fail during terrain flattening include the following:
S1B_EW_GRDM_1SDH_20190829T082631_20190829T082731_017798_0217E7_3BDE
S1B_EW_GRDM_1SDH_20190801T085900_20190801T090000_017390_020B34_F625