Sentinel-1 External DEM regions not covered

Quick question on external DEMs for Sentinel-1:

If we use external DEMs to preprocess Sentinel-1 data by using gpt, if the DEM does not fully cover the imagery, does it automatically download the necessary tiles?

Thank you

according to my experience,

  • if it is partly covered: the available tiles are downloaded and the rest of the image will not be processed.
  • If there is no DEM at all: the process will fail or assume a flat area.