What is the meaning of these messages. Are the “previously generated files” related to the ‘coarse coregistration’ performed in the standard coregistration step? Can someone please clarify this? I hope this can be a useful information for everybody!
The coregistration refinement is doing 1 single operation:
it is taking the external DEM and it is using it to resample the image by correcting topographic distortions.
In other words, the sw is not going to re-process the cross-correlation between patches, this was already done during the initial co-registration (and this is the reason why it says that files from the amplitude correlation are kept).
The coregistration refinement is kept separate at a later step to make sure that the DEM is well aligned with the data before using it to resample images.
The sw knows when to keep co-registration partial results and when to re-process them. This can be used also for re-processing the coregistration after changing some parameters (so that only affected steps will be redone. steps not affected by the change will be kept unchanged). This improves efficiency and flexibility.