After I imported two sentinel 1a SLC format in IW mode images to software(SNAP 6 ) and I used "S1 TOPS COREGISTRATION WITH ESD " for coregistration step.
In page that opened, I SET THESE PARAMETERS as below :
1- I entered the first and second images .
2- I selected IW1 and VV with 1 to 9 bursts for first image.
3- I selected IW1 and VV with 1 to 9 bursts for second image.
4,5 - I selected automatic download for orbits .
6-7 And used default values for geocoding
((Now, how can I check that applied orbit and coregistration are correct??))
In second step I used “INTERFROGRAM FORMATION”
After this step by clicking on " phase_ifg_vv … " file , only PURPLE is shown on the screen.
please help me on this problem.
It should be mentioned that I used 3 types of DEM ( SRTM - GDEM and ASTER ), but the result is the same.