I ran the DinSAR workflow in SNAP and managed to get the output displacement map. This has been converted to vertical displacement. However, the values seem a little too big for displacement over a period of slightly over 10 days. Anyone knows if these values feasible? Am I doing something wrong?
After unwrap-> phase to displacement -> convert to vertical
What is the unit of the y-axis? Assuming your processing has been correct the result still contains the effect of the atmosphere, which can be large. Here’s a review-article about the issue:
As mentioned by mengdahl atmosphere may have considerable contribution.
I would propose, instead of converting directly to vertical, to generate a second interferogram from the other orbit (ascending or descending) for the same period and then combine asc & desc to calculate the true vertical motion.
mengdahl and mfoumelis,
Thank you for that insight and the linking regarding the atmospheric contribution to INSAR derived displacements. I assume S1-A might not have the same asc/desc pass over the same period, so I guess the only option is from another satellite? Also, how can i combine the results from the asc and des passes? Will an averaging scheme do the job?
Any space-born SAR system has both ascending and descending orbits, for which acquisitions cannot be at exactly the same time. Selecting insar pairs from orbits close in time is a common practice, assuming no much change happened in between.
Please note that asc & desc insar measurements are done along different line-of-sight (LOS) and cannot be combined simply using averages. You need to geometrically combine considering acquisition geometries. There should be several related publications in literature.
Hy
I have some similar problems with the too big vertical displacements. Could you please mention some publications, or application method to combine asc/desc measurements?
Thanks
Hi all
I did the interferogram for the San Francisco Bay (Oct, 6 to Dec, 05 2014), I don’t know wether is correct. Please, give me yours opinions about this!!!
Using the phase to displacement operator, is the resulting displacement positive towards satellite (i.e. uplift) or positive away from the satellite (i.e. increase in range)?
