[Help]: SBAS results different from GMTSAR SBAS processing results

[kinreich]

Hello, I ran a time series processing once using GMTSAR manual, and once using pygmtsar, and got very different results for

OS and software version

• OS: Ubuntu 20.04.5 LTS
• PyGMTSAR version: pygmtsar-v2023.3.11
• GMTSAR: 4.2.2

Steps to reproduce the problem I ran the timeseries on 72 ascending scenes, and 107 interforgrams, pairs : time was 30 days between them, as well as yearly pairs. meters: up to 150 meters (default) I used the same data in both of the processing analyses: same dem file, same wavelength filter, same corr file for correlation filter.

For GMTSAR they produce a velocity grid to look at, and for pygmtsar I produced a velocity grid from the total displacement divided by the time passed (in years).

I compared between the processing stages, and found that the differences in grd files are seen only after running SBAS (unwrap and phasefilt files see no difference)

Screenshot Here is the velocity grd (mm/year) for pygmtsar analysis:

Here is the velocity grd (mm/grd) for GMTSAR analysis:

Could you help explain why we would see such a difference in final results with the two analyses?