Dear all,
i tried to generate a DEM over an area following the tutorial inside this platform (and also other platforms); steps are described below.
Imagine: Sentinel 1 SB
S1B_IW_SLC__1SDV_20180118T051811_20180118T051839_009221_01085B_C971
S1B_IW_SLC__1SDV_20180903T051813_20180903T051841_012546_017252_C1F3
Steps:

coregistration DEM SRTM 1 sec

interferogram formation

sentinel debrust

goldstein phase filtering

multi-looking (n. of looks: 6, GR square pixel )

export and import in SNAPHU ( 16 tiles 8 core to elaborate, DEFO mode)

Phase to elevation

Range doppler Terrain correction DEM SRTM 1 sec

export to Tiff
But when i look the result in Qgis i have values from -700 to +2000; maximum value of +2000 could be correct for the mountain area but the -700 is absolutly wrong because the minimum land elevation is about -10 m; this is due to the reference system for elevation (geoidic or mean sea level or distance from satellite) or i miss something?
Thanks a lot
Francesco

For DEM-generation the shorter the temporal baseline the better. So 6/12 days in the case of S1. Be aware that the errors caused by atmosphere will seriously degrade the quality of your DEM with respect to SRTM and other official DEM products.

Thanks, i manage to produce a more accurate DEM, i remove the flat earth correction ( downgrade the polynomial to 1) and apply the TOPO mode, add the thermal correction of S1; this is the result but the problem of elevation remain.
I also notice that DEM starts with a quota of +20 + 30 m, my AOI has an elevation of -10 +10 m (plain), maybe this could be also a problem?
Thanks
Francesco

sorry, i’ll explain better, the polynomial i reduced is not the orbit one but is the flat earth polynomial degree inside the interferogram formation (i read inside the help that for plains it suits well)
the orbit polynomial degree was set to 3
Thaks
Francesco