Clarifications on the type of EGM used in DEM/DTM files after processing in SNAP

Microwave Toolbox
1

Hi all, I am a beginner passionate about SAR data processing and I am trying to better understand the process of developing DEM/DTM files using SNAP. I followed the following procedure with a Sentinel 1-A source file (S1A_IW_GRDH_1SDV…):

Applying the _Orbit algorithm

Applying the _Calibration algorithm

Speckle filter

Radiometric Terrain Flattening

Range-Doppler Terrain Correction

At the end of this process I get a DEM/DTM file as a band, but I did not understand what kind of EGM (Earth Gravitational Model) is used in this DEM/DTM file. I searched for information in the forum and in the program documentation, but I could not find a clear answer.
I assume that using in the last phase as a reference DEM the SRTM 1 arc sec I should have an EGM96.

If I look at the elevation.hdr file of the.img file I don’t see an EGM specifically.

Can you help me better understand which EGM is used in the DEM/DTM files generated with this procedure?

Thank you very much for your support!

elevation.hdr (698 Bytes)

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Perhaps this helps:

[Online Help – STEP]
“Please note that for ACE, Copernicus and SRTM, the height information (being referred to geoid EGM96) is automatically corrected to obtain height relative to the WGS84 ellipsoid.”

So when the input is SRTM, the output elevation band of the “Range-Doppler Terrain Correction” process contains heights relative to the WGS84 ellipsoid surface (vertical reference).
The hdr-file only shows information about the horizontal reference.

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