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isce-framework / isce2

InSAR Scientific Computing Environment version 2
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fetchOrbit.py Error to download POD #842

Open binfenhuayun opened 5 months ago

binfenhuayun commented 5 months ago

first, an Error of 'Failed to find S1A orbits for tref 2017-04-01 11:09:14' will occur, which is strange, maybe you can use ASF based on python requests and beautifulSoup instead, second, I am a little curious, why you used the orbit file the day before imaging day while correcting the image using POD? There is difference between ISCE and ESA SNAP, can somebody to explain it?

Arctic-Ambrun commented 3 months ago

First go to the ESA to download the orbit file manually https://dataspace.copernicus.eu/ Next, take care of the name of POD. There are 3 dates, OPOD release time - OPOD vaild start time -O POD vaild end time. the orbit files in GNSSRD format is calculated and not accurate enough, so if possible, use POEORB ISCE is better in SAR satellites and SNAP is better in Sentinel series satellites.

EJFielding commented 1 month ago

Note that the Copernicus Sentinel-1 orbit files have 26 hours of data, starting 1 hour before midnight the day before the full day of data, and ending 1 hour after midnight the day after the full day, so the "start time" is always in the day before the SAR acquisition to be processed.