With the S1TBX beta version, the option has become available to automatically download Restituted Orbit files for Sentinal-1A products when needed. The advantage of Restituted orbit over the precise orbits is that they should become avaliable more quickly.
However, we have noticed that the location from which the S1TBX downloads the Sentinal-1A Restituted Orbits files is not up-to-date. In fact it seems to be a week behind of the official source for orbit files: https://qc.sentinel1.eo.esa.int/aux_resorb/
Why is this? We really need those Restituted Orbits as soon as we have downloaded the product.
Indeed! What good is near-real time SAR data if we don’t have the orbits to process them?
Can we still expect an answer on this topic from one of the developers?
Patience please. Currently, you may go to the QC website and download the orbits you need. This is a 180 day revolving archive (I don’t know why since they are so small). We routinely download the files and keep them all in our own archive with the full history and make them available to the toolbox to automatically download orbit files as needed.
In the future, we’ve been told the ground segment will make all orbit files available via FTP. Another solution could be if the files are not found on our server then the software could try to find it in the QC website but, there’s no plans to develop this just now.
Thanks for the answer Iveci. Can you give an indication on what you mean by “routinely”? Is this every day, week or perhaps even month? This would enables us to make a well funded decision on whether we need to develop our own orbit-file downloading tools or not. Thanks in advance.
This is a good example where crowd funding may work. If enough people need this then SvH, gfun and others could propose to fund a solution. This is open source, I could see many students developing solutions for very little compensation needed.
I’m not able to get restituted orbit files directly from SNAP 2.0.2, although I can see they are available at https://qc.sentinel1.eo.esa.int/ (January, part of February 2016).
I wonder if there is already an available FTP server to download them more quickly and easier than now. I find it difficult to know the orbit files I need to process, I mean name files are not clear for me, so I have to download all the orbit files for a month and it is quite tedious.
I would advise you to download directly from https://qc.sentinel1.eo.esa.int/ since the ftp source used by s1tbx for automatic download is usually not up-to-date and to our experience misses some orbit files now and then… The naming of the orbit files is rather straightforward, the only things relevant for you are the second and third timestamp in the filename, which give the time-span covered by this particular describing the orbit. So the only thing you need to know is the acquisition time of your product and make sure you download the orbit files that covers this time. Hope this helps!
I see 2015 orbits are still available here https://qc.sentinel1.eo.esa.int/, but what about 2014 ones?
For how long 2015 will be available, anyone knows?
Any historic orbit files will be downloaded by the Apply Orbit operator. The QC website for some reason only offers a revolving archive. The SNAP archive should be complete except for the very latest.
I would like to ask how long after radar image is available in scihub is precise orbit file available to download (for InSAR). I have read several topics here and time was not specified just was mentioned It is not available right after image acquisition. I am asking because I would like to know if it is possible to make interferogram (displacement calculation) right after downloading of the new image (second from the pair) so near real time.
The S1 precise orbit files (POEORB) are available about 3 weeks after image acquisitions. For example, the most recent files available for https://qc.sentinel1.eo.esa.int/ are for acquisitions from 30th Oct/1st Nov.
How do we decide which orbit file (Precise or Restituted) to use for the orbit file correction in Sentinel-1 GRD data?
Always use precise if available. They should be available a month after acquisition. If you are using products within that month then you’ll have to use the res orbits.
Thanks for the prompt reply. Since its better to manually download the precise orbit file from https://qc.sentinel1.eo.esa.int/aux_poeorb/ , how do I apply this file for the correction?
Hi, The S1 orbit files have 3 dates in the filename: the creation date, the start validity date and the end validity date. The creation date is when the file was created while the validity dates refer to the range of dates of the orbit data in the file. For example the file S1A_OPER_AUX_POEORB_OPOD_20180814T120735_V20180724T225942_20180726T005942 was created yesterday at 12:07:35 UTC for orbit data between 24th July at 22:59:42 and 26th July at 00:59:42 (i.e. just over 24 hours). If there are two files with the same validity dates, choose the one with the most recent creation data. Obviously the range of validity dates should include the date of your product.
Thanks for the help. But how do I apply the manually chosen orbit file on my data in SNAP?
You shouldn’t need to manually get any orbit files. SNAP will find the right one and apply it.
Hi, thanks for the explanation!
And if my image can fit in more orbit files, (time windows) can I choose which one I want?
Should it be the same?
Hi, if there are two orbit files of the same type that have validity dates that include the date/time of your image, then choose the one with the most recent creation date.