I am in the process of writing software that generates images directly from Sentinel-1 Level-0 (RAW) data files. So far I’ve successfully processed a Stripmap (SM) image, and am now working on Interferometric Wide Swath (IW).
Unfortunately, there seem to be some holes in the documentation, and I’ve had to guess at a few parameters. For example, I’ve not been able to find documentation on the elevation and azimuth beam address parameters in the Measurement data file, and so I’ve had to make certain assumptions about the antenna pattern and squint angle.
I realize this forum is primarily concerned with the Sentinel-1 Toolbox, which doesn’t handle Level-0 data. But I’d like to compare notes with anyone who has tried processing Level-0 data from scratch, and would be happy to share what I know about it.
Yes, I’ve seen that document. Figure 3-5 on page 3-8 shows a plot of the SCANSAR Azimuth Antenna Pattern, which is useful but still leaves out a lot of detail we’d like to know.
As for adding our code into SNAP, that raises an interesting question: Are there any instances where Level-0 data is available but Level-1 and/or Level-2 data are not? If Sentinel data is always provided in all three levels, would there ever be a need to do the image formation from scratch? To directly answer the question, yes, it’s possible we might be able to contribute the code (although my current software is written in Python and would take some effort to make compatible with SNAP). But why would anyone want it?
My company (Valkyrie Systems Corporation) is primarily a radar signal processing house. The reason we are processing Level-0 files is to use it as test data for various advanced SAR products and processing. But that’s a pretty niche application.
I’d like to tell you that many S-1 images in different places are still in Level 0 that is why I raised this topic in the below link, so I think it is worth if you like to share your code within SNAP.
For some specialized applications like observation of the ocean surface the user might want to tweak the Level-0 to Level-1 processing to better suit his/her needs.
Is this data from the early mission phases when systematic Level-1 SLC production was not yet activated globally? In that case you could request ESA to reprocess the old datasets.