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I'm trying to provide a source of GPS almanac files (in SEM format) for a non-connected / sometimes connected network.

I know that I can download them from the USCG NAVCEN. However I don't want to have to air-gap them across to my network.

So the plan is to (somehow) get them from a GPS receiver, format them into SEM, and serve them up using a file share / web server. I'm confident about the last step. I have a rough idea of how to download the almanac, but no code. I've seen some online resources that allow writing SEM, but nothing that provides all of

  1. a simple API
  2. open source
  3. (obviously) maintained

So at this stage I'm considering writing the "missing parts". Has anyone actually tried this? Any recommendations for usable (open source) blocks.

share|improve this question
Good info here – Mapperz Aug 1 '12 at 13:24
Thanks for the followup, but I'm not sure what part of the data on that page relates to which part of my question. If it was the bit about the SEM file layout, then its probably worth noting that the SEM almanac file format is formally defined in ICD-GPS-870A ( – BradHards Aug 3 '12 at 0:02
Any updates? I would be very interested to see your results. – robguinness Jul 26 '13 at 7:51
Its still on the list of things to do. – BradHards Jul 28 '13 at 5:38
I think most of what you are looking for can be found in OSGRS. – user45423 Jan 22 '15 at 22:24

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