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Apparently, the UK government wants to convert the OneWeb satellites into its own UK SatNav system, following Brexit which limits the UK's access to Galileo's Public Regulated Service [reports from the BBC and theRegister].

While, some reports are less and some are skeptical on the technical viability, I haven't seen any reports detailing how one might convert a communications satellite into a SatNav satellite. After all, the satellites involved in the GPS or Galileo systems carry atomic clocks and other special equipment.

So, how would one cobble together a SatNav system from comms satellites already in orbit?

What features implemented in comms satellites can be exploited for determining the location of a ground receiver?

Dohn Joe
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  • I think you have to bear in mind the possibility that this is just a mistake. Note this comment is not intended to be making a political point. I can imagine that one might be able to make use of low-precision clocks on a large number satellites to produce a high-accuracy position but, well that would not be anything like GPS: you'd need completely new silicon for the device on the ground for instance. I think it is more likely that they've just made a mistake. –  Jul 03 '20 at 15:26
  • See this (PDF). which may be part of the answer. –  Jul 03 '20 at 15:32
  • @tfb thank you for the PDF. So, there may be means to to SatNav from LEO. However, it does not suggest that the OneWeb constellation currently in orbit could be used right away. – Dohn Joe Jul 03 '20 at 16:06
  • No, I think that is correct. But OneWeb have only launched a small number of the satellites they planned to launch: it's possible that the unlaunched ones can be repurposed. I believe that this may be hard-to-impossible and you would still need new silicon for the receivers as the frequencies are completely different. As I said I think this is almost certainly just a mistake. –  Jul 03 '20 at 16:14
  • I have found no evidence that there is any intention to use the existing satellites for this. – MikeB Jul 03 '20 at 18:07
  • In the case of the UK it seems the answer is wishful thinking. – GdD Jul 04 '20 at 14:47
  • @tfb So, if there was a relatively easy way to convert comms-birds into kind of nav-birds by installing purpose-built silicon: that means the OneWeb constellation is worthless to the UK w.r.t. achieving their goal of a post-Brexit SatNav system? In other words, the in-orbit constellation would be mere by-catch in the UK's aquisition, since the only path would be to launch more, newly-modified OneWeb satellites? – Dohn Joe Jul 06 '20 at 07:41
  • @DohnJoe: I meant new silicon for the receivers (the frequencies OneWeb uses are different than GPS for instance). But yes, I suspect the currently in-orbit satellites are not useful for navigation. –  Jul 06 '20 at 10:46
  • @GdD: There is also the fact that one of the stated goals is to bring jobs back to the UK. Now, the satellites are built by Airbus, a multi-national company of mostly EU countries, and are launched by ArianeSpace, a company owned by Airbus and a French company. So, that seems to be more wishful thinking. By saving OneWeb, it looks like the Brits have mostly saved jobs in France and Germany. – Jörg W Mittag Jul 07 '20 at 05:12

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