[time-nuts] Iridium source?

John Todd jtodd at pch.net
Mon Oct 5 16:24:05 EDT 2015

I’m working on a project that needs a good clocking source deep inside 
of noisy environments (data centers and the like.)  This can’t be 
network-based - it needs to be independent of the systems surrounding 
it, and GPS/GPS-like systems will often be unreachable.  I’ve read up 
a bit on Iridium - it appears that there is some mention of Boeing 
saying (see slide three in below link) that the Iridium LEO network can 
be used not just as a GPS assist, but as an actual timing source.  Their 
frequencies on the timing side seem to penetrate buildings better.  
Before you say “Iridium doesn’t work indoors!”, this may not be 
the case with their timing signals.

Has anyone actually used this method for obtaining high-precision time?  
If so, is it possible to do with something smaller/cheaper than the full 
Iridium chipset?  I think the Iridium Core 9523 is something like $1300, 
which puts it outside of consideration for the large deployment we’re 
looking at doing, and we don’t need the voice/data TX or RX 


Apologies if this is not on-topic here or if there are obvious data that 
I’m missing - I’m a bit new to this niche of the world.  I can’t 
find any mention of this topic past 2012, and it’s sparse even at 


John Todd - Senior Technologist - jtodd at pch.net - +1-415-831-3123

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