Hi John:
It seems like the indoor improvement over GPS is based on the much stronger
signal level of the Iridium signal.
Note the two signals are both in the 1.6 Ghz area.
Page 15 of this document says the BOM cost is under $20 for this service (no
mention about the monthly subscription).
The last page has names and companies of the people involved, Per Enge at
Stanford.
http://scpnt.stanford.edu/pnt/PNT11/2011_presentation_files/13_Whalen-PNT2011.pdf
http://gps.stanford.edu/people/enge.htm
I've asked Per about ordinary people using this time source.
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
John Todd wrote:
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
components.
https://transition.fcc.gov/bureaus/pshs/docs/summits/911%20Location%20Acuracy/Barry_Martin.pdf
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 that.
JT
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John Todd - Senior Technologist - [email protected] - +1-415-831-3123
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