[time-nuts] Symmetricom TimeSource 2700
hmurray at megapathdsl.net
Wed Nov 30 01:44:44 EST 2011
> I don't know how (or if) they deal with the distance from the cell. The
> accuracy of the PPS signal from CDMA time receivers is usually specified as
> no better than 10 microseconds or so, so they may just assume the cell tower
> is close enough not to make it worse than 10 microseconds.
I'm pretty sure at least some systems have something much better than that.
The FCC requires some sort of pretty good location reporting for 911. I
think the requirement is something like better than 100 yards more than 95%
of the time.
The cell phone companies can do it any way they want. GPS is one choice.
Another is triangulation from cell towers. 100 meters is 300 ns which is a
lot less than 10 microseconds.
These are my opinions, not necessarily my employer's. I hate spam.
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