Yes for both questions.. somewhat
I do not believe accuracy to 25 meters can be claimed,
even though someone trying to sell you something will
tell you anything you want to hear. There are 3 and
perhaps 4 ways of identifying location, the problem is
that equipment needs to be located at the cellsite for
the carrier. Equipment vendors use such techniques as
the timing difference between when each cellsite sees
the signal, timing difference between antennas located
at the same cellsite, the strength of the signal
transmitted by the phone, timing infomation located in
the bit stream in some wireless technologies like TDMA
(time division multiple access) and CDMA, and I've heard
something on the timing in CDMA (code division multiple
access) and using the reference gps from the cellsite,
all cellsites in CDMA systems use gps timing to time all
users on the cellsite (Sprint, Primeco...). Cellular
carriers also can pinpoint a phone to a single antenna
beam on a single cellsite from reports in the network
switching office. Research the subject 'time of
arrival' and see what you come up with. Wireless phones
at the end of the year will have gps installed in them
by some of the manufacturers, if they hit the market,
Big Brother is watching, will again have a new twist.
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