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From: - René -
Subject: Re: Can anyone explain the design of tracking systems?
Date: Mon, 16 Dec 2002 15:10:55 +0100
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On Mon, 16 Dec 2002 12:02:10 +0100, "Frithiof Andreas Jensen"
>In GSM at least, on entering a new cell and periodically after that, the
>handset reports the signal strengt from the nearest (up to six) transmitters
>so that the optimal "base" site can be chosen. Not triangulation, but pretty
It seems that in GSM data transfer the non-infinite transmission delay
over distance needs to be corrected by time compensation. This
effectively locates the phone on a rather precise circle around the
base. It also seems that more bases will be in range of the phone and
make the same timing calculation. With 3 such basis you are
pin-pointed exactly. I do not know wheather this is a standard mode or
a mode that can be requested by the "men in black" - but it is
certainly feasible. (with GSM that is)
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