TELECOM 247

On Sun, 04 Jun 2006 12:37:02 +0100, Ian Dalziel
wrote:


AFAIK that uses only the current cell that the phone is logged into.
It does not need the more precise location given by the phase
difference firmware in the phone.

--
Cynic

On Sun, 04 Jun 2006 11:22:00 GMT, Taylor wrote:


I may not know all the details of the technology, but it would appear
that I know more than yourself. Phone firmware that enables the phone
to send an accurate location was introduced specifically to enable
tracking, and has no other purpose.

--
Cynic

On 4 Jun 2006 11:23:57 GMT, Huge wrote:


Strange then that there are several models of phone that do not have
the ability.

--
Cynic

On Sun, 04 Jun 2006 12:41:17 +0100, Ian Dalziel
wrote:


If a company were to routinely switch on a mobile that was turned off,
it would certainly *not* attract customers. Quite the reverse.


Why? I am very cynical about the motives of government and government
agencies - which is what this is partly to do with.

--
Cynic

On Sun, 04 Jun 2006 16:03:17 +0100, Derek ^
wrote:


You obviously do not know of the phase difference technology that has
been in use for some time. Prior to that, it was possible to know
which cell the phone was in, and perhaps make a guess as to how far
away the phone is from the base by its signal strength.

What you can do these days is to send a specific locate signal to
the phone. The phone will then proceed to receive two or three base
station service signals (provided there is more than one within
range). Using the difference in time between the synchronised base
signals, it can determine its relative position to an accuracy of
about 100m. There is an ambiguity when only 2 base stations are
within range, which can usually be resolved by using other factors.

--
Cynic

On 2006-06-04, Cynic wrote:

That is not true.

The received signal strength of the phone and the basestation must
be known to allow the network to hand over the call to the base station
with the best signal.

The timing advance (i.e. distance from the base station) must be known
to correct for the time taken for the signal to reach the base station
from the phone.

--
David Taylor

On 2006-06-04, Cynic wrote:

This is not a phase difference, it is a timing advance. The
timing advance is required to allow the phones signals to reach
the base station during its timeslot, to correct for the few microseconds
taken for the signal to reach the base station.

It has always been used, and has always been necessary. My Nokia,
with NetMonitor enabled, can display the timing advance data if I wish.
It is not incredibly accurate.

--
David Taylor

On Mon, 05 Jun 2006 20:51:59 +0800, tim(not at home)
wrote:


Try putting mobile phone and tracking into a search engine. There
is not *a* web site that offers the service. There are *lots* of web
sites that offer the service!


Perhaps you could explain what information that the base station
routinely collects that could be used to determine a 2-D location.


GPS would not be much good for tracking the average mobile phone.
Mobile phones are typically carried in a way that would block the GPS
signals for most of the time (GPS frequencies are blocked by the human
body). Its usefulness would be to the owner of the phone who wishes
to use it as a GPS rather than a 3rd party who wishes to locate the
phone.

--
Cynic