[LINK] question re mobile phone tracking

[Adam Todd]

At 01:56 PM 29/10/2006, Antony Barry wrote:

>On 29/10/2006, at 1:21 PM, Geoffrey Ramadan wrote:
>
>>It can only be tracked if the phone is ON. From my understanding,
>>the phone needs to communicate to a Base Station it's ID. The
>>Mobile network needs to know which cell the mobile phone is
>>associated with in order to know where to route any phone calls.
>>
>>This does not mean it knows its location, only which network cell
>>it is in.
>
>I presume this is done by triangulation?

Yep.  But ...

>If so you need the phone to
>be received at three stations and the time delay differences to be
>compared?

Basically.  The problem with Telstra, as was demonstrated during the recent 
blue mountains missing tourist where his coverage was only to one tower, is 
that Telstra never bothered with the idea of logging (on access or in real 
time) each cells chatter with mobile units.

Other networks in Australia have some degree of ability.  Specifically the 
3G networks which use the method to actually route broadband data from one 
cell to the next.

See a voice call can be interrupted for an unnoticeable period of time and 
transferred to another cell and yu cut over.

However, broadband doesn't work that way.  The PPP layer, which is a pity 
it was used, required a pretty much "fixed" connection, and when 
transferring, it needs to negotiate.

Try using Broadband on a mobile phone on a train!  It's interesting and 
FRUSTRATING.  But the voice call goes on and one!

If you are using broadband and voice at the same time, you can actually 
hear the "transfer" take place as the broadband dies!

If you are a nerdy type, you might also grab the cell info from your phone 
as you trek around and therefore can do the reverse of finding your 
location, hence find the location of the towers!

>If you were tracking position continuously I guess you
>could do two stations as the two point ambiguity in the intersection
>of two circles would be resolved by looking at the movement over time.

Yes but GPS is so cheap now!