[LINK] question re mobile phone tracking

[Geoffrey Ramadan]

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? 
No - I believe the phone looks at signal strength, and responds to the 
Base station which has the greatest signal strength.

In regards to Telstra Location Based Services, I am not sure what 
technique they use.

> If so you need the phone to be received at three stations and the time 
> delay differences to be compared? 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.
This is one technique you can use. Another is to compare signal strength 
between base stations

Geoffrey Ramadan
> Tony
>
> phone : 02 6241 7659 | mailto:me at Tony-Barry.emu.id.au
> mobile: 04 1242 0397 | mailto:tony.barry at alianet.alia.org.au
> http://tony-barry.emu.id.au
>
>