Spy/Counterspy

[Pawel]

Hi,

On Apr 27, 2010, at 5:38 AM, "Peter Gutmann (alt)" <pgut001.reflector at gmail.com 
 > wrote:

> GPS tracking units that you can fit to your car to track where your  
> kids are
> taking it (or *cough* other purposes) have been around for awhile  
> now.  It's
> interesting to see that recently the sorts of places that'll sell  
> you card
> skimmers and RFID cloners have started selling miniature GPS jammers  
> that plug
> into cigarette-lighter sockets on cars (general-purposes ones using  
> internal
> batteries have been around for awhile).  In other words these are  
> specifically
> designed to stop cars from being tracked.
>
> (Some of the more sophisticated trackers will fall back to 3G GSM- 
> based
> tracking via UMTS modems if they lose the GPS signal, it'll be  
> interested to
> see how long it takes before the jammers are updated to deal with 3G  
> signals
> as well, hopefully while leaving 2G intact for phonecalls).

Just wondering, why wouldn't GPS trackers use 2G to determine the  
location?

And, also, does it even need a cell service subscription for location  
determination, or is it enough to query the cell towers (through some  
handshake protocols) to figure out the proximities and coordinates?

>
> Peter.

Thanks,
   Pawel. 

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