On Tue, 2004-07-06 at 13:42, Brian Densmore wrote:
> I read it is a GPS transponder. which if that is correct it is
> both a transmitter and receiver. Which of course would make 
> sense. How would a GPS know where it was if it didn't receive
> an answer it requested from a satellite?

The satellites send the information out constantly, and don't know (or
care) if anyone is listening.

A normal GPS receiver listens, and based on what it hears, figures out
where (and when) it is.  The only person it shares this information with
is the one holding the receiver.

See http://www.garmin.com/aboutGPS/ for more details.

This Coke can most likely then proceeds to encode the position data in
some way and transmit it over the cell phone network while you are
talking to the prize patrol.  I guess it is up to the lucky winner to
make sure he/she is in a place where both the cell phone network and the
GPS satellites can be seen before placing the call.
--
Kendric Beachey (who works at Garmin)