"Bill Kearney" <wkearney99@hotmail.com> amazed us all with the following
in news:NYidnfsjSbBzQWnanZ2dnUVZ_vShnZ2d@speakeasy.ne t:

>> And your post highlights something that I find interesting. GPS is
>> the acronym for "Global Positioning Satellite." Therefore, in order
>> to offer GPS as a service, a unit would need to communicate with
>> satellites.
>
> NO, NO, NO! GPS is a receive-only system. Your unit is listening for
> multiple satellites. Based on what it 'hears' and the timing, it
> triangulates a location.
>
> At no point, at no time, NOT EVER, do any of the GPS units transmit
> back to the satellites. THINK ABOUT IT. The power to get a signal
> back to orbit is non-trivial. That and managing the traffic from a
> bajillion different GPS unit would be nigh-on impossible.
>
>

So by listening to the satellites, communication is happening.

Thanks for nothing.