GPS back-up: World War Two technology employed
bbc.co.uk
bbc.co.uk
Any time one of your devices contacts a GPS satellite, it's telling a system of satellites owned and maintained by the US government exactly where you are.
It does not seem at all far-fetched that some government "intelligence" agency is collecting, mining, and processing this data.
Please, if I'm wrong about the system being totally US-controlled, I would love to be corrected.
"Satellite service is wireless and requires a clear line of sight toward the satellite" http://faq.findmespot.com/index.php?action=showEntry&data=11...
Many phones can use GLONASS, the Russian system, so, for example, the 'GPS' in your iPhone or Lumia may not always be using the GPS system to compute your location.
GPS receivers are just that. They do not transmit anything to the satellite.