I thought these devices needed to have clear line of sight access to multiple satellites in orbit? How does this work if your sitting inside a fairly enclosed aluminium tube
You need the signal from 4 satellites to get an accurate reading and you don't need to be in a direct line of sight (contrary to popular believe) with the satellite for your device to figure out where it is at...! GPS satellites are in essence, a very friendly clock! It is an extremely accurate clock that sends its signals in all directions at the speed of light constantly saying hello and giving the time..., it is a coded signal so that your device knows when the signal left the satellite and when it arrived at your device.., this signal has the limited capability to penetrate structures as long as they are not too thick with concrete, rebar etc...., but inside an airplane you can still get it.