20,000km of which 100km is air and the rest mainly a vacuum
The other thing is that the GPS in phones seems to need 'help' from the mobile towers, "assisted GPS"
Not that the air it has to pass through is nothing - 10.3 tonnes air pressure per square metre, but the concrete just blocks more. The vacuum is not much of a barrier to it especially at those microwave frequencies of a bit more than 1 GHz.
That Russian space station Mir is worth seeing. You need to look up just what time of day and what part of the sky to look at. Yes, that is one known science which is centuries old, unlike a number of modern pseudosciences like psychology.
The MIR "space station" was destroyed by the Russians (by plunging it back to earth) more than 20 years ago.
That is if you believe it existed in the first place....