GPS won't work if we don't know General Relativity

We know that as per the general theory of relativity, gravity affects time. GPS Satellites revolving around the earth are experiencing gravity that is four times weaker than on the ground and thus the time will run fast there.

Clocks on earth are experiencing strong gravity of the earth and thus the time will run slow for us relative to the satellite. 

GPS accounts for relativity by electronically adjusting the rates of the satellite clocks, and by building mathematical corrections into the computer chips which solve for the user's location.

Without the proper application of relativity, GPS would fail in its navigational functions within about 2 minutes.

So the next time your plane approaches an airport in bad weather, and you just happen to be wondering "what good is basic physics?", think about Einstein and the GPS tracker in the cockpit, helping the pilots guide you to a safe landing.