GPS, or the Global Positioning System, was created by the United States military in 1995 for troops to locate themselves and targets, no mattter the conditions on the battlefield. Flash forward 20 years and almost everyone has access to GPS. It’s hard to believe that only a couple of decades ago you needed a map and a compass to get somewhere! Now, both of those are neatly coupled on one portable device.
It’s pretty amazing how these satellites actually determine your position. Each of them contains super accurate atomic clocks and emits a radio frequency that is received by whatever device you’re using. This radio frequency contains the satellite’s time and position, and because light moves at one speed, your device can determine how far away it is from each satellite by measuring the time it takes to receive a signal.