The Global Positioning System (GPS) is made up of satellites, ground stations, and receivers.
GPS is a system of 30+ navigation satellites circling Earth. We know where they are because they constantly send out signals. A GPS receiver in your phone listens for these signals. Once the receiver calculates its distance from four or more GPS satellites, it can figure out where you are.
Satellites act like the stars in constellations—we know where they are supposed to be at any given time.
The ground stations use radar to make sure they are actually where we think they are.
A receiver, as you might find in your phone or in your parent’s car, is constantly listening for a signal from these satellites. The receiver figures out how far away they are from some of them.
Once the receiver calculates its distance from four or more satellites, it knows exactly where you are.
