How GPS Works
GPS (Global Positioning System) is a navigation system comprised of information sent from orbiting satellites to earth. Twenty–four satellites circle the earth twice a day, transmitting signals to earth. The signals are then interpreted by a GPS receiver to determine a user’s positioning. When four or more satellites are in the receiver’s view, it can calculate 3D positioning (latitude, longitude and altitude).
GPS receivers use triangulation to calculate positioning. Triangulation means the receiver compares the time of the signal’s transmission with the time it was received - ’travel time.’ With this information, the receiver can determine an exact location. The logic behind GPS is to use satellites’ positions in space as references to calculate positions on earth.
Today, GPS technology is used worldwide for navigation, asset monitoring, people tracking, and more. GPS’ accuracy (civilian receivers are accurate to about 15 meters; military receivers, about 1 meter) makes it an incredibly reliable way to track objects and calculate locations.
Learn more about GPS technology at How Stuff Works.