 1972 Global Positioning System

The Global Positioning System (GPS) is a space-based global navigation satellite system that provides reliable, three-dimensional positioning, navigation, and timing services to worldwide users on a continuous basis in all weather, day and night, anywhere on or near the Earth.24 satellites orbit around the Earth twice a day, transmitting signaled information to GPS receivers that take this information and use triangulation to calculate the user's exact location.Ultimately, the GPS is the descendant of the United States Navy's "Timation" satellite program and the United States Air Force's "621-B" satellite program.