GPS required the development, testing, and refinement of receivers, atomic clocks, and other components.
Developing GPS components began in 1973, when the Joint Program Office was established under the Air Force to run and maintain the system. As designs evolved, positioning and navigation accuracy improved.
GPS resulted from a combination of parallel efforts in the 1960s. Defense Department planners decided to combine the best technologies from these various programs—the Navy’s Transit and TIMATION, the Air Force’s 621B, and the Army’s SECOR—into one. At a meeting over Labor Day weekend in 1973, they created the Defense Navigation Satellite System. It was later renamed the NAVSTAR Global Positioning System, now generally known as GPS.