Definicija: A radio navigation system developed by the U.S. Department of Defense that uses a constellation of 24 earth satellites, which are monitored by ground-based control stations, to provide precise, continuous worldwide positioning and timing information.

Definicija: A device that includes an antenna, a radio receiver, and a processor for use with the worldwide GPS (Global Positioning System). A GPS receiver uses position and time information from four GPS satellites to calculate precise information about its current location, its speed of travel, and the current time.