The Global Positioning System is a satellite navigation system, developed by the Allies during the Great World War II. Requiring an effective way to scout enemy positions quickly, Allied scientists developed the ultimate scout: a spaced-based satellite system capable of granting the commander visibility over the entire battlefield.
Due to the extreme technological expertise needed, a GPS satellite could only be granted to an Allied base that had a tech center. Once built, Allied technicians would prepare a satellite for launch, and after preparations were made, the satellite would be launched into medium Earth orbit, revealing the topography of the area of operation, as well as the location of any enemy units.
On Great World War III, Allies has retooled their GPS service. Since there are a period of peace, a number of GPS satellite has been launched to serve various task. Realizing the existance of Soviet old space program, the Allies put more security on their GPS via the usage of advance cypher techniques. To cater on this added protocol, Allies has relocated their services in a special service building called Spy Satellite Uplink. Due to the arduous task heavily involving cypher, the computer in the uplink center is connected directly to the Radar and Navigation facility inside any command center and when the uplink failed (due to power problem and/or sabotage) the map and the entire location display is "reseted" back to any input available from existing units and structures, putting back the "fog of war" to the map.
Following the war, GPS was commonly used for both military and civilian purposes, however, by the First Tiberium War, Nod had developed several specialized techniques and technologies for fooling GPS; forcing GDI to resort to old-fashioned methods of scouting. Regardless, the GPS satellite formed the backbone of the future satellite network of the Global Defence Initiative.