GPS or Global Position System is an electronic system, which is use satellites, to determine the position on the planet of someone or something. The U.S. Army invented and developed the GPS during the Cold War for military use. A few years later, the system became public and accessible to all. Today, GPS is the first location-based system. It is used by the military, the aviation and the maritime world. Also, millions of people use it when they move or travel. GPS has replaced many instruments that were common uses to locate such as a compass, sextant and maps. This electronic device is constantly improving and allows each of us to identify the simplest way. GPS consists to identify our position represented on a screen of a GPS used. Its ease of use makes no reference to its unusual history and how much this system is complex and sophisticated through satellites, which compose the system and the process to create maps.
The GPS was born following the defeat of the United States to Vietnam War. After analyzing the causes of this defeat, the US military realized that the location of its troops and its vehicles was not accurate and was one of the principal causes of this failure. Thus, the US Department of Defense decided to create its own location system called GPS (Global Position System). Following the launch of the first artificial satellite by the Soviet, the American researchers have perceived that the frequency sounds changed according to its movement and its distance. They concluded that a satellite could be a location tool. In 1959, "the Navy built the first satellite navigation system called TRANSIT and was intended to locate submarines"[Mar12]. In 1974, the US launched their first satellite GPS system "NAVSTAR" (Satellite Navigation for Time and Ranging). It included 11 satellites in 1985. In 1986, a new more powerful GPS system is developed and starts to replace the Transit system.
