GPS is the acronym of (Global Positioning System) a satellite navigation system managed by the United States Department of Defense.

Initially the GPS system was projected for military purposes, to furnish accurate targeting of various military weapons as cruise missiles.

Subsequently, to also take advantage of this technology in the civil applications, the US Government decided to liberalize the GPS system, but limiting however the precision to some hundred of meters (100/150 meters).

Only in May 2000, the Bill Clinton president, decided to remove the limitations, carrying the signal to the 10/20 meters, with a global terrestrial coverage managed by 24 satellites.

Today on the market there are different devices as PDA, pocket pc phone, cellular, smartphone that directly integrates a GPS receiver, while separate receivers can easily be connected, to the mobile devices without GPS, using USB cables or wireless Bluetooth connections.

Soon also in Europe it will be active the new terrestrial positioning system, better known also with the Galileo name or Galileo Positioning System.