Global_Positioning_System

The Global Positioning System, usually called GPS, and originally caled NAVSTAR, is a satellite navigation system used for determining one's precise location anywhere in the world.  A GPS receiver receives transmissions from three satellites, and determines one's position by triangulating this data.

The GPS was designed by and is controlled by the [[United States/Department of Defense|United States Department of Defense]].  It is used by countless civilians as well, who can use the GPS's Standard Positioning Service free of charge.  A more accurate Precise Positioning Service is availble to the United States military and other, mostly government users.

The GPS normally consists of 24 satellites in 6 orbital planes.  Each satellite circles the earth twice every day.

The first GPS satellite was launched in 1978.  The final, 24th satellite was launched in 1994.