The Global Positioning System (GPS) was developed by the U.S. Department of Defense and MIT to provide precise location and time information to military users from a system of orbiting satellites. Originally intended for military use, GPS is now freely accessible to anyone with a GPS receiver and is used widely for navigation, surveying, and tracking applications both on land and sea. Maintained by the U.S. government, GPS consists of over 30 active satellites orbiting 20,200 km above the Earth that transmit signals allowing GPS receivers to determine their precise location.