GPS
The
Global Positioning System (
GPS) is a space-based
satellite navigation system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites. It is maintained by the
United States government and is freely accessible to anyone with a
GPS receiver.
The GPS program provides critical capabilities to military, civil and commercial users around the world. In addition, GPS is the backbone for modernizing the global air traffic system.
The GPS project was developed in 1973 to overcome the limitations of previous navigation systems,[SUP]
[1][/SUP] integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s. GPS was created and realized by the
U.S. Department of Defense (DoD) and was originally run with 24 satellites. It became fully operational in 1994.