Noun

Singular global positioning system

Plural global positioning systems

global positioning system (plural global positioning systems)

1. Any system which enables a mobile receiver to determine its precise location based on signals received from satellites such as those of the US military, the Russian GLONASS system, or the proposed Galileo European alternative system.

Synonyms

• GPS

The Global Positioning System (GPS) is a space-based global navigation satellite system that provides reliable location and time information in all weather and at all times and 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 by anyone with a GPS receiver.

The GPS System was created and realized by the American Department of Defense (DOD) and was originally based on and run with 24 satellites. It was established in 1973 to reduce the large number of navigation aids and to overcome the limitations of previous navigation systems.

Structure

The GPS consists of three parts: the space segment, the control segment, and the user segment. The U.S. Air Force develops, maintains, and operates the space and control segments. GPS satellites broadcast signals from space, which each GPS receiver uses to calculate its three-dimensional location (latitude, longitude, and altitude) plus the current time.

The space segment is composed of 24 to 32 satellites in medium Earth orbit and also includes the boosters required to launch them into orbit. The control segment is composed of a master control station, an alternate master control station, and a host of dedicated and shared ground antennas and monitor stations. The user segment is composed of hundreds of thousands of U.S. and allied military users of the secure GPS Precise Positioning Service, and tens of millions of civil, commercial, and scientific users of the Standard Positioning Service (see GPS navigation devices).