What is "global positioning system"

Global Positioning System \Glob"al Po*si"tion*ing Sys"tem\ n. (gl[=o]"b'l p[-o]*z[i^]sh"[u^]n*[i^]ng s[i^]s"t[e^]m) A worldwide system of electronic navigation in which a vessel, aircraft or missile determines its latitude and longitude by measuring the transmission time from several orbiting satellites. GPS is more precise than any other navigation system available, yielding position accurate within 10 meters 95% of the time.

Syn: GPS.

Note: The precision of the GPS is dependent upon the very high timing accuracy of atomic clocks. Although the military originally intentionally degraded the signal and thus the accuracy for civilian users, GPS was nevertheless more precise than any other navigation system available. In 2000, President Clinton issued an executive order discontinuing the degrading of the signal for civilians.

On June 26, 1993 . . . the U.S. Air Force launched the 24th Navstar satellite into orbit, completing a network of 24 satellites known as the Global Positioning System, or GPS. With a GPS receiver that costs less than a few hundred dollars you can instantly learn your location on the planet -- your latitude, longitude, and even altitude -- to within a few hundred feet. This incredible new technology was made possible by a combination of scientific and engineering advances, particularly development of the world's most accurate timepieces: atomic clocks that are precise to within a billionth of a second.

--http://www4.nationalacademies.org/beyond/beyonddiscovery.nsf/web/gps?OpenDocument

n. 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 http://en.wikipedia.org/wiki/GLONASS system, or the proposed http://en.wikipedia.org/wiki/Galileo%20(satellite%20navigation) European alternative system.

The Global Positioning System (GPS), also known as Navstar, is a global navigation satellite system (GNSS) that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The GPS system operates independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the GPS positioning information. The GPS system provides critical positioning capabilities to military, civil, and commercial users around the world. The United States government created the system, maintains it, and makes it freely accessible to anyone with a GPS receiver.

The United States began the GPS project in 1973 to overcome the limitations of previous navigation systems, integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s. The U.S. Department of Defense (DoD) developed the system, which originally used 24 satellites. It became fully operational in 1995. Roger L. Easton, Ivan A. Getting and Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it.

Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS and implement the next generation of GPS Block IIIA satellites and Next Generation Operational Control System (OCX). Announcements from Vice President Al Gore and the White House in 1998 initiated these changes. In 2000, the U.S. Congress authorized the modernization effort, GPS III.

In addition to GPS, other systems are in use or under development. The Russian Global Navigation Satellite System ( GLONASS) was developed contemporaneously with GPS, but suffered from incomplete coverage of the globe until the mid-2000s. There are also the planned European Union Galileo positioning system, China's BeiDou Navigation Satellite System, the Japanese Quasi-Zenith Satellite System, and India's Indian Regional Navigation Satellite System.