The Global Positioning System (GPS) is the only fully functional
Global Navigation Satellite System (GNSS). Utilizing a constellation of at least
24 Medium Earth Orbit satellites that transmit precise microwave signals, the
system enables a GPS receiver to determine its location, speed, direction, and time.
Other similar systems are the Russian GLONASS (incomplete as of 2007) and the upcoming
European Galileo positioning system.
Developed by the United States Department of Defense, GPS is officially named NAVSTAR GPS
(Contrary to popular belief, NAVSTAR is not an acronym, but simply a name given by Mr. John Walsh,
a key decision maker when it came to the budget for the GPS program). The satellite constellation is
managed by the United States Air Force 50th Space Wing. The cost of maintaining the system
is approximately US$750 million per year, including the replacement of aging satellites,
and research and development.
Following the shootdown of Korean Air Lines Flight 007 in 1983, President Ronald Reagan
issued a directive making the system available for free for civilian use as a common good.
Since then, GPS has become a widely used aid to navigation worldwide, and a useful tool for
map-making, land surveying, commerce, and scientific uses. GPS also provides a precise time
reference used in many applications including scientific study of earthquakes, and synchronization
of telecommunications networks.
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2007 Nasson Institute