From WordNet (r) 3.0 (2006) [wn]:
GPS
n 1: a navigational system involving satellites and computers
that can determine the latitude and longitude of a receiver
on Earth by computing the time difference for signals from
different satellites to reach the receiver [syn: {Global
Positioning System}, GPS]
From The Free On-line Dictionary of Computing (8 July 2008) [foldoc]:
Global Positioning System
GPS
<communications> (GPS) A system for determining postion on the
Earth's surface by comparing radio signals from several
satellites. When completed the system will consist of 24
satellites equipped with radio transmitters and atomic clocks.
Depending on your geographic location, the GPS receiver
samples data from up to six satellites, it then calculates the
time taken for each satellite signal to reach the GPS
receiver, and from the difference in time of reception,
determines your location.
["Global Positioning by Satellite"? Precison? Coverage? Web
page?]
(1998-02-10)