WordNet (r) 3.0 (2006):

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]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

GPS
       Global Positioning System (GPS)


The Free On-line Dictionary of Computing (30 December 2018):

Global Positioning System
GPS

    (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)