The Global Positioning System (GPS) is a technical marvel made  possible by a group of satellites in Earth's orbit that transmit precise  signals, allowing GPS receivers to calculate and display accurate location, speed and time information to the user.        By capturing the signals from three or more satellites (among a  constellation of 31 satellites available), GPS receivers are able to  triangulate data and pinpoint your location.      With the addition of computing power and data stored in memory such  as road maps, points of interest, topographic information and much more,  GPS receivers are able to convert location, speed and time information into a useful display format.   GPS  was originally created by the United States Department of Defense  (DOD) as a military application. The system has been active since the  early 1980s but began to become useful to civilians in the late 1990s.  Consumer GPS has since become a multi-billion dollar industry with a  wide ...