Above: Artist's conception of a Global Positioning System (GPS) satellite in orbit. (Illustration courtesy of NASA.) Below: A GPS ground receiver -- here set up on the flank of Augustine Volcano (Cook Inlet, Alaska) -- recording the signals sent by four or more of the orbiting GPS satellites. (Photograph by Jerry Svarc, USGS.)
URL: https://pubs.usgs.gov/publications/text/GPS.html
Last updated: 05.05.99
Contact: bhanks@usgs.gov