The global Positional System(GPS)
Introduction
Definition
Space segment
Control segment
User segment
Bibliography
Bibliography
http://en.wikipedia.org/wiki/Global_Positioning_System
http://www.gps.gov/applications/
http://www.gps.gov/students/
http://www.gps.gov/systems/gps/space/
http://www.gps.gov/systems/gps/control/