Global Positioning  System(GPS)

  System that provides location  and time  information  in all weather  conditions any where on near the Earth where  is an unobstructed line of sight to four or more GPS  satellite the  system provides to critical capabilities to military civil and commercial  users around  the world GPS satellites circle the earth twice a day  in very precise orbit and transmit signal information  to Earth ,GPC receivers take this  information and use triangulation to calculate  the users exact location E essentially .the GPS receiver  time difference tells  the GPS receiver  how for  away the satellite is now with  distance measurement from afaw more satellites . the receiver can determine the users position and display it on the units electronic map.