SURVEYING Subject Code : Presented By : Topic : GPS ( ) ( ) ( )

What is GPS… The Global Positioning System (GPS) is a Constellation of Earth-Orbiting Satellites maintained by the United States Government for the purpose of defining Geographic positions on & above the Surface of the Earth.

History… 1969—Defense Navigation Satellite System (DNSS) formed 1973—NAVSTAR Global Positioning System developed 1978—first 4 satellites launched 1993—24th satellite launched; initial operational capability 1995—full operational capability

It consist of three segment… Control Segment Space Segment User Segment

 Military.  Search and rescue.  Disaster relief.  Surveying.  Marine, aeronautical and terrestrial navigation.  Remote controlled vehicle and robot guidance.  Satellite positioning and tracking.  Shipping.  Geographic Information Systems (GIS).  Recreation. User Segment

Control Segment Space Segment User Segment Three Segments of the GPS Monitor Stations Ground Antennas Master Station

GPS Satellites GPS Satellites The GPS Operational Constellation consists of 24 satellites that orbit the Earth in very precise orbits twice a day. GPS satellites emit continuous navigation signals.

Application of GPS technology Location - determining a basic position Navigation - getting from one location to another Tracking - monitoring the movement of people and things Mapping - creating maps of the world Timing - bringing precise timing to the world For Military uses -- Foot soldiers -- Vehicles -- Aircraft -- Marine vessels also for survey and geology

GPS Satellite Vehicles… Four atomic clocks Two solar panels Battery charging Power generation 1136 watts S Band antenna satellite control 12 element L Band antenna – user communications

Where GPS can not be used… Inside buildings In caves Parking garages Other subterranean locations Under water

Thanks