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Global positioning system


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Global positioning system

  1. 1. Global Positioning System BY DHIREN PARYANI 0206CS111026
  2. 2. What is the GPS?  Orbiting navigational satellites  Transmit position and time data  Handheld receivers calculate  latitude  longitude  altitude  velocity  It is maintained by the US government and is freely accessible to anyone with a GPS receiver
  3. 3. History of the GPS  1969—Defense Navigation Satellite System (DNSS) formed  1973—NAVSTAR Global Positioning System developed  1978—first 4 satellites launched Delta rocket launch
  4. 4. History of the GPS  1993—24th satellite launched; initial operational capability  1995—full operational capability  May 2000—Military accuracy available to all users
  5. 5. How does GPS work?  Measuring distance by measuring time Satellites send coded signals indicating their position in space and the exact time the signals are being sent  Receivers use the time it takes signal to travel from satellite to receiver to determine distance from satellite to receiver  Information from multiple satellites is used to determine position through ‘triangulation’ 
  6. 6. Three Segments of the GPS Space Segment User Segment Control Segment Ground Antennas Master Station Monitor Stations
  7. 7. Control Segment US Space Command Hawa ii Cape Canaveral Kwajalein Atoll Ascension Is. Master Control Station Diego Garcia Monitor Station Ground Antenna
  8. 8. Space Segment
  9. 9. 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. 
  10. 10. GPS Communication and Control
  11. 11. GPS receivers  A GPS receiver's job is to locate four or more satellites, figure out the distance to each, and use this information to deduce its own location.    Hand-held receivers for recreational use with accuracy of 10-15 meters Vehicle mounted receivers for navigation or agricultural use with accuracy of < 1 meter Backpack or tripod mounted receivers for surveying use with accuracy of 5 – 10 centimeters
  12. 12. More about GPS receivers  Receivers require clear line-of-sight; thus, they will not work indoors or where tall objects obscure the sky
  13. 13. Errors  Troposphere causes delays in code and carrier But they aren’t frequency dependent But the errors are successfully modeled  Errors due to Multipath  Receiver noise
  14. 14. Errors  Forces on the GPS satellite  Earth is not a perfect sphere and hence uneven gravitational potential distribution  Other heavenly bodies attract the satellite, but these are very well modeled  Not a perfect vacuum hence drag but it is negligible at GPS orbits  Solar radiation effects which depends on the surface reflectivity, luminosity of the sun, distance of to the sun. this error is the largest unknown errors source
  15. 15. DGPS  Errors in one position are similar to a local area  High performance GPS receiver at a known location.  Computes errors in the satellite info  Transmit this info in RTCM-SC 104 format to the remote GPS
  16. 16. 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
  17. 17. Application of GPS Technology  Private and recreation  Traveling by car  Hiking, climbing, biking  Vehicle control  Mapping, survey, geology  English Channel Tunnel  Agriculture  Aviation  General and commercial  Spacecraft  Maritime
  18. 18. Screen Capture of a GPS enabled phone
  19. 19. GPS Navigation
  20. 20. Any Queries?
  21. 21. Thank You!!