Global Positioning System

GLOBAL POSITIONING SYSTEM  INTRODUCTION: ABSTRACT Global Positioning System (GPS) is Global Positioning System the only system today able to show ones (GPS) is a satellite-based own position on the earth any time in any navigation system developed weather, anywhere. This paper addresses and operated by the US this satellite based navigation system at Department of Defense. GPS length. The different segments of GPS viz. permits land, sea and airborne space segment, control segment, user users to determine their threesegment are discussed. In addition, how this dimensional position, velocity amazing system GPS works, is clearly and time. This service is described. The various errors that degrade available to milatary and the performance of GPS are also included. civilian user Around the clock DIFFERENTIAL GPS, which is used to in all weather,any where in improve the accuracy of measurements, is the world also studied. The need, working and implementation of DGPS are discussed at length. Finally, the paper ends with advanced application of GPS.

Three Segments of the GPS Space Segment

User Segment Control Segment Ground Antennas Master Station

Monitor Stations

History of the GPS  1969—Defense

 1993_24TH

satellite Navigation Satellite launched ,initial System (DNSS) formed operational capability  1973—NAVSTAR Global  1995_ full Positioning System operational capability developed  May 2000_military  1978—first 4 satellites launched accuracy available Delta rocket launch to all users.

The GPS Constellation

Position is Based on Time Signal leaves satellite at time “T”

T

T+3

Signal is picked up by the receiver at time “T + 3”

Distance between satellite and receiver = “3 times the speed of light”

How does GPS work? 

Satellite ranging   



Distance measurement  

 

Satellite locations Satellite to user distance Need four satellites to determine position Radio signal traveling at speed of light Measure time from satellite to user

Low-tech simulation Pseudo random code Comlex signals Unique satillite to each satellite All satellites use same freqency information theory economial

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  private and recreation travelling by a car , hiking, climing, biking vehicle control English channel tunnel Agriculture , aviation general and commercial , space craft 

GPS Operation Jargon  “Waypoint”

or “Landmark”  “Track” or “Heading”  “Bearing”  CDI  Route  Mark  GOTO GPS/Digital Telephone

GPS Websites  

  

REFERENCES: Satellite CommunicationT.Pratt And C.W.BostainJohn Wiley And Sons. www.iec.org www.sss-mag.com http://www.gps education resource.com/gps news.htm

USDO NAVSTAR Home page information on the GPS constillation How stuff works GPS good everyday language explanation Trimble GPS tutorial flash animations GPS Way point registry data base of coordinates 

CONCLUSION 

GPS, a satellite based navigation system, thus can be used to determine the position of an object on earth. As discussed above, its application field is vast and new applications will continue to be created as the technology evolves.



GPS can also interfaced with other similar projects such EU’S ,GALILEO to account for unpredictable applications.thus the GPS constellation,like man made stars in the sky ,can be used for guiding and navigation.