Assignment GPS

8/7/2019 Assignment GPS

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Introduction to theIntroduction to theGlobal Positioning SystemGlobal Positioning System

Equipped By :Equipped By :

Luqman Bin JamilLuqman Bin Jamil

Adnan ShahAdnan Shah


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What is the GPS?What is the GPS?

Orbiting navigational satellitesOrbiting navigational satellites

Transmit position and time dataTransmit position and time data

Handheld receivers calculateHandheld receivers calculate latitudelatitude

longitudelongitude

altitudealtitude

velocityvelocity


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What is the Global PositioningWhat is the Global Positioning

System?System? Department of Defense developed, worldwide,Department of Defense developed, worldwide,satellitesatellite--based radio navigation systembased radio navigation system

Consists of 24 operational satellitesConsists of 24 operational satellites

Provides specially coded satellite signals thatProvides specially coded satellite signals thatcan be processed in a GPS receiver, enablingcan be processed in a GPS receiver, enablingthe receiver to compute position, velocity andthe receiver to compute position, velocity andtimetime

Four GPS satellite signals are used to computeFour GPS satellite signals are used to computepositions in three dimensions and the time offsetpositions in three dimensions and the time offsetin the receiver clockin the receiver clock


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History of the GPSHistory of the GPS

19691969Defense Navigation SatelliteDefense Navigation Satellite

System (DNSS) formedSystem (DNSS) formed

19731973NAVSTAR Global PositioningNAVSTAR Global PositioningSystem developedSystem developed

19781978first 4 satellitesfirst 4 satellites

launchedlaunched

Delta rocket launchDelta rocket launch


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History of the GPSHistory of the GPS

1993199324th satellite24th satellite

launched;(21 active, 3launched;(21 active, 3

spare) initialspare) initial

operational capabilityoperational capability

19951995full operationalfull operational

capabilitycapability

May 2000May 2000MilitaryMilitaryaccuracy available toaccuracy available to

all usersall users


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SatellitesSatellites

Each GPS satellite orbits the Earth twice a dayEach GPS satellite orbits the Earth twice a day

Each satellite transmits signals to EarthEach satellite transmits signals to Earth

GPS receivers measure the time between whenGPS receivers measure the time between when

satellites sent a signal relative to the GPSsatellites sent a signal relative to the GPS

receiver receiving the signalreceiver receiving the signal

Tells how far away the satellite isTells how far away the satellite is

Signals from several satellites will give accurateSignals from several satellites will give accurateresultsresults


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Component of the SystemComponent of the System

Space segmentSpace segment 24 satellite vehicles24 satellite vehicles

Six orbital planesSix orbital planes

Inclined 55Inclined 55oo withwithrespect to equatorrespect to equator

Orbits separated by 60Orbits separated by 60oo

20,200 km elevation above20,200 km elevation aboveEarthEarth

Orbital period of 11 hr 55Orbital period of 11 hr 55minmin

Five to eight satellitesFive to eight satellitesvisible from any point onvisible from any point onEarthEarth

Block I Satellite VehicleBlock I Satellite Vehicle


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Where are the 24 GPS satellites?Where are the 24 GPS satellites?

The 24 GPS satellites (21 active, 3The 24 GPS satellites (21 active, 3spare) are in orbit at 10,600 milesspare) are in orbit at 10,600 milesabove the earth. The satellites areabove the earth. The satellites arespaced so that from any point onspaced so that from any point onearth, four satellites will be aboveearth, four satellites will be abovethe horizon. Each satellite containsthe horizon. Each satellite contains

a computer, an atomic clock, and aa computer, an atomic clock, and aradio.With an understanding of itsradio.With an understanding of itsown orbit and the clock, theown orbit and the clock, thesatellite continually broadcasts itssatellite continually broadcasts itschanging position and time On thechanging position and time On theground, any GPS receiver containsground, any GPS receiver containsa computer that "triangulates" itsa computer that "triangulates" its

own position by getting bearingsown position by getting bearingsfrom three of the four satellites.from three of the four satellites.The result is provided in the form ofThe result is provided in the form ofa geographic positiona geographic position -- longitudelongitudeand latitudeand latitude -- to, for most receivers,to, for most receivers,within a few meterswithin a few meters


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Control Segment

Space Segment

User Segment

Three Segments of the GPSThree Segments of the GPSThree Segments of the GPSThree Segments of the GPS

Monitor Stations

Ground

Antennas

Master Station


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Position and coordinates.Position and coordinates.

The distance anddirection betweenThe distance anddirection between

any two waypoints, or a position and aany two waypoints, or a position and a

waypoint.waypoint.

Travel progress reports.Travel progress reports.

Accurate time measurement.Accurate time measurement.

Four Basic Functions of GPSFour Basic Functions of GPS


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Position is Based on TimePosition is Based on TimePosition is Based on TimePosition is Based on Time

T + 3Distance between satellite

and receiver = 3 times the

speedof light

TSignal leaves satellite at time T

Signal is picked up by the

receiver at time T + 3

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Assignment GPS