GPS TechnologyCS302 PRESENTATION

Presented byAbhishek B JangidMd Syed AhamadNikhil CherianMd Rahul Islam

GPS Technology

2Reference

Wikipedia Documentation:

http://www.nhdfl.org/library/pdf/Forest%20Protection/Introduction%20to%20Global%20Positioning%20System.pdf

http://www.gps.gov/systems/gps/control/

GPS Technology

3What is GPS(The Global Positioning System) Technology???

provides users with positioning, navigation, and timing (PNT) services

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4Three Segments of GPS

Space Segment A constellation of 32 satellites(since 2012). Earlier it

was 24 satellites. Satellites are located 12000 miles above from earth. 6 orbital planes inclined 55 degree with the equator. Their orbit ensures receiving a unique code signal from at

least four satellites at any given time Distance is calculated each signal received at the ground

Available in 24Hrs on the globe with an accuracy of 100 meters

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5Control Segment

16 monitoring stations (10 NGA + 6 air force ) and master control station manage & monitor the constellation(Before it was only 5 stations).

Basis of GPS technology is precise of time & position information.

Tracts the satellites To correct the orbital and time information

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7User Segment

User Segment Consists of users and their GPS receivers Users are limitless

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8But Why Satellites??

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9Idea!!

•Effective for thousands of miles.•Can be tracked with more accuracy.

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10GPS distance

Trilateration (a more complex version of triangulation) to determine its position on the surface of the earth by timing signals from three satellites in the Global Positioning System.

Demonstrate using 2D visualization. The 3 satellites can locate objects in

their range.

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11Trilateration

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12Measuring distance

They constantly broadcast 2 pieces of information: Location and Time

Use electromagnetic waves to carry the signal. (c= 300,000 km/s) Lets say ,they have synchronised their clocks. We

can use a time line to measure the respective time to reach the receiver. Then by using , t*s=d (t=time ,s=300,000 km/s ,d=distance.

We can measure distance ,d. Then by using the Location provided ,we can exactly locate the place of receiver.

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13Measuring distance using clock

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14How GPS Works!

The GPS receivers first download the orbital information of all the satellites and stored it for future use

Triangulation Once both satellite and position are known for

at least 4 satellites, the receiver can determine a position by triangulation.

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16GPS Errors

User mistakes account for most GPS errors Satellite clock errors Orbit errors Ionospheric and Tropospheric interference Multipath interference, Selective availability, No.

of satellite visible, satellite geometry.

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17Some GPS terminology

2D Positioning There may be a substantial error in the horizontal

coordinate 3D Positioning

More accuracy

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THANK YOU