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Feth-Allah DEHMANI. Oral Presentation. Global Positionning System (G.P.S). M2 ISTRe. Global Positionning System. SUMMARY. Presentation ( When ? , Where ?, Why ?...) How it works ? Applications Limits , competition. Global Positionning System. Presentation. - PowerPoint PPT Presentation
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Global Positionning System(G.P.S)
M2 ISTRe
Feth-Allah DEHMANI
Oral Presentation
Global Positionning System
Presentation (When ? , Where ?, Why ?...)Presentation (When ? , Where ?, Why ?...)
How it works ?How it works ?
ApplicationsApplications
Limits, competitionLimits, competition
SUMMARY
Presentation
Invented in 1978 by USA’s defence department
Civilian using allowed in 1985
Can position every place in Earth every time
Global Positionning System
Presentation
24 satellites
Elevation = 20,200 Km
Send orbital position and the exact time of emission
GPS Transmitters
Global Positionning System
Presentation
GPS Receptor
Electronic card
Data treatment
Radio transmissio
n
NMEAnorm
Antenna
Global Positionning System
How it works
How to localize ?
For each satellite… The receptor chooses the maximum visible satellites.
Calculates distance D = S / T
Calculates T = TOR – TOS
Global Positionning System
It saves time of sending (TOS) and time of reception of data (TOR).
1 satellite somewhere on a sphere.
How to localize ? 2 satellites somewhere on a cercle. 3 satellites latitude and longitude. 4 satellites latitude , longitude and
altitude.
Global Positionning System
How it works
NMEA norm Encryption which allow data processing by a computer.
Datas are sending to the computer with sentences form called frame.
Exemple
RMC sentence
Latitude Longitude
Global Positionning System
How it works
Applications
Global Positionning System
Civilian use How to reach a place ?
To locate yourself on a map (mountains, deserts…)
Agriculture
Applications
Global Positionning System
Military use To guide missiles.
To chase someone.
Limits, competitions
Global Positionning System
Impresisions due to the receptor intern clock.
(1nS = 30 m)
USA monopoly on this systeme they can introduce errors on datas emited by satellites.
New GPS satellite have problems with data emitted
It is not consistent with data from the other generation of satellite
Limits, competitions
Global Positionning System
Since 1999 : European Positionning system named Galileo
- Better accuracy : < 1m
- Inform the user within seconds of a failure of any satellite
- Ready in 2010
Thank you !
Global Positionning System
