global positionning system (g.p.s) m2 istre feth-allah dehmani oral presentation

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

ApplicationsGlobal Positionning System

Civilian use How to reach a place ? To locate yourself on a map (mountains, deserts…)

Agriculture

ApplicationsGlobal Positionning System

Military use To guide missiles. To chase someone.

Limits, competitionsGlobal 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, competitionsGlobal 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