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Transcript of Navigation System
Navigation System
Date:
Group Members
• Aamir Sultan• Hamza Parvez• Muhammad Usman • Adnan Walidad • Muhammad Waqar
The Presentation will explain:
• Introduction to Navigation System• Navigation System in automobiles• History• Components• Working• Errors &limitations• Applications
Introduction &History Presentor:Muhammad Usman
Introduction
What is a Navigation System?• The word Navigation is a combination of two
Latin words “navis” means boat and “agire” means guide .• Traditionally meant the art or science of
moving the ships and other watercraft safely from one place to another.
• Today word Navigation used in broad sense. Navigation system define as a system
providing useful information to determine the position of a boat, car or airplane etc,
Navigation System In Automobiles
• GPS is used in automobiles for Navigation purposes.
What is GPS?• GPS stands for Global Positioning System.• GPS is the first man made Satellite
Navigation System.
History
When GPS started?• The GPS project was developed in 1973.• It became fully operational in 1995. Who invented the GPS?• GPS was invented by two American engineers
Ivan Alexander , Bradford Parkinson and an American scientist Roger L. Easton with the co-operation of US Deptt Of Defense(DoD).
Why did they start GPS?• To keep the track of enemies, but later in
1991 they open it for civilians.
History
Ivan Alexander( physicist &engineer)
Bradford Parkinson(engineer)
Roger L.Easton(scientist)
Inventors of GPS
Components Presentor:Adnan Walidad
What are the components of GPS?• There are 3 components of GPS.1)Space ComponentIt includes the satellites and Delta rockets. What Delta rockets do? • They launch the satellites. What is a satellite?• A GPS satellite is a smaller object in space which is
orbiting in its orbits around the earth at a height of 20,200km and with a speed equal to 14,000 km/hour, relative to the Earth .A satellite completes two revolution around earth in one day.
Components
Components
It is operating on solar energy. It sends GPS signals to the earth.
What is a GPS signal?• A GPS signal is a radio signal sent by the GPS
satellite ,the signal travels at speed of light(c=3x10^8 m/s).
• A GPS signal contains information about the satellite.
How many satellites GPS contain?• There are 24 satellites currently working in
GPS ,but in case of any technical error in any of 24 ,further satellites are launched.
Components
Delta Rocket(satellite launcher)
GPS satelliteArrangement of satellites in space around earth
Components
What is an Atomic clock?• An atomic clock uses the vibrations of an
atom to calculate the time .
Components
Atomic Clocks
Components
2)Control componentThe control component of a GPS includes the
stations around the world where the GPS satellites are monitored. These bases include Schriever Air Force Base in Colorado, a station in Hawaii, a station on Ascension Island, another on Kwajalein Island, and one on Diego Garcis Atoll. The control component is responsible for ensuring that the GPS satellites are in working condition and functioning properly.
Components
Different Locations of Control Stations
Components
3)User Component• The user component includes the GPS receivers. What is a GPS receiver ?• A GPS receiver is a device which receives GPS signal sent by a satellite.
A GPS receiver consist of a clock and almanac. What is a GPS receiver clock?• A GPS receiver has a clock which measures the time of the signal from
satellite to reach the GPS receiver. What is an almanac?• An almanac is a set of information. What is the function of almanac?• An almanac is just like a diary it tells the position of satellite to the
receiver , e.g. the satellite will be above the city A at 9:30:10 pm and it will be above the city B at 3:10:01 am. So it knows the position of every satellite at any time.
Components
GPS receivers
Working Presentor:Aamir Sultan
Working
How GPS works?1. Distance of receiver from 3 satellites.2. Location of these 3 satellites.3. Distance of receiver from these locations.
Working
How the distance of receiver from satellite is determined?
• s=vt (m) s=ct (m) where, c=speed of light=3x10^8 (m/s)
Working
Car with GPS receiver
Satellite 1
Distance between satellite
and receiver
s=x
Working
How the location of satellite is determined How much above the city ?• The GPS satellites are at a distance of
20,200km above the earth .
Working
Car with GPS receiver
Satellite 1
Distance between satellite
and receiver
s=x
20,2
00 K
m
City A
Working
How distance between GPS receiver and city A is determined?
Pythagoras theorem Hyp^2=Perp^2+Base^2
2
Hyp
Working
Car with GPS receiver
Satellite 1
Distance between satellite
and receiver
s=x
p=20
,200
Km
b=?
s^2=p^2+b^2 b^2=s^2-p^2
Distance between receiver and city A
Working
Car with GPS receiver
Satellite 1
Distance between satellite and receiver
s=x
p=20
,200
Km
b
Distance between receiver and city A
Other Possibilities
Working
b
Working
Satellite 2
cCity B
Working
c
Working
Map •Plot the data on map
Working
Trilatrelation
Working
P1
P2
Working
Still we do not know that whether we are at position P1 or P2.
Satellite 3
d City C
working
d
Working
P1
P2
Working
So we are at position P1 on the map
Errors & Limitations Presentor:Hamza Parvez
Errors &LimitationsThere are following errors in GPS. Multipath Errors Almanac Errors Errors In GPS Clock What are multipath errors During their traveling from satellite to GPS
receiver ,GPS signals can strike with trees, electromagnetic field, buildings etc. After striking these are reflected at a certain angle and thus increases the time to reach the receiver when the time .Producing error in distance.
Errors &Limitations
How multipath errors are corrected? They are corrected by introducing a
stationary receiver at a high altitude. First the GPS signal sent to these stationary satellite and then sent to car GPS signal
receiver. This method is called “differential method”.
Errors &Limitations
What are Almanac Errors?• Due to the pull force of sun and moon on the
satellites, the position of their orbits are slightly changed .
• Now ,although the position of their orbits are changed but almanac shows the orignal position .
Errors &Limitations
How almanac error is corrected?• It is corrected by updating the almanac. Who updates the almanac?• Almanac is updated by the control
department.
Errors &Limitations
What are the GPS clock Errors?• A GPS uses an ordinary quartz clock for
measuring time ,which can not measure too small time of a GPS signal from satellite
to GPS receiver. How this Error is corrected? The error is corrected by using mathematical
equations.
Applications Presentor:Muhammad Waqar
Applications
The End
Thanks for your participation.