This document provides information about a navigation system presentation. It includes: - An introduction to navigation systems, their history, components, working, and errors/limitations. - The presentation will be given by 5 group members and will explain navigation systems in automobiles, their history from 1973, and components including satellites, control stations, and receivers. - It will describe how GPS works using trilateration to determine a receiver's position from distances to 3 or more satellites, and will discuss errors from multipath signals, almanac inaccuracies, and clock errors in receivers. - The presentation concludes by noting it will also cover applications of navigation systems.

1. Navigation
System
Date:

2. Group Members
• Aamir Sultan
• Hamza Parvez
• Muhammad Usman
• Adnan Walidad
• Muhammad Waqar

3. The Presentation will explain:
• Introduction to Navigation System
• Navigation System in automobiles
• History
• Components
• Working
• Errors &limitations
• Applications

4. Introduction &History
Presentor:Muhammad Usman

5. 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,

6. 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.

7. 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.

8. History
Ivan Alexander
( physicist &engineer)
Bradford Parkinson
(engineer)
Roger L.Easton
(scientist)
Inventors of GPS

9. Components
Presentor:Adnan Walidad

10.  What are the components of GPS?
• There are 3 components of GPS.
1)Space Component
It 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

11. 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.

12. Components
Delta Rocket
(satellite launcher)
GPS satellite
Arrangement of
satellites in space
around earth

13. Components
 What is an Atomic clock?
• An atomic clock uses the vibrations of an
atom to calculate the time .

14. Components
Atomic Clocks

15. Components
2)Control component
The 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.

16. Components
Different Locations of Control Stations

17. 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.

18. Components
GPS receivers

19. Working
Presentor:Aamir Sultan

20. Working
 How GPS works?
1. Distance of receiver from 3 satellites.
2. Location of these 3 satellites.
3. Distance of receiver from these locations.

21. 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)

22. Working
Car with GPS
receiver
Satellite 1

23. 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 .

24. Working
Car with GPS
receiver
Satellite 1
20,200Km
City A

25. Working
 How distance between GPS receiver and city
A is determined?
 Pythagoras theorem
Hyp^2=Perp^2+Base^22
Hyp

26. Working
Car with GPS
receiver
Satellite 1
p=20,200Km
b=?
s^2=p^2+b^2
b^2=s^2-p^2
Distance between receiver
and city A

27. Working
Car with
GPS
receiver
Satellite 1
p=20,200Km
b
Distance between receiver
and city A
Other Possibilities

28. Working
b

29. Working
Satellite 2
c
City B

30. Working

31. Working
Map
•Plot the data on map

32. Working
Trilatrelation

33. Working

34. Working
 Still we do not know that whether we are at
position P1 or P2.
 Satellite 3
d City C

35. working
d

36. Working

37. Working
So we are at position P1 on the map

38. Errors & Limitations
Presentor:Hamza Parvez

39. Errors &Limitations
There 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.

40. 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”.

41. 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 .

42. 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.

43. 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.

44. Applications
Presentor:Muhammad Waqar

45. Applications

46. The End
Thanks for your participation.