GPS is a satellite-based navigation system that provides location and time information to users around the world. It consists of 24 satellites in orbit that transmit signals used by GPS receivers to calculate the user's position. The system was developed by the United States military in the 1970s and became fully operational in 1994. GPS provides accurate positioning for applications like navigation and tracking of vehicles, ships, and other assets. It is maintained by the US government and accessible to all with a GPS receiver.

2. What’s it?
• It is a Space based satellite
navigation system.
• Provides : location and time
information in all weather
conditions.
• Maintained by the United
States government
• Accessible to anyone with a GPS
Receiver.

3. History:
• On June 26, 1993, the U.S. Air Force launched
the 24th NAVSTAR Satellite into orbit.
• The network of 24 satellites known as GPS.
• Roger L . Easton is widely credited as the
primary inventor of GPS.
• It became fully operational in 1994.

4. Types of GPS:
• They vary according to our need.
Major types:
• GPS Navigators
• Hand-held GPS
• GPS Trackers
• Emergency GPS

5.  It consist of three segments.
 Space Segment
 Control Segment
 User Segment
 Calculate :
 three-dimensional Location
 the current time.

6. Segment description:
• Space segment:
Composed of satellites.
Constellation refers to “set of satellites”
NAVSTAR composed of 24 satellites.
Function : Transmit signal from space on the basis
of which the time and position of the user is
measured.

7. • Control Segment:
Holds:
 5 ground based monitor station
 3 antennas
 a master control station
Function:
Monitor station  master controller
Antenna  GPS receiver

8. User Segment:
• Holds:
GPS Receiver
User community
• Function:
Converts SV Signals into
Position ,
time,
velocity.

9. Working:
Basically working holds three task as follows:
• The GPS transmits signals from the satellites
down to earth.
• GPS Receiver then analyzes the data that was
received.
• Then uses the mathematical concept of
triangulation to compute the exact location of
the user.

10. Accuracy:
It depends upon the types of receiver.
Most hand-held GPS units have about 10-20 meter
accuracy.
Differential GPS (DGPS) obtains much higher
accuracy.
As recorded by the roving units, producing an
accuracy greater than 1 meter.

11. Advantages:
Easy to navigate
GPS works in all weather.
100% coverage on the planet.
Easy to integrate into other technologies like Cell
phone.
Best navigating system in water.

12. Disadvantage:
GPS signals are not accurate due to some obstacles to
the signals.
Atmospheric conditions such as geomagnetic storms
makes it not accurate.
If GPS on a battery operated device, there may be a
battery failure we need an external power supply
which is not always possible

13. GPS Application:
• Google Earth is the most famous application that
uses the signals received by the GPS receivers.
• United States and European countries show a rapid
growth in using GPS for the car navigations and the
number of GPS equipped mobile phone usage.

14. Some Application:
• DeLorme Street Atlas 2010
• Gramin nRoute
• Top Grossing Apps on iTunes
• LOCiMOBILE Apps for tracking people
• GPS Tracking Lite v2.0

15. Recent Development:
Block IIA:
– upgraded version of the GPS Block II satellites.
– Developed by Rockwell International
– As of November 2012, there were 9 Block IIA
satellites.
GPS Block IIR:
-"R" in Block IIR stands for replenishment.
-Developed by Lockheed Martin
-As of November 2012, there were 12 IIR
satellites

16. Current development:
GPS Block III:
• development by Lockheed Martin
• GPS III will provide more powerful signals in
addition to enhanced signal reliability, accuracy,
and integrity.
• GPS III series is the newest block of GPS satellites

17. Future of GPS:
The future will hold a lot more surprises.
Automobiles are tested on moving on their own without
the assistance of a driver.
Tests have begun in using unmanned aircrafts.
The green plant density of a certain area can be
calculated or estimated.

19. Conclusion:
• GPS has truly helped man to advance in more ways
than one.
• It is also going to bring a great revolution by its
development.

20. Presented by,
I.Madhumithah, I M.Sc(CS).,
G.Venkataswamy Naidu College,
Kovilpatti.