This a seminar on GPS Technology that will cover the topic for the final year student.

2. Introduction to GPS
The Global Positioning System (GPS) is a
satellite based navigation system.
 The Global Positioning System (GPS) is a
location system based on a constellation of
about 24 satellites orbiting the earth at
altitudes of approximately 11,000 to
12,000miles.
The concept of GPS was introduced by united
states department of defense(DOD).

3. What is GPS?What is GPS?
• GPS is the only system today able
show your exact position on the
earth any time, in any weather,
any where ground stations, located
world wide, continuously monitor
them.
• Also known as NAVSTAR
( Navigation Satellite Timing and
Ranging Global positioning
system) provides instantaneous
position, velocity and time
information.

4. 1969- Defense Navigation Satellite system (DNSS)
formed.
1973- NAVASTAR Global Positioning System
Developed.
1978- First 4 Satellites launched.
1993—24th satellite launched.
1995—full operational capability.
May 2000—Military accuracy available to all users.
History of GPS

5. SATELLITES IN SPACE
GROUND CONTROL STATIONS
RECEIVERS
Elements Of GPS

6. Operational GPS Structure
 SPACE SEGMENT
CONTROL SEGMENT
USER SEGMENT

8. Space segment
•24 GPS space
vehicles satellite (SV).
•Satellites orbit the
earth in 12hr.
•There are six orbital
planes with
nominally four SVs
in each.
•This constellation
provides 5 to 8 SVs
from any point on the
earth.

9. • The control segment consist of tracking stations
located around the world.
•The GPS control segment called the operational
control system ,includes all fixed locations ground
based monitor stations located throughout the
world.
Control segment

10. User segment
•The GPS user segment consist of GPS
receivers and user community.
•The GPS receivers coverts SV signals into
position, velocity and time estimates.
•Four satellites required to compute the
four dimensions of x,y,z(position) and time.

12. Working of GPS
The GPS system works by
determining how long it takes a
radio signal transmitted from a
satellite to reach a land based
receiver and then, using time to
calculate distances between the
satellite and earth station
receiver.
The distance between the
satellite and receiver the
mathematical relationship.
Distance =velocity *time.

13. Advantages of GPS
-Fast speed .
-Leads u in right direction .
-Helps improve mapping skills.
-Makes navigation easier .
-Has panic buttons built in .
-You can be found easier if in danger or in
accident .

14. Disadvantages of GPS
People focus on GPS more than road
accident.
Needs good care and handling.
 Required External power.
Needs batteries (handheld ones).

15.  Services:
Standard Positioning Service
Precise Position Service
Differential Global Positioning System

16. Standard Positioning Service
Civil worldwide use the SPS without charge or
restrictions.
Most of the receivers are capable of receiving
the information's .
100m Horizontal accuracy.
156m Vertical accuracy.
340 nanoseconds time accuracy.

17. Precise Position Service
 Authorized users with cryptographic equipment
and keys and specially equipped receivers use PPS.
 PPS is highly accurate military positioning,
velocity and timing service which will be available
on a continuous, worldwide basis to users.
 22m horizontal accuracy.
27.7m Vertical accuracy.
200 nanosecond time accuracy.

18. It is used to correct bias
errors at one location with
measured bias errors at a
known position.
 DGPS removes common
mode errors common to
both reference and remote
receiver.
DGPS accuracy of 1-
10m.
 DGPS

20. Application of GPS Technology
Positioning
Navigation system
Military purpose
Time synchronization
Tracking

21. Satellite Geometry :
Propagation Delay Internal Clock Errors :
 Multipath :
Limitations of GPS

22. Global positioning Satellite
GPS satellites orbit at a height of
about
12,000 miles (19,300 km) and
orbit the
earth once every 12 hours.
About 24 GPS satellites orbit
the earth every
12 hours.

23.  Conclusion
The technology of the Global Positioning System is allowing for
huge changes in society. The applications using GPS are
constantly growing. The cost of the receivers is dropping while at
the same time the accuracy of the system is improving. This
affects everyone with things such as faster Internet speed and
safer plane landings.
 more reliable and accurate measurements.
 less costly to corporations - since the error
removing equipment will no longer be needed.
 more affordable and accessible to consumers.
 greater incentive for the development of new
uses.

24. THANKTHANK
YOU ONE &YOU ONE &
ALLALL