A presentation on global positioning system presented under the course of precision agriculture in Sylhet Agricultural University ,Sylhet -3100

1. Welcome to my
presentation
Abu Hanif
B.Sc Agrill. Eng.
ID: 1405017, Reg: 2503

2. G.P.S. SYSTEM

3. CONTENTS
• HISTORY.
• WHAT IS GPS?
• GPS ELEMENTS.
• HOW IT WORKS?
• GPS SIGNALS & FREQUENCIES.
• SOURCES OF GPS SIGNAL ERRORS.
• HOW TO IMPROVE THE ACCURACY OF GPS.
• LIMITATIONS.
• APPLICATIONS(VEHICLE TRACKING).
• FUTURE OF GPS.
• CONCLUSION.

4. HISTORY:
• Navigating by stars (requires clear nights and careful measurements)
most widely used for centuries
• The GPS project was developed in 1973 to overcome the limitations
of previous navigation systems.
• GPS was created and realized by the U.S. Department of Defense
and was originally run with 24 satellites.
• It became fully operational in 1995. “Bradford Parkinson”, “Roger L.
Easton”, and “Ivan A. Getting” are credited with inventing it.

5. WHAT IS GPS?
• GPS means :
 A space-based satellite navigation system
provides location and time information in all weather.
 Maintained by the United States government and is freely
accessible by anyone with a GPS receiver.

6. GPS ELEMENTS.
Three segments
1. Space segment.
2. Control segment.
3. User segment.
Space Segment Control Segment
User Segment

7. SPACE SEGMENT
 GPS satellites fly in circular orbits at an altitude of 20,200 km and
with a
 period of 12 hours.
 Powered by solar cells.
 The satellites continuously orient themselves to point their solar
panels toward the sun and their antenna toward the earth.
 Orbital planes are centered on the Earth.
 Orbits are designed so that, at least, six satellites are always within
line of sight from any location on the planet.

8. CONTROL SEGMENT
The CS consists of 3 entities:
Master Control System
Monitor Stations
Ground Antennas

9. MASTER CONTROL STATION
The master control station, located at Falcon Air
Force Base in Colorado Springs,
Responsible for overall management of the
remote monitoring and transmission sites.
Check-up is performed twice a day, by each of 6
stations, as the satellites complete their journeys
around the earth.
Can reposition satellites to maintain an optimal
GPS constellation.

10. MONITOR STATIONS
Falcon Air Force Base in
Colorado,
Cape Canaveral,
Florida,
Hawaii,
Ascension Island in the
Atlantic Ocean,
Diego Garcia Atoll in the
Indian Ocean,
Kwajalein Island in the South
Pacific Ocean.
 Checks the exact altitude, position, speed,
and overall health of the orbiting
satellites.
 The control segment ensures that the GPS
satellite orbits and clocks remain within
acceptable limits.
 A station can track up to 11 satellites at a
time.
 This "check-up" is performed twice a day,
by each station.

11. Applications
Civilian
 Geotagging : Applying locationcoordinates to digital objects such as photographs
and other documents.Disaster Relief/Emergency Services
 Vehicle Tracking Systems
 Person Tracking Systems
 GPS Aircraft Tracking
 Telematics: GPS technology integrated with computers and mobile
communications technology in automotive navigation systems.

12. Applications
Military:
 Target Tracking: Tracking potential ground and air targets before flagging
them as hostile.
 Navigation
 Missile and Projectile Guidance: Allows accurate targeting of various military
weapons including cruise missiles and precision-guided munitions
 Reconnaissance
 Search and Rescue: Downed pilots can be located faster if their position is
known.