Global Positioning System (GPS) is a satellite-based navigation system consisting of 24 satellites and their ground stations. It is used worldwide to determine accurate positions on Earth. GPS was developed by the US Department of Defense and provides worldwide coverage, navigation capabilities with 10-20 meter accuracy, and a common coordinate system to replace existing systems. It works by satellites continuously broadcasting time signals, which are used by GPS receivers to calculate distances and determine the user's location. GPS has many applications including navigation, mapping, tracking resources and people, aviation, and defense uses such as missile guidance systems.

1. Introduction to Global Positioning systems
and its Applications
Prof. Sumant Das
Dept. of Civil Engg.
MEFGI, Rajkot

2. Global Positioning System (GPS)

3. Global Positioning System (GPS)
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In 1973 the U.S. Department of Defense
decided to establish, develop, test, acquire,
and deploy a spaceborne Global Positioning
System (GPS). The result of this decision is the
present NAVSTAR GPS (Navigation Satellite
Timing And Ranging Global Positioning
System).

4. Definition of GPS:
The Global Positioning System
(GPS) is a worldwide satellitebased radio navigation system
formed from a constellation of
24 satellites and their ground
stations. It’s used to determine
accurate geodetic position &
altitude on the earth surface.

5. GPS General Characteristics
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Developed by the US
Department of Defense
Provides
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Accurate Navigation
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10 - 20 m
Worldwide Coverage
24 hour access
Common Coordinate System
20,200 Km above the Earth
Designed to replace existing
navigation systems
Accessible by Civil and Military

6. Basic Principles of GPS:
 The GPS System Consists of 24 Satellite
that broadcast Signals containing
information about their position and time.
 A GPS receiver processes signal from at
least 4 Satellites.
The GPS system and receiver is the
constancy of the speed of light.

7. GPS – How it works
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All satellites have clocks set to exactly the same time.
All satellites know their exact position in space from
data sent to them from the systems controllers.
Each satellite transmits its position and a time signal.
The signals travel to the receiver delayed only by
distance traveled.
The receiver calculates the distance to each satellite
and trilaterates its own position.

12. Types:
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Single frequency- Static mode GPS surveying
Dual frequency- requires post processing only.

13. GPS Segments
Space Segment
Space Segment
24 Satellites
4 satellites in 6 Orbital Planes
inclined at 55 Degrees
20200 Km above the Earth
12 Hourly orbits
In view for 4-5 hours
Designed to last 7.5 years
Different Classifications
Block 1, 2, 2A, 2R & 2 F
Control Segment
User Segment
Control Segment
1Master Control Station
Responsible for collecting tracking data from the
monitoring stations and calculating satellite
orbits and clock parameters
2.5 Monitoring Stations
Responsible for measuring
pseudorange data. This orbital
tracking network is used to
determine the broadcast
ephemeris and satellite clock
modeling
Ground Control Stations
Responsible for upload of information to the
satellites
User Segment
1.The most visible segment
2 GPS receivers are found in
many locations and applications

14. Three Segments of the GPS
Space Segment
User Segment
Control Segment
Ground
Antennas
Master Station
Monitor Stations

15. Space Segment

4 satellites in 6 Orbital
Planes inclined at 55
Degrees
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• 12 Hourly orbits
24 Satellites
20200 Km above the Earth
Orbits
Equator
4
55
3
2
1
Satellites
– In view for 4-5 hours
• Designed to last 7.5 years
• Different Classifications
– Block 1, 2, 2A, 2R & 2 F

16. Control Segment
Monitor and Control
Colorado
Springs
Hawaii
Master Control Station
Monitor Station
Ground Antenna
Kwajalein
Ascension
Islands
Diego
Garcia

17. Control Segment
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Master Control Station
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Responsible for collecting tracking data from the monitoring
stations and calculating satellite orbits and clock parameters
5 Monitoring Stations
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Responsible for measuring pseudorange data. This orbital
tracking network is used to determine the broadcast
ephemeris and satellite clock modeling

Ground Control Stations
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Responsible for upload of information to the satellites

18. User Segment
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The most visible segment
GPS receivers are found in many
locations and applications

19. GPS Segments
Space Segment
Satellite Constellation
User Segment
Ground
Antennas
Monitor
Stations
Master Control Station
AFSCN
FAIRBANKS
Control Segment
ENGLAND
COLORADO SPRINGS
SOUTH
KOREA
USNO WASH D.C.
VANDENBERG, AFB
CAPE CANAVERAL
Master Control Station (MCS)
Ground Antenna (GA)
Advanced Ground Antenna
Monitor Station (MS)
BAHRAIN
HAWAII Master Control Station
KWAJALEIN
ASCENSION
ECUADOR
National Geospatial-Intelligence Agency (NGA) Tracking Station
GeospatialAlternate Master Control Station (AMCS)
ARGENTINA
DIEGO
GARCIA
TAHITI
SOUTH
AFRICA
NEW ZEALAND

20. Who Uses It?
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Everyone!
Merchant, Navy, Coast Guard vessels
Commercial Airliners, Civil Pilots
Surveyors
Commercial Truckers
Cars now being equipped
Communications and Imaging Satellites
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Space-to-Space Navigation
Any system requiring accurate timing

21. Application of GPS
Power Grid
Interfaces
Precision farming
Personal Navigation
Trucking &
Shipping
Surveying &
Mapping
Aviation
Railroads
Recreation
Off shore
Drilling
Communications
Fishing &
Boating

22. Applications
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Civilian Purpose
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Locations
Mapping
Monitoring
Construction Control
Emergency services
Boundaries
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Agriculture - Slope Staking
Tracking of people,
vehicles
Sports (boating, hiking,…)
Archeology
Public Transport
Town Planning
Hydrographic Surveying
Topographical Mapping
Cadastral Surveying
GIS Application

23. Defense Application
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Navigation (night & bad weather)
Call in target coordinates
Guidance system for missiles
Ships used them for minesweeping,
rendezvous, and aircraft operations