1. A
TECHNICAL SEMINAR
ON
GLOBAL POSITIONING SYSTEM (GPS)

2. Global Positioning System (GPS)
 GPS is a space-based satellite navigation system that provides
location and time.
 It is maintained by the ‘United States government’ .
History:
 The design of GPS is based partly on similar ground-based
radio navigation systems, such as LORAN and the Decca
Navigator developed in the early 1940s, and used during World
War II.
 The first satellite navigation system, used by the United States
Navy, was first successfully tested in 1960.
 Interagency GPS Executive Board (IGEB) oversaw GPS
policy matters from 1996 to 2004.

3.  After that the National Space-Based Positioning,
Navigation and Timing Executive Committee was
established by presidential directive in 2004.
Basic concept of GPS :
 A GPS receiver calculates its position by precisely timing the signals
sent by GPS satellites .
• the time the message was transmitted
• precise orbital information.
• the general system health and rough orbits of all GPS satellites.

4. Structure:
 The current GPS consists of three major segments-
Space Segment (SS),
Control Segment (CS),
User Segment (US).
Space Segment(SS)-
 The space segment is composed of 24 to 32 satellites in medium
Earth orbit and also includes the payload adapters to the boosters
required to launch them into orbit.

5. Control segment(CS)-
The control segment is composed of-
• master control station(MCS),
• alternate master control station,
• a host of dedicated and shared
• ground antennas and
• monitor stations.

6. User segment(US)-
•The user segment is composed of hundreds of thousands of U.S. and allied
military users of the secure GPS Precise Positioning Service, and tens of
millions of civil, commercial, and scientific users of the Standard Positioning
Service.

7. Satellite frequencies:
Band Frequency Description
L1 1575.42 MHz Coarse-acquisition (C/A) and encrypted
precision.
L2 1227.60 MHz military codes and newer satellites.
L3 1381.05 MHz Used for nuclear detonation (NUDET)
detection.
L4 1379.913 MHz Being studied for additional ionospheric
correction
L5 1176.45 MHz Proposed for use as a civilian safety-of-
life
Demodulation and decoding:
Navigation equations:

8. Various Global Positioning Systems:
 NAVASTAR GPS – America’s Global Positioning System
GLONASS – Russia's global navigation system. Fully operational
worldwide.
Galileo – a global system being developed by the European Union
and other partner countries, planned to be operational by 2014 (and fully
deployed by 2019).
Beidou – People's Republic of China's regional system, currently
limited to Asia and the West Pacific.
COMPASS – People's Republic of China's global system, planned to
be operational by 2020.
IRNSS – India's regional navigation system, planned to be
operational by 2013, covering India and Northern Indian Ocean.
QZSS – Japanese regional system covering Asia and Oceania.

9. Applications:
 Civilian,
Restrictions on civilian use-
The U.S. Government controls the export of civilian receivers. All
GPS receivers capable of functioning above 18 kilometres altitude require
license.
 Military,

10.  Communication,
The navigational signals transmitted by GPS satellites encode a variety
of information.
This information is encrypted encoding used by the U.S. military.
Conclusion:
GPS technology is playing a important in modern living.

11. THANK YOU…..