The document explains GPS (Global Positioning System) as a satellite-based navigation system that allows users to determine their precise position and time through radio signals. It describes the three segments of the GPS system: space, control, and user, and highlights the ranging principle used by receivers to calculate location. Additionally, it covers various applications of GPS and mentions the existence of four global navigation satellite systems (GPS, GLONASS, Galileo, and Compass).

1. GPS Surveying
by
Dr. Rambabu Palaka,
Associate Professor
Civil Engineering Department
B.V. RAJU INSTITUTE OF TECHNOLOGY
August 2017

2. What is GPS?
 The Global Positioning System is a satellite-based radio
navigation system for determination of precise position and
time, using radio signals from the satellites, in real-time or in
post-processing mode.
 The Navigation Satellite Timing and Ranging Global
Positioning System (NAVSTAR GPS) developed by the U.S.
Department of Defense (DoD)
 It permits users with suitable receivers to establish their
position, speed and time on land, sea or in the air, at any time
of the day or night and in any weather condition.

3. GPS System
The GPS system has 3 major segments: space, control and user.
1. The Space Segment consists of a constellation of 24 satellites
orbiting the earth at an altitude of 20,200 km. These
satellites act as reference points from which receivers on the
ground determine their position.
2. The Control Segment consists of 5 stations here on earth
which track the satellites.
3. The User Segment consists of antennas and receiver-
processors.

5. How does GPS work?
GPS receivers use the principle of "RANGING".
The receiver measures the distance from a location on earth to
the positions of several satellites to determine the latitude and
longitude of the position on earth.

6. With four satellites you get a precise
point for your position and you also
know your elevation.
You have a position but no
check on its quality!

13. Applications of GPS
 Providing Geodetic Control
 Photogrammetry - it is the science of making measurements
from photographs, especially for recovering the exact positions of surface
points
 Finding out location of offshore drilling
 Pipe line and power line survey
 Navigation of civilian ships and planes

15. GNSS
(Global Navigation Satellite System)
There are four GNSS systems in existence
GPS, GLONASS, Galileo & Compass
1. The Global Positioning System (GPS) is also called NAVSTAR GPS
(Navigational System with Time and Ranging )operated by United States
Government.
2. The GLObal NAvigation Satellite System (GLONASS) operated by the
Russian Government.
3. The Galileo Navigation Satellite System to be operated by European Union.
4. The Compass Navigation Satellite System to be operated by Chinese
Government.

16. Q&A