02-04-2010, 03:02 AM
Global Positioning System
Global Positioning System is an System to Identify the Position on Globe through a Network Of Satellites.
The Global Positioning System (GPS) is a U.S. space-based global navigation satellite system. It provides reliable positioning, navigation, and timing services to worldwide users. The Space, Control and User are the three segments of this . The User Segment is composed of hundreds of thousands of U.S. and allied military users of the secure GPS Precise Positioning Service. The Space Segment is composed of 24 to 32 satellites in Medium Earth Orbit . The Control Segment is composed of a Master Control Station, an Alternate Master Control Station, and a host of dedicated and shared Ground Antennas and Monitor Stations.
Basic concept of GPS:
A GPS receiver calculates its position by precisely timing the signals sent by the GPS satellites high above the Earth. Each satellite continually transmits messages like, precise orbital information, the time the message was transmitted, system health and rough orbits.
Space segment:
It is is composed of the orbiting GPS satellites, or Space Vehicles (SV) in GPS parlance. It has six planes with four satellites each and the six planes have approximately 55° inclination (tilt relative to Earth's equator) and are separated by 60° right ascension .
Control segment:
There are a)a Master Control Station (MCS),
b)Alternate Master Control Station
c)four dedicated Ground Antennas and
d)six dedicated Monitor Stations.
User segment:
It is is composed of U.S. and allied military users of the secure GPS Precise Positioning Service. civil, commercial and scientific users of the Standard Positioning Service come inder this segment. GPS receivers may include an input for differential corrections, using the RTCM SC-104 format. This is typically in the form of an RS-232 port at 4,800 bit/s speed. Many GPS receivers can relay position data to a PC or other device using the NMEA 0183 protocol
for more etails, visit the page:
http://en.wikipediawiki/Global_Positioning_System
Visit this link for a report:
http://geology.isu.edu/geostac/Field_Exe...lox_en.pdf
PPT: