24-12-2010, 04:35 PM
gps final presentation.ppt (Size: 1.81 MB / Downloads: 147)
By – Rajkaran Chauhan
WHAT IS GPS
GPS, which stands for Global Positioning System, As the name suggest it is a system to find out your location any where and anytime on the surface or near the earth surface. Developed by the United States Department of Defense, GPS is officially named NAVSTAR-GPS.
At 12,600 miles (20,200 km) altitude. (12 hour orbit period).
30 satellites (24+6) with 6 spare space Vehicles or SVs.
6 orbital planes (55° inclination).
4 satellites in each plane. Monitored by 5 ground control stations.
Manufactured by Rockwell International, later by Lockheed M&S
Satellite weighs ~1900 lbs, 2.2m body, 7m with solar panels.
7-10 year expected lifetime.
GPS satellites use Atomic Clocks for accuracy, but because of the expense, most GPS receivers do not.
It works by using radio frequency broadcast from the orbiting satellite.
Civilian units only receive the L1 frequency.
History and facts
Started development in 1973.First four satellites launched in 1978.
Full Operational Capacity (FOC) reached on July 17, 1995.
In 2005, the first modernized GPS satellite was launched and began transmitting a second civilian signal (L2C) for enhanced user performance.
3 satellite signals are necessary to locate the receiver in 3D space 4th satellite is used for time accuracy.
GPS receiver uses latitude, longitude, and altitude to calculate its three-dimensional location
The most recent launch was on May 28, 2010.The oldest GPS satellite still in operation was launched on November 26, 1990.
Glonas and Galileo are another positioning system developed by Russia and European union respectively Glonas-24 and Galileo -30