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The story of the GPS system!
The global positioning system or GPS system helps in the identification
of one's specific location on the Earth's surface. A network of
satellites, signals, ground-based hardware and software, and people
coordinates this major process. The GPS system is composed of a
constellation of 24 satellites originally put into orbit by the U.S.
Department of Defense. A GPS receiver on the ground can use signals from
these satellites to calculate its precise location.
Originally, commercial GPS system units were accurate to only about 100
meters. Since it was developed for the military they restricted complete
rights to the use of these systems. This was done using a program called
Selective Availability. However, in the year 2000, the U.S. government
removed Selective Availability. This meant total access to the public
and resulted in improving the accuracy of basic handheld units to within
about 3 meters.
Today, with additional information from ground based correction services
such as WAAS accuracy can be improved dramatically. The WAAS (Wide Area
Augmentation Service) is a system of ground based reference stations
located across the United States. These stations receive GPS system
signals and correct them for inaccuracies caused by clock drift and by
the atmosphere. These corrected signals are then broadcast from a
satellite. GPS receivers equipped with WAAS technology can receive and
interpret this corrective signal.
The accuracy of a location measurement using the GPS system depends on
the technology and features of the receiver. High-end receivers can
calculate locations accurate to within centimeters. But even the
low-end, commercial handheld receivers, available at reasonable prices
to the public, may be accurate to within three meters. Some of the best
known brands in the aviation and civil customers category are Garmin and
Magellan.
For more information on related products and services, please choose
from the following menu of items.
GPS
Maps /
Software
Tracking
About The Author:
Garima Sharma is a successful author and publisher at
www.1st-at-gps-tracking.com. Recommending gps equipment and associated
products
28-06-04
