| Sam Wormley 2008-01-09, 3:33 pm |
| NOAA To Ensure Global Navigation Satellite System Accuracy
http://www.gpsdaily.com/reports/ NO...9
99.html
by Staff Writers
Washington DC (SPX) Jan 07, 2008
NOAA will lead an international effort to pinpoint the locations of
more than 40 global positioning satellites in Earth orbit, which is
vital to ensuring the accuracy of GPS data that millions worldwide
rely upon every day for safe navigation and commerce.
NOAA personnel will compile and analyze satellite orbit data from 10
analysis centers worldwide to ensure the accuracy of GPS information.
For the next four years NOAA's National Geodetic Survey will serve as
the Analysis Center Coordinator for the International Global
Navigation Satellite Systems Service, a voluntary federation of more
than 200 organizations that provide continuous global
satellite-tracking data.
"For GPS receivers to provide accurate information, the precise
location of positioning satellites as they orbit the Earth must first
be determined," said David Zilkoski, director of NOAA's National
Geodetic Survey. "NOAA looks forward to leading this international
partnership to produce the highest quality satellite position data
possible."
The Global Navigation Satellite Systems, which include the U.S.-based
Global Positioning System, the Russian GLONASS system, and the
upcoming European Galileo system, are used for accurately determining
the geographic position of any point on Earth.
A GPS receiver calculates its position by measuring the time it takes
a signal to travel from the satellite to the receiver. Because the
signal travels at a known rate and the time is precisely measured
using an atomic clock, the receiver can calculate its distance from
the satellite. By repeating this process from four or more GPS
satellites whose orbits are precisely known, the GPS receiver can
determine its position.
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