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| Swarming. Connecting NAVSTAR (bottom), GALILEO (top) and GLONASS is a global effort(Illustration by Guy Lawrence for ENR) |
Major vendors of global positioning receivers now claim to link with American and Russian satellites, offering more accuracy and reliability than the U.S. NAVSTAR GPS system alone. “This is a much-needed step in our industry,” says Tim Tometich, GPS manager of McAninch Corp., an earthmoving contractor in West Des Moines, Iowa.
Financial and political volatility has hampered progress of the Global Navigation Satellite System (GNSS). But the network is starting to show signs of life again. As more nations launch wireless navigation systems, the all-encompassing term “GNSS” is slowly overshadowing “GPS,” which refers to the U.S. network alone.
Major positioning vendors, namely, Trimble Navigation Ltd., Topcon Positioning Sytems Inc. and Leica Geosystems Inc.—released new GNSS receivers this year. Users say the costs have not changed but GPS-only units are dropping in price by as much as 20%.
Vendors promise links with the European Union’s forthcoming GALILEO satellite network, due in 2010 but two years behind schedule. Meanwhile, the Russian Federation, which once neglected to maintain its GLONASS network—resulting in a 50% drop in working satellites since it went online in 1995—plans to send up several more “birds” by 2007.
The U.S. Dept. of Defense, which operates GPS, also is upgrading. It launched a “modernized” bird last September, with more expected to be flown in 2008. “Our dependence on these types of systems is only going to increase,” says Charles Dull, assistant director of geospatial applications for the Dept. of Agriculture Forest Service.
With more receivers available with GNSS interoperability this year, construction users have “an increased availability in positioning when working in difficult environments, such as around trees,” says Mark Nichols, general manager of Caterpillar Trimble Control Technologies LLC, a joint-venture research and development company in Dayton, Ohio. An expanded global network will boost signals inside “urban canyons” as well, Dull adds.
wners, architects, consulting engineers and contractors who use wireless devices to monitor, survey and build expect to get greater precision from global positioning systems in the next few years. But international cooperation will determine just how fast it happens.
