9/29/2005
CORS gives accuracy to global positioning
RIGBY - Little fanfare greeted the construction of a small receiver on a permanent concrete base at the Idaho Transportation Department maintenance yard in Driggs this summer.
But users who depend on locating technology to make their jobs easier and more accurate are looking forward to being able to access this receiver. It is a CORS: Continuously Operating Reference Station, a Global Positioning System (GPS) receiver mounted on a permanent concrete structure.
The receiver collects satellite data 24 hours a day and determines a highly accurate position (latitude and longitude) on the earth, according to Rayce Ruiz, land surveyor for ITD District 6 in Rigby. The data can be accessed via the Ethernet by GPS users.
"The CORS is a reference used to correct observed GPS data for higher accuracy," Ruiz explained. Several groups of users including surveyors, geologists, engineers, Geographic Information Systems (GIS) users, emergency service providers, earth-movers, and farmers access CORS data because of its accuracy.
Besides using the Ethernet, a UHF radio can be linked with the CORS. The radio broadcasts a correction to enable the GPS user to get Real Time Kinematic positioning.
"Our location section will use this RTK capability to perform our surveys in the Driggs-Victor area," Ruiz said.
The CORS in Driggs is one of three stations that will be installed at locations throughout eastern Idaho in partnership with universities or projects. CORS is part of the statewide Intelligent Transportation System. Stations are going up at BYU-Idaho in Rexburg and will be installed at Idaho State University in Idaho Falls.
The CORS at BYU was funded through the Menan-Lorenzo Interchange project. The transportation department was looking for a close government or educational site to install the station, Ruiz said.
"We could not donate the funds to a private company for a site," he said. "BYU-Idaho is in the vicinity of the project, so I approached the university to be a partner. The CORS will be used during the design and construction of the interchange."
Funds for the CORS at ISU in Idaho Falls were tied to the St. Leon Interchange project in much the same way. The university uses GPS as an educational tool and training in its classes.
As director for the Eastern Section of the Idaho Society of Professional Land Surveyors, Ruiz has been working on CORS for about two years, coordinating the installation of CORS with local land surveyors.
He says applications for CORS vary by user. Surveyors want the RTK feature. GIS users want GPS for mapping. Geologists locate rock formations and seismic spots. Earth movers use GPS to set grades. Farmers use GPS to plow the rows in their fields.
Ruiz will use CORS in his survey work for ITD.