Reprinted from The New Haven Register
by: Maria Garriga, Register Staff 01/04/2004
NORTH HAVEN — The 45- ton bulldozer mashing its way through the mud off Clintonville Road knows exactly where it’s going.
Cruising through an excavation site in North Haven, the bulldozer can "see" the terrain — not just what’s on it, but what’s under it, and what will be built there in the future.
Outfitted with a satellite-driven global positioning system, the mud-caked, lumbering yellow CAT offers a glimpse into construction’s future.
The bulldozer’s operator can see the terrain via a screen with 3D graphics worthy of the latest video games, thanks to antennas, a radio transmitter and computers equipped with a satellite-fed tracking program.
Using GPS, the bulldozer can grade earth with a precision that allows it to pinpoint a position or depth to within a quarter of an inch.
Sweeney Excavation of Hamden was one of the first in the state to use GPS technology to guide its bulldozers, starting nine months ago. The results have been so impressive that the company plans to attach the technology to its backhoes, as well.
"It’s another tool. I don’t have to rely on engineers or surveyors," said David McKosky, a heavy equipment operator for the past 45 years.
He’d never used computers before, but mastered the system in a week, delighted by the independence the technology gave him.
Normally, surveyors set stakes to mark places where soil needs to be added or removed. But heavy equipment often knocks the stakes down, McKosky said, requiring a surveyor to redo the work.
Also, the bulldozer operator would have to wait for the engineers and surveyors to map everything out every morning, because the machines moved blindly. The operators could not tell where future buildings or pipelines would be set, and often had to move piles from one spot to another repeatedly as one heap got in the way of another project.
That slowed down each project considerably and drove up the costs, said Robert Sweeney, company president and founder.
With the Trimble SiteVision GPS, a computerized 3D model of the terrain gets fed into flash cards that operators insert into computers on the bulldozers.
As the bulldozer rumbles forward, the satellite system tracks its position using several control points and a base station.
The base station computer feeds the changing coordinates into a program that pinpoints the position of the machine and its shovel in relation to a computerized model of the work site.
The operator sees a real-time, 3D computer model of the terrain, with the bulldozer on it in motion.
The operator also sees a computerized map of blueprints in three dimensions, showing where future buildings will be, where the future road will be, and even where the underground utilities will be.
Changes to the work site are programmed right into the computerized model.
"Before we would just make a mess and clean it up," Sweeney said. "Now the operator knows these wood chips need to be moved in advance so the sewer mains can come through."
GPS catching on
GPS will work best for contractors on large work sites, said one industry expert.
"GPS technology is not foolproof. You can only use it for certain hours of the day — it has to do with satellite availability and the number of trees on the site," said Mike Jiantonio, manager of the instruments division at Superior Products in Southington.
Trees interfere with satellite signals, he explained.
Jiantonio said while his company sells the equipment, few contractors are willing to put in the large investment at this point. But the technology has stirred excitement in the construction industry.
New England Construction, a trade magazine, featured Sweeney’s use of GPS technology in a recent cover story, "Controlling Grade Without Stakes."
Bob Wiedenmann Jr., a Wallingford-based developer who often works with Sweeney, said the GPS system will become more heavily used on large work sites.
"On larger projects, you really save time. It does two things: eliminates potential mathematical problems in setting the stakes, and eliminates vandalism, when kids knock over the stakes intentionally or by accident," Wiedenmann said.
Investing in the future
Most cars equipped with GPS come within 10 to 20 meters of accuracy.
"That’s not acceptable in our business," Sweeney said.
He has been researching GPS technology for four years and finally jumped in last March by fitting out two of his bulldozers with the equipment.
So far he’s invested $200,000 in the equipment, but it’s an investment he expects will be returned many times over.
"We are going to grow in leaps and bounds. We are looking for operators," said Sweeney.
Sweeney said he has been so impressed by GPS technology that he has personally invested in Trimble, the Sunnyvale, Calif.-based company that makes the SiteVision system.
The 39-year-old Hamden native — he still lives there with his wife and three children — bought his first backhoe at 19.
From there he has built up a company with 36 employees that works with the nation’s largest residential owner-developers, such as Toll Brothers and Avalon Bay.
His greatest worry is that his senior operators, men like McKosky, are retiring in waves.
They brought experience, spatial reasoning skills and visualization ability that contractors need in order to turn a work site into a building.
The new technology may help by giving less experienced operators some of the visualization that comes as second nature to the old hands, Sweeney said.
"That’s what limits the field so much — a good operator needs to be able to visualize. This technology can visualize for the operator," he said.