The building of more and more satellite positioning networks throughout the world is creating a boon for contractors using machine control.
"The addition of network technology in conjunction with machine control is a powerful combination when utilized by progressive companies," said Jason Killpack, senior product marketing manager for Topcon Positioning Systems.
By the very nature of the technology, networks are constructed in local areas. Connecting the local areas with other "local" networks create an environment ripe for use by contractors who operate in divergent jobsites over a large area. For example, Lengemann of Florida, a major supplier of positioning solutions for construction, surveying and engineering professions, has the entire state under a single network. The distributor strategically placed local networks; contractors can use part or all of the network depending on the size and location of the job and the need that arises.
The ability of new software to allow rolling iron to tap into existing GPS and GNSS networks, Killpack said, "gives the user the ultimate flexibility to perform any jobsite preparation quickly. Using a 3-D system, the operator simply dials into the local network to establish an RTK correction from the network."
Using a network-local, privately owned or public-instead of a standalone base-to-rover, RTK technology saves on equipment costs and time since the user does not need to own or set up a local station. The network also dramatically expands the operating range.
In the new technology, a digital UHF radio may broadcast correction to rovers up to eight miles away. In contrast, however, a network rover uses cellular technology and can easily fix a position at 20 miles from the nearest base station in reasonable conditions. A network also eliminates localization errors so an operator can be assured of always being on the right coordinate, thus simplifying the entire construction process.
Using a network and machine control software, an operator simply turns on his machine, and the system knows where it is on the site model and can immediately go to work. Such a coordinated network partnership reduces setup time every day as the network is always on and available for corrections to the machines or grade checkers.
Further, using a network eliminates the need for a local base station on site and extends the range in which the machine or man can operate substantially," reducing costs on various levels.
Roy Boyd with Boyd Instrument and Supply of Horsham, PA, listed six reasons why networks work well with his machine control setup:
- No base needed on the site-operators can start work before the foreman shows up
- The base receiver can now be a rover-running more sites with the same number of receivers
- Networks can use signals from both GPS and GLONASS satellites and be adapted for machine control
- The network is operational 24/7
- Less receivers to buy and maintain
As with all precise measurement technology, atmospheric conditions and curvature of the earth impart errors over distance that must be accounted for in order to maintain high accuracy.
It is important, experts say, for maximum performance and maximum productivity, that operators to investigate the best way to achieve millimeter accuracy with the new technology. It is equally important to make sure that networks you employ on jobsites offer vertical correction that can be used by an unlimited number of rovers on the same site without interference.
Combining this around-the-corner technology with precise positional information calculated from the network correction miles away gives the machine or man-rover a precise position in real time-an important tool on any jobsite or construction project.
Construction Business Owner, January 2009
