Explore 3-D Alternatives

Investing in 3-D grade control technology can be an intimidating experience. The type of work will dictate the most appropriate system to use.

Today, you can select either GPS or ATS construction total station positioning technology. "GPS-based grade control systems are ideal for larger site projects and long-term, multi-phase projects," says Catherine Mansfield, Trimble Construction. "ATS construction total station-based grade control systems are ideal for contractors who need the flexibility to move from site to site frequently, work in confined spaces or perform high-precision grading with their dozer of motor grader."

ATS systems also offer a 3-D grading solution for jobs where GPS is not viable, such as in urban canyons, heavily forested areas or jobsites with numerous overhead obstructions, such as highway overpasses.

The best way to actually get started with 3-D technology is open for debate. Mansfield highly recommends buying the whole package, rather than start with a GPS or ATS-based rover system, then progress to a machine-mounted system.

"Whether you choose to invest in machine-mounted or rover systems first, both options allow you to get an understanding of using positioning technology for construction earthmoving," she states. "However, at a customer panel session at Trimble Dimensions 2005, a key message from all customers (small, medium and large contractors) was that if they had to do it over again, they would have started with more systems and not less. They believed they would have realized a much higher payback if they had invested in more systems up front.

"Additionally, it is important to note that if a contractor invests only in a machine-mounted system initially, they will need to hire services to come in and set up the control," she adds.

Rover as a first step

Other experts believe the rover provides a good introduction to 3-D before jumping into machine automation. "The best route to get into this is to probably start managing your software and a GPS rover, not necessarily jumping right into machine control," says Matt Kohler, sales manager for machine automation, Western U.S., Leica Geosystems. "Most people like to use those steps, manage their data, before they take that leap of faith. Having said that, you are going to start seeing a true payback once you really go to machine control because you are going to see that dramatic jump in productivity."

But there is a learning curve. "I have seen people be successful both ways," says Kohler. "But there are growing pains when you jump in and try to do it all at once." Data management is the key to the whole process "If you don't have the data, you are pretty much sunk." If the data is not prepared, the grader or dozer sits idle.

"Either implementation path can result in rapid payback if the contractor is savvy about bidding, job costing and project management," says Richard Rybka, Topcon Positioning Systems. "Most contractors will still want to start with a GPS rover system for two reasons. Many contractors are intimidated by technology, especially satellite positioning products. Starting with a survey system helps them get acquainted with the technology and learn the operational requirements. Secondly, a GPS rover system is multi-functional and can be used for laying out features like storm sewer, verifying topos and tracking earthwork volumes, as well as checking grades.

"The next level of implementation would involve adding indicate systems on heavy scrapers and large dozers and excavators," says Rybka. "To reach the optimum level, fully automatic systems would be added to fine grading equipment like motor graders and dozers with six-way blades."

Ken Autry, president of Fayetteville, NC-based Autry Grading, currently has Topcon 3-D grade control installed on eight pieces of iron, including automatic systems on four Volvo motor graders, two automatic systems on dozers and two indicate systems on scrapers. "We started out with a rover system," notes Autry, "and as we saw what it could do for us, we started adding to it."