The Next Step in the Evolution of GPS-based Surveying and Machine Control

Even in good times, road building is a highly competitive industry, but when the general economy goes soft it becomes even more so. Then, experienced contractors find themselves competing for a smaller pool of projects both with each other, and with new competitors attracted to the market as a replacement for vanishing commercial work.

"We are always looking for a competitive advantage," says Ruben Cuevas, Chief Surveyor of Lake County Grading Co., LLC, in Libertyville, Ill., "and these days that usually comes in the form of advanced technology. I guess you could say we are classic 'early adopters'.

"We saw the value of GPS-based surveying technologies early on. We have had our own base stations and rovers for quite a while now. We keep jobsite information on laptops, and record things like undercuts and as-builts electronically on virtually all of our jobs.

"We also got onboard with GPS-based machine controls early on. In 2005 we equipped a pair of dozers with Topcon 3DMC systems as a test. Based on that experience, we now have nearly a dozen 3DMC-equipped dozers, and have recently added our first grader."

That background made Lake County Grading a natural candidate for the next step in the evolution of GPS-based surveying and machine control - networking. So, when their Topcon distributor, Positioning Solutions of Carol Stream, IL invited Lake County Grading to participate in a real-time Global Networked Satellite System (GNSS) machine control network they were building, the answer was a resounding "yes."

GNSS networks link a number of base stations together via a computer network, usually through the internet. One of the best known is the Albuquerque Real Time GNSS Network (ARTGN), but there are at least 35 similar systems in the United States. Japan and Europe are very well covered, China has at least 10 systems, and there is even one in Dubai.

Specialized software creates a virtual position anywhere inside the network. That allows a surveyor to get centimeter-accurate observations anywhere in the networked area using just a rover on a pole. The effect is the same as if a mobile GPS base station was operating a few meters away.

"Topcon was a major contributor to ARTGN," said Positioning Solutions president Jerry Bickner. "So, all of that experience was available to us when we started to build our own PSC Net. Our vision is for a seamless network that covers the five states in which we operate, Illinois, Indiana, Michigan, Missouri, and Wisconsin.

"What makes PSC Net different is that virtually all of the existing GNSS applications are heavily oriented toward survey support, and we wanted to focus on machine control," Bickner said. "Frankly, survey support is a lot easier, but we see machine control as the greater opportunity in the future.

"The difference is that a surveyor can afford to wait 15 or 20 seconds for a correction, but that's not nearly good enough for a moving dozer or grader. Machine control requires much quicker response, and software that can compensate for the natural time lag, or 'latency,' built into any network.

"PSC Net started with a half dozen Topcon reference stations in our Indianapolis office about three years ago because we had both a strong market presence and a strong technical base there. Chicago was the second area to be added, but we have kept the network computers and processing in Indianapolis to take advantage of the experience there.

"Today, we have more than 40 reference stations operating and are adding four more each month on average. Our goal is to cover all of the major metropolitan areas in the five states seamlessly within the next three years or so."

PSC Net is unique in more than its focus on machine control. For example, nearly all of the reference stations are owned by individual customers rather than by Positioning Solutions.