The Ups and Downs of GPS

by Curt Bennink
Created: August 20, 2007

Wire up your GPS systems for optimal performance and minimal downtime.

Sukut Construction has machines equipped with factory-installed Caterpillar AccuGrade (such as this dozer), as well as aftermarket Trimble systems.
Sukut Construction has machines equipped with factory-installed Caterpillar AccuGrade (such as this dozer), as well as aftermarket Trimble systems.
Antennas are removed every night, so the connection point to the antenna can see a lot of wear.
Antennas are removed every night, so the connection point to the antenna can see a lot of wear.
The AccuGrade display is integrated right into the dash of the dozer.
The AccuGrade display is integrated right into the dash of the dozer.
Systems for excavators, such as this one from Leica Geosystems, allow operators to stay productive while approaching tolerances within a couple of inches.
Systems for excavators, such as this one from Leica Geosystems, allow operators to stay productive while approaching tolerances within a couple of inches.
This is the view from the seat of Garrett Excavation's motor grader. All of the necessary information is in front of the operator.
This is the view from the seat of Garrett Excavation's motor grader. All of the necessary information is in front of the operator.
The plan starts as a 2-D drawing from the engineer (left) and is converted to a 3-D model (right).
The plan starts as a 2-D drawing from the engineer (left) and is converted to a 3-D model (right).

Garrett Excavation just purchased its first factory pre-wired unit, a John Deere dozer. "I am fairly excited about it," says Garrett. All of the equipment in the past had aftermarket wiring and valves installed. "You have to re-route around all of the OEM stuff. The valve is not integrated to the hydraulics like it would be if it came from the factory. It builds up heat, and you see a lot of hose failures and leaks as the machine gets some wear on it that you wouldn't see if it was factory."

This may not be as much of an issue with newer machines. "It is easier to install grade controls onto newer machines with electro-hydraulic controls," says Lodge. "Often, it may only require a cable to run the machine in automatic mode vs. having to install a valve package to accomplish the same thing. Install time is greatly reduced when the machine's hydraulic system supports electro-hydraulic control vs. having to install hydraulic valves, hoses and fittings."

Factory pre-wired equipment allows for plug-n-play installation. "All of the parts are done at the factory and it is nice and neat," says Garrett. "It is a good factory fit. The John Deere dozer has special places for each component, so you are isolating the components more. You are getting them out of harm's way.

"Some of the equipment we have now has cords running on the bottom of the cab and the guys are stepping on them," says Garrett. "When you disconnect them, you have ends that are flopping around. They can get slammed in the door. So there are a bunch of potential problems by doing it the old way."

Lodge admits, "Factory-installed systems are typically a little more expensive than the aftermarket systems."

But according to Garrett, any potential cost difference is not really an issue. "The uptime and the reliability will more than offset it," he states.

Sukut Optimizes Jobsite Efficiency
Sukut Construction Inc., Santa Ana, CA, is one of the most progressive construction contractors in the country. It moves over 150 million cu. yds. of earth per year with more than 250 major pieces of equipment, and is at the front of the industry in the re-power movement to clean up engine emissions. "We have one of the cleanest fleets in the industry today," says Michael Bobeczko, director of marketing.

The contractor is also finding innovative ways to implement GPS technology to maximize jobsite efficiency. Because the technology plays such an important role in every project, Sukut Construction has a department dedicated specifically to GPS.

The process starts by creating a 3-D model from 2-D civil engineering drawings. "In most of the cases, they are not drawn accurately," says Matt Eklund, GPS program manager. "So we convert that 2-D model into 3-D and create a virtual rendered model of the site."

When drawing discrepancies are identified, a request for information (RFI) is generated and sent to the engineer. "You catch many errors prior to becoming major problems," says Eklund. Prior to using modeling, errors would not be found until the surveyor staked the site and performed the calculations.

Model making can be complex. "The 3-D model making is kind of an artwork," says Eklund. "You have to understand the intent of the engineer. There are a lot of gray areas that are filled in during model making. Someone experienced in the field would make the best model maker because they are digitally making that model from field experience." For instance, Nancy Hewitt, one of Sukut Construction's GPS/CAD engineers, is a 25-year veteran who made the transition from a field grade checker to a computer modeler.

Significant time is required to convert the plans from 2-D to 3-D. "Depending upon the quality of the plan, it is very labor intensive, sometimes taking weeks," says Eklund. "Typically, we do most of the initial work here in the office and then take the model to the field. I have someone on site who then tweaks the model and responds to what the needs are on site."

To get a first-hand look at its use of GPS grade control, Equipment Today visited the Laguna Crossing project where Sukut Construction was moving 1,656,000 yds. for the Irvine Company. On this site, Kerry Callahan, GPS coordinator, who has decades of grade checker experience, was responsible for keeping the GPS-equipped equipment moving. This job was particularly difficult, as the plan was being changed from single-family homes to multi-family residences to reflect a shift in the housing market.

"The biggest challenge on a project like this with a changing plan is the equipment is moving 20,000 yds. of earth or more a day," says Eklund. "Those machines have to fill to grade. If plans are constantly changing, you have to re-grade the site. We try to keep on top of the game so you don't have to do that."

Having a GPS site coordinator allows the flexibility to make required changes in the field. "Plus, if there is a blip in the model, I look at the contours, fix it and give it back," says Callahan. This streamlines the whole process. "If I tried to fix it through the office, I would have to try to explain what the operator explained to me. This way, nothing is lost in translation and the problem gets addressed more quickly."

The company's use of GPS continues to evolve. For example, there are fewer job stakes on site, yet the foreman needs to have a picture of where he is in order to make decisions. "I would expect a trend to have GPS in the foremen's trucks," says Eklund. "That is the next generation technology."

In future, you may also see two-way data communication - each dozer with GPS will have an IP address and can be tracked via the Internet. "It is going to be a GIS world where you click on a site and see all of your equipment online," says Eklund. "You will be able to click on any piece of equipment and know everything about it."