Systems That Use Satellites to Guide Excavation

The cost of Trimble grade control technology varies widely depending on the machine type, earthwork application and accuracy requirements. Regardless of cost, the company believes the systems provide significant tangible benefits via increased productivity, reduced production costs and material savings.

Leica DigSmart 3D

Leica Geosystems' DigSmart 3D Excavator Guidance System is designed to accurately guide the excavator operator to the proper jobsite location and digging depth. A graphic color monitor in the cab displays the project design information and 3-D GPS position, enabling the operator to set proper bucket elevation and position. Dual GPS antennas are used to pinpoint the exact position of the bucket teeth.

SmartTools operation facilitates easy implementation of the system. For example, the SlopeTool mode automatically adjusts the dig depth information to compensate for machine slope and roll; this, in turn, helps to prevent over excavating. The TrenchTool mode enables the operator to select the center line reference from the design, then key in the desired trench width. The system will then guide the operator where to cut and to what depth.

The system software also offers a high level of integration with survey data from the company's line of survey instruments. The work can be surveyed with a total station or GPS rover, and the data transferred directly to the excavator.

According to Leica, there are several benefits to implementing 3-D GPS technology, including:

• It empowers the operator to know where to dig and to what grade anywhere on the job by placing the job plans directly in the cab.
• It results in a vast reduction in staking and re-staking requirements.
• Overall efficiency is improved via reduced downtime associated with waiting for survey control, re-staking and grade checking.
• Cost savings can be realized via reduced re-work, minimal staking/re-staking, savings on materials and improved operating efficiency.

Caterpillar AccuGrade

Caterpillar is preparing to launch its first excavators and backhoe-loaders with laser and GPS machine control and guidance technologies integrated into the machines, available from the factory and supported by the company's dealer network. The initial offering will be available in the first quarter of 2007.

The systems vary from a laser reference system on the backhoe-loader to a full GPS system for excavators. AccuGrade technology provides the foundation for the GPS system.

AccuGrade has been available for several years on the company's dozers and motor graders. It will now be a key component for achieving grade on excavation projects.

"AccuGrade technology is designed into the excavator to maximize safety, reliability and productivity," says Thomas Bucklar, regional manager, North America, Machine Control and Guidance Division, Caterpillar Inc. "With state-of-the-art sensors and consistent factory installs, centimeter-level accuracy is achievable."

According to Bucklar, the technology will provide significant benefits any time you are digging to grade. "The information needed to get to grade is now in the cab," he explains. "It takes grade checkers out of harm's way. And it allows the operator to hit grade consistently, even in blind cuts."

Despite offering varied capabilities, Bucklar believes the payback will be quick for both the laser and GPS-based systems.

"Many contractors using these technologies have quoted productivity gains of 50%, while cutting costs significantly," he states. "When you couple that with the uptime achieved through Caterpillar's reliability and dealer support, the contractor will be more competitive and profitable at the same time."