GPS in the Earthmoving Industry

GPS when applied in the earthmoving industry can be a viable asset to contractors and increase the overall efficiency of the job. Since GPS satellite positioning information is free to the public, it allows for everyone to take advantage of its uses. Heavy equipment manufacturers in conjunction with GPS guidance system manufacturers have been co-developing GPS guidance systems for heavy equipment since the late 1990s. These systems allow the equipment operator to use GPS position data to make decisions based on actual grade and design features. Some heavy equipment guidance systems can even operate the machine's implements automatically from a set design that was created for the particular jobsite. GPS guidance systems can have tolerances as small as two to three centimeters making them extremely accurate compared to relying on the operator's skill level. Since the machine's GPS system has the ability to know when it's off the design grade, this can reduce surveying and material costs required for a specific job.

GPS Technology was officially introduced as a guidance system for earthmoving machines in the late 1990s. Since this time, many manufacturers of earthmoving equipment now offer GPS and other guidance systems, as a factory option. Many companies exist that also sell GPS guidance systems for the earthmoving industry as a retrofit option. The two main companies for heavy equipment guidance systems are Trimble and Topcon. In April 2002, Trimble and Caterpillar Inc. began a joint venture known as Caterpillar Trimble Controls Technology LLC (CTCT). "The joint venture develops machine control products that use site design information combined with accurate positioning technology to automatically control dozer blades and other machine tools". Though aftermarket kits were available from various companies to retrofit an existing machine for GPS guidance, Caterpillar Inc. was the first heavy equipment manufacturer to offer GPS guidance systems as a factory option from the dealer called an ARO (Attachment Ready Option).John Deere soon followed with their own version of ARO called "Integrated Grade Control" in 2006 on many Track-Type Tractors (TTT) and Motorgraders (MG).

While there are various GPS systems currently used in the heavy equipment industry, they can typically be categorized as either "indicate only" or "fully automatic". Both systems can utilize one or two GPS receivers. Using only one GPS receiver limits how the guidance system can orient the machine's position in respect to the site design. Using two GPS receivers gives the guidance system two points of position allowing it to calculate what angle the machine is on relative to the site plan. The following describes "indicate only" and "fully automatic" in more detail.

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