In civil engineering

Civil engineering

Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings...

, machine control is used to accurately position earthwork

Earthworks (engineering)

Earthworks are engineering works created through the moving or processing of quantities of soil or unformed rock.- Civil engineering use :Typical earthworks include roads, railway beds, causeways, dams, levees, canals, and berms...

 machinery based on 3D design models and GPS systems

GPS in the Earthmoving Industry

- 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...

, and thus aid machine operators to e.g. control the position of a road grader

Grader

A grader, also commonly referred to as a road grader, a blade, a maintainer, or a motor grader, is a construction machine with a long blade used to create a flat surface. Typical models have three axles, with the engine and cab situated above the rear axles at one end of the vehicle and a third...

's blade. Many machine control systems utilize the differential GPS system

Differential GPS

Differential Global Positioning System is an enhancement to Global Positioning System that provides improved location accuracy, from the 15-meter nominal GPS accuracy to about 10 cm in case of the best implementations....

 to improve the positioning accuracy.

There are three dominant manufacturers of machine control systems: Trimble Navigation Limited, Topcon

Topcon

Topcon is a Japanese manufacturer of optical equipment for ophthalmology and surveying. Their headquarters are in Itabashi, Tokyo. They are affiliated with Toshiba, which holds 40% of Topcon's stock.-History of Topcon:...

 Positioning Systems and Leica Geosystems

Leica Geosystems

Leica Geosystems based in eastern Switzerland produces products and systems for surveying and geographical measurement...

. In 2010, The Kellogg Report was published to serve as a resource for comparing the systems from these and other manufacturers.