In civil engineering, machine control is used to accurately position earthwork machinery based on 3D design models and GPS systems, and thus aid machine operators to e.g. control the position of a road grader's blade. Many machine control systems utilize the Real Time Kinematic (RTK) system to improve the positioning accuracy.
There are five dominant manufacturers of machine control systems: Leica Geosystems, MOBA Mobile Automation AG, Trimble Navigation Limited, Unicontrol and Topcon Positioning Systems. In 2010, The Kellogg Report[1] was published to serve as a resource for comparing the systems from these and other manufacturers.