How does 3D GPS machine control for excavators work?

Posted by Matt Lacey on

How does 3D GPS machine control for excavators work?

Machine control for excavators is the clear way forward for construction and groundworks. It allows operators to work more independently, efficiently, accurately and safely.

But how does it actually work? We explain in brief terms below…

GNSS Positioning:

Excavator guidance systems rely on GNSS (often referred to as GPS) technology to determine the machine's precise position on the construction site.

GNSS receivers are mounted on the excavator, which continuously receive signals from satellites and corrections from base stations to determine its location to within 20mm. The primary antenna is used to determine an accurate coordinate at the bucket, and the secondary antenna is used to provide a constant machine heading in the cab display.

Machine Sensors:

Excavators are equipped with a number of Inertial Measurement Unit (IMU) sensors. One of these sensors is mounted in the body of the machine to determine pitch and roll. The remaining sensors are fitted to each of the moving components of the machine (i.e. boom, dipper, bucket hitch). These sensors communicate to provide real-time data about the position and movement of the excavator's components.

Calibration and Setup:

Machine control systems require calibration to ensure accurate operation. The relationship between the mounting of the sensors with the position of the machine must be determined, as well as the exact location of the GNSS antennas in relation to the machine’s moving parts. This calibration is most efficiently completed with a total station to measure physical elements of the machine and the position of GNSS antennas.


Software processes data from the GNSS, IMU, and other sensors to create a digital representation of the excavator on site. The software compares the real-time position of the excavator with the desired design or reference model, which represents the target excavation shape and depth.

Machine control systems like Unicontrol have a touch screen cab display. This interface provides the operator with a visual representation of the excavation site, including the design and the current position of the excavator's bucket in real-time. The system provides visual and audible cues and values to the operator to achieve the desired depth, slope, or shape of the excavation.

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