GPS & Machine Control Systems
Machine control uses GPS and sensors to guide dozers, graders and excavators to a digital grade. It improves accuracy and reduces stakes and grade checkers on the ground. It also changes where people stand, what operators watch and what can go wrong.
- Equipment Operators
- Surveyors
- Grade Crews
What is installed
- GNSS antennas and masts on the machine and sometimes on blades or booms.
- Sensors (inclinometers and cylinder sensors) that measure blade or bucket position.
- A cab display with a 3D design model that shows cut and fill.
- A base station or network to improve accuracy, plus a rover on a pole carried by surveyors.
New hazards
- Distraction: watching the screen instead of the surroundings. See Cell Phone Distractions.
- Tall masts and antennas that can strike overhead lines, bridges and branches. See Overhead Power Lines.
- Worker on foot: surveyors with rovers walking near moving machines. See Proximity Warning Systems.
- Over-trust in the system: a bad calibration, lost signal or wrong design file can mean cutting too deep or into utilities.
- Cables and sensors that catch on obstructions or fail.
- Installation hazards: climbing on machines and working at heights.
Safe practice
- Get training on the display, calibration and how to switch to manual control. Know what to do if signal drops.
- Look around before moving. Use mirrors, cameras and spotters; do not rely only on the screen.
- Lower or fold masts where clearance is tight. Check height before passing under lines or bridges.
- Keep ground workers outside the swing and travel zones, and agree on hand signals or radio calls before they approach. See Backing & Spotters.
- Check the design model against utility locates and field conditions. Call 811 and verify before digging. See Call 811.
- Calibrate and check against a known point at the start of each shift and after impacts.
- Keep screens secure and out of the line of sight to the work.
Checklist
- I know how to disable machine control and run manually
- Mast height and clearance are checked
- Ground workers and the operator have a communication plan
- Utilities are located and marked in the design
- The system has been checked against a known benchmark
Standards & references
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