GCS600 grade control system is designed for excavation, trenching, grading and profile work. Excavator operator programs for depth and or slope, references the laser system to a benchmark, and digs. Indicator light and tone guides the operator to accuracies within an inch, Trimble says. A pitch and roll sensor compensates for machine footing attitude, eliminating the need to level the machine before working. An optional Laser-Catcher features re-benches with the laser without returning to the original benchmark, allowing for work across a greater area as the machine can move location. The system can be upgraded to GPS (GCS900), which gives the operator access to site plans through the CB430 in-cab control box.