A ground contour sensing system and method for a vehicle with a mowinghead. The system includes a sensor system that measures a ground contour infrontof the mowing head, and generates contour measurement signals； and acontrollerthat determines whether to move the mowing head based on the contourmeasurement signals, and generates movement commands for the mowing headwhen it determines to move the mowing head. The mowing head can include tiltandlift cylinders, and the controller can determine whether to move the mowingheadusing the tilt or lift cylinders. The sensor system can include a pivot armthat movesin response to changes in the ground contour, and an angle sensor thatmeasures anangle of the pivot arm. There can be one or more sensor systems positionedbetween the right and left sides of the mowing head.
