A method of guiding a vehicle in adjacent swaths across terrain that may
slope comprising the steps of: (1) determining the tilt of the vehicle
with respect to Earth due to a slope of the terrain; (2) determining the
position with respect to Earth of a predetermined location that is fixed
relative to the vehicle; and (3) using the tilt and position
determinations to provide information for guiding the vehicle to prevent
gaps and overlaps between adjacent swaths as the slope changes.
