US Patent 7490678 GPS controlled guidance system for farm tractor/implement combination

Embodiments of the present invention comprise a system for positioning a drawn implement being pulled by a vehicle traveling generally along a desired path of movement, the vehicle having a mounting hitch on the rear end thereof where a system hitch is configured to adjust its angular orientation relative to the vehicle mounting hitch and a global positioning system receiver operable to detect the position of the implement relative to the desired path as the vehicle moves generally along the desired path and generate a signal that is indicative of the lateral position of the implement relative to the desired path and means for controlling the hitch means to adjust the angular orientation of the hitch means so that the implement follows the desired path of movement in response to the global positioning system signals.