US Patent 7904222 Trailer articulation angle estimation

This invention takes the advantage of existing radar, vision and ultrasonic sensors available for side blind spot detection, rear view, rear virtual bumper, and rear parking assist. Using a sensor fusion technique to combine the useful information from these sensors, the trailer articulation angles as well as trailer track width and tongue length is accurately estimated. When an active steering system is present, vehicle and trailer can be controlled with increased stability by applying the trailer information.