To determine the relative angle of a trailer relative to the towing vehicle a good way is to have a small short focal length black and white camera mounted on the towing vehicle pointing at a distinct horizontal marker on the nose of the tow cup. Unique blocks on this marker can be converted into an angle which can be fed into a program designed to predict the position of the trailer when it is reversed. Other information will be fed into this program such as steering angle. Has anyone worked on a problem similar to this? Any help gratefully appreciated.