[Gdeaver]

The Sharp IR sensors have a range up to 59". Not enough. Sonar has the range but the cone of detection is very large at this distance and the economical sonar sensors only return the distance to the first ping. What would work is a Laser time of flight instrument. Can't use them because of the amount of radiation they use. So as far as I know there is no perfect targeting system other than the camera to use this year.