US Patent 7116613 Optical beam position active sensing and control using satellite beams

A beam position control system controls a position of a beam directed from a beam source. The beam position control system includes a beam position sensing system that generates one or more satellite beams which are used to determine the position of a main beam. A beam offset computation block determines a relative position of the main beam with respect to a desired main beam position and provides beam offset information to a controller that generates a compensation signal used to adjust the main beam position to the desired main beam position via a beam actuation system.