Solution to the Control Problem of Laser Path Tracking Using Risley Prisms

A control system is proposed for tracking a desired path with a laser beam. The proposed control system successfully eliminates the singularities associated with utilizing a pair of Risley prisms as the laser ray steering device. The analysis in this paper leads to an accurate derivation of the prisms' paraxial equations, in addition to introducing an efficient algorithm for finding the prisms' exact orientations given a desired ray steering direction.