Optimal estimation of the central normal of a heliostat using UKF

The aiming accuracy of the optical axis of a heliostat directly affects the working efficiency of a concentrating solar tower plant. Due to the size of heliostat, it is difficult to measure the orientation of the optical axis directly during the tracking process. With a computer-vision based measuring system, the center of reflecting beam of a heliostat can be detected, but the result is disturbed by internal and external interferences. This paper presents a method to estimate the orientation of optical axis of a tracking heliostat using unscented kalman filter based on the measured beam center data. Simulation results and estimations based on actual measurements are presented in the paper.