Angle measurement system based on Risley prisms and normal tracing method

Abstract

Because of factors such as aberration, processing defects, and beam symmetry loss, the three important performances of traditional autocollimators in terms of measuring range, measurement accuracy and working distance cannot be improved at the same time. In this paper, the Risley prisms normal tracing angle measurement system is built according to the method of "normal tracing", and the angle measurement is realized by tracing the normal angle change of the mirror to be measured. When using this method for angle measurement, by rotating the Risley prisms, the measurement beam is incident on the mirror surface in the near-specular normal direction and reflected, so as to realize the trace measurement of the normal direction of the reflective mirror. The experiment shows that when the normal tracing method is used for angle measurement, the system error related to distance in the autocollimator system is greatly reduced. Within the precision range allowed by the experimental environment, the measured data of the normal tracing angle measurement system based on Risley prisms does not show obvious systematic error characteristics.