METHOD FOR CORRECTING POINTING ERRORS OF BIAXIAL ROTATION SYSTEM BASED ON SPHERICAL CAP FUNCTION

摘要

A method for correcting the pointing errors of a biaxial rotation system based on a spherical cap function, comprising: error collection: selecting stars or radio sources distributed evenly in a star catalogue for tracking and observation to obtain the theoretical position and measurement position of the stars, and subtracting the measurement positions and the theoretical positions to obtain the error distribution; error model fitting: selecting a suitable orthogonal spherical cap function model for the obtained error distribution and performing fitting to calculate an error fitting coefficient, the orthogonal spherical cap function model comprising a hemispherical harmonic function HSH, a Zernike spherical cap function ZSF, and a longitudinal spherical cap function LSF; and error control and compensation: putting the error model and the related fitting coefficient into a pointing control system for compensation. In the present method for correcting the pointing errors of a biaxial rotation system based on a spherical cap function, the model has strong stability and is not easily affected by measurement noise; there is no need to determine the form of the model on the basis of the frame form of the telescope, and the correction accuracy is high.