Correction method of heading calibration for calibration theodolite

To precisely and effectively complete the heading calibration of a theodolite, this paper analyzes the effect of single error on the heading calibration, and builds a correct model of the heading calibration when the collimating and orientation errors are involved at the same time according to the heading calibration principle. It provides the specific correction and verification methods. Experimental and measurement results indicate that the orientation error measured by positive and inverse pointing methods is equivalent to the error between orientation error and collimating error. The research in this paper proves the feasibility and effectiveness of the correction method and disciplines the method of heading calibration at the dock, which will make sure TTC complete mission successfully.