Factor Analysis for the Impactions on Principal Point Accuracy in Exact Measuring Angle Method

This paper analyzes three factors that impact on the principle point accuracy: the instrument tilt error in the measurement process, the number of sampling points and the scope field of view angle (scope that the sampling points coverage). For the third factor, this paper builds the mathematical model and makes derivation of formula. The result shows that the three factors have different impacts on the principal point accuracy. In the case of the accuracy of measurement reaching micron level and the number of sampling points greater than 200 in the experiment, the scope field of view angle is the most important factors to the principal point accuracy. In the exact measuring angle method, to improve the principle point accuracy, only improving the accuracy of measurement and the number of sampling points is not enough. The scope field of view angle is necessary.