Test of Weights of Direction Obsevations of Different Classes in Chinese Astrogeodetic Nets

In order to test and evaluate correctness and reasonableness the weights,which obtained from direction observations of different classes in astrogeodetic nets of our country,two methods are given;1、Using Helmert's simplified calculated formula,the estimation of variance  of observed directions and the best estimated value  are made;2、The weight intervals of direction obscrvations of different classes are determined under certain requirement of precision.Through calculation and analysis,we recognized that the weights of direction observations of different classes,which used in astrogeodetic network adjustment,are more appropriate and reasonable.