Abstract:It is difficult to get the optimal result using empirical weight ratio in combination positioning, due to differences in observation noise and orbit accuracy between GNSS systems. Based on this, Helmert variance component estimation is introduced into GPS/GLONASS/BDS combined positioning, determining the reasonable weight ratio of the GPS/GLONASS/BDS combined single point positioning and baseline solution. Based on a set of experimental data, the experimental results show that the method can reasonably determine the weight ratio of the observations of the GPS/GLONASS/BDS combined positioning. The optimal weight ratio of pseudo-range observations is 5∶1∶1, the optimal weight ratio of phase observations is 1∶1∶1, which improves the accuracy and reliability of the GPS/GLONASS/BDS combined positioning.