A priori and effective estimation of variance factors based on the code chipping rate in BeiDou navigation satellite system positioning

In multi-frequency and multi-constellation BeiDou Navigation Satellite System (BDS), the observation type is increased, and the observation precision is inevitably different. Consequently, it is difficult to determine the variance factors of various observations. Variance component estimation can reasonably determine the weights of different types of observations and greatly improve positioning accuracy, but the prerequisite is that there are enough redundant observations, which may not be met in the case of BDS. In addition, it has relatively high time and space complexity. In this study, a priori and effective estimation of variance factors based on the code chipping rate is proposed to properly adjust and determine the observation weights in BDS, thus better characterizing the observation precision while simplifying the calculation. Both static and kinematic experiments were conducted to verify the effectiveness of the new method. The results show that the proposed method is suitable for both open and obstructed environments, and the accuracy and reliability of single point positioning are improved while high efficiency is met.