Comparison and Analysis of BeiDou-3 Satellite Attitude Quaternions Products from Different Analysis Centers and Their Application in PPP

Objectives: The satellite attitude quaternion products have been proposed by International GNSS Service (IGS) in the third data reprocessing campaign(repro3). These satellite attitude quaternion products are not only contributed to combining the precise satellite products during the eclipse season, but also can improve the reliability of precision point positioning (PPP) when satellites are in abnormal yaw attitude. Methods:In this paper, the four final and rapid BeiDou-3 satellite attitude products provided by WHU (Wuhan University), GFZ (Geo Forschungs Zentrum) and CODE (Center for Orbit Determination in Europe) analysis centers have been compared. Then attitude model characteristic of BeiDou-3 navigation satellite system (BeiDou-3) with different type from different analysis centers have been also analyzed in the eclipse seasons, and the effect of different satellite model on satellite clock and kinematic PPP have been investigated. Results: The results demonstrate that the BeiDou-3 yaw angle difference can reach up 120° from different analysis centers when the sun elevation angle is approximately 0°. In this period, different analysis centers used the different attitude model, and the difference of quaternions yaw angle could reach up to 120°. Furthermore, when the satellite attitude quaternions are used from different analysis centers, the PPP positing accuracy can be improved during the eclipse season. In detail, a significant improvement rate is achieved by using WHU rapid products, compared with nominal attitude strategy, the 3D positioning accuracy of kinematic PPP solutions with satellite attitude quaternions can be improved approximately 18.4 %. Conclusion: Although the positioning accuracy of PPP solutions can be improved by using the publicly BeiDou-3 attitude model, various attitude strategies may be adopted in the different analysis centers. Therefore, in order to obtain reliable PPP results, the satellite attitude quaternions should be used.