双线程滑动窗口多系统GNSS超快精密定轨实现及评估

全球导航卫星系统（GNSS）超快精密定轨为GNSS实时应用提供了高精度空间基准。基于天地协同定位、导航与授时（PNT）网络服务中心实现了四系统GNSS卫星超快精密定轨，并对定轨结果进行精度评价。介绍了天地协同PNT网络的概念内涵以及网络服务中心部署的超快精密定轨软件架构和详细功能，并针对实时应用需求提出了一种双线程滑动窗口超快精密定轨策略。最后利用重叠弧段比较、与外部轨道产品比较以及卫星激光测距（SLR）检核3种方式对定轨结果进行了精度评价。结果表明，与武汉大学分析中心的最终事后精密轨道产品相比，四系统GNSS MEO卫星预报6 h弧段的径向均方根（RMS）误差整体在2~5 cm水平，BDS2 IGSO卫星最小一维RMS误差在10~15 cm水平；GPS和Galileo卫星的SLR检核残差均值在1~3 cm水平，标准差在3~6 cm水平，能够满足后续厘米级实时应用对空间基准的精度需求。

Implementation and assessment of multi-GNSS ultra-rapid precise orbit determination based on a two-thread sliding window strategy

Multi-global navigation satellite system(GNSS) ultra-rapid precise orbit determination provides high-precision space reference for GNSS real-time applications. The multi-GNSS ultra-rapid precise orbit determination at space-ground collaborative positioning, navigation and timing(PNT) network service center is implemented and the accuracy of the orbit determination results are evaluated. The conceptual essence of the space-ground collaborative PNT network, and the architecture and detailed functions of the ultra-rapid precise orbit determination software deployed on the network service center are introduced. Additionally, a two-thread sliding window ultra-rapid orbit determination strategy is proposed to meet real-time application requirements. Finally, the accuracy of the orbit determination results is evaluated in three ways: through overlapping orbit comparison, comparison with other precise orbit products, and satellite laser ranging(SLR) checking. The results show that the root mean square(RMS) error of multi-GNSS medium-Earth orbiting(MEO) satellites in the radial direction ranges between 2 and 5 cm during a 6-hour predicted arc, and the minimum one-dimensional RMS error of the BDS2 IGSO satellite is at the level of 10~15 cm, when compared with the final orbit products from the analysis center of Wuhan University. The mean value and standard deviation of SLR residuals for the GPS and Galileo satellites are at 1~3 cm and 3~6 cm, respectively. The results meet the accuracy requirements of the space reference for centimeter-level real-time applications.