BeiDou B2/Galileo E5b短基线紧组合相对定位模型及性能评估

随着GPS和GLONASS系统的现代化以及Galileo和BeiDou卫星导航系统的建设,GNSS正朝多频多系统的方向发展。本文对BeiDou B2/Galileo E5b短基线紧组合相对定位的模型与算法进行了研究,详细推导了BeiDou B2/Galileo E5b短基线紧组合相对定位的模型与算法,并对其定位性能进行了分析。重点分析了BeiDou B2与Galileo E5b频点的接收机间差分系统间偏差的长期稳定性,结果表明:基线两端的接收机类型(包括固件版本)相同时,差分系统间偏差接近于0;基线两端的接收机类型不同时,差分系统间偏差较大,但具有长期稳定性,因此能够事先标定并作为改正数用于后续的定位中。最后基于BeiDou B2/Galileo E5b单频单历元相对定位试验对系统间紧组合模型的定位效果进行了比较验证。结果表明,相对于传统的松组合模型,使用改正系统间偏差的紧组合模型能够显著提高模糊度固定的成功率,尤其是在遮挡比较严重、单系统可观测到的卫星数较少的情况下,模糊度固定成功率可以提高10%~25%。

Model and Performance Analysis of Tightly Combined BeiDou B2 and Galileo E5b Relative Positioning for Short Baseline

With the modernization of GPS and GLONASS, and construction of Galileo and BeiDou, multi-frequency multi-GNSS is a trend.For the first time this paper investigates the model, algorithm, and performance of tightly combined relative positioning using BeiDou B2 and Galileo E5b observations for short baselines.The model and algorithm was first deduced in detail.Then the long stability of between-receivers differential inter-system bias (DISB) between BeiDou B2 and Galileo E5b observations was analyzed emphatically.It is shown that for baselines with identical receivers (the same firmware version), the DISB is close to zero;for baselines with different receiver types, the DISB is significant but with long stability, which allows for a-prior calibration of these DISBs.Finally, the performance of tightly combined positioning was evaluated using single frequency BeiDou B2 and Galileo E5b observations in an instantaneous approach.It is demonstrated that the DISB corrected tightly combined model can significantly improve the ambiguity resolution performance with respect to the loosely combined model.The improvement can be especially significant (10%~25%) under environments where the navigation signals are serious blocked or the observed satellite for each system is limited.