多频多模PPP-RTK应用于动态载体定位

Multi-frequency and Multi-GNSS PPP-RTK for Kinematic Platform Positioning

【目的】固定模糊度的精密单点定位(Integer ambiguity resolution-enabled precise point positioning,PPP-RTK)是最前沿的全球导航卫星系统(GNSS)定位技术。现有文献广泛研究了静态PPP-RTK,而动态PPP-RTK研究仍有不足。【方法】本文构建了多频多模PPP-RTK模型并测试了该模型的静态仿动态和真动态定位性能,同时探究了多频相对于双频和多系统相对于单系统的优势。【结果】结果表明,在静态仿动态模式下,三频BDS2+Galileo PPP-RTK将双频PPP-RTK的模糊度首次固定时间(Time-to-first-fix,TTFF)从60s缩短至30s,模糊度固定成功率(Ambiguity success rate,ASR)从99.82%提升至100%,定位精度提升了5%。GPS+BDS2+BDS3+Galileo四系统PPP-RTK将定位精度进一步提升了30%。在船载动态定位中,三频Galileo PPP-RTK将双频PPP-RTK的TTFF从125s缩短至100s,ASR从81.9%提升至92.08%,定位精度提升了15%。BDS2+BDS3+Galileo三系统PPP-RTK将TTFF缩短至5s,ASR提升至99.72%,定位精度提升至3cm。农机定位中,多频多模观测值对定位的提升与船载定位相似。GPS+Galileo+BDS2+BDS3四系统定位结果最优,其TTFF为4s,ASR为99.89%,定位精度优于3cm。

[Objective]Integer ambiguity resolution-enabled precise point positioning,also known as PPP-RTK,is the state-of-the-art positioning technique using global navigation satellite systems(GNSSs).Compared with static PPP-RTK that has been comprehensively studied,investigations on kinematic PPP-RTK are rather limited.[Methods]This work formulates a multi-frequency and multi-GNSS PPP-RTK model and analyzes its performances in both simulated kinematic and real kinematic modes.We also investigate the advantages of triple-frequency positioning over dual-frequency positioning and demonstrate the benefits of multi-GNSS.[Results]For the simulated kinematic mode,the results show that triple-frequency BDS2+Galileo positioning reduces,compared to the dual-frequency case,the time-to-first-fix(TTFF)from 60 s to 30 s,improving the ambiguity success rate(ASR)from 99.82%to 100%,and the positioning accuracy by 5%.Quad-system observations combining GPS+BDS2+BDS3+Galileo further improves the accuracy by 30%.In the case of kinematic boat positioning,the triple-frequency Galileo observations also contribute to positioning,as the TTFF is decreased from 125 s to 100 s,the ASR is increased from 81.9%to 92.08%,and the positioning accuracy is improved by 15%.The benefits of multi-GNSS are remarkable as the BDS2+BDS3+Galileo triple-system positioning reduces the TTFF to 5 s,improves the ASR to 99.72%,and achieves the positioning accuracy of better than 3 cm.Regarding to the kinematic tractor positioning,the improvement benefited from the triple frequency is similar to that of kinematic boat positioning.The best positioning performance is achieved by GPS+Galileo+BDS2+BDS3 quad-system positioning.The corresponding TTFF is 4 s,the ASR is 99.89%,and the positioning accuracy is better than 3 cm.