摘要
The expansion of Global Navigation Satellite Systems(GNSS)and Regional Navigation Satellite Systems(RNSS),along with broadcasting of additional signals,ofers more options for Precise Point Positioning(PPP).Utilizing a number of constellations and frequencies provides more precise and reliable Observable-Specifc Bias(OSBs)and atmospheric products,thereby enhancing the performance of PPP with Ambiguity Resolution(PPP-AR)and PPP-RTK systems.Additionally,the emergence and refnement of satellite-based augmentation services targeting PPP,such as BDS-3 Precise Point Positioning(PPP-B2b)and High Accuracy Service(HAS),have further expanded the applications of multi-GNSS and multi-frequency PPP.In this contribution,we comprehensively overview the developmental history of major systems and the construction of global satellite-based augmentation systems.The model of multiGNSS and multi-frequency PPP-RTK is then established,encompassing both the server and user sides.Benefting from the modernization of GPS,refnement of Galileo,and stable operation of BDS,the convergence time of PPP foat solutions is less than 9 min,while the convergence time of fxed solutions is under 5 min.The PPP-RTK system can achieve instantaneous convergence with high-confdence atmospheric products,maintaining positioning accuracy within 2.5 cm.Furthermore,vehicular experiments demonstrate that the PPP-RTK technology can maintain a positioning accuracy of around 10 cm even in rapidly changing observational conditions.For augmentation services such as PPP-B2b and HAS,after correcting for orbit,clock,and code biases,the convergence time can be reduced to under 15 min,with positioning accuracy of approximately 16 cm.Finally,we present our outlook for the future of BDS.
基金
funded by the National Science Fund for Distinguished Young Scholars of China(Grant No.42425003)
the National Natural Science Foundation of China(Grant No.42388102,No.42230104)
the Fundamental Research Funds for the Central Universities(No.2042025kf0026).
