| GNSS is a global system that provides real-time navigation,timing,and highprecision positioning services.It is widely used in various fields.China’s BDS-3 system has been fully established and provides global positioning services.Due to its importance in navigation and positioning,comprehensive and in-depth research on the performance of the BDS-3 system and its combined positioning performance with other GNSS systems is needed.Precise Point Positioning(PPP)is a flexible,cost-effective,efficient,and widely applicable method in GNSS positioning,making it a research hotspot.This paper will focus on the following research aspects related to the BDS-3 system:(1)The study investigated the impact of Inter-System Bias(ISB)between BDS-2/BDS-3 on PPP positioning performance.After incorporating ISB estimation,the following improvements were observed in static mode: Convergence efficiency increased by 2.2%,12.1%,and 8.6% in the E/N/U directions,respectively.Positioning accuracy improved by 8.3%,4.4%,and 2.6% in the E/N/U directions,respectively.In dynamic mode,convergence efficiency improved by 18.6%,17.1%,and 3.9%,while positioning accuracy increased by 6.3% and 6.5% in the E and N directions,respectively.The positioning accuracy in the U direction remained comparable.(2)The study conducted a comprehensive analysis of the new signals B1C/B2 a from BDS-3 satellites,considering multiple indicators such as data completeness and carrierto-noise ratio.The BDS-3 signals at different frequencies showed similar performance,comparable to the GPS signals at the same frequencies.The static and dynamic PPP positioning accuracies for BDS-3(B1C/B2a)in three directions were 0.96 cm,1.24 cm,1.83 cm,and 1.88 cm,2.33 cm,4.03 cm,respectively.Compared to the old signals,the static PPP positioning accuracies in the N and E directions remained similar,while in the U direction,it improved by 11.2%.In dynamic PPP,the positioning accuracy in the N direction remained similar,while in the E and U directions,it improved by 9.3% and 5.6%,respectively.In both static and dynamic modes,the convergence efficiency of BDS-3(B1C/B2a)was higher in the N direction compared to the E and U directions.In static mode,the convergence time for BDS-3 new signals in the N,E,and U directions was14.2 min,27.6 min,and 23.5 min,respectively,representing an improvement of 12.3%,30.8%,and 20.3% compared to the old signals.In the simulated dynamic mode,the convergence time for BDS-3 new signals in the N,E,and U directions was 29.6 min,51.3min,and 65.3 min,respectively,representing an improvement of 22.7%,35.9%,and 12.5%compared to the old signals.The addition of the GPS system resulted in significant improvements in both positioning accuracy and convergence time.(3)The study compared GPS/BDS-3 triple-frequency PPP with individual singlesystem triple-frequency PPP solutions.The results showed that the GPS/BDS-3 combined system exhibited improved positioning performance compared to the single systems.BDS-2/BDS-3 system also demonstrated slightly better positioning performance compared to the BDS-3 system.The different signal combinations within the BDS system showed similar positioning performance.For GPS/BDS-3 triple-frequency static PPP,the positioning accuracy in the North/East/Up directions reached 0.86 cm/1.15 cm/1.56 cm.In the simulated dynamic PPP,the positioning accuracy in the North/East/Up directions reached 1.28 cm/1.66 cm/3.11 cm.Figure [32] table [18] reference [115]... |
