摘要:
给出了顾及电离层二阶项和三阶项延迟改正的非差精密单点定位(precise point positioning,PPP)模型。利用全球均匀分布的38个IGS跟踪站,对比分析了不同纬度、不同电离层环境下电离层高阶项延迟对GNSS观测值以及静态PPP解算的影响。实验结果表明,电离层高阶项延迟对低纬度地区的静态PPP的定位结果影响最为显著,可达3～5mm;而对高、中纬度的影响则较小,分别为亚mm和mm级水平;且其影响主要体现在南北(N)方向,呈向南偏移的趋势,尤其是在低纬度地区,该分量可达3mm以上,是E方向和U方向的2～3倍。此外,电离层活跃程度对定位结果也有一定影响,其活跃期影响值相对于平静期影响...
Abstract:
We modified the un-differenced precise point positioning(PPP) mathematical model considering the second-and third-order ionospheric correction.The influence of the higher-order ionospheric corrections on both GNSS observations and static PPP are analyzed with respect to aspects of site location and ionospheric environment by using a globally distributed network which is composed of 38 IGS tracking stations.Numerical experimental results show that,higher-order ionospheric influences on the observation as well as static PPP at low-latitude regions are more significant than that of mid-and high-latitude regions.For static PPP,the influence in low-latitude regions(<30°) reaches about 3-5mm,and is only a sub-millimeter in other regions(>30°).Furthermore,the impact is mainly visible in the direction of North and South direction,showing a southward migration trend,especially at the lower latitudes where the influence value is likely to be more than 3 mm,2 to 3 times that of the East and Up components.The level of ionospheric activity may also have impact on positioning results,and the influence during active periods is about 20-30% higher than that of quiet periodd.
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