GNSS增强系统中精密实时钟差高频估计及应用研究

GNSS星基差分增强系统依赖于实时轨道及钟差增强信息。本文主要研究多GNSS实时精密钟差估计模型,在传统非差基础上优化待估参数,实现了一种高效的Multi-GNSS实时钟差简化估计模型。基于PANDA软件开展了实时轨道数据处理与分析,经过验证可获得的GPS/北斗MEO/Galileo实时轨道径向精度1~5cm,北斗GEO/IGSO卫星径向精度约10cm。分析发现本文优化的实时钟差简化估计模型单历元解算效率较高,可应用于实时钟差增强信息高频(如1Hz)更新,且解算获得的实时钟差不存在常偏为绝对钟差;基于实时轨道,通过该模型可获得实时钟差精度GPS约0.22ns,北斗GEO约0.50ns、IGSO/MEO约0.24ns,Galileo约0.32ns。在此基础上,利用目前所获取的MultiGNSS实时数据流搭建了Multi-GNSS全球实时增强原型系统,并基于互联网实时播发增强信息,可初步实现实时PPP厘米级服务、伪距米级导航定位服务。

Study on a High-frequency Multi-GNSS Real-time Precise Clock Estimation Algorithm and Application in GNSS Augment System

GNSS satellite-based differential augment system is based on real-time orbit and clock augment message.The multi-GNSS real-time precise clock error estimation model is studied, and then the parameters estimated in traditional un-difference model are optimized and a high-efficient real-time clock simplified model is proposed and realized.The real-time orbit data processing based on PANDA is also analyzed.The results indicate that the real-time orbit radial accuracy of GPS, BeiDou MEO and Galileo is 1~5cm, and the radial accuracy of the BeiDou GEO/IGSO satellite is about 10cm.It is found that the optimized real-time clock simplified model is more efficient in one epoch than un-difference model and can be applied to high-frequency (such as 1Hz) updating of real-time clock augment message.The results show that the real-time clock error obtained by this model is absolute value and there is no constant bias.Based on the real-time orbit, the GPS real-time clock precision of the simplified model is about 0.24ns, BeiDou GEO is about 0.50ns, IGSO/MEO is about 0.22ns and Galileo is about 0.32ns.Using the multi-GNSS real-time data stream in GFZ, a multi-GNSS real-time augment prototype system is built and the real-time augment message is being broadcasted on the Internet.The real-time PPP centimeter-level service and meter-level navigation service based on pseudorange are realized based on this prototype system.