Zhang Jiantao, Li Weiwei
College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266590, China.
Sensors (Basel). 2024 Apr 12;24(8):2472. doi: 10.3390/s24082472.
The Galileo satellite navigation system now provides initial services. With further satellite launches, the performance of Galileo will gradually improve, and new services will be introduced. This study aims to provide a comprehensive analysis of Galileo Single Point Positioning (SPP) using different broadcast ephemeris data sources. This study investigates the completeness of Galileo navigation message records from different institutions. The results show that IGS provides the best completeness across different data sources (ECR > 70%), while IGN exhibits the lowest completeness. Analyze the proportions of different data sources within the Galileo navigation message in the broadcast ephemeris files provided by IGS during the study period. The proportions of FNAV_258, INAV_513, INAV_516, and INAV_517 during the study period are 25.83%, 24.76%, 23.61%, and 25.80%, respectively, suggesting better data completeness for FNAV_258 and INAV_517 and poorer completeness for INAV_513 and INAV_516. Finally, this study explores SPP solutions for GPS and Galileo systems using different data sources. The results indicate that a higher ECR corresponds to better positioning performance. Although GPS exhibits smaller error fluctuations and smoother positioning results, Galileo's SPP positioning accuracy surpasses that of GPS. The introduction of dual-frequency observations effectively reduces data dispersion and enhances vertical positioning accuracy.
伽利略卫星导航系统现已提供初始服务。随着更多卫星的发射，伽利略系统的性能将逐步提升，并将引入新的服务。本研究旨在使用不同的广播星历数据源对伽利略单点定位（SPP）进行全面分析。本研究调查了来自不同机构的伽利略导航消息记录的完整性。结果表明，在不同数据源中，国际GNSS服务（IGS）提供了最佳的完整性（ECR>70%），而法国国家地理信息研究所（IGN）的完整性最低。分析了研究期间IGS提供的广播星历文件中伽利略导航消息内不同数据源的比例。研究期间，FNAV_258、INAV_513、INAV_516和INAV_517的比例分别为25.83%、24.76%、23.61%和25.80%，这表明FNAV_258和INAV_517的数据完整性较好，而INAV_513和INAV_516的数据完整性较差。最后，本研究探索了使用不同数据源的GPS和伽利略系统的SPP解决方案。结果表明，较高的ECR对应于更好的定位性能。虽然GPS的误差波动较小，定位结果更平滑，但伽利略的SPP定位精度超过了GPS。引入双频观测有效地减少了数据离散度，并提高了垂直定位精度。
