The recent advances in GNSS positioning of the recent decades have been possible by the development of increasingly efficient software and online calculation tools. The differences between these online PPP calculation...The recent advances in GNSS positioning of the recent decades have been possible by the development of increasingly efficient software and online calculation tools. The differences between these online PPP calculation tools result in a different level of performance. Our study shows that for 24-hour or 6-hour observation time, the Canadian Spatial Reference System for PPP (CSRS-PPP), CenterPoint RTX Post-Processing (RTX), Magic/GNSS, Institut Geographique National-PPP (IGN-PPP) and RTKLIB tools have almost similar level of performance with International Terrestrial Reference Frame (ITRF) solutions considered as reference solution. Average deviations on the three components X, Y and Z for the different tools compared to ITRF solutions do not exceed 1 cm. However, the CSRS-PPP tool gives deviations of less than 5 mm. Calculations from the observations of 2 h and 1 h show that the RTX and CSRS-PPP tools keep deviations similar to those obtained with 24 h and 6 h, while RTKLIB and IGN-PPP give deviations exceeding 6 cm and sometimes failures of some calculations for IGN-PPP.展开更多
文摘The recent advances in GNSS positioning of the recent decades have been possible by the development of increasingly efficient software and online calculation tools. The differences between these online PPP calculation tools result in a different level of performance. Our study shows that for 24-hour or 6-hour observation time, the Canadian Spatial Reference System for PPP (CSRS-PPP), CenterPoint RTX Post-Processing (RTX), Magic/GNSS, Institut Geographique National-PPP (IGN-PPP) and RTKLIB tools have almost similar level of performance with International Terrestrial Reference Frame (ITRF) solutions considered as reference solution. Average deviations on the three components X, Y and Z for the different tools compared to ITRF solutions do not exceed 1 cm. However, the CSRS-PPP tool gives deviations of less than 5 mm. Calculations from the observations of 2 h and 1 h show that the RTX and CSRS-PPP tools keep deviations similar to those obtained with 24 h and 6 h, while RTKLIB and IGN-PPP give deviations exceeding 6 cm and sometimes failures of some calculations for IGN-PPP.
文摘随着北斗卫星导航系统(BDS)的全球组网成功,基于BDS的应用研究正在如火如荼的进行中,尤其是包括BDS在内的多频多模融合定位正成为研究的重点.利用MGEX(Multi-GNSS Experiment)多个测站的BDS、GPS、GLONASS、Galileo观测数据,基于RTKLIB开源代码,在Visual Studio 2017平台上进行了BDS/GPS、BDS/GLONASS、BDS/Galileo三种组合系统的精密单点定位(PPP)实验,从静态PPP、动态PPP、可见卫星数、精度衰减因子(DOP)等方面对比分析了三种组合系统的定位性能.实验结果表明:BDS/GPS组合系统的可见卫星数最多,各DOP值最小,静态PPP收敛后三个方向的精度优于6 cm.不论是静态PPP还是动态PPP,其定位性能都最好;BDS/GLONASS、BDS/Galileo组合系统动态PPP的定位抖动较大,可见卫星数都要小于BDS/GPS组合系统,收敛时间较长,两者的动态PPP定位性能也差于BDS/GPS组合系统.
文摘针对国际GNSS服务局(International GNSS Service,IGS)不同分析中心卫星轨道和钟差产品之间的差异,利用IGS提供的综合精密产品和不同分析中心的精密产品,比较分析了不同分析中心精密轨道和精密钟差产品的区别。在此基础上,使用同一分析中心的卫星轨道和钟差产品,将IGS综合精密产品的静态精密单点定位(Precise Point Positioning,PPP)单天解作为参考值,基于RTKLIB比较了不同分析中心精密产品PPP单天解相对于IGS PPP单天解的点位分量误差。算例表明:尽管不同分析中心的精密轨道和精密钟差产品存在差异,然而在采用同一分析中心精密产品进行精密单点定位时,其X、Y、Z坐标分量偏差均在mm级,其点位定位误差在[2 mm 8 mm]之间波动,表明了同一分析中心的轨道和钟差产品具有自洽性和一致性。因此,在IGS精密卫星轨道和钟差产品未发布前,用户可以配套使用IGS不同分析中心的卫星轨道和钟差产品来取代IGS最终精密轨道和精密钟差产品,以得到高精度定位结果。
