日本的准天顶系统(Quasi-Zenith Satellite System,QZSS)除了基础的定位、导航、授时服务以外,还开发了GNSS轨道和钟差估计系统MADOCA(Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis)。MADOCA通过L6E增强信号每...日本的准天顶系统(Quasi-Zenith Satellite System,QZSS)除了基础的定位、导航、授时服务以外,还开发了GNSS轨道和钟差估计系统MADOCA(Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis)。MADOCA通过L6E增强信号每30 s播发一次GNSS实时轨道改正,每1 s播发一次钟差改正,也可以通过Ntrip协议或FTP服务获取实时产品,从而实现实时精密单点定位(Real-time Precise Point Positioning,RTPPP)服务。以GFZ事后精密星历和钟差产品为参考,对MADOCA和CNES实时精密轨道与钟差产品进行评估,统计了径向、切向、法向轨道误差,钟差误差,空间信号测距误差(Signal-in-Space Range Error,SISRE),仅考虑轨道误差的SISRE以及精密参数的可用性。最后基于MADOCA和CNES实时产品,进行GPS单系统和GPS/GLONASS双系统实时精密单点定位,对比了基于两种实时产品的RTPPP定位精度、收敛时间和可靠性。结果表明,12个IGS站动态PPP定位精度在东、北方向上优于0.1 m,天顶方向优于0.4 m;使用MADOCA精密产品进行GPS/GLONASS双系统定位,其收敛速度比使用CNES精密产品更快。展开更多
The Global Navigation Satellite System (GNSS) is widely utilized for accurate positioning.One commonly applied method to obtain precise coordinate estimates is by implementing the relative positioning in network mode....The Global Navigation Satellite System (GNSS) is widely utilized for accurate positioning.One commonly applied method to obtain precise coordinate estimates is by implementing the relative positioning in network mode.However,this approach can be complex and challenging.Fortunately,The Japan Aerospace Exploration Agency (JAXA) offers freely available satellite orbit and clock correction products called Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis (MADOCA),which can enhance positioning accuracy through the precise point positioning (PPP) method.This study focuses on evaluating PPP static mode positioning using MADOCA products and comparing the results with the highly precise relative positioning method.By analyzing a network of 20 GNSS stations in Indonesia,we found that the PPP method using MADOCA products provided favorable positioning estimates.The median discrepancies and the corresponding median absolute deviation (MAD) for easting,northing,and up components were estimated as 9±18 mm,10±9 mm,and 3±40 mm,respectively.These results indicate that PPP with MADOCA products can be a reliable alternative for establishing Indonesia's horizontal control networks,particularly for orders 0,1,2,and 3,and for a broad spectrum of geoscience monitoring activities.However,considerations such as epoch transformations and seismic activities should be taken into account for accurate positioning applications that comply with the definition of the national reference framework.展开更多
文摘日本的准天顶系统(Quasi-Zenith Satellite System,QZSS)除了基础的定位、导航、授时服务以外,还开发了GNSS轨道和钟差估计系统MADOCA(Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis)。MADOCA通过L6E增强信号每30 s播发一次GNSS实时轨道改正,每1 s播发一次钟差改正,也可以通过Ntrip协议或FTP服务获取实时产品,从而实现实时精密单点定位(Real-time Precise Point Positioning,RTPPP)服务。以GFZ事后精密星历和钟差产品为参考,对MADOCA和CNES实时精密轨道与钟差产品进行评估,统计了径向、切向、法向轨道误差,钟差误差,空间信号测距误差(Signal-in-Space Range Error,SISRE),仅考虑轨道误差的SISRE以及精密参数的可用性。最后基于MADOCA和CNES实时产品,进行GPS单系统和GPS/GLONASS双系统实时精密单点定位,对比了基于两种实时产品的RTPPP定位精度、收敛时间和可靠性。结果表明,12个IGS站动态PPP定位精度在东、北方向上优于0.1 m,天顶方向优于0.4 m;使用MADOCA精密产品进行GPS/GLONASS双系统定位,其收敛速度比使用CNES精密产品更快。
文摘The Global Navigation Satellite System (GNSS) is widely utilized for accurate positioning.One commonly applied method to obtain precise coordinate estimates is by implementing the relative positioning in network mode.However,this approach can be complex and challenging.Fortunately,The Japan Aerospace Exploration Agency (JAXA) offers freely available satellite orbit and clock correction products called Multi-GNSS Advanced Demonstration Tool for Orbit and Clock Analysis (MADOCA),which can enhance positioning accuracy through the precise point positioning (PPP) method.This study focuses on evaluating PPP static mode positioning using MADOCA products and comparing the results with the highly precise relative positioning method.By analyzing a network of 20 GNSS stations in Indonesia,we found that the PPP method using MADOCA products provided favorable positioning estimates.The median discrepancies and the corresponding median absolute deviation (MAD) for easting,northing,and up components were estimated as 9±18 mm,10±9 mm,and 3±40 mm,respectively.These results indicate that PPP with MADOCA products can be a reliable alternative for establishing Indonesia's horizontal control networks,particularly for orders 0,1,2,and 3,and for a broad spectrum of geoscience monitoring activities.However,considerations such as epoch transformations and seismic activities should be taken into account for accurate positioning applications that comply with the definition of the national reference framework.
