模糊度固定是提升精密单点定位精度和快速收敛的主要因素之一,相位偏差、硬件延迟与模糊度参数无法正确分离是导致模糊度非整数特性的主要原因。采用德国地学研究中心(GFZ)公开发布的包含相位偏差的整数钟产品GBM,并基于全球分布的5个M...模糊度固定是提升精密单点定位精度和快速收敛的主要因素之一,相位偏差、硬件延迟与模糊度参数无法正确分离是导致模糊度非整数特性的主要原因。采用德国地学研究中心(GFZ)公开发布的包含相位偏差的整数钟产品GBM,并基于全球分布的5个MGEX连续跟踪站年积日290~296的观测数据,对比分析单伽利略卫星导航系统(Galileo)精密单点定位(Precise Point Positioning,PPP)在固定解模式和浮点解模式下的定位精度和模糊度固定率。实验结果表明,模糊度固定模式下的定位精度,5个测站E方向提升都在83%以上,N方向提升在55%以上,U方向除了MATG测站,其他在65%以上,模糊度固定率方面,除了MATG站以外都优于60%。展开更多
High-rate GPS data from the United States continuously operating reference stations in the Alaska region are processed using the recently developed precise point positioning(PPP) technique. The traditional PPP techniq...High-rate GPS data from the United States continuously operating reference stations in the Alaska region are processed using the recently developed precise point positioning(PPP) technique. The traditional PPP technique does not fix ambiguities into their integers because these ambiguities do not have an integer nature when data from a single receiver, as well as precise orbit and clock corrections, are used. Additional corrections, i.e.,uncalibrated phase delay(UPD), are needed to fix integer ambiguities and consequently improve positioning accuracy. This study proposes a methodology to compute for wide-lane and L2(the second L-band frequency) UPDs using the geometry-based model and subsequently applies these parameters to the computation for ambiguity-fixed solutions. The instantaneous displacements of near-field sites, as well as the permanent deformations after the earthquake, are therefore obtained for the January 5, 2013,Alaska earthquake. The real-time performance of PPP solutions are assessed by considering realistic data latency and data interval of corrections. Ambiguity-fixed solutions are compared with ambiguity-float ones. The comparison shows that the positioning accuracy can be improved significantly when the ambiguities are fixed correctly. Thesolutions using the real-time corrections are also compared with those using post-processing corrections, i.e., Center for Orbit Determination in Europe final orbit and clock.Although the accuracy is somehow degraded because of the data latency and data interval, the real-time results are satisfactory for use in monitoring the small-scale deformation(1–2 cm) caused by the Alaska earthquake. In addition, the kinematic ambiguity-fixed PPP solutions for7 days around the earthquake are calculated to obtain permanent pre- and post-earthquake deformations. The deformations computed from real-time and post-processing corrections do not appear to be significantly different.展开更多
提出一种新的模糊度固定方法,并把算法应用到精密单点定位(Precise Point Positioning,PPP)中,将模糊度进行选择固定,以实现恶劣环境下快速、有效获得较高PPP固定解的目的。该方法以模糊度固定成功率和Ratio因子为约束条件,基于最小方...提出一种新的模糊度固定方法,并把算法应用到精密单点定位(Precise Point Positioning,PPP)中,将模糊度进行选择固定,以实现恶劣环境下快速、有效获得较高PPP固定解的目的。该方法以模糊度固定成功率和Ratio因子为约束条件,基于最小方差优先固定的模糊度子集选取方法实现PPP中模糊度的部分固定。算例从模糊度固定可靠性、收敛速度以及PPP固定解精度等方面对部分模糊度固定方法进行了分析。结果表明,该方法使得PPP模糊度固定的平均可靠性比传统固定方法提高了近一倍、参数解算的平均收敛时间缩短了1/4左右。因此,更适合在初始阶段观测信息较少或残余误差较大而难以固定全部模糊度的时候,快速获得较高精度的PPP固定解。展开更多
提出利用GPS参考网估计电离层延迟、卫星相位偏差的算法,用于实现区域内精密单点定位(Precise Point Positioning,PPP)的整周模糊度快速固定.利用站间距约为100～200km的参考网进行实验,结果表明:电离层延迟的内插和外推精度均优于1dm,...提出利用GPS参考网估计电离层延迟、卫星相位偏差的算法,用于实现区域内精密单点定位(Precise Point Positioning,PPP)的整周模糊度快速固定.利用站间距约为100～200km的参考网进行实验,结果表明:电离层延迟的内插和外推精度均优于1dm,卫星相位偏差估值的日内变化不超过0.2周;此外,单天内不同时刻始,固定PPP整周模糊度所需时长最多不超过10min,且当模糊度成功固定后,三维位置解较之相应浮点解的精度改善优于80%.新算法可望解决PPP普遍存在的收敛时间过长问题,增强了PPP技术的实用性.展开更多
文摘模糊度固定是提升精密单点定位精度和快速收敛的主要因素之一,相位偏差、硬件延迟与模糊度参数无法正确分离是导致模糊度非整数特性的主要原因。采用德国地学研究中心(GFZ)公开发布的包含相位偏差的整数钟产品GBM,并基于全球分布的5个MGEX连续跟踪站年积日290~296的观测数据,对比分析单伽利略卫星导航系统(Galileo)精密单点定位(Precise Point Positioning,PPP)在固定解模式和浮点解模式下的定位精度和模糊度固定率。实验结果表明,模糊度固定模式下的定位精度,5个测站E方向提升都在83%以上,N方向提升在55%以上,U方向除了MATG测站,其他在65%以上,模糊度固定率方面,除了MATG站以外都优于60%。
基金supported by the National Natural Science Foundation of China(41274036,41231174)the Chinese Scholarship Council Program(201208420050)the‘‘111 Project’’of China(B07037)
文摘High-rate GPS data from the United States continuously operating reference stations in the Alaska region are processed using the recently developed precise point positioning(PPP) technique. The traditional PPP technique does not fix ambiguities into their integers because these ambiguities do not have an integer nature when data from a single receiver, as well as precise orbit and clock corrections, are used. Additional corrections, i.e.,uncalibrated phase delay(UPD), are needed to fix integer ambiguities and consequently improve positioning accuracy. This study proposes a methodology to compute for wide-lane and L2(the second L-band frequency) UPDs using the geometry-based model and subsequently applies these parameters to the computation for ambiguity-fixed solutions. The instantaneous displacements of near-field sites, as well as the permanent deformations after the earthquake, are therefore obtained for the January 5, 2013,Alaska earthquake. The real-time performance of PPP solutions are assessed by considering realistic data latency and data interval of corrections. Ambiguity-fixed solutions are compared with ambiguity-float ones. The comparison shows that the positioning accuracy can be improved significantly when the ambiguities are fixed correctly. Thesolutions using the real-time corrections are also compared with those using post-processing corrections, i.e., Center for Orbit Determination in Europe final orbit and clock.Although the accuracy is somehow degraded because of the data latency and data interval, the real-time results are satisfactory for use in monitoring the small-scale deformation(1–2 cm) caused by the Alaska earthquake. In addition, the kinematic ambiguity-fixed PPP solutions for7 days around the earthquake are calculated to obtain permanent pre- and post-earthquake deformations. The deformations computed from real-time and post-processing corrections do not appear to be significantly different.
文摘提出一种新的模糊度固定方法,并把算法应用到精密单点定位(Precise Point Positioning,PPP)中,将模糊度进行选择固定,以实现恶劣环境下快速、有效获得较高PPP固定解的目的。该方法以模糊度固定成功率和Ratio因子为约束条件,基于最小方差优先固定的模糊度子集选取方法实现PPP中模糊度的部分固定。算例从模糊度固定可靠性、收敛速度以及PPP固定解精度等方面对部分模糊度固定方法进行了分析。结果表明,该方法使得PPP模糊度固定的平均可靠性比传统固定方法提高了近一倍、参数解算的平均收敛时间缩短了1/4左右。因此,更适合在初始阶段观测信息较少或残余误差较大而难以固定全部模糊度的时候,快速获得较高精度的PPP固定解。
文摘提出利用GPS参考网估计电离层延迟、卫星相位偏差的算法,用于实现区域内精密单点定位(Precise Point Positioning,PPP)的整周模糊度快速固定.利用站间距约为100～200km的参考网进行实验,结果表明:电离层延迟的内插和外推精度均优于1dm,卫星相位偏差估值的日内变化不超过0.2周;此外,单天内不同时刻始,固定PPP整周模糊度所需时长最多不超过10min,且当模糊度成功固定后,三维位置解较之相应浮点解的精度改善优于80%.新算法可望解决PPP普遍存在的收敛时间过长问题,增强了PPP技术的实用性.
