Low-cost Global Navigation Satellite System(GNSS)devices offer a cost-effective alternative to traditional GNSS systems,making GNSS technology accessible to a wider range of applications.Nevertheless,low-cost GNSS dev...Low-cost Global Navigation Satellite System(GNSS)devices offer a cost-effective alternative to traditional GNSS systems,making GNSS technology accessible to a wider range of applications.Nevertheless,low-cost GNSS devices often face the challenges in effectively capturing and tracking satellite signals,which leads to losing the observations at certain frequencies.Moreover,the observation peculiarities of low-cost devices are in contradistinction to those of traditional geodetic GNSS receivers.In this contribution,a low-cost PPP-RTK model that considers the unique characteristics of different types of measurements is developed and its performance is fully evaluated with u-blox F9P receivers equipped with three distinctive antenna configurations:vertical dipole,microstrip patch,and helix antennas.Several static and kinematic experiments in different scenarios are conducted to verify the effectiveness of the proposed method.The results indicate that the mixed-frequency PPP-RTK model outperforms the traditional dual-frequency one with higher positioning accuracy and fixing percentage.Among the three low-cost antennas tested,the vertical dipole antenna demonstrates the best performance under static conditions and shows a comparable performance as geodetic antennas with a positioning accuracy of 0.02 m,0.01 m and 0.07 m in the east,north,and up components,respectively.Under low-speed kinematic scenarios,the helix antenna outperforms the other two with a positioning accuracy of(0.07 m,0.07 m,0.34 m).Furthermore,the helix antenna is also proved to be the best choice for vehicle navigation with an ambiguity fixing rate of over 95%and a positioning accuracy of(0.13 m,0.14 m,0.36 m).展开更多
针对未来遥感、导航等卫星对地面测控设备的距离测量精度由米级提高到厘米级这一问题,简要介绍了航天测控常用的距离零值标校方案,并量化分析了天线和模拟信道设备引入的距离零值变化,认为必须引入与工作链路同时工作的距离零值自校准...针对未来遥感、导航等卫星对地面测控设备的距离测量精度由米级提高到厘米级这一问题,简要介绍了航天测控常用的距离零值标校方案,并量化分析了天线和模拟信道设备引入的距离零值变化,认为必须引入与工作链路同时工作的距离零值自校准链路。针对扩频测距系统对自校准链路的信号形式进行了讨论,并对工作信号电平与自校准链路信号电平之间的相互影响进行了理论分析及仿真,认为自校准链路信号电平低于工作信号电平10 d B是一个较优的选择。展开更多
精密单点定位技术(precise point positioning,PPP)虽可以提供全球厘米级定位,但是需要数十分钟实现收敛,而PPP-实时动态定位(real-timekinematic,RTK)则依赖区域参考站以提供大气延迟改正信息,限制了系统服务范围。实现了一种多频多模...精密单点定位技术(precise point positioning,PPP)虽可以提供全球厘米级定位,但是需要数十分钟实现收敛,而PPP-实时动态定位(real-timekinematic,RTK)则依赖区域参考站以提供大气延迟改正信息,限制了系统服务范围。实现了一种多频多模观测值PPP方法,仅需要卫星轨道、钟差和信号偏差即可实现全球范围内的瞬时厘米级定位,解决了PPP收敛慢、PPP-RTK服务范围有限和成本高的难题。结合现有星基增强改正数编码和播发方式,构建了一个兼容北斗PPP-B2b服务的广域瞬时厘米级服务系统,并评估了其轨道、钟差和信号偏差等增强信息精度。中国区域静态和车载动态数据验证结果表明,该系统可以95%的置信率在1min内实现厘米级精密定位,可满足自动驾驶等领域对快速、高精度和高可信定位的需求。展开更多
基金National Natural Science Foundation of China,41974027,Xingxing Li42204017,Xin Li+2 种基金National Postdoctoral Program for Innovative Talents,China,BX20220239,Xin Lithe special fund of Hubei Luojia Laboratory,220100006,Xin Lithe Fundamental Research Funds for the Central Universities,2042022kf1001,Xin Li.
文摘Low-cost Global Navigation Satellite System(GNSS)devices offer a cost-effective alternative to traditional GNSS systems,making GNSS technology accessible to a wider range of applications.Nevertheless,low-cost GNSS devices often face the challenges in effectively capturing and tracking satellite signals,which leads to losing the observations at certain frequencies.Moreover,the observation peculiarities of low-cost devices are in contradistinction to those of traditional geodetic GNSS receivers.In this contribution,a low-cost PPP-RTK model that considers the unique characteristics of different types of measurements is developed and its performance is fully evaluated with u-blox F9P receivers equipped with three distinctive antenna configurations:vertical dipole,microstrip patch,and helix antennas.Several static and kinematic experiments in different scenarios are conducted to verify the effectiveness of the proposed method.The results indicate that the mixed-frequency PPP-RTK model outperforms the traditional dual-frequency one with higher positioning accuracy and fixing percentage.Among the three low-cost antennas tested,the vertical dipole antenna demonstrates the best performance under static conditions and shows a comparable performance as geodetic antennas with a positioning accuracy of 0.02 m,0.01 m and 0.07 m in the east,north,and up components,respectively.Under low-speed kinematic scenarios,the helix antenna outperforms the other two with a positioning accuracy of(0.07 m,0.07 m,0.34 m).Furthermore,the helix antenna is also proved to be the best choice for vehicle navigation with an ambiguity fixing rate of over 95%and a positioning accuracy of(0.13 m,0.14 m,0.36 m).
文摘针对未来遥感、导航等卫星对地面测控设备的距离测量精度由米级提高到厘米级这一问题,简要介绍了航天测控常用的距离零值标校方案,并量化分析了天线和模拟信道设备引入的距离零值变化,认为必须引入与工作链路同时工作的距离零值自校准链路。针对扩频测距系统对自校准链路的信号形式进行了讨论,并对工作信号电平与自校准链路信号电平之间的相互影响进行了理论分析及仿真,认为自校准链路信号电平低于工作信号电平10 d B是一个较优的选择。
文摘精密单点定位技术(precise point positioning,PPP)虽可以提供全球厘米级定位,但是需要数十分钟实现收敛,而PPP-实时动态定位(real-timekinematic,RTK)则依赖区域参考站以提供大气延迟改正信息,限制了系统服务范围。实现了一种多频多模观测值PPP方法,仅需要卫星轨道、钟差和信号偏差即可实现全球范围内的瞬时厘米级定位,解决了PPP收敛慢、PPP-RTK服务范围有限和成本高的难题。结合现有星基增强改正数编码和播发方式,构建了一个兼容北斗PPP-B2b服务的广域瞬时厘米级服务系统,并评估了其轨道、钟差和信号偏差等增强信息精度。中国区域静态和车载动态数据验证结果表明,该系统可以95%的置信率在1min内实现厘米级精密定位,可满足自动驾驶等领域对快速、高精度和高可信定位的需求。
