通过分析基于飞行时间(time of flight,TOF)的超宽带(ultra wide band,UWB)距离测量的特性,利用卡尔曼滤波及其变式处理原始TOF测距值,剔除TOF测距粗差并对距离观测值进行降噪处理以减小观测误差的影响;同时利用已知长度分析多路径效应...通过分析基于飞行时间(time of flight,TOF)的超宽带(ultra wide band,UWB)距离测量的特性,利用卡尔曼滤波及其变式处理原始TOF测距值,剔除TOF测距粗差并对距离观测值进行降噪处理以减小观测误差的影响;同时利用已知长度分析多路径效应和非视距环境等对TOF测距系统误差的影响规律。基于该实验数据的定位结果表明,在较好地改正TOF测距系统误差的情况下,UWB静态定位精度能达到10 cm以内,动态定位精度优于0.2m。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
多系统精密单点定位（precise point positioning,PPP）模糊度固定及部分模糊度固定策略对实现快速模糊度固定至关重要。评估了当前GPS/GLONASS/BeiDou/Galileo 4系统星座状态下PPP首次模糊度固定时间所能够达到的水平。当首次模糊度固...多系统精密单点定位（precise point positioning,PPP）模糊度固定及部分模糊度固定策略对实现快速模糊度固定至关重要。评估了当前GPS/GLONASS/BeiDou/Galileo 4系统星座状态下PPP首次模糊度固定时间所能够达到的水平。当首次模糊度固定时间小于300s时,GPS固定模式的固定解比例仅为28%,若改为GPS/GLONASS/BeiDou/Galileo固定模式,则固定解比例可高达90%。GPS固定模式的首次模糊度固定时间为533s,而GPS/GLONASS/BeiDou/Galileo固定模式仅需176s,改进了约67%。4系统模糊度固定情况下全部模糊度固定解的首次模糊度固定时间为290s,而部分模糊度固定解的这一时间则为166s,部分模糊度固定策略在多系统PPP模糊度固定中的运用使得首次模糊度固定时间大约缩短了43%。未来GPS、GLONASS、BeiDou和Galileo 4个全球导航卫星系统的可视卫星个数可达120颗,PPP首次模糊度固定时间有望进一步缩短,从而有力推动PPP在实时定位领域中的应用。展开更多
Chinese Beidou satellite navigation system constellation currently consists of eight Beidou satellites and can provide preliminary service of navigation and positioning in the Asia-Pacific Region.Based on the self-dev...Chinese Beidou satellite navigation system constellation currently consists of eight Beidou satellites and can provide preliminary service of navigation and positioning in the Asia-Pacific Region.Based on the self-developed software Position And Navigation Data Analysis(PANDA) and Beidou Experimental Tracking Stations (BETS),which are built by Wuhan University,the study of Beidou precise orbit determination,static precise point positioning (PPP),and high precision relative positioning,and differential positioning are carried out comprehensively.Results show that the radial precision of the Beidou satellite orbit determination is better than 10 centimeters.The RMS of static PPP can reach several centimeters to even millimeters for baseline relative positioning.The precision of kinematic pseudo-range differential positioning and RTK mode positioning are 2-4 m and 5-10 cm respectively,which are close to the level of GPS precise positioning.Research in this paper verifies that,with support of ground reference station network,Beidou satellite navigation system can provide precise positioning from several decimeters to meters in the wide area and several centimeters in the regional area.These promising results would be helpful for the implementation and applications of Beidou satellite navigation system.展开更多
The GPS,DORIS,and SLR instruments are installed on Haiyang 2A(HY2A)altimetry satellite for Precise Orbit Determination(POD).Among these instruments,the codeless GPS receiver is the state-of-art Chinese indigenous onbo...The GPS,DORIS,and SLR instruments are installed on Haiyang 2A(HY2A)altimetry satellite for Precise Orbit Determination(POD).Among these instruments,the codeless GPS receiver is the state-of-art Chinese indigenous onboard receiver,and it is the first one successfully used for Low Earth Orbit(LEO)satellite.Firstly,the contribution assesses the performance of the receiver through an analysis of data integrity,numbers of all tracked and valid measurements as well as multipath errors.The receiver generally shows good performance and quality despite a few flaws.For example,L2 observations are often missing in low elevations,particularly during the ascent of GPS satellites,and the multipath errors of P1 show a slightly abnormal pattern.Secondly,the PCO(Phase Center Offset)and PCV(Phase Center Variation)of the antenna of the GPS receiver are determined in this contribution.A significant leap for Z-component of PCO up to-1.2 cm has been found on 10 October 2011.Thirdly,the obtained PCO and PCV maps are used for GPS only POD solutions.The post-fit residuals of ionosphere-free phase combinations reduce almost 50%,and the radial orbit differences with respect to CNES(Centre National d’Etudes Spatiales)Precise Orbit Ephemeris(POEs)improve about 13.9%.The orbits are validated using the SLR data,and the RMS of SLR Observed minus Computed(O-C)residuals reduces from 17.5 to 15.9 mm.These improvements are with respect to the orbits determined without PCO and PCV.Fourthly,six types of solutions are determined for HY2A satellite using different combinations of GPS,DORIS,and SLR data.Statistics of SLR O-C residuals and cross-comparison of orbits obtained in the contribution and the CNES POEs indicate that the radial accuracy of these orbits is at the 1.0 cm level for HY2A orbit solutions,which is much better than the scientific requirements of this mission.It is noticed that the GPS observations dominate the achievable accuracy of POD,and the combination of multiple types of observations can reduce orbit errors caused by data gaps and maintain more stable and continuous orbits.展开更多
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。
文摘多系统精密单点定位（precise point positioning,PPP）模糊度固定及部分模糊度固定策略对实现快速模糊度固定至关重要。评估了当前GPS/GLONASS/BeiDou/Galileo 4系统星座状态下PPP首次模糊度固定时间所能够达到的水平。当首次模糊度固定时间小于300s时,GPS固定模式的固定解比例仅为28%,若改为GPS/GLONASS/BeiDou/Galileo固定模式,则固定解比例可高达90%。GPS固定模式的首次模糊度固定时间为533s,而GPS/GLONASS/BeiDou/Galileo固定模式仅需176s,改进了约67%。4系统模糊度固定情况下全部模糊度固定解的首次模糊度固定时间为290s,而部分模糊度固定解的这一时间则为166s,部分模糊度固定策略在多系统PPP模糊度固定中的运用使得首次模糊度固定时间大约缩短了43%。未来GPS、GLONASS、BeiDou和Galileo 4个全球导航卫星系统的可视卫星个数可达120颗,PPP首次模糊度固定时间有望进一步缩短,从而有力推动PPP在实时定位领域中的应用。
文摘Chinese Beidou satellite navigation system constellation currently consists of eight Beidou satellites and can provide preliminary service of navigation and positioning in the Asia-Pacific Region.Based on the self-developed software Position And Navigation Data Analysis(PANDA) and Beidou Experimental Tracking Stations (BETS),which are built by Wuhan University,the study of Beidou precise orbit determination,static precise point positioning (PPP),and high precision relative positioning,and differential positioning are carried out comprehensively.Results show that the radial precision of the Beidou satellite orbit determination is better than 10 centimeters.The RMS of static PPP can reach several centimeters to even millimeters for baseline relative positioning.The precision of kinematic pseudo-range differential positioning and RTK mode positioning are 2-4 m and 5-10 cm respectively,which are close to the level of GPS precise positioning.Research in this paper verifies that,with support of ground reference station network,Beidou satellite navigation system can provide precise positioning from several decimeters to meters in the wide area and several centimeters in the regional area.These promising results would be helpful for the implementation and applications of Beidou satellite navigation system.
基金supported by the National Natural Science Foundation of China(Grant No.41231174)the Open Fund of Key Laboratory of Precision Navigation and Technology,National Time Service Center(Grant No.2012PNT06)the Fundamental Research Funds for the Central Universities of China(Grand No.2012618020201)
文摘The GPS,DORIS,and SLR instruments are installed on Haiyang 2A(HY2A)altimetry satellite for Precise Orbit Determination(POD).Among these instruments,the codeless GPS receiver is the state-of-art Chinese indigenous onboard receiver,and it is the first one successfully used for Low Earth Orbit(LEO)satellite.Firstly,the contribution assesses the performance of the receiver through an analysis of data integrity,numbers of all tracked and valid measurements as well as multipath errors.The receiver generally shows good performance and quality despite a few flaws.For example,L2 observations are often missing in low elevations,particularly during the ascent of GPS satellites,and the multipath errors of P1 show a slightly abnormal pattern.Secondly,the PCO(Phase Center Offset)and PCV(Phase Center Variation)of the antenna of the GPS receiver are determined in this contribution.A significant leap for Z-component of PCO up to-1.2 cm has been found on 10 October 2011.Thirdly,the obtained PCO and PCV maps are used for GPS only POD solutions.The post-fit residuals of ionosphere-free phase combinations reduce almost 50%,and the radial orbit differences with respect to CNES(Centre National d’Etudes Spatiales)Precise Orbit Ephemeris(POEs)improve about 13.9%.The orbits are validated using the SLR data,and the RMS of SLR Observed minus Computed(O-C)residuals reduces from 17.5 to 15.9 mm.These improvements are with respect to the orbits determined without PCO and PCV.Fourthly,six types of solutions are determined for HY2A satellite using different combinations of GPS,DORIS,and SLR data.Statistics of SLR O-C residuals and cross-comparison of orbits obtained in the contribution and the CNES POEs indicate that the radial accuracy of these orbits is at the 1.0 cm level for HY2A orbit solutions,which is much better than the scientific requirements of this mission.It is noticed that the GPS observations dominate the achievable accuracy of POD,and the combination of multiple types of observations can reduce orbit errors caused by data gaps and maintain more stable and continuous orbits.
