利用恒星日滤波改进精密单点电离层延迟提取
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摘要
利用非组合精密单点定位(PPP)可以提取高精度的电离层延迟。测站多径误差会影响伪距和相位测量精度,影响实时PPP电离层延迟提取的精度以及收敛速度。对于静态观测站,利用对GPS卫星地面跟踪的时间重复性进行恒星日滤波可以消除多径误差的影响。通过事后处理提取前几日的码和载波相位残差序列,利用恒星日滤波建立多径误差改正模型,修正实时观测数据,可以改善实时电离层延迟估计性能。对IGS观测站的实测数据分析表明,应用恒星日滤波多径误差修正后,实时电离层延迟提取的精度由0.185m提高到0.028m,新进卫星的电离层参数估计收敛时间由80min减少为35min。
Uncombined precise point positioning(PPP)could be used to extract ionospheric delay with high accuracy.However,parameters estimation in PPP requires long converge time due to the high correlation between ionosphere and ambiguity parameters.Further more,the multipath effects at tracking station degrade the precision of code and phase measurements,thus impact the performance of PPP ionospheric delay estimation.For static observation stations,sidereal filtering could be used to eliminate multipath errors by taking advantage of the ground track repeat period of GPS satellites.After extracting the code and carrier phase residuals of the past few days in post-processing,multipath error correction model could be established with historical residual series by sidereal filtering,so as to improve the performance of real-time ionospheric delay estimation.Experiments with IGS observation data showed that with the application of sidereal filtering,real-time ionospheric delay extraction error decreased from 0.185 mto 0.028 mand convergence time of ionospheric parameters for newly rising satellites reduced from 80 minutes to 35 minutes.Improvements in single station ionosphere delay estimation could refine ionosphere model of local network.On the other hand,precise satellite slant ionosphere delay can be obtained at a lower elevation,which can reduce the layout density need of reference station network.
Uncombined precise point positioning(PPP)could be used to extract ionospheric delay with high accuracy.However,parameters estimation in PPP requires long converge time due to the high correlation between ionosphere and ambiguity parameters.Further more,the multipath effects at tracking station degrade the precision of code and phase measurements,thus impact the performance of PPP ionospheric delay estimation.For static observation stations,sidereal filtering could be used to eliminate multipath errors by taking advantage of the ground track repeat period of GPS satellites.After extracting the code and carrier phase residuals of the past few days in post-processing,multipath error correction model could be established with historical residual series by sidereal filtering,so as to improve the performance of real-time ionospheric delay estimation.Experiments with IGS observation data showed that with the application of sidereal filtering,real-time ionospheric delay extraction error decreased from 0.185 mto 0.028 mand convergence time of ionospheric parameters for newly rising satellites reduced from 80 minutes to 35 minutes.Improvements in single station ionosphere delay estimation could refine ionosphere model of local network.On the other hand,precise satellite slant ionosphere delay can be obtained at a lower elevation,which can reduce the layout density need of reference station network.
引文
[1]Zhang Baocheng,Ou Jikun,Li Zhisheng,et al.Determination of Ionospheric Observables with Precise Point Positioning[J].Chinese Journal of Geophysics,2011,54(4):950-957(张宝成,欧吉坤,李子申,等.利用精密单点定位求解电离层延迟[J].地球物理学报,2011,54(4):950-957)
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[3]Seepersad G,Bisnath S.Reduction of Precise Point Positioning Convergence Period[C].Proceedings of the25th International Technical Meeting of the Satellite Division of the Institute of Navigation,TN,2012
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[5]Brunini C,Azpilicueta F.GPS Slant Total Electron Content Accuracy Using the Single Layer Model Under Difierent Geomagnetic Regions and Ionospheric Conditions[J].J Geod,2010,84:293-304
[6]Gelbed A.Applied Optimal Estimation[M].Cambridge,Massachuserts:The MIT Press,1974:160-162
[7]Takasu T.RTKLIB:Open Source Program Package for RTK-GPS[C].FOSS4G2009,Tokyo,Japan,2009
[8]Joz W,Hsieh C H.Statistical Modeling for the Mitigation of GPS Multipath Delays from Day-today Range Measurements[J].J Geod,2010(84):223-232
[9]Choi K,Bilich A,Larson K M,et al.Modiifed Sidereal Filtering:Implications for High-rate GPS Positioning[J].Geophys Research Letters,2004,31:1-4
[10]Ragheb A E,Clarke P J,Edwards S J.GPS Sidereal Filtering:Coordinate and Carrier-Phase-Level Strategies[J].Joural Geodesy,2007,81(5):325-335
[11]Yin Haitao,Gan Weijun,Xiao Genru.Modified Sidereal Filtering and Its Effect on High-rate GPS Positioning[J].Geomatics and Information Science of Wuhan University,2011,36(5):609-611(殷海涛,甘卫军,肖根如.恒星日滤波的修正以及对高频GPS定位的影响研究[J].武汉大学学报·信息科学版,2011,36(5):609-611)
[2]Carcanague S,Julien O,Vigneau W,et al.A New Algorithm for GNSS Precise Positioning in Constrained Area[C].Proceedings of the 24th International Technical Meeting of the Institute of Navigation,San Diego,CA,2011
[3]Seepersad G,Bisnath S.Reduction of Precise Point Positioning Convergence Period[C].Proceedings of the25th International Technical Meeting of the Satellite Division of the Institute of Navigation,TN,2012
[4]Wen Z,Henkel P,Güunther C.Reliable Estimation of Phase Biases of GPS Satellites with a Local Reference Network[C].The 53rd IEEE Intern.Symposium ELMAR,Zadar,Croatia,2011
[5]Brunini C,Azpilicueta F.GPS Slant Total Electron Content Accuracy Using the Single Layer Model Under Difierent Geomagnetic Regions and Ionospheric Conditions[J].J Geod,2010,84:293-304
[6]Gelbed A.Applied Optimal Estimation[M].Cambridge,Massachuserts:The MIT Press,1974:160-162
[7]Takasu T.RTKLIB:Open Source Program Package for RTK-GPS[C].FOSS4G2009,Tokyo,Japan,2009
[8]Joz W,Hsieh C H.Statistical Modeling for the Mitigation of GPS Multipath Delays from Day-today Range Measurements[J].J Geod,2010(84):223-232
[9]Choi K,Bilich A,Larson K M,et al.Modiifed Sidereal Filtering:Implications for High-rate GPS Positioning[J].Geophys Research Letters,2004,31:1-4
[10]Ragheb A E,Clarke P J,Edwards S J.GPS Sidereal Filtering:Coordinate and Carrier-Phase-Level Strategies[J].Joural Geodesy,2007,81(5):325-335
[11]Yin Haitao,Gan Weijun,Xiao Genru.Modified Sidereal Filtering and Its Effect on High-rate GPS Positioning[J].Geomatics and Information Science of Wuhan University,2011,36(5):609-611(殷海涛,甘卫军,肖根如.恒星日滤波的修正以及对高频GPS定位的影响研究[J].武汉大学学报·信息科学版,2011,36(5):609-611)