导航卫星天线相位中心变化估计及对LEO精密定轨影响
Estimation of GPS Antenna Phase Center Variation and Its Effect on Precise Orbit Determination of LEOs
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摘要: 精确标定导航卫星发射天线相位中心对于高精度GNSS(globalnavigationsatellitesystem)数据处理十分重要,对于低轨卫星(lowearthorbit,LEO)精密定轨更是如此。本文以GPS为例,首先探讨了一种基于LEO简化动力学精密定轨残差建模的方法,对导航卫星发射天线相位中心变化(phasecentervariation,PCV)进行标定,与IGS08_1745.atx(internationalGNSSservice,IGS)的PCV比较结果表明,本文所得PCV在天底角低于14°部分与IGS的PCV差异约1mm,并且有效地将天底角(nadirangle)拓展至17°;最后采用多种方案讨论了导航卫星PCV对JASON2精密定轨的影响。结果表明,导航卫星PCV可导致1～2cm的定轨误差。其中利用本文所得PCV可实现3DRMS约3cm、径向约1cm的定轨精度,与采用IGS的PCV定轨精度相当,本方法可为北斗卫星发射天线相位中心变化的标定提供参考。Abstract: AccuratecalibrationofGPSsatellitetransmittingantennaphasecentersisveryimportantforpreciseGNSSdataprocessing,aswellasforpreciseorbitdeterminationofLEOs.ThispapertakesGPSasthestartingpointforanewmethodbasedonresidualsfromspace bornedatatocalibrateGPSsatelliteantennaPCVs.PCVsobtainedfromJASON 2GPSresidualsarecomparedwithigs08_1745.atx.Resultsshowthattheagreementisabout1mm～2mmbelow14°,andtheestimatedGPSPCVsvaluesisextendeduptonadirangleofprecisely17°.SeveralschemesweredesignedtoconsidertheeffectsofGPSPCVsonthepreciseorbitdeterminationofLEOs.Resultsshowthaterrorsabout2cmcanbecausedbyGPSPCVs.TheresultingPCVsobtainedthesameaccuracyorbitsasonesu singIGSPCVs,withaccuracyatabout3cmin3D,and1cmintheradialdirection.ThemethodusedinthispapercanprovidereferencesforcalibratingtheantennaphasecentervariationofBEIDOUsat ellites.
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