Formation flying Low Earth Orbiters (LEOs) are important for implementing new and advanced concepts in Earth observation missions.Precise Baseline Determination (PBD) is a pre-requisite for LEOs to complete specified mission targets.PBD is usually performed based on space-borne GNSS data,the relative corrections of phase center and code residual variations play crucial roles in achieving the best relative orbit accuracy.Herein,the influences of antenna Relative Phase Centre Variations (RPCVs) and Single-Difference (SD) Melbourne-Wübbena (MW) Combi-nation Residuals Variations (SD MWVs) on PBD are studied.The methods were tested using flight data from Gravity Recovery And Climate Experiment (GRACE) and GRACE Follow-On(GRACE-FO).Results showed that the maximum values for RPCVs and SD MWVs were 14 mm and 0.32 cycles,respectively.Then,the RPCVs correction significantly enhanced the baseline accuracy;the K-Band Ranging (KBR) measurement consistency improved by 30.1％ and 37.5％for GRACE and GRACE-FO,respectively.The application of SD MWVs further improved the accuracy and reliability of PBD results.For GRACE,the ambiguities fixing success rate increased from 85.1％ to 97.9％ and a baseline consistency of 0.57 mm was achieved for the KBR measure-ments.It was found that the correction of both RPCVs and SD MWVs reduced the carrier phase observation minus computation residuals from double-difference ionosphere-free combination.In addition,in-flight data processing demonstrated that RPCVs and SD MWVs estimations for the current period could be used for the previous and subsequent periods.

Bin YI;Defeng GU;Bing JU;Kai SHAO;Houzhe ZHANG

College of Liberal Arts and Sciences,National University of Defense Technology,Changsha 410073,China;TianQin Research Center for Gravitational Physics and School of Physics and Astronomy,Sun Yat-sen University(Zhuhai Campus),Zhuhai 519082,China;National Key Laboratory of Science and Technology on Aerospace Flight Dynamics,Beijing Aerospace Control Center,Beijing 100094,China

中国航空学报（英文版）

[1]Bin YI;Defeng GU;Bing JU;Kai SHAO;Houzhe ZHANG-.Enhanced baseline determination for formation flying LEOs by relative corrections of phase center and code residual variations)[J].中国航空学报（英文版）,2022(02):185-194

LEOs,Orbiters,RPCVs,bbena,Residuals,MWVs

Enhanced,baseline,determination,formation,flying,by,relative,corrections,phase,center,code,variations,Formation,Low,Earth,are,important,implementing,new,advanced,concepts,observation,missions,Precise,Baseline,Determination,PBD,requisite,complete,specified,targets,usually,performed,space,borne,GNSS,data,play,crucial,roles,achieving,best,orbit,accuracy,Herein,influences,antenna,Relative,Phase,Centre,Variations,Single,Difference,Melbourne,Combi,studied,methods,were,tested,using,flight,from,Gravity,Recovery,And,Climate,Experiment,GRACE,Follow,On,FO,Results,showed,that,maximum,values,cycles,respectively,Then,significantly,enhanced,Band,Ranging,KBR,measurement,consistency,improved,application,further,reliability,results,ambiguities,fixing,success,increased,was,achieved,ments,It,found,both,reduced,carrier,minus,computation,residuals,double,difference,ionosphere,free,combination,In,addition,processing,demonstrated,estimations,current,could,used,previous,subsequent,periods

0.525676