Study On Statistical Characterization And Description Method Of BDS Signal-in-space Error

As an important space information infrastructure independently developed by China,Bei Dou Navigation Satellite System(BDS)is also a major member of the Global Navigation Satellite System(GNSS),which can provide users with functions such as Navigation,positioning,timing,speed measurement and short message communication.Both in military and civilian,BDS play a huge and irreplaceable role.As BDS gradually realizes the transition from beidou 2 to beidou 3,its service scope also expands from the asia-pacific region to the world.After entering the Global market,BDS will face the dual competition and challenge of the Global Positioning System(GPS)of the United States and the Global Navigation Satellite System(GLONASS)of Russia,and the System performance will become one of the key factors determining the success or failure.Performance indicators of satellite navigation system include: accuracy,soundness,continuity and availability.Among them,accuracy and soundness are the basic performance of navigation system,and continuity and usability are the extended performance based on accuracy and soundness.They can reflect the performance of the system from multiple aspects.Therefore,the study on accuracy and soundness is of great significance both for itself and for the future study on continuity and usability.Therefore,this paper focuses on the accuracy and integrity of beidou space signal,and mainly does the following work:(1)The errors of satellite orbit and satellite clock of broadcast ephemeris are extracted by using post precise ephemeris as reference under unified spatio-temporal reference.The mean,standard deviation and root mean square statistics were used to analyze the orbital and timely clock accuracy of Medium Earth Orbit(MEO),Inclined Geosynchronous Orbit(IGSO)and Geostationary Earth Orbit(GEO).(2)The factors affecting the orbit error are analyzed from the aspects of satellite maneuver and the change of solar altitude Angle,and the periodicity of the error change is analyzed.The characteristics of orbit error variation duration and periodic variation consistency caused by satellite maneuver and solar altitude angle variation are analyzed.(3)According to the characteristics that the Two-Way Satellite Time and Frequence Transfer of beidou leads to the insignificant correlation between orbital error and satellite clock error and the statistical characteristics of beidou orbit and timely clock error,a method for describing BDS signal-in-space User Range Error(SISURE),which is different from GPS,is proposed,and the correctness of the proposed SISURE method is proved by correlation analysis.(4)Based on the description method of beidou SISURE,the statistical characteristics of SISURE are analyzed and the irrationality of User Range Accuracy(URA)of beidou broadcast ephemeris is verified.Based on the improved description method of beidou SISURE,URA capable of meeting the requirements for the integrity of various satellites was calculated.