Research On Beidou Satellite Clock Offset Estimation And Prediction

Along with the global networking gradual completion of China Beidou Navigation System(BDS),the BDS system has received more and more status in the field of global navigation and positioning(GNSS).As a national blade,the BDS system has played a huge role in national economic construction and national defense construction.Studying BDS system related information was becomed the research hotspots in GNSS fields.In this paper,studied the precision satellite clock estimation module,prediction algorithm and clock offset data quality control method,improved the prior estimate information for clock offset estimation,proposed a clock offset prediction algorithm for BDS systems and optimized clock offset data quality control method,improved the estimation and prediction precision of BDS satellite clock offset.Around the key techniques of BDS satellite clock offset estimation and prediction studied the main information as follows:1)The various error sources that affect the BDS satellite clock estimation accuracy are analyzed in detail,and the error correction model and weakening method are obtained.And the parameter elimination and recovery method in least squares estimation and the root mean square information filtering process are deduced.2)Studied the stochastic model,function model and noise level of Beidou satellite clock offset in estimating,and improved the prior estimate information and function module,which improved the estimation accuracy and frequency stability.The clock estimation accuracy improved by 19.56% and the frequency stability improved by 25.61%.3)Studied the frequency stability between BDS-3 satellite and BDS-2 satellite,between different satellite types and between different satellite clocks on-orbit.The analyzed results show that BDS-3 frequency stability increased by 20.85%-75.09% compared with BDS-2 and the frequency stability of MEO satellite is better than that of IGSO satellite.The stability of the hydrogen atomic clock is higher than that of the rubidium atomic clock by 40.16%-65.60%,and the long-term stability of the hydrogen atomic clock is much better than that of the rubidium atomic clock.4)Studied the correlation among BeiDou satellites,proposed a new satellite clock offset prediction method based on the correlation among BeiDou satellite clocks,comparaped with traditional method the prediction accuracy can improv by 7.3%.As well as frequent clock offset jump and data missing,this paper develops the polynomial without a periodic term.The clock offset prediction method proposed in this paper has achieved good prediction results,BDS-3 satellite clock prediction accuracy improved by 6.4% at least.5)Studied the correlation between satellite clock offset and orbit error as well as the ability of satellite clock offset to absorb orbit error.The results show that the satellite clock offset can absorb 95% of the orbital error in radial and partial tangential error,and some extent compensate for the positioning error caused by the orbital error.Using coupled satellite orbit and clock difference products,the positioning accuracy of a single BDS system can reach decimeter-level positioning results.