Analysis Of Beidou Data Quality And Positioning Accuracy

Bei Dou Navigation Satellite System(BDS)is a self-developed navigation and positioning system in China.It is an important space infrastructure for navigation,positioning and timing in China.Currently in the construction phase of the global navigation system,it is expected to achieve global navigation and positioning capabilities by 2020.Compared with other navigation systems,Beidou navigation system has the characteristics of broadcasting multi-frequency signals,mixed constellations(GEO,MEO and IGSO)and combining the functions of navigation,positioning,timing,location reporting and short message communication services.In particular,the increase of new satellites and new signals in the Beidou global navigation system stage and the improvement of performance in various aspects have led to the complexity and difference in the evaluation of Beidou data quality and positioning accuracy.In addition,the Beidou data quality and positioning accuracy assessment is the basis for the follow-up Beidou PNT service,and is an essential part.Therefore,this paper is based on the data quality assessment and positioning accuracy evaluation of Beidou New Satellite,based on the data quality assessment software realized by independent preliminary design.The data quality and positioning accuracy of Beidou-2 and Beidou-3 were evaluated and compared with other navigation systems.The main research contents of this paper are as follows:(1)The theory and method of data processing in Beidou are expounded in detail.Based on the analysis of the basic function model of Beidou positioning,the linear combination of Beidou dual-frequency and tri-frequency observation data is studied.The parameter estimation method Kalman filtering method and the ambiguity fixing method LAMBDA algorithm are derived in detail.(2)Based on the GNSS observation data of the multi-mode IGS tracking station,the data of the Beidou-2 different constellation observation data and the Beidou-3 new satellite new signal observation data are from the data integrity index,signal-to-noise ratio,multipath and cycle-to-hop ratio.Conduct research analysis and use zero-baseline inspection system for observed noise.The results show that the Beidou-3 satellite data quality is good and the performance is superior.In particular,the system deviation existing in the Beidou-2 satellite is not detected in the observation data.In terms of system noise,most double differential carriers on all available signals.The phase residual varies from-0.05 to 0.05 cycles(-1 to 1cm).(3)For positioning accuracy,from pseudo-point single point positioning,precise singlepoint positioning,different distance RTK positioning and other different positioning modes.Positioning accuracy analysis was carried out under different combinations of Beidou-2,Beidou-3,GPS,Beidou-2/GPS and Beidou-3/GPS.The results show that the Beidou-3positioning accuracy is better than Beidou-2 and GPS in single system SPP and RTK positioning.In single system PPP positioning,GPS positioning accuracy is better than Beidou-3 than Beidou-2;joint system SPP and RTK positioning In the middle,the Beidou-3/GPS combined positioning accuracy is better than the Beidou-2/GPS positioning accuracy.In the joint system PPP positioning,the Beidou-3/GPS positioning accuracy is equivalent to the GPS positioning accuracy.(4)The characteristics of the Beidou-3 data are analyzed,and the indicators and methods of the Beidou-3 data quality assessment are summarized.Designed a data quality assessment software that is compatible with multiple systems such as BDS and GPS.Initially realize the function of the Beidou-2 tri-band data and the Beidou-3 new satellite new signal data quality assessment.