Differential Positioning Performance Of BeiDou Satellite System

In recent years,as the global satellite navigation system(GPS(America),GLONASS(Russia),Galileo(Europe),the Beidou Satellite navigation System(BDS China)and regional augmentation System,such as QZSS(Japan)and IRNSS(India))constantly updated,the improvement of broadcast signal quality and global satellite constellation,the positioning technology is also constantly innovated,focus on national security and economic development in our country,our government attaches great importance to the construction of Beidou satellite navigation system,tries the best to explore and develop the satellite navigation system with independent intellectual property rights.Compared with other satellite constellation,the construction of Beidou satellite navigation system is gradually becoming mature,and plan to reach the global coverage from the Asia-pacific region by 2020,realize the transition from the Beidou second to the third generation and the positioning accuracy will also increase several times.Beidou satellite system is a hybrid constellation consists of geostationary orbit satellites(GEO),the medium earth orbit satellites(MEO)and inclined synchronous orbit satellites(IGSO),and has already broadcasted signals with triple frequency in each satellite.It has very high research value because of the important status and unique advantages in global satellite navigation system,as the research of Beidou system at home and abroad deepens in recent years,the higher positioning accuracy is required and gradually developed from the traditional single point positioning to high-precision differential positioning technology.The accuracy of positioning has been greatly improved and the market share of the domestic Beidou satellite terminal has been increasing steadily in the process of civil construction.Currently,there are few studies on the combination of narrow lane ambiguity and Kalman innovation vector in the Beidou triple frequency differential positioning,and few research on dynamic positioning performance of low-cost single frequency navigation module based on network base station,we carry out the research on the performance of high-precision differential positioning of Beidou triple frequency through the combination of kalman filter and narrow lane ambiguity resolved by step-wise procedure,and study the RTK positioning performance of low-cost navigation module based on the network base station,the specific work as follows:(1)Based on the unique advantages of Beidou triple frequency,we use the real measured data to study the performance of differential positioning in middle long baseline,first,the dual-frequency geometry-free method combined multi-epoch averaging method id used to detect carrier phase cycle slip and eliminate the gross error in the data preprocessing,second,the pseudorange and carrier phase geometry-free and ionospheric-free combination is adopted to detect three frequency multipath error,then the B3 narrow lane ambiguity is resolved with the aid of wide lane ambiguity and ionosphere-free combination,and then use the observation epoch selecting strategy the paper presents that combining the construction of kalman filter innovation vector using the B3 narrow lane ambiguity in adjoin epoch with the filter divergence condition,finally,we get the centimeter-level differential positioning accuracy in middle-long baseline and shorten the time to first-fixed solution effectively.(2)With the global networking and the rapid development of domestic Beidou terminal industry,and based on Beidou traffic application target in 2020,we study the positioning performance of low-cost(less than 10 $)single-frequency BDS + GPS navigation and positioning module and research the static and kinematic differential positioning with the aid of network CORS stations that could broadcast real-time RTCM data,the interpolation method is used to modified the satellite position and the geometric distance in double-difference model that resolved the unstable positioning problem due to the different output frequency between the rover and base station,then,we simulate the open environment and urban shading situation through the different dynamic experiments,and get the centimeter-level static positioning accuracy as well as decimeter-level RTK positioning accuracy.In this paper,we give consideration to both the differential post-processing and real-time positioning,both the expensive receiver and low-cost positioning module,analysis research work both differential positioning and real-time dynamic RTK positioning,both expensive and cheap navigation and positioning receiver module of differential positioning,analyze the performance of Beidou differential positioning comprehensively,it has certain guiding significance to the research of positioning of Beidou third generation satellite and the development of Beidou low-cost terminal in the future.