Analysis And Research On Precision Single-point Positioning Accuracy Of Beidou Combined System

Precise Point Positioning(PPP)technology uses a single station GNSS receiver to observe the pseudo-range observations and carrier phase observations,and uses the high-precision satellite ephemeris and satellite orbit clock products provided by relevant agencies,etc.The method of model correction or parameter estimation carefully considers the influence of errors related to satellite positioning,receiver positioning,and signal propagation on positioning.The main research contents of this paper include: establishment of mathematical model and PPP error correction model,accuracy analysis of static precise single-point positioning and accuracy analysis of dynamic precise single-point positioning.(1)Eliminate ionospheric errors,eliminate satellite and receiver hardware delay errors,and eliminate ambiguity through the establishment of mathematical models.The establishment of the PPP error correction model can eliminate errors in the satellite,receiver,and signal propagation processes,thereby improving positioning accuracy.(2)Select 10 stations and analyze the accuracy of the static precise single-point positioning of the stations.By selecting 6 different height angles(7 °,15 °,20 °,30 °,40 °,45 °),Four single systems,three combined dual systems,three combined three systems,and four systems from the number of visible satellites,position accuracy factor values ??(PDOP),east,north,zenith,and three-dimensional directions(E,N,U,3D)to perform error analysis to get the best single system,dual system,triple system.First,the best single system is compared with three combined dual systems,and the improvement rate is obtained by the RMS value.Secondly,the dual system with the best positioning effect is compared with the three combined three systems,and the improvement rate is obtained by the RMS value.Finally,the three systems with the best positioning effect are compared with the four systems,and the improvement rate is obtained by the RMS value.(3)Consistent with static precise single-point positioning,the same station is still selected,and the accuracy analysis of dynamic precise single-point positioning is performed on the station.Using the same method,at six different height angles,the number of visible satellites,PDOP values,E,N,U,An error analysis is performed in3 D four directions to obtain the single system,double system,and three system with the best positioning effect,and the improvement rate is obtained by calculating the RMS value.(4)The accuracy analysis results of static precise single-point positioning and the accuracy analysis results of dynamic precise single-point positioning are analyzed,and the best positioning system is obtained.