High-rate Continuous-epoch Phase Difference Method To Monitor GNSS Phaes Data Quality

It is the foundation of high accuracy GPS navigation and positioning for the high quality observation data.With the rapid increase of CORS stations of different sizes in the world,to monitor the performance of each system and ensure the high-precision positioning,quality analysis of data are urgently required,including data integrity,cycle slip,pseudorange multipath effect and so on.However,these indicators can not reflect the actual quality of the GNSS phase.Therefore,a method to using high-frequency ephemeris method to reflect the quality of GNSS data is proposed.Based on this,the main work is as follows:(1)High-rate continuous-epoch phase difference method to monitor GNSS phase data quality is proposed.The calculation formulas of three-dimensional coordinate corrections for continuous-epoch stations are deduced;the mean values and standard deviations in each direction are solved;the upper bound value,lower bound value,and continuous observation anomaly ratio are defined.The algorithm is implemented through the C#programming language.(2)The factors affecting the phase data quality are studied.In the process of exploration,we control the same variables,and study the influence of ephemeris,frequency and station latitude on the phase data quality.It is concluded that the use of the broadcast ephemeris and the precise ephemeris has little effect on the phase data quality;the phase data quality of the data obtained by the single frequency receiver and the dual frequency receiver is equal,while the influence of the stations at different latitude on the phase data quality is different.(3)TEQC software is used to analyze the common data quality index,the maximum value of L1 pseudo range multipath effect of three stations is 0.46 and the minimum value is 0.15;the maximum value of L2 pseudo range multipath effect MP2 is 0.60 and the minimum value is 0.15;the SNR1 maximum value of L1 carrier signal to noise ratio is 48.84,the minimum value is 43.83,and the maximum SNR2 value of L2 carrier is 44.15,the maximum value is 27.44,and O/slips is more than 670.According to the experience value of data detection,we can see that the data quality of the selected sites all meet the above requirements.(4)Bernese software is used to analyze the feasibility and reliability of the method.The results obtained by this method are compared with those obtained by Bernese.It shows that the continuous-epoch correlation coefficients of the two softwares are in the range of 0.6-0.7,which shows that the method used to evaluate the data quality is reliable.