Preliminary Analysis Of The Service Performance Of Beidou Experimental Satellite System

Satellite navigation systems have been widely used in daily life and production.Therefore,it is necessary to make an objective and appropriate assessment and analysis of the corresponding data quality and service performance of the satellite navigation system,so as to ensure the accuracy and reliability of the system service.Since 2017,China has officially started construction of the Beidou third-generation global satellite navigation system.Prior to that,the Beidou experimental satellite system was formed and a new global navigation signal was broadcasted to verify the corresponding technical system of the Beidou Global System.Therefore,by analyzing the data quality of the BeiDou Experimental Satellite System,we can initially understand the BeiDou Global System's performance indicators and evaluate the BeiDou Global System's positioning service performance.At the same time,the BeiDou Experimental satellite system also verified some new user algorithms adopted in the BeiDou global system.Realizing and evaluating these new user algorithms is also an important part of the system performance evaluation.Based on the above reasons,the dissertation makes a preliminary analysis of the quality of the measured data of the Beidou Experimental satellite system.Focusing on some of the possible system errors of the Beidou Experimental satellite system,the paper focuses on experiments and analyses.In addition,the paper also implemented a new correction model and user algorithms for the Beidou Global System,and conducted preliminary evaluations and tests on the accuracy and availability of these models and algorithms.The following is the main content of the thesis research.1.The paper describes the method used to evaluate system performance.2.Based on the actual observation data of a large number of BeiDou experimental satellite,the paper analyzes the basic performance of BeiDou global system signals,including satellite visibility,noise level,signal-to-noise ratio change,and multipath characteristics.In particular,the multi-path characteristics,the paper focused on the analysis,through long-term ground omnidirectional antenna data analysis of the B1I,B3I,B1C,B2a and B2b frequency multi-path characteristics,further through the large-caliber parabolic antenna data for comparative,analysis found The multipath value has a pseudorange deviation of the order of 0.1m.3.The paper compares and analyzes the relationship between the various parts of the BeiDou space signal error,studies the correlation between the error components,and then uses a variety of methods to verify the analysis,indicating that there may be a negative correlation between the BeiDou system's current orbital radial error and clock error.So the formula for calculating the spatial signal accuracy also needs to be modified.4.The paper implemented the Beidou Global Ionospheric Model User Algorithm.Then,based on the measured data,the spatial distribution and time variation of the accuracy of the Beidou Global Ionospheric Model were analyzed.Using the high-precision ionospheric grid data and the dual-frequency measured data,the Beidou Global Ionospheric Model and the GPS System and the Beidou Second Generation System Klobuchar were compared and analyzed.The performance of the Beidou Global Ionospheric Model was verified by a pseudo-range single point positioning.5.The dissertation implements an 18-parameter broadcast ephemeris algorithm.Using precise ephemeris as a reference,18-parameters broadcast ephemeris has been compared with 16-parameter broadcast ephemeris,and verify its accuracy,which indicate that the accuracy of the 18-parameter ephemeris can be used for user navigation and positioning..6.The paper also conducted joint positioning tests of Beidou Experimental satellite and Beidou second generation satellite.After joining the Beidou Experimental satellite,the number of visible satellites of the Beidou system can be effectively increased,the PODP value can be reduced,and the stability and reliability of positioning services can be improved.The joint positioning accuracy is comparable to that of the Beidou ?,because there is a certain deviation between the Beidou Experimental satellite and the second generation satellites in the pseudo-range residuals.