Research On Common-view Time Comparison Method Based On BDS-3 New System Signal

Time is an important reference for national production and life,and precise time plays a vital role in the fields of economy,military,technology and life.Time comparison is the basis of time transmission and time synchronization,and it is also an important technical means to achieve high-precision time-frequency services.Common view time comparison is a high-precision time comparison technology,which has some advantages such as simple operation,low equipment cost,and convenient use.Therefore,it is widely used in the field of remote time comparison.The Bei Dou-3navigation satellite system（BDS-3）will complete the global networking in 2020,and broadcast the global new system signals B1C,B2a,etc.The new system signals have wider signal bandwidth and anti-interference ability.It is stronger,and the user can use the navigation signals of multiple frequency points in combination,which can significantly improve the positioning and timing accuracy of the BDS-3.This paper studies the common-view time comparison method based on the BDS-3 new system signal,which can evaluate the common-view time comparison accuracy of the dual-frequency combination of the BDS-3 new system signal（B1C and B2a）,and expand the BDS-3 in the time-frequency field.Applications.The main research work of the thesis includes:（1）The basic composition of the Global Navigation Satellite System（GNSS）and the development status of foreign GNSS systems were introduced,and the basic information such as the space constellation and space-time system of BDS-3 was expounded.Advantages compared with other GNSS systems,the basic principles of commonly used GNSS time alignment methods are studied.（2）The basic information of the new system signal is introduced,and it is compared with the signal systems of other GNSS systems,and its advantages in the common view time comparison are analyzed.The principle of Beidou common-view time comparison and the method of BDS-3 satellite orbit calculation are studied,and the differences between the 16-parameter broadcast ephemeris model and the 18-parameter broadcast ephemeris model are compared.factors,the dual-frequency ionospheric-free combination model of the new system signal（B1C and B2a）was studied,and the ionospheric delay error was corrected by this model,and other main errors were corrected by different algorithms or models.（3）Extract ephemeris data and pseudorange observations according to the data processing algorithm of common view time comparison,and use the minimum The square fitting method is used to process the observed data.The gross errors in the data processing process are eliminated by using the 3σrule,and the elimination algorithm is verified.Finally,Kalman filtering and Vondrak filtering are used to filter the original common-view time comparison results respectively,and the two filtering results are compared and analyzed.（4）The common-view time comparison algorithm based on the new BDS-3 signal system is implemented.The original observation data was collected by building an experimental platform of two observation stations,and the observation data of a single station was analyzed.At the same time,the common clock difference and the common viewing time comparison between the two stations were carried out.The results show that:BDS-3 The zero-baseline comparison result of the dual-frequency combination of the new system signal（B1C and B2a）has less noise than the Beidou-2（B1I and B3I）dual-frequency combination,and its standard deviation is 43.72%higher than that of Beidou-2;Compared with the BDS-2（B1I and B3I）,the accuracy of the common-view time comparison results of the frequency combination is improved by 53.36%,and its frequency stability is in the order of 10^-14.