Study On High Precision Time Synchronization Method In Satellite Navigation And Positioning System

As a basic physical variable, time has very important meaning in every field. The technology of time comparison in high precision is the key in the realization of high precision time system, and it is also one of the important technologies in constructing the satellite navigation and positioning system, and it affects the precision of navigation, location and time transfer of the system directly. Then the high precision time synchronization method in satellite navigation and positioning system is systematically studied and discussed in this paper. The main works are summarized as follows:1. The history of the technologies of time synchronization development at home and abroad is simply reviewed, and the theoretical meaning and practical application of this paper are dissertated.2. According to the principle of the method of two-way satellite-ground time comparison by wireless radio, the computation model in the ECI frame, which is expanded to the second order of the velocity and the first order of acceleration of satellite and ground-station, is derived.3. When having time comparison between the GEO, GPS, GLONASS, Galileo satellites and the ground-station, the influences magnitude of distance correction time delay in the computation model of the method of two-way satellite-ground time comparison by wireless radio on the relative satellite-ground clock bias have been computed and analyzed, and the influences of the items of distance correction time delay on the relative satellite-ground clock bias that should be accounted for are summarized in the 1ns and 1ps computation precision.4. The influences of the main error sources to the method of two-way satellite-ground time comparison by wireless radio are analyzed and summarized, and the quantity levels that the error sources should reach are also summarized in different precision demands.5. The detailed expressions of the Sagnac effect on GEO, IGSO, MEO satellites in the ECI frame are formulated when the ground-station is on the equator and the inverse aspect in the method of satellite common-view time comparison. The software of the computation of Sagnac effect is worked out.6. The influences of the other relative effects on time transfer, such as the gravitational frequency shift, time dilation, eccentricity effect, and so on, are also analyzed and summarized.7. Some basic models, such as the polynomial model, the interpolation model with Tchebytchev polynomials, and the gray system model, which are used to predict the clock bais of atomic clock in short- medium- and long-term, are discussed and analyzed, using four satellite clocks which were launched at different times.