Satellite Clock Performance Analysis And The Offset Forecast

The satellite clock is the basis of satellite navigation system, the performance ofthe satellite clock and the clock error predicting are the key factors that affect theaccuracy of navigation and positioning. Autonomous navigation system and PrecisePoint Positioning System depend mainly on the high-precision clock error prediction.Besides, analysis of the satellite clock performance is the foundation of high-precisionclock error predicting.Satellite clock performance and clock error predicting are both studied in thisthesis. Statistical formulae of satellite clock performance are given and statisticalmethods of different frequency standards are analyzed. Empirical formula and terrestrialenvironments are combined to consider the effect of light intensity, temperature,rubidium signal and magnetic field strength on the atomic clock output frequency. Thefrequency characteristics of light intensity, temperature, and magnetic field strength arerespectively theoretically created and calculated, as is done with the atomic clock driftcharacteristics. The ground measured data indicates that the light intensity, frequencydrift have a direct impact on the life of atomic clocks. And the measured data of thesatellite clock error on-orbit also exhibits an evident periodicity of properties.Three types of algorithms, quadratic polynomial model, Kalman filtering and graymodel, are investigated to seek a better candidate for data processing of satellite clockbias on orbit. Meanwhile, analysis of the advantages and disadvantages of the threealgorithms are surveyed respectively. To suppress noise effectively, the Kalman noisevariance matrix is taken into account based on the satellite clock noise characteristics.During data processing, the data’s periodical behavior is emphasized. And the selectionof periodic items is mainly analyzed in the prediction model with periodic item. Besides,the impact of periodical behavior on quadratic polynomial prediction model istheoretically provided.The comprehensive analysis of the performance of the satelliteclock and the high-precision clock error prediction technology establish the theoreticalbasis for improving the accuracy of navigation and positioning navigation system.