Error analysis of prediction orbit determined by GLONASS ephemeris

The equation of satellite orbital motion was derived in the conventional terrestrial coordinate system. By analyzing the fitting precision of satellite prediction orbit determined by GLONASS(global navigation satellite system) broadcast ephemeris,it is pointed out that the simplified models of perturbation force, the choice of numerical integration methods and the neglect of the polar motion are main factors causing the orbit fitting error, among which the simplified models of perturbation force is the most effective one. Through integrating the equation of orbital motion of satellite for 30 min, it can be found that the orbit fitting error due to the simplified force model, the numerical integration method and the neglect of the polar motion are respectively 0.827 m, 0.224 m and 0.025 m. Therefore controlling the precision loss of orbital prediction cased by the simplification of models of perturbation force, especially by the truncation of high order terms of Earth gravitational perturbation and simplification of models of Sun and lunar gravitational fields can improve the fitting precision of prediction orbit.