Abstract: This paper first establishes a satellite orbit dynamics model perturbed by the Earth’s non-spherical gravity, and then develops a numerical orbit propagator programmed by C++ language, with the Runge-Kutta-Fehlberg 7(8) integrator. In this modeling process, the precession, nutation and some other astronomical quantities are considered through two standards released by U.S. Naval Observatory in 1981 and 2005, respectively. By comparing the simulation results with that of the professional software STK, it shows that the magnitudes of position vector differences between these two standards and STK are both not more than the decimeter level, and that of velocity vector differences are both not more than the level of millimeter per second. Therefore, the model and orbit propagator are both prove to be valid, and the difference of orbit propagation caused by referencing the old and new standards is slight.

Key words: non-spherical gravity, precession, astronomy standard, satellite orbit