Secular dynamics of navigation satellites in the MEO and GSO regions

In this study, a dynamical model is developed to describe the secular evolution of navigation satellites under the geocentric reference frame with the Laplace orbit as the fundamental plane. The disturbing function, involving the effects of Earth's oblateness and lunisolar gravitational attraction, is averaged over the orbital periods of both the satellite and the perturbers. In the regions of medium-Earth orbits and geosynchronous orbits, there are varieties of lunisolar resonances for governing the secular dynamics of navigation satellites. Among these resonances, we are interested in the ones occurring at the critical inclinations as well as the lunar node resonances. For each resonance of interest, the resonant center and width are identified analytically. Finally, dynamical maps are compared with the analytical results.