Medium-orbit navigation satellite orbit long-term forecasting method

The invention discloses a medium-orbit navigation satellite orbit long-term forecasting method, which comprises the steps of obtaining a first-order change rate of an average orbit element under conservative perturbation force, the conservative perturbation force comprising earth non-spherical perturbation force and sun-moon three-body gravitation perturbation force; obtaining a first-order changerate of the average orbital element under non-conservative perturbation force, the non-conservative perturbation force comprising solar light pressure perturbation force; and calculating the averageorbital element of a navigation satellite according to the first-order change rate of the average orbital element under the conservative perturbation and the first-order change rate of the average orbital element under the non-conservative perturbation. According to the method, calculation is performed under the conservative perturbation force and the non-conservative perturbation force respectively, so that the long-term