An analytical generator for drag-free satellite orbits

The generator incorporates a technique for the rapid computation of lunisolar perturbations, in which simple formulae related to a stationary disturbing body and a uniform ring of mass are combined. Short periodic perturbations, from all sources, are in general neglected; but it was arranged that the value of mean motion derived from the position and velocity vectors input to the generator at epoch was independent of this particular orbital position. The main effects of J2, J2,2, the third-degree harmonics other than J3, lunisolar gravity and solar radiation were represented, so the generator should be suitable for use with any orbit for which the accuracy requirements are compatible with the neglect of atmospheric drag, J3, geopotential harmonics of degree greater than 3 and the effects of the lunar orbit's eccentricity. For a geostationary satellite, the error should not be more than 0.01 deg over a month.