AAS 95-410

Inertial Propagation of an Earth-Fixed Point Using Perturbed Kepler Algorithms

D. S. Anderson, Senior Engineer, McDonnell Douglas, Houston, TX

Abstract

It is shown in this paper how Cartesian and element method orbital state propagators can be used for propagating the inertial position & velocity of an Earth-fixed location by configuring the perturbation models appropriately, and without altering the onorbit differential equations of motion for the propagator. This method will allow, for example, the nonintrusive testing of flight Navigation algorithms at an Earth-fixed location using changes only in the algorithm initialization data. This data reconfiguration should also extend to the case of orbital state propagation in a flight GPS receiver filter, in which case integration of the rigorous dynamics of Earth-fixed motion also becomes possible.