Nature and reduction of errors in near-earth autonomous satellite navigation

Abstract

This paper studies the potential of autonomous satellite navigation through prediction of both spacecraft ephemeris and orientation of the Earth. Error sources identified and discussed quantitatively are: aerodynamics; direct and indirect solar radiation; gravity of the Earth, sun, and moon; motion of the rotational pole; rotation rate of the Earth; satellite clock; and the spacecraft tracking system. A device that has already been demonstrated in orbit can be used to effectively cancel the acceleration uncertainties due to atmosphere and solar radiation. Navigation error introduced by the remaining error sources are determined for two spacecraft altitudes (1000 and 150 km) and a prediction interval of one year. Anticipated improvements in modeling the geopotential, tracking system accuracy, and satellite timekeeping are also discussed. The results show that this concept of an autonomous satellite navigation system is suitable for a wide variety of satellite missions.