Nonlinear Observer for the Orbital States of an Earth Satellite

Abstract

<p>The objective of satellite orbit determination is to find accurate values of a set of orbital elements which describes the orbit of the satellite, using observations of the satellite. The extended Kalman filter has been widely used for the estimation of the orbital states. The purpose of this work is to find an alternative approach that would reduce the amount of on-line computation required. A nonlinear observer is proposed for this application. Its stability problem is studied through the second method of Liapunov. The performance of the "nonlinear observer is then evaluated with simulated orbits. AIthough many secondary effects on the dynamics of the satellite have been omitted, the simulation is indicative of results that can be obtained in real situations.</p>