Comparison of Relative Mean Orbital Element Estimation Methods for Spacecraft Formation Flying

Abstract

Accurate relative state estimation is a necessity for precision spacecraft formation ying. Inaccurate estimation can lead to excessive fuel use and possible spacecraft collision. Control of mean di erential elements has been identi ed as a promising formation-keeping strategy when considering secular perturbative forces such as J2 and atmospheric drag. This work compares the performance of several di erent techniques for estimating mean di erential orbital elements of a controlled spacecraft in formation ight with a passive target. Inter-satellite range measurements, line of sight measurements, and single di erence pseudorange and carrier phase measurements from the Global Positioning System constellation are considered. An extended Kalman lter and a Gauss-Newton batch estimator are formulated for the di erent measurements and their performances evaluated when subjected to measurement noise. These estimators are compared on the basis of their nal estimation accuracy, and noise levels for inter-satellite range and LOS measurements to achieve precise formation ight are presented.