Relative dynamics for formation flying satellites : a preliminary design study for the control subsystem

The Centre for Large Space Structures and Systems Inc. (CLS3) is planning a low Earth orbit formation flying satellite mission with four nanosatellites. The project will be a collaboration between companies and Universities, with CLS3 contributing with the control subsystem. Although formation flying satellites constitute a potentially cost efficient formula for some satellite missions, several issues need to be resolved before they can be used efficiently. The propulsion subsystem is one of the systems that induce the most restrictions on the duration of the mission. With an optimized orbit selection and control system the amount of fuel spent to retain the desired formation can be lowered. This thesis investigates several models that have potential use for the design of the control system. Moreover, some methods to improve the selection of orbits are reviewed. Specifically, the usage of linear models enables analytical solutions to be found, for example formations where the satellites move in a circle around the center of the formation. These solutions can be used to find similar solutions for the available non-linear models. In addition, dynamic models that include the effect of the most prominent perturbations, the geopotential anomaly and atmospheric drag, are evaluated. The knowledge of how these perturbations affect the individual satellites and the formation is essential to the design the control subsystem. Furthermore, this knowledge can be used to choose orbits that are less susceptible to the effects of perturbations.Validerat; 20101217 (root