Satellite Formation Flying

Abstract

This thesis report has explored the complex field of satellite formation flying, focusing on Guidance, Navigation and Control (GNC) strategies for maintaining formations of multiple satellites. The research has been guided by a series of research questions aimed at improving the understanding and implementation of GNC systems for satellite formations. The report begins by providing an overview of the background and context of satellite formation flying, highlighting its significance in modern space missions. It emphasizes the need for precise control systems to maintain formations and addresses the challenges posed by various disturbances and constraints. To address these challenges, the report presents a detailed methodology for developing an end-to-end GNC system. This methodology involves the use of nonlinear dynamics models, including considerations for Earth’s oblateness and drag effects, to describe the motion of satellites within the formation. Additionally, the report explores the use of both absolute and relative dynamics models to enable the control of large satellite formations. Throughout the report, the performance of the GNC system is analyzed through various simulations and experiments. Different thruster models, including variable and fixed thrusters, are evaluated, shedding light on their effectiveness in maintaining formations. The analysis also considers the impact of energymatching conditions on reducing the frequency of maneuvers. The results of the simulations demonstrate the challenges and limitations of the Sliding Mode Controller (SMC) based control system, particularly in the context of real-world thruster implementations. Tracking errors and drift in formations are observed, necessitating further research into mitigating these issues. In the final chapters, the report explores potential areas for future research and improvements. These include investigating alternative thruster models, optimizing control algorithms, and developing strategies for reducing drift in formations. In conclusion, this thesis report provides valuable insights into the complexities of satellite formation flying, and the challenges faced by GNC systems. It offers a comprehensive methodology for developing
and analyzing these systems and highlights areas for future research. Ultimately, the report contributes to the ongoing advancements in satellite formation flying, paving the way for more precise and efficient space-based operations.