Definition of navigation strategies for proximity operations between two small satellites

This Master’s Thesis presents the definition of a navigation strategies for the Space Rider Observer Cube (SROC) mission, conceived to demonstrate autonomous rendezvous and docking technologies for small satellites. Originally designed to operate with the Space Rider vehicle, the mission was re-scoped: the target platform was replaced by a cooperative 12U CubeSat, enabling a fully symmetric proximity operations scenario between two identical spacecraft. In this framework, the thesis focuses on the design and validation of a navigation algorithm capable of accurately estimating the relative pose (position and velocity) between the two vehicles during proximity and docking maneuvers. The work includes a complete redefinition of the mission’s Sensor Suite, comprising two Narrow Field of View and one Wide Field of View optical cameras, LIDAR, Relative GNSS, and Intersatellite Link sensors, together with an analysis of their performance and the derivation of noise models for covariance tuning. The main contribution lies in the design, implementation, and validation of a Kalman Filter for estimating the relative state (position and velocity) between the two satellites during proximity operations. After the tuning of the process and measurement noise covariance matrices (Q and R), the algorithm was integrated into the mission flight simulator developed in Simulink and tested under nominal conditions across several mission phases, including Hold Points and Final Approach. The system performance was evaluated in terms of Absolute (AKE), Mean (MKE), and Relative (RKE) Knowledge Errors, defined by ESA mission requirements. Simulation results confirm that the proposed navigation architecture achieves stable convergence and high accuracy while maintaining reduced computational complexity. The developed framework contributes to the ongoing advancement of autonomous navigation for small satellite proximity missions, paving the way for future in-orbit servicing, inspection, and active debris removal operations.