Beacon-Enhanced Attitude Control using Optical Communication Terminals: Design and Validation in the QUBE Mission

Abstract

Achieving sub-degree pointing accuracy is essential for optical satellite communication. To ensure accuracy, the QUBE mission demonstrates a novel two-stage attitude control system, combining absolute pointing with ultra-fine tracking using a laser beacon signal. While we demonstrated the absolute control with successful link establishment, the beacon-tracking concept has undergone ground-based testing, and in-flight data confirm stable incident angles under operating conditions. This sets the stage for future in-orbit validation. Our analysis indicates that beacon-based tracking can improve the accuracy of relative alignment in distributed satellite systems by a factor of ten for advanced communication applications.