Ground-based testbed design for evaluation of point, acquisition, and tracking control systems in optical inter-satellite links between two 6U nanosatellites

This paper discusses a testbed that implements a beam acquisition and tracking system essential for inter-satellite optical communication. It summarizes the results of optical and control system design. Recent research on free-space optical communication has been thriving due to the increasing demand for data transmission in clustered operations of small satellites. However, since the distances between satellites are often hundreds of kilometers, a beam acquisition and tracking system is necessary to establish communication by accurately detecting and tracking the position of the target satellite. The optical system of the testbed, developed by Telepix, shows the attenuated output and flatness of wavefront propagated over long distances. The control system applies an adaptive control method to manage disturbances, resulting in the successful reduction of beam pointing errors to the desired level, as demonstrated by simulation results. In the future, this technology holds potential for various applications, including clustered operations of small satellites using free-space optical communication, as well as communication between ground stations and deep-space optical communication.