Fine Pointing Assembly for Optical Ground Station

Abstract

The mini optical ground station (MISO), on top of the Aerospace Engineering faculty, serves the purpose of demonstrating Free Space Optical Communication technology. A downlink from low earth orbit imposes pointing requirements beyond what can be achieved by the telescope mount. A Fine Pointing Assembly (FPA), the topic of this thesis, aims to reduce residual pointing error to facilitate coupling into a single-mode fiber architecture. This thesis addresses the design, implementation, and characterization of FPA to fulfill this job in a lab environment. The FPA was built as a feedback control system actuating a fine steering mirror to counteract tip-tilt with feedback from a SWIR camera and the center of the gravity tracking algorithm. The bandwidth of this system is limited by latency from software implementations of the interfaces. The developed FPA removes 76% of the Tip-Tilt disturbance energy and can be improved by mitigation efforts toward latency reduction.