Panoramic steering modules for optical wireless communications on small UAS

Optical Wireless Communications (OWC) offer high-bandwidth, covert and jam-resistant datalinks that can complement RF communications, particularly for small Unmanned Aerial System (sUAS) operation in RF contested environments – like the battlefields in Ukraine. OWC characteristics are enabled by compact beam-forming possible in the optical domain which can provide extremely directional datalinks. However, it is challenging to deploy OWC onto sUAS because the precision beam-control required is at odds with their size, weight and power plus cost (SWAP+C) constraints. Compact OWC systems for sUAS must provide stabilized steering of the datalink, ideally, in any direction. In this paper, we present and compare three panoramic steering systems that we developed for sUAS OWC. Each system utilizes a different panoramic steering element in between the same OWC back-end and 2-axis Fine Steering Mirror (FSM) front-end. The implementations use: 1) direct-drive DC motor above the FSM, 2) gear-coupled DC motor below the FSM and 3) piezo-driven rotator below the FSM. We compare each system’s line-of-sight control including speed, accuracy, repeatability, and jitter measured in flight on a sUAS.