Automated pointing, acquisition, and tracking control loop handoff and fade recovery demonstrated across a mobile-to-static 7.5 km terrestrial link
Krunal Patel, Radha A. Venkat, Michelle P. O'Toole, Katherine T. Newell · 2025
Free Space Optical (FSO) communications require robust Pointing, Acquisition, and Tracking (PAT) schemes to maintain a link, especially in terrestrial environments and while operating on-the-move. We have previously developed a PAT scheme that uses multiple control modesto achieve coarse and fine pointing, initial link acquisition, and coarse and fine beam tracking. Terrestrial and maritime environments pose unique PAT challengesthat typically require experienced link operator personnel to maintain the link. However, we have recently developed the capability to reduce operator burden with automated transition between the control modes. We will present architecture and results of our updated PAT control scheme as demonstrated on a 7.5 km link across the Chesapeake Bay in Maryland with a static node on a tripod and a mobile node mounted on a test vehicle. The test results illustrate the transition between PAT control states in action, show the ability to maintain the link through vehicle platform motion effects and demonstrate automatic link recovery after line-of-sight (LOS) blockages.