Multielement FSO Transceivers Alignment for Inter-UAV Communications

Given the increased interest in aerial communications, free-space optics (FSO) has gained considerable attention for its ability to deliver wider bandwidth, license-free, and secure communication. FSO was initially developed for fixed platforms. As such, the current push to introduce mobility is one of the greatest challenges for FSO developers. This paper presents the first open-loop alignment/stability analysis of hovering multirotors proven to maintain an FSO link despite inherent instability. Communication distance, wavelength, and platform deviation are among the many parameters evaluated in our model. We characterize fiber-bundle transceivers, as an example of optical arrays and their applicability to aerial FSO communication. Our simulation is based on static lab measurements combined with theoretical analysis and optical geometrical intersection models. Analyses indicated that rotational deviation has a much higher impact on performance than translational deviation. Current commercial multirotor platforms proved adequate for future FSO communication, with 16% to 30% expected throughput when employing suitable optical arrays. We conducted a parametric sweep test to determine optimal and marginal receiver parameters based on platform characteristics and performance metrics. This analysis was conducted and reported as one example of the many applications that our developed mathematical models support.