Spherical FSO receivers for UAV communication: geometric coverage models

We present several analytical models to calculate the intersection surface of a spherical cap with a solid cone where either one of them is experiencing perturbations in its attitude. These models are developed to quantitatively analyze the mutual alignment, and thus performance, of mobile free-space optical (FSO) communication nodes used in air-to-ground and ground-to-air FSO links. Same models can be also applied to various geometrical alignment problems in the presence of instability. Examples include coverage area of imaging, radar, and optical communication satellites while orbiting unstable orbits. These models provide a closed-form direct mapping between platform dynamics and FSO link performance facilitating a priori performance prediction and easing feedback requirements in real-time tracking systems.