Modeling of aerial-to-aerial short-distance free-space optical links

Abstract

Increased RF noise floor, crowded and scarce wireless spectrum, and security are issues challenging present-day aerial wireless communication. Optical wireless (or free-space optical (FSO)) is an alternative communication system applicable to air-to-air (A2A) or air-to-ground (A2G) applications. An FSO link is able to provide high bandwidth, low-power, and secure communication for various unmanned aerial systems (UASs) and ground nodes, including mobile and fixed stations. However, unlike RF, optical communication is highly sensitive to misalignment and platform instability that causes unavoidable communication interruptions. Developing aerial optical wireless communication systems requires modeling the effects of UAS instability on the FSO system performance, including FSO link throughput. This work aims to develop a rigid and simple modeling framework for A2A FSO communication links. The framework is abstract, general, and platform-independent. The model relates instability to averaged percentage alignment (APA), which can be used to predict throughput and other performance-related parameters. A planer arrays of optical transmitters and receivers is used and proposed as a promising technology for FSO communication with large field-of-view and diversity-ready performance. Also, a novel alignment model using geometric intersection is developed and analyzed against simulated and real multi-rotor platforms.