Extended horizon satellite and marine communications system for marine renewable energy

This thesis presents a body of work done in the area of marine communications systems. The goal is to investigate, develop and test a communications system that allows a user to view and control a Remotely Operated Vehicle from beyond the horizon. A number of methods of implementing this system are considered, including point-to-point communications links, satellite communications, and using a phenomenon known as the evaporation duct to extend wireless communications beyond the horizon. The first main contribution of this work, 1) is a review of the relevant literature and current state-of-the-art marine communications technologies, particularly evaporation duct communications. From this background information, two technologies are chosen for further development and testing as the main contributions of this work – evaporation duct and satellite communications. The second contribution, 2) is an investigation into the properties of the evaporation duct in the Irish Sea. The third contribution, 3) is an investigation into the relationship between antenna height, frequency and evaporation duct height. The fourth contribution, 4) is to build and test a 44 km long over the horizon communications link using the evaporation duct. The final contribution, 5) is where a method of encrypting and authenticating a video feed through the evaporation duct and satellite communications links is demonstrated to show that a secure link is possible, and to compare the performance of the communications links.