Microwave Propagation in Maritime Environments

A simple question that arises when dealing with maritime communications is: How would one offload large quantities of data from sea to shore and vice versa if one cannot use conventional solutions such as satellite communications or cellular data? In this note, we describe the first prototype solutions that were produced. They gave rise to SeaFi, which has become an enabling technology in the context of oceanic and coastal research. Measurements at sea are key to scientific research projects such as, for example, HIGHWAVE, a recently started ERC Advanced Grant project that relies partly on the possibility of measuring breaking waves in real time. Since the bottleneck is the real-time transmission of data, transferring measurement data at sea using SeaFi instead of using conventional satellite communications or a cellular data connection quickly became an evidence. To assess the resilience of SeaFi, a series of offshore experiments were performed from May to July 2018. Those experiments led on June 6, 2018, to a world record for the longest wireless microwave transmission at sea between a moving ship and a lighthouse, using the SeaFi communication system. In addition, the proposed solution also promises a better future for lighthouses around the world that are now gradually falling into disuse. This breakthrough in maritime telecommunications could change the way scientific researchers retrieve data in real time at sea in the coming years.