Current surface-ship communication systems are not able to maintain point-to-point high data rate links, up to 10 Mbits/s, within a large range (over 10 NM). However, such specification is required if a real-time video transmission from a small boat to its carrier is considered. As a result, this new requirement should be analyzed by considering the constraints induced by the marine environment and by the system platform integration in the light of new technologies. In the first part, an analysis of the characteristics that distinguish a real-time video transmission from a standard high data-rate link is proposed. Then, different propagation models are used to determine the radio channel properties in the marine environment. This analysis is complemented by a qualitative study of phenomena induced by the sea-state degradation. The third part begins with a transmission channel study at long range which demonstrates the necessity of using antennas with directive properties. The development of a channel model including the attitude of platforms as well as the antenna radiating parameters is detailed. Finally, the research of radiating structures with directive properties and adapted to each platform is discussed in the last section. The proposed solution for the small boat is developed thereafter. Based on a S-band circular array, its design provides a maximum gain greater than 10 dBi while remaining compatible with onboard integration.
