Abstract

The full-depth, remotely-operated survey system "KAIKO", developed by the Japan Marine Science and Technology Center, comprises a launcher suspended from the Yokosuka support ship by a primary cable, and a vehicle launched from the launcher and connected by a secondary cable. This equipment is designed for deep-sea studies at depths of approximately 11,000 meters. Real-time high speed data transmission at a maximum 840 Mbps, the fastest used for any remotely operated vehicle (ROV), was needed to transmit the five-channel video signal captured by the six underwater cameras mounted on the vehicle, together with the large volume of measurement data obtained by the latest underwater surveying equipment. Because bi-directional communication is required to support the simultaneous transmission of the launcher's on-board equipment control data and the measurement data, the overall transmission rate of the entire system is 1.2 Gbps. In the design weight and electrical power consumption were kept to a minimum. An optical power monitor, which splits the optical signal immediately before the receptor and constantly monitors the optical signal power level, is also provided to ensure problems with the optical fiber and other optical transmission components contained within the cables are detected early, thus improving the overall reliability of the system. This report describes the high-speed underwater data transmission equipment developed for the KAIKO system.