Fiber Optic Telemetry for Deep Sea Robotics

Abstract

Abstract Teleguided Work in the deep sea requires broad band data transfer in twodirections without crosstalk or other electromagnetic interferences. Furthermore power supply to the seafloor is necessary in the range of tens ofkilowatts. A multipurpose umbilical of 8 – 10 km length represents abottleneck, especially as inertial masses of ROVs and various forces andmoments accompanying deep sea work have to be compensated. Fiber optic telemetry allows for broad band data and video transfer free ofinterference and over long distances. These systems require a small crosssection in the umbilical, thus giving space for high voltage power supply andstrength members in a cable with an overall diameter in the range of 20 mm. Theperformance of deep sea robotics is increased as high definition multichannelcolour video and sonar transmission becomes possible, telemetry data bandwidthis increased and power supply through the cable can be provided. The scope, structure and test results of fiber optic telemetry systems fordeep sea robotics are presented. Introduction: Deep sea robotics Exploration, control and use of the deep sea increase constantly. The deepsea, with water depth beyond 1000 m, covers 60% of the earth's surface, whereasthe deep sea plains and troughs with an average water depth of 4000 – 5000 mcover almost half of the globe. We learn to understand that global change isalso influenced by deep sea processes, be they geologic, biologic oroceanographic, at least if we concentrate on medium (10 – 103 years)and long term (103 - 106 years) processes. The deep seaoffers in addition a number of eventually attractive uses such as mining ofpolymetallic nodules or clathrates, to give just examples. Or the disposal ofwastes in geologically calm deepsea soils where more long term stable barriersexist than on land. It goes without saying that such uses must be effected inan environmentally acceptable manner. This, in turn, requires extended andcomplicated research and control of the many interdependent aspects of the deepsea.