Smart Tether for Relative Localization of Moored and Towed Bodies

SPA and our subcontractor, UCSD, propose the development of a Smart Optical Fiber Tether (SOFT) system capable of providing real-time location data with respect to an anchor position to within 3.3 feet (1 meter) for a 100-foot (~30 meter) long tether. The system consists of integrated fiber Bragg grating (FBG) sensors to monitor the strains on the smart tether and an instrumentation system to interrogate the deformation data of the tether and provide real-time location data. The proposed shape measurement technology is an extension of SPA's ongoing research efforts to monitor the shape of towed sonar arrays. During Phase I, the research team will develop a breadboard prototype SOFT system to demonstrate on a 20 foot (6 meter) tether section. The scientific research to be explored in the Phase I effort includes examining the strain transfer from the tether structure to the FBG sensors, the effect of the number of sensors to shape complexity resolution, and investigating error sources in the system for mitigation analysis. During the Phase I Option, the research team will continue to experiment with the breadboard system and begin development efforts for the Phase II program by investigating integration design issues with a cable manufacturer.