KCF/PSU Smart Tether Retrofit Device for Localization of Tethered Bodies

A method is needed to measure the location of a submerged body relative to a tethered buoy. The application targeted in this proposal is unmanned crawling robots used to localize submerged mines and other targets. The crawlers require a 60-70 foot tether, creating a large error circle when operating in shallow water. A simpler application that will also benefit from this technology is Long Base Line (LBL) navigation transponders. We propose to retrofit the tether with an inexpensive yet robust sensing system to accurately predict the crawler position relative to the buoy. The system derives the relative position using a simple crawler-mounted tri-axial load cell tension sensor and a time-tracking position integrating algorithm. The retrofit device will be simple and robust. Installation will require only an external load cell mounting bracket on the crawler, and no modification of the tether or buoy. In Phase I, we will assess the feasibility and outline the benefit to be achieved by retrofitting LBL navigation transponders and unmanned crawling robots with the proposed device. After building a scaled demonstration unit, we will test the prototype under various flow conditions in a simulated flow tank at Penn State University. In Phase II, we will develop and demonstrate a full-scale KCF/PSU Smart Tether and test it in a large test tank the Penn State Applied Research Laboratory.