Conversion of UEP Signatures Between Different Environmental Conditions Using Shaft Currents

In this paper, we investigate an approach that allows naval vessels to continuously estimate their underwater electric potential (UEP) signature strength, by converting a beforehand measured reference UEP signature to the present environmental conditions. The approach is intended to improve risk assessment during mine counter measure (MCM) operations and to be used within integrated ship signature management systems (ISSMS). It is therefore designed to depend only on data available in these scenarios and to be simple and fast, rather than just being as accurate as possible. After explaining the concept and deducing the conversion relations, the approach is tested using numerical simulations and ranged UEP data of a ship (CFAV Quest). The results show that it is well suited to convert UEP signatures between different water conductivities and sensor depths, while it is not capable of converting between different seabed conductivities. The signature conversion is best for intact hull coatings, while hull-to-anode currents lower the correlation between signature and shaft currents, and hence impair the conversion quality.