Mapping and Localization in Unknown Underwater Electric Field Using Passive Electric Sense System

In nature, some fish species are sensitive to electric fields and these fish are called weakly electric fish. Inspired by the ability of weakly electric fish, this article presents a passive electric sense system for freely swimming underwater robot, and realizes electric field mapping and localization. First, we present the characteristics of underwater electric field, and express these in Maxwell’s equations. Then, a Gaussian process (GP)-based approach for interpolation and extrapolation of the underwater electric field is derived, and this approach is embedded with underwater electric field characteristics. This interpolation method is capable of mapping the electric field within the environment, and we can obtain information about the unknown electric field. Finally, based on the electric field maps we constructed, we propose a method for 2-D electro-localization of underwater robot, which is able to fuse multiple constructed electric field maps of different frequencies. In the water environment with unknown electric field emitters, an underwater robot with the passive electric sense system is used for mapping and localization experiments. The experimental results demonstrate the effectiveness of our electro-localization method, and extend the application to unknown electric field sources by mapping method.