In the water volume of a three-layer model, an object that generates an electric field is positioned. Synthetic data, measured by sensors positioned in the water volume, is used to determine the surface current distribution that generates the electric field. This report describes the implementation of the Haar base, which is a wavelet based set of base function. It is a part of the ongoing works at FOI to develope a continuous electric signature model. We show how the position of the sensors affects the inversion as well as how the complexity in the inversion increases when increasing the number of expansion coefficient in the Haar base.