Characterization of UXO-like targets using broadband electromagnetic induction sensors

We have inverted broadband electromagnetic induction data over an isolated target to determine its electrical conductivity, magnetic permeability, radius, and depth using a sphere model. Studies using synthetic data of a concentric, broadband, electromagnetic sensor indicate that the technique is dependable and produces fast-converging solutions. The geometrical parameters obtained through this technique are very close to true values, and the electric parameters for noise-free data are correct to within a few percent. When 10% noise is added to the data, the geometric parameters are still well determined, but the electric parameters are poorly resolved, particularly for a sphere that is both conductive and permeable. Tests on the experiment data show that volume-equivalent size and depth to a target can be reasonably estimated for a nonspherical object.