Analyzing the effects of conductive and permeable soil on the EMI response for UXO discrimination

Unexploded ordinances (UXO) are buried typically in the top 1 m of soil. Low frequency (from tens of Hertz up to several hundreds of kHertz) electromagnetic induction (EMI) sensing has been identified as one of most promising technology for UXO detection as well for discrimination. They use the principle of EM1 in which unseen object are detected by sensing eddy current induced in metal by a primary magnetic field. It is known that the EMI sensors are sensitive to the scatters electromagnetic parameters (conductivity and permeability). Therefore, in this paper, low frequency scattering from a highly conducting and permeable metallic objects buried in geological soil are exposed and analyzed from the unexploded ordnances (UXO) detection and discrimination point of new. The method of auxiliary sources (MAS) in conjunction with thin skin approximation (TSA) is used for understanding physics of electromagnetic induction (EMI) scattering phenomena. Several numerical examples are designed to show how the geological soil´s electromagnetic parameters (conductivity and permeability) affect object´s EMI response.