A physically complete model applied to BUD time-domain EMI data

摘要

In this paper a physically complete model called the Normalized Surface Magnetic Source (NSMS) model is applied to data collected using the Berkeley UXO Discriminator time-domain sensor. The sensor has three pairs of rectangular transmitters and eight pairs of receivers that measure gradients of scattered fields. The system is cart-based and produces well-located EMI data sets. In order to take advantage of this high quality data the NSMS technique is utilized for the BUD instrument. The NSMS is a very simple and robust technique for predicting the EMI responses of various objects. The technique is applicable to any combination of magnetic or electromagnetic induction data for any arbitrary homogeneous or heterogeneous 3D object or set of objects. The NSMS approach uses magnetic dipoles, distributed on a fictitious closed surface, as responding sources for predicting an object's EMI response. The amplitudes of the NSMS sources are determined from actual measured data and the resulting total NSMS is used as a discriminant. To demonstrate the applicability of the NSMS technique, we compare actual and predicted data for various UXO. The data were collected at Yuma Proving Ground UXO sites by personnel from the University of California, Berkeley.