Underground ；Multi-layer Media

 This paper includes a variety of media location data generated in the paper.According to the wideband near-field signal propagation model, sample data were generated based on four layers of media with known media types. The main differences between simulated data and real data are errors due to electromagnetic dispersion, multipath and noise, which are not currently taken into account because of different electromagnetic characteristics in inhomogeneous media. The setting of condition variables in the experiment was shown in Table I.