Exploiting EMI Signals During Active Transmission

摘要

Theoretically, signals measured during the transmit period (the 'on- time') provide information about the instantaneous magnetization and current gathering in objects illuminated by a transmitter. In this SEED project, we examined the potential of on-time EMI data for improving the detection and discrimination of UXO and in rejecting clutter and noise. Through a combination of modeling and analysis of experimental data, we found that on-time data provide a number of theoretical and practical enhancements to aid in UXO characterization. This work also supported a more thorough understanding of the physical mechanisms being exploited by existing on-time instruments and their capabilities and limitations. We provide a theoretical basis that links our understanding of existing off-time pulsed induction and always-on frequency domain responses to the full waveform response. This approach provides for estimation of the magnetic properties of targets (e.g., demagnetization factors and bulk magnetic susceptibility) that are not obtainable with conventional off- time pulsed induction methods.