Geometric Constraints for the Detection of Perfect Conductors

Abstract

The aim of this study was to investigate potential for the fixed wing Spectrem AEM system to detect perfect conductors. The methodology extends previous results in successful detection of perfect conductors in the twin helicopter Gemini AEM experiment. Primary fields in the square-wave Spectrem response are conventionally estimated by using the latest time samples in each half-cycle. Measured Spectrem aircraft attitude, coupled with physical constraints using tow-cable geometry and drag, were collectively used to devise a new primary field prediction for high altitude data. The new prediction method was then applied to survey data to produce a secondary field. Time constants predicted from the new secondary field estimation were sensitive to values 10 times greater than time constants using conventional late-time reference approach.