A Null-Field Method for Estimating Underground Position

The geometric characteristics of low-frequency magnetic dipole fields and their relative insensitivity to the host media have made low-frequency coils useful for underground geolocation. A robust and succinct method is presented for converting dipole field measurements into estimates of receiver position. A noisy half-space model of the Earth is used to model the receiving environment. A perfectly conducting sphere immersed in a homogeneous conducting background is used to study the localized effects of buried metals.