Joint processing of total-field and gradient magnetic data

Abstract

The processing of aeromagnetic data to account for levelling has been improved using gradient data. Utilising multiple magnetometers allows measurements of magnetic gradients and minimises the diurnal variation and other common-mode noise. We develop an equivalent source technique for jointly processing total-field and gradient data that makes use of a well known but rarely used relationship between the derivatives of the magnetic field and the derivative of its source to relate both datasets to a common equivalent source distribution. This approach treats the observed gradients as an additional and independent dataset instead of being just supplemental information. The direct result of joint processing is a set of enhanced data that incorporates information from both types of observed data as well as a higher signal-to-noise ratio. The methodology of the joint equivalent source processing technique is presented and demonstrated with a field example. Our method diminishes higher frequency noise, accentuates mid-frequency signals, and has higher resolution than that of total-field data alone.