Validating airborne vector gravimetry data for resource exploration

Abstract

Airborne gravimeters based on inertial navigation system (INS) technology are capable, in theory, of providing direct observations of the horizontal components of anomalous gravity. However, their accuracy and usefulness in geophysical or geological applications is unknown. Determining the accuracy of airborne horizontal component data is complicated by the lack of ground-surveyed control data. We determine the accuracy of airborne vector gravity data internally using repeatedly flown line data. Multilevel wavelet analyses of raw vector gravity data elucidate the limiting error source for the horizontal components. We demonstrate the usefulness of the airborne horizontal component data by performing Euler deconvolutions on real vector gravity data. The accuracy of the horizontal components is lower than the accuracy of the vertical component. Wavelet analyses of data from a test flight over Alexandria, Ontario, Canada, show that the main source of error limiting the accuracy of the horizontal components is time-dependent platform alignment errors. Euler deconvolutions performed on the Timmins data set show that the horizontal components help in constraining the 3D locations of regional geological features. It is thus concluded that the quality of the airborne horizontal component data is sufficient to motivate their use in resource exploration and geological applications.