Applicability of cheap and lightweight magnetic sensors to geophysical exploration

 In recent years, there was a notable technological advancement in geophysical sensors. In the case of magnetometry, several sensors were used having the common feature to be miniaturized and lightweight, thus idoneous to be carried by UAV in drone-borne magnetometric surveys. Moreover, such sensors have the common feature to be very cheap, so that it is in principle very easy to have the resources to combine two or three of them to form gradiometers. Nonetheless, another common feature is that their sensitivity ranges from 0.1 to about 200 nT, thus not comparable to that of alkali vapor, standard flux-gate or even proton magnetometers. However, their low-cost, small volume and weight remain as very interesting features of these sensors. In this communication, we want to explore the range of applications of small tri-axial magnetometers commonly used for attitude determination in several devices. We compare the results of ground-based surveys performed with conventional geophysical instruments with those obtained using these sensors.