Magnetometer and Gradiometer make it possible to dectect ferrous objects and layers from the air. This geophysical technique is applied mainly to detect metal objects, like UXO, in undisturbed rural areas, in mining and for mapping ore bodies. The gradiometer is a magnetometer which measures the changes in the magnetic field (the gradient of the field). Compared to the magnetometer, a gradiometer increases the accuracy of the measurements and decreases the sensitivity for regional changes of the earth's magnetic field. Both technologies can also be applied for water bottom research.
Magnetometer and gradiometer measure the earth's magnetic field. This field consists of the the so-called main field, which slowly varies and causes variations due to local deviations such as the presence of ore or ferrous objects in the underground. By measuring these local deviations of the total magnetic field, the location of ferromagnetic objects and layers can be determined. The dimension of the deviation is proportional to the amount of ferromagnetic material in the underground. To detect metallic objects, peak values in the registered data are analysed according to their horizontal and vertical position, approximate dimensions and the ferrous mass of the metal object.
*Drone magnetometer is currently under development.