The magnetic instruments are classified into two main types: the mechanical instruments that measure the direction or a component of its direction of the magnetic field; and the magnetometers that are instruments capable of measuring the amplitude and/or a component of the magnetic field. The magnetometer is equipped with two sensors in different heights. The height difference usually varies between 0.5 and 1.5 m. The magnetic field is measured by both sensors simultaneously, hence, in this case, one does not need to correct data for the diurnal variations (the Earth’s magnetic field cancels by subtracting the two readings). The gradiometer surveys can substantially increase a resolution for near surface bodies. This effect is widely used in tasks dealing with the nearsurface prospection. Mapping of archaeological objects, search for metallic pipelines or unexploded ordnance and similar applications heavily rely on the gradiometric measurements.
Potential Results
The aim of a magnetic survey is to investigate the subsurface on the basis of the anomalies in Earth’s magnetic field resulting from the magnetic properties of the underlying rocks or buried artifacts. The potential results coming from fluxgate gradiometers in the archaeological domain are the detection of buried structures and ditches, metal objects and artifacts, and anthrosoils.