Magnetic field measurement

Operating principle of magnetic field measurement

Particular magnetic properties play an important role in detecting ferromagnetic objects in the ground. Magnetic field measurement makes use of the fact that foreign materials in the ground have a different effect on the Earth's magnetic field. These fluctuations in the Earth's magnetic field are measured by a magnetometer. This branch of science is also referred to as geomagnetics. Local deviations in the magnetic field on the Earth's surface indicate ferromagnetic materials in the ground. In this way, geomagnetics can be used to detect various objects such as contaminated sites (e.g., unexploded bombs) or archeological sites.

Operating principle of magnetometers & gradiometers

A differential circuit of two opposite and spatially separate magnetometers allow deviations from the Earth's natural magnetic field to be measured. Such a measurement system is referred to as a gradiometer.
If the same magnetic field is present at both magnetometers, the resulting signal is zero. Magnetic anomalies in the ground, such as, for example, an unexploded bomb, unexploded ordinance, or even archeological structures, can be correspondingly visualized because they produce a different magnetic field in the two magnetometers.