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Electromagnetics (TDEM)

Particularly in areas with magnetic but non-metallic interferences, like areas with recycling layers and brick debris we use electromagnetics. With this method, we can also detect non-magnetic metal-objects (e.b. brass).

Principle of Measurements

The electromagnetics we use are so-called two-coil systems, the function principle of which is based on induction. These systems are composed of a transmitting and a receiving coil. During the measurement, an alternating current in the transmitting coil generates a so-called primary magnetic field. In conductive interfering bodies, electrical currents are excited by the alternating field, which in turn generate their own (secondary) magnetic field. With the receive coil, the changes in the secondary magnetic field can be registered and thus anomalies can be detected.


With the electromagnetic method, the substrate itself is excited and its reaction is analyzed, so this method is also referred to as an active geophysical method. Since the conductivity of the substrate is investigated with electromagnetics, non-magnetic but conductive disturbance bodies such as infantry ammunition can also be detected.

The maximum detection depth depends on the coil size and the size of the objects. With our mobile systems, detection of large bodies up to a depth of 3.0 m is possible. For larger depths, we use a large loop, with which such a body can be seen even in depths of up to 6 m. The depth of penetration can be reduced locally, however, by filling and other objects.

Applied Technique

At TAUBER, we have different coil sizes for the various challenges. For example, we use 1 x 1 m and 1 x 0.5 m coils for the detection of medium and large disturbance bodies in the upper 2 - 3 m. For the detection of small-caliber ammunition, we have systems with smaller transmit coils for better object discrimination and precise localization. For areas where larger depths need to be detected, we use a large grinding system which we can flexibly adapt to the situation. We offer

  • Surface survey
  • Surface survey with the large loop for increased depth range
  • Borehole detection with the large loop
  • Detection of shallow water areas