Complex Markers for a Mine Detector

This paper describes a novel type of metal markers for eddy current metal detection systems using precise positioning information. The new design for metal markers which are compounded by an ordered array of metal plates with different magnetic parameters has three fundamental advantages: 1. the markers are sensed directly by the metal detector, and no additional hardware is required; 2. the signatures are sharp; 3. not only the position but also the speed of the detector head can be evaluated. In the case of a stand-alone inertial navigation system for evaluating the position of the detector, the precision would be low due to the sensor noise and its integration. However, knowledge of the relative positions and potentially of the detector head speed over the markers can be used as auxiliary information, and so the eddy-current mapping system will be capable of determining the size of the magnetic imprint of a detected metal object and its position relative to the markers. This increases the reliability of the object discrimination during humanitarian demining, and decreases the numbers of false alarms, which nowadays constitute 99.9% of all alarms emitted by an ordinary mine detector.