Magnetic anomaly detection of moving objects

Abstract

Magnetometry is commonly used to detect and locate stationary as well as moving objects made of magnetic materials. The problem consists of detecting and determining any anomaly in the geomagnetic field generated by the presence and/or motion of a magnetic object, with the latter presenting a more challenging case. The data collected by a sensor or an array of sensors are treated by common signal and data processing techniques or by the objective base function (OBF) optimization methods which is the method employed in this work. A novel fluxgate sensor developed by the Sensors Laboratory is used to collect magnetic field data in an appropriately designed setup in the laboratory. The data are generated by a weakly magnetized object moving at a constant velocity and various distances from the sensor. The OBF method is used to construct the energy detection criterion. Results show that the energy value decreases at longer distances but the object is clearly detected even when the signal is buried in background noise. The performance of the overall system is promising for detecting and tracking moving objects in adverse environments such as marine traffic.