Magnetic Anomaly Detection Using Continuous Angle Alignment of Three-Axis Magnetic Signal

A magnetic anomaly detection (MAD) scheme detects magnetic changes generated from the ferromagnetic target in the geomagnetic field. The three-axis magnetic vector sensor is considered as a technique to extend the detection range for the MAD scheme. However, in the conventional MAD scheme, the scheme detects only the magnitude signal calculated from the three-axis signal, and thus, the sensitivity of the three-axis signal which has been changed by the target cannot be directly reflected. In addition, when the axis of the magnetic vector sensor is physically rotated during the installation, the detection probability of the MAD scheme using the three-axis signal is deteriorated because the strength and pattern of the three-axis signal are changed by the rotated axis. In this paper, we propose a continuous angle alignment-based MAD (CAA-MAD) to extend the detection range of the target and to reduce the false alarm rate. Experimental results show that the proposed CAA-MAD can extend the detection range significantly compared with the conventional magnitude-based MAD.