Advances in Magnetic Sensing Technologies for Small Target Detection: A Review

Under the influence of the geomagnetic field, ferromagnetic objects exhibit magnetic (MAG) anomalies. Additionally, nonmagnetic or weakly magnetic metallic targets can induce eddy current magnetic fields when subjected to alternating magnetic field excitation. Magnetic detection technology provides a technical approach for detecting, identifying, and localizing objects by leveraging their magnetic characteristics. The application of magnetic technology for detecting small targets, such as unexploded ordnance (UXO) and autonomous underwater vehicles (AUVs), has garnered increasing attention. Notably, methods for detecting large targets, including submarines and sunken ships, differ significantly from those used for small targets. This article systematically highlights advances in magnetic sensing technologies for small target detection. It discusses typical methods and sensor systems for detecting magnetic signals generated by small targets, with a focus on comparing passive, active, and dual-mode methods. Furthermore, this article outlines data processing techniques and solutions for improving sensor response and solving target feature information. Lastly, it offers insights into the developmental trends and future prospects for magnetic detection technologies in small target applications.