The Impact of Magnet Structures on Target Magnetic Anomaly Detection

Abstract To address the limitation of short detection ranges in conventional magnetic sensors, excitation magnetic fields can be used to enhance the target’s magnetic anomaly and thereby extend the detection range. By arranging permanent magnets to create excitation magnetic fields around the magnetic sensor, targets are magnetized, producing significant magnetic anomalies that can be detected by the sensor. Four different magnet configurations were tested in simulations to compare the response characteristics of the magnetic sensor using a typical iron rod as the target. Based on these simulations, a magnetic detection device was designed and experimentally validated. The results demonstrate that excitation magnetic fields effectively increase the magnetic anomaly and detection range compared to conditions without permanent magnets. When two permanent magnets are placed vertically with the magnetic sensor’s measurement point at the center, the excitation field has the most pronounced effect on the iron rod’s magnetization, resulting in the largest magnetic anomaly and improving signal acquisition. This study offers a novel approach to enhancing the detection capabilities of magnetic sensors.