Direction finding of moving ferromagnetic objects inside water by magnetic anomaly

The remote sensing methods by the use of magnetic anomaly are gaining importance in applications of defense technologies and industrial purposes recently. In this study, it is aimed to determine the remote detection, the variation of characteristic of the voltage in the sensor relative to the motion, the effects of material length, magnetic permeability and direction of motion of the object on this characteristic and to convert them to a useful mathematical expression by using magnetic anomaly of ferromagnetic objects such as submarines moving inside water. For this purpose, first of all, a water tank of 1 m3 is prepared and approximately a homogeneous magnetic field of 10−3 T is created within this water tank. Ferromagnetic materials with six different lengths and permeabilities are moved in three different directions relative to the position of the sensor by means of a computer controlled x-y scanner designed for this experiment inside this magnetic field. The magnetic change caused by this motion at the point where the sensor is positioned is detected as the output voltage of the sensor. A mathematical expression is formulated taken into account the variations of the sensor output voltage with respect to the length, magnetic permeability and the direction of motion of the material and it is validated by the experimental results. This study clearly shows that the existence and the direction of motions of ferromagnetic objects with different lengths and magnetic permeabilities inside water can be detected with high accuracy.