A multi-sensor network for direction finding of moving ferromagnetic objects inside water by magnetic anomaly

Abstract

In this study, it is aimed to detect remotely the direction and the velocity of a moving object inside water by magnetic anomaly by the use of a multi-sensor network. This study is the extension of single sensor case the results of which are previously published. A three-step approach is used for finding the direction and the velocity of a moving object inside water. First, a uniform magnetic field is established in the test bed that is developed to simulate the practical environment. By the use of this test bed, the magnetic field created is determined. Second, the characteristic relations between the parameters depending upon the length of the ferromagnetic object, magnetic permeability and the direction of the motion of the object appearing in the model of the voltage variation and the direction angle are obtained. Third, a multi-sensor network is utilized for the determination of direction and velocity of any moving object inside the environment. The multi-sensor network produces a moving fixed magnitude voltage wave. The effects of the material magnetic permeability and the length are also studied in this work. It was seen that the relative permeability and the length could affect the magnitude of the wave obtained but not the shape of it. It is seen that the peak of the wave magnitude remained fixed throughout the direction of the motion of the moving ferromagnetic object even the permeability and the length of the object are different. This method clearly shows good results and the direction and the velocity of motions of ferromagnetic objects with different length and magnetic permeability inside water can be detected with high accuracy. It was seen that the number of the sensors and the way to deploy them were important for obtaining the fixed magnitude moving voltage wave in the region. This method is also suitable for the determination of material from which an object is produced.