In this paper, the underwater vehicle's magnetic stealth characteristic is numerically studied based on the finite element method (FEM). The inductive magnetic flux density of an underwater vehicle with different sailing direction is simulated and analyzed. It shows that the maximum inductive magnetic flux density is inversely proportional to the distance above the ship. Because of the influence of geomagnetic south and north poles, the maximum inductive magnetic flux density is larger when the underwater vehicle sails south or north comparing to east or west. It can be concluded that when the underwater vehicle is about to hide from the magnetic anomaly detection device on the aircraft, it is suggested that the underwater vehicle dives deeper and sails east or west instead of other direction.
Normally underwater vehicles are made up of ferromagnetic materials such as steel. As a result, when magnetic underwater vehicle is sailing under the sea, it will generate inductive magnetic flux density which superimposes onto the earth's background magnetic field. Hence the change of spatial magnetic field distribution around the target is formed, which probably causes the underwater vehicle to be tracked by magnetic anomaly detection device on the aircraft. Therefore, the magnetic stealth characteristic of underwater vehicle draws more and more country's attention in the last two decades.
Wang (2012) proposes an underwater large target detection method based on magnetic anomaly detection and gradient anomaly detection. Zhou (2018) establishes a submarine magnetic field model using boundary elements method for aeromagnetic anomaly detection. Zhou (2018) researches on magnetic signature at high altitude for submarine based on two dimensional Fourier transform and analyzes the magnetic signature of the spatial distribution in the spatial domain and the frequency domain. Zhou (2009) proposes a new magnetic field extrapolation method in magnetic silencing of ships based on the Tikhonov regularization method. Zhou (2010) researches on the magnetic field extrapolation of ships based on boundary equivalent magnetic source method.
