Research on ship's magnetic field extrapolation method based on virtual plane and boundary integral formula

A ship in the earth’s magnetic field gets a magnetization and creates a local anomaly. The high-precision extrapolation of a ship's magnetic field is an important task for magnetic stealth. In this paper, a virtual plane is constructed between the ship and the measurement surface beneath it. With the limited measurement data on the measurement surface beneath the ship, the magnetic field on the virtual plane is calculated by inverse algorithm. A boundary integral formula model on virtual plane for the ship's magnetic field is established. Automatic boundary truncation and adaptive meshing algorithms are applied to the virtual plane, which effectively improve the extrapolation accuracy. As a result, the model is suitable for both short-range and long-range extrapolation.