关键词: 磁场动态检测, 等效磁性模型, 磁偶极子, 磁场校正

Abstract: As the dynamic detection of ship magnetic fields has the advantages of simple measuring equipment, high-level concealment and low construction cost, it has become a ship magnetic field detection method that is being actively developed by navies all over the world. Based on the basic principles of the dynamic detection of ship magnetic fields, this paper establishes a mathematical model for the dynamic detection of ship magnetic fields. Accordingly, it simulates and analyzes the influence degree of various dynamic factors on the measured magnetic field in detail, and proposes an inversion correction method for the measured magnetic field considering the influence of these dynamic factors. Specifically, an equivalent magnetic inversion correction model of the ship is constructed by using multi-source dynamic measurement data, which is solved by lasso regression. Subsequently, the magnetic field data in the dynamic measurement process is corrected by inverting the equivalent magnetic parameters. The experimental results demonstrate that during the dynamic magnetic field detection in four different navigation directions, the dynamic variation ranges for the ship's heading, trim, and roll are 2°, 1°, and 1°, respectively. When the magnetic measurement noise is 20 nT, the maximum absolute error in the measured magnetic field is 493 nT, with a relative error of no less than 5.32%. After applying the correction method proposed in this study, under typical measurement conditions where the heading, trim, roll, and magnetic measurement noise are 0.1°, 0.01°, 0.01°, and 5 nT, the maximum absolute error in the corrected magnetic field is reduced to 22 nT, with the relative error not exceeding 0.55%. Physical scale model experiments have shown that in the dynamic measurement of the magnetic field in four different sailing directions of a ship, when the amplitude of dynamic heading change is 4º, the maximum absolute error before correction is 374 nT, and the relative error is no less than 3.44%. After correction, the maximum absolute error of the magnetic field is 146 nT, and the relative error is no more than 2.35% . This method has great engineering guiding significance for improving the accuracy and application scope of the dynamic detection of ship magnetic fields.

Key words: magnetic field dynamic detection, equivalent magnetic model, magnetic dipole, magnetic field correction