A rapid measurement method for ship’s longitudinal and athwartship induced magnetic field

Abstract

Abstract Induced magnetic field (IMF) measurement is a key step in the ship’s magnetic field treatment process. In this paper, a new method for rapid measurement of longitudinal and athwartship IMF is proposed, which can improve the traditional measurement method that is either time-consuming and labor-intensive, or dependent on the magnetic field uniformity of geomagnetic simulation coils. Using the geomagnetic simulation coil in the close-wrap magnetic treatment facility, a mapping model between the coil magnetic field and the ship’s magnetized field excited by the coil is constructed in a single-heading. Based on this single-heading-measurement method, numerical simulations and hull experiments are carried out. By combining the regularization technology, the results show that the proposed method can quickly and accurately measure the ship’s IMF, and can suppress the influence of measurement error on obtaining the IMF. Compared with the geomagnetic simulation method, proposed method not only has a great calculation accuracy and strong robustness, but also requires a lower magnetic field uniformity of the geomagnetic simulation coil, and can be used as a fast emergency measurement method for ship’s IMF in engineering.