US 12,392,921 B2
Underwater ferromagnetic target detection method and system employing multiple power frequency radiation sources
Tianxu Zhang, Hubei (CN); Qinghui Zhang, Hubei (CN); Cheng Yang, Hubei (CN); Tao Zhang, Hubei (CN); Jiawei Wang, Hubei (CN); and Jiandong Tan, Hubei (CN)
Assigned to HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY, Hubei (CN); and WUHAN INSTITUTE OF TECHNOLOGY, Hubei (CN)
Filed by Huazhong University of Science and Technology, Hubei (CN); and Wuhan Institute of Technology, Hubei (CN)
Filed on Dec. 30, 2022, as Appl. No. 18/148,460.
Claims priority of application No. 202111679624.7 (CN), filed on Dec. 31, 2021.
Prior Publication US 2023/0243997 A1, Aug. 3, 2023
Int. Cl. G01V 3/17 (2006.01); G01V 3/08 (2006.01); G01V 3/165 (2006.01); G01V 3/38 (2006.01)
CPC G01V 3/17 (2013.01) [G01V 3/083 (2013.01); G01V 3/165 (2013.01); G01V 3/38 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An underwater ferromagnetic target detection method employing multiple power frequency radiation sources, comprising the following steps:
(1) a step in which a power frequency electromagnetic field and seawater act on an underwater ferromagnetic target: a power transmission network generating a power frequency electromagnetic field in a spatial range, an underwater ferromagnetic target generating an induced electromagnetic field under the action of the power frequency electromagnetic field, and seawater inside and outside the underwater ferromagnetic target generating alternating currents under the action of the power frequency electromagnetic field, and the alternating currents acting on the underwater ferromagnetic target to generate a secondary magnetic field; if there is a ship on the water serving as a secondary radiation source acting on the underwater ferromagnetic target, performing step (2); or, if there is no ship on the water serving as a secondary radiation source acting on the underwater ferromagnetic target, adding the induced electromagnetic field generated by the underwater ferromagnetic target and the secondary magnetic field generated by the underwater ferromagnetic target under the action of the seawater inside and outside the underwater ferromagnetic target to obtain a total electromagnetic field generated by the underwater ferromagnetic target, and performing step (3);
(2) a step in which the ship on the water serving as the secondary radiation source acts on the underwater ferromagnetic target: an induced current generated by the ship on the water under the action of the power frequency electromagnetic field (wave) generating a power frequency electromagnetic field (wave) serving as the secondary radiation source that acts on the underwater ferromagnetic target nearby, obtaining a secondary magnetic field generated by the underwater ferromagnetic target, and using the secondary magnetic field, the induced electromagnetic field generated by the underwater ferromagnetic target, and the secondary magnetic field generated by the underwater ferromagnetic target under the action of the seawater inside and outside the underwater ferromagnetic target as a total electromagnetic field generated by the underwater ferromagnetic target, and performing step (3); and
(3) a step of performing underwater ferromagnetic target detection: the total electromagnetic field generated by the underwater ferromagnetic target disturbing the power frequency electromagnetic field, so as to acquire a power frequency electromagnetic field distribution around the underwater ferromagnetic target, and performing underwater ferromagnetic target detection according to the power frequency electromagnetic field distribution.