Shaft-rate magnetic field modeling method from magnetic axis rotation
The shaft-rate magnetic field is a passive signal source for underwater detection because of its low frequency and long underwater propagation distance.In order to effectively detect the underwa-ter shaft-rate electromagnetic field,firstly,based on the real ship test,it was confirmed that there were new shaft-rate magnetic field sources besides the shaft-rate electric field coupling.Then,based on the simulation of the low frequency magnetic field measurement,the mechanism of the shaft-rate magnetic field from the rotation of the magnetic shaft was revealed.Furthermore,the mathematical model of the shaft-rate magnetic field of the magnetic axis was established based on the ellipsoid of ro-tation.Finally,the detectability of the magnetic field from the rotating shaft-rate was verified through the real ship test.The results show that the fluxgate sensor can reliably detect the shaft-rate magnetic field signal generated by the rotation of the magnetic axis at a distance of 42 m,which can be a new source of underwater detection.