Research on the detection of ferromagnetic objects based on the phase characteristics of industrial frequency electromagnetic fields

At present, the common detection technology pathways about underwater ferromagnetic objects such as underwater cruisers, shipwrecks, submarine metallic minerals, cave banks, etc. are sonar detection, laser/radar detection, geomagnetic anomaly detection, etc. Among them, the underwater target / object echoes due to the development of silencing technology and the sea background noise is very close, so the sonar detection means face serious challenges; because of seawater has a shielding effect on high-frequency electromagnetic waves, so the laser / radar and other active emission of high-frequency electromagnetic wave detection method for deep water layer object detection is more difficult. All over the world are erected with large transmission networks of different scales, can be radiated to the surrounding space stable 50Hz/60Hz frequency electromagnetic field (wave), and the frequency of frequency electromagnetic waves by seawater and other environmental media attenuation impact is very small. Therefore, in the detection and positioning of underwater ferromagnetic objects, the industrial frequency electromagnetic field (wave) detection means will play an important role. This paper analyzes and studies the characteristics of the phase change of the interaction between the industrial frequency electromagnetic field and ferromagnetic objects, and the results show that when the industrial frequency electromagnetic field acts on the ferromagnetic object, its phase will change significantly, producing local industrial frequency electromagnetic field anomalous signal, which provides a theoretical basis for the industrial frequency electromagnetic field detection of ferromagnetic objects.