METHOD FOR DETECTION OF UNDERWATER FLOATING OBJECT WITH STATIONARY DEGAUSSING DEVICE IN GUARDED WATER AREA Russian patent published in 2001 - IPC

FIELD: non-tradional passive systems for detection of underwater and surface floating objects. SUBSTANCE: during motion of a modern surface and underwater floating object in the natural earth's geomagnetic field the hull of the floating object gets magnetized and acquires a magnetic field. During motion of a magnetized floating object in conducting water of the sea area currents are induced and a transistory magnetic field is set up, which unmasks the floating object and reduces its concealment. To eliminate the natural magnetic field of the floating object, the latter uses a stationary degaussing device, consisting of windings - solenoids with direct current flowing in them, spaced apart in various parts of the floating object. Since the power mains voltage from the power mains and power source varies when the floating object power-generating units are cut in and out, transient process arise in the supply circuit of the degaussing device in the form of spikes. This results in radiation of electromagnetic field to the water area surrounding the floating object. Reception of the given signal with the aid of a transducer of electromagnetic waves to an electric signalwithin a frequency range from 0.1 to 100 Hz carries information on an appearance of a floating object in the guarded water area. EFFECT: enhanced reliability. 3 cl, 1 dwg