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TRODYNAMICS AND WAVE PROPAGATION

Parametric Method of Underwater Radio Navigation in Arctic Conditions G. Ya. Shaidurova, *, G. N. Romanovaa, and D. S. Kudinova a

Siberian Federal University, Krasnoyarsk, 660036 Russia *e-mail: GShy35@ yandex.ru

Received December 25, 2018; revised March 27, 2019; accepted April 12, 2019

Abstract—The article considers a radio navigation method for determining the coordinates of marine underwater vehicles (UV) without surfacing (including under Arctic pack ice) based on electromagnetic (EM)– acoustic (AC) wave interaction in the skin layer of sea water. Energy estimates for the radio channel are obtained as a function of water conductivity and UV location depth. The results of laboratory tests are shown, confirming the parametric effect and the use of this phenomenon for receiving electromagnetic signals underwater at the difference frequency of EM and AC oscillations. DOI: 10.1134/S1064226920070116

INTRODUCTION Severe weather conditions in the Arctic—storms, ice fields, winds—are an extremely difficult obstacle for piloting marine underwater vehicles (UV) with receiving arrays towed near the sea surface. Transmission and reception of signals via a buoy required surfacing of the UV, which is not always possible due to the thickness of the ice layer. Onboard inertial navigation equipment (gyrocompass, lag) do not provide the necessary UV piloting accuracy, especially when during geodetic and geophysical surveys of the seafloor and prospecting for mineral resources, which requires periodic correction of coordinates from satellite navigation system data. Due to seawater’s significant absorption of electromagnetic (EM) waves, ultralow frequencies in the 75– 78 Hz range [1] using powerful land-based radio stations and large curtain arrays are of the Seafarer (United States) and Zeus (Russia) projects are used. The Seafarer system, which has a transmitter power of 10 MW and a 100 × 100 km2 area of a horizontal array curtain sunk in the ground, reached a range of 5000 km at a frequency of 75 Hz, with a seawater reception depth of up to 100 m [1]. Due to the complexity and high cost of these systems, it is of interest to seek alternatives, including for communication and navigation. Study [2] discussed the possibility of creating submarine seismic survey systems involved in prospecting for hydrocarbons in the Arctic. Currently, wide-body ships and towed seismic streamers up to 1000 m or more are used for this. As well, icebreakers must be

used in ice conditions. This marine seismic survey method is inefficient for the North. Study [3] indicated the possibility of underwater radio communications that use parametric demodulation of signals from terrestrial radio stations operating at frequencies fe ± F by having the UV irradiate the water surface with acoustic radiation at a frequency fa, which is close to that of an EM wave fe. In this case, in the skin layer, low frequency F signals occur, which are poorly absorbed by seawater and can be received by the UV receiver. Work [4] is interesti