Research of acoustic noises and characteristics of multipath effect in shallow arctic seas to optimize parameters of hydroacoustic communication equipment

Field studies of acoustic sea noises and multipath effect characteristics of signal propagation in shallow Arctic seas covered by drifting ice are carried out. The research is made for the purpose of optimization of characteristics of the equipment of a hydro-acoustic channel of digital communications determined for control and operative diagnostics of technically complex underwater objects, such as submerged buoy stations, producing oil and gas platforms and pipelines. A most modern technology of equipment construction, OFDM-type (orthogonal frequency-division multiplexing), which provides simultaneous emanation of large amounts of narrow-band carrier frequencies for parallel binary code transfer, are planned to be used on the channel of communication. Parallel code transfer with some redundancy added provides high speed of data transfer, maximum remotability and noise immunity. Basic OFDM technology is particularly targeted for multipath effect jamming protection and pulse noise jamming peculiar to shallow ice-covered seas. Statistical measures for levels and nature of sea noises and quantitative meanings of amplitude distribution and certain acoustic rays’ time delays caused by tending and drift velocity influence are received, as well as hydrological conditions. The results of the studies allow the reasonable choice and calculations of equipment parameters with OFDM technology, and they also allow providing reception of specified performance characteristics in adverse hydrological conditions.

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