Propagation Features of Pulse Pseudo-Random Signals from an Extended Shelf into the Deep Sea During Reception At Different Depths

The article discusses the results of an experiment conducted in the Sea of Japan in August 2023 on an acoustic path with a length of 144.4 km under summer-autumn hydrological conditions. The study focused on the propagation of pulsed pseudo-random signals from an extended shelf into the deep sea when received at depths of 69, 126, 680, and 914 meters. An analysis of the experimentally obtained impulse characteristics revealed a group of ray arrivals with a duration of approximately 0.5 sec, with a maximum close to a center at all depths. The experiment involved receiving broadband pulse signals with a central frequency of 400 Hz at a distance of 144.4 km from the source of navigation signals (SNS) located on the shelf at a depth of 30 m and a sea depth of 45 meters. Signal information was received using a system equipped with hydrophones distributed up to a depth of 1000 meters, allowing for long-term signal recording at fixed depths. The experimental findings facilitated the study of impulse characteristics of the acoustic waveguide, determination of effective signal propagation speeds at different depths, and formulation of conclusions regarding the potential for utilizing autonomous underwater vehicles (AUVs) for climate monitoring of marine areas at depths up to 1000 meters.