EXPERIMENTAL VALIDATION OF A LONG-RANGE UNDERWATER ACOUSTIC COMMUNICATION METHOD IN THE SEA OF JAPAN

The study focuses on developing and experimentally validating an ultra-long-range hydroacoustic communication method capable of data transmission over distances exceeding 1,000 km in the complex acoustic environment of Russia's coastal seas. The proposed method employs frequency manipulation with tonal pulses in a narrow low-frequency band (300–500 Hz), ensuring robustness against multipath propagation, intersymbol interference, and Doppler distortions. A key feature of the method is the use of signal frames containing synchronization M-sequences and information components processed via the Goertzel algorithm for dominant frequency detection. Experimental verification in the Sea of Japan achieved record-breaking message transmission over 1073 km with a signal-to-noise ratio near 0 dB, demonstrating just 1–3% decoding error probability at 4 bits/s. The results confirm the feasibility of establishing an information support system for underwater vehicles across Russia's entire exclusive economic zone, with strategic implications for marine reconnaissance, navigation, and monitoring. This method enables covert one-way communication with autonomous underwater vehicles, including long-range gliders.