Acoustic Watermarking for Air ASW Systems

The Navy seeks to enhance its ability to distinguish active source transmissions among a multitude of active sonobuoys during high-altitude anti-submarine warfare (ASW) operations through the application of watermarking technology. This SBIR submission introduces watermarking technology that encodes watermarks into the frequency spectrum of sonar transmissions. While primarily designed for frequency modulated (FM) waveforms, this technique can be adapted to function with continuous waveform (CW) pulses and accommodate motion between the source and receiver. Remarkably, it also facilitates covert communication by toggling between desired watermarks.  Of particular interest to the Navy is source de-confliction, which involves matching direct blast signals with their corresponding echoes. While watermarks may remain detectable after reflection, additional strategies are explored, including buoy placement and decision models, to de-conflict pings while allowing rapid ping rates and near-simultaneous pinging.