2025_programme: Exploring the Acoustic Near-field of the Kauaʻi Beacon Source
- Day: June 19, Thursday
Location / Time: A. TERPSIHORI at 11:40-12:00
- Last minutes changes: -
- Session: 12. Observing the Oceans Acoustically
Organiser(s): Bruce Howe, Kay Gemba
Chairperson(s): Bruce Howe, Kay Gemba
- Lecture: Exploring the Acoustic Near-field of the Kauaʻi Beacon Source
Paper ID: 2227
Author(s): Elizabeth Taylor (University of Hawaiʻi at Mānoa), Eva-Marie Nosal (University of Hawaiʻi at Mānoa), Bruce Howe (University of Hawaiʻi at Mānoa), Nicholas Durofchalk (Naval Postgraduate School), Kay Gemba (Naval Postgraduate School)
Presenter: Elizabeth Taylor
Abstract: The Kauaʻi-Beacon (KB) source was reactivated in March 2023 after a 15-year hiatus for long-range acoustic applications in the Pacific Basin, including tomography and navigation. KB is located on the seafloor off the coast of Kauaʻi at a depth of 810 m and transmits a 44-period m-sequence pseudo-random noise signal with a 75 Hz carrier frequency on a nominal 2 percent duty cycle schedule. Recent studies demonstrated successful reception of the signal at Wake Island, Monterey Bay and Ocean Observatories Initiative (OOI) sensor network, achieving 30dB of processing gain. The KB signal can ultimately be used to navigate undersea vehicles and determine ocean properties along long-range paths. However, since KB is installed on the seafloor, local effects (e. g. from bathymetry and seabed properties) potentially affect the far-field signal; indeed several studies from the early 2000s demonstrated a relatively complex acoustic near-field at KB. Fortuitously, the ALOHA Cabled Observatory (ACO) hydrophone, leveraged here as a “KB near-field receiver of opportunity”, receives the KB signal at 166 km from the KB source with precise timing. ACO is seafloor-mounted, 100 km north of Oʻahu at 4,728 m depth. Our work aims to advance the understanding of underwater acoustic propagation in the acoustic near-field of KB by processing and investigating the KB signal as received at ACO. This presentation will discuss our methods and preliminary findings, including observations of the effects of seasonal and tidal factors on the received signal [work supported by the Office of Naval Research Ocean Acoustics program].
- Corresponding author: Ms Elizabeth Taylor
Affiliation: University of Hawaiʻi at Mānoa
Country: United States
