Effect of Gauge Length on Distributed Acoustic Effect of Gauge Length on Distributed Acoustic Sensing Performance for Baleen Whale Monitoring.

Clark, Marie-Ève, Cauchy, Pierre, Blouin, Stéphane et Bouffaut, Léa (2026). Effect of Gauge Length on Distributed Acoustic Effect of Gauge Length on Distributed Acoustic Sensing Performance for Baleen Whale Monitoring. Dans OCEANS 2026 - Monterey.

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Résumé

Distributed Acoustic Sensing (DAS) converts underwater fiber-optic cables into dense sensor arrays for marine monitoring, including ship and baleen whale detection. Detection performance is governed by the gauge length (GL), an acquisition setting set as a trade-off between optical signal-to-noise ratio (SNR) and bandwidth. Longer GLs improve optical SNR by integrating more backscattered light into strain measurements, at the cost of reduced frequency response. Here, we investigate the effect of the GL on strain amplitude, SNR, and noise floors using data collected on a telecommunication cable crossing the St. Lawrence Estuary in Quebec, Canada with a FOSINA DxS interrogator during controlledsource playbacks. Raw optical data were processed with GLs of 5 to 20 m. Analysis of a playback tone at 100 Hz shows that increasing the GL reduced measured noise levels, with a GL of 10 m providing the best SNR overall, generally consistent with theoretical predictions. The estimated pressure-to-strain conversion factor increased systematically with GL by 0.76- 0.77 dB/m, indicating a potential GL dependence not fully captured by the theoretical DAS response model considered here. The findings of this work provide an empirical basis for GL selection for monitoring whale calls near 100 Hz, while demonstrating that optimal configuration remains considerably influenced by the source-to-cable geometry.

Type de document :	Document issu d'une conférence ou d'un atelier (Conférence)
Validation par les pairs :	Non
Mots-clés :	Détection acoustique distribuée ; Câbles de télécommunication ; Surveillance des mammifères marins ; Fibre optique ; Surveillance sous-marine ; Détection acoustique ; Diffusion de signaux acoustiques / Distributed Acoustic Sensing ; Telecommunication cables ; Marine mammal monitoring ; Fiber optic ; Underwater monitoring ; Acoustic detection ; Acoustic playbacks.
Départements et unités départementales :	Institut des sciences de la mer de Rimouski (ISMER)
Date de dépôt :	17 sept. 2026 15:01
Dernière modification :	17 sept. 2026 18:05
URI :	https://semaphore.uqar.ca/id/eprint/3634