2025_programme: DAS reception of acoustic communications from an AUV

• Day: June 20, Friday
    Location / Time: A. TERPSIHORI at 09:50 - 10:10
• Last minutes changes: -
• Session: 05. Distributed Fiber-Optic Sensing technology for underwater acoustical monitoring
  Organiser(s): Alexander Gavrilov, Evgenii Sidenko, Hefeng Dong
  Chairperson(s): Hefeng Dong, Evgenii Sidenko
• Lecture: DAS reception of acoustic communications from an AUV
  Paper ID: 2341
  Author(s): John POTTER, Simon Hagen Hoff, Emil Wengle, Sebastian Sikora
  Presenter: John Potter
  Abstract: We present a low-cost field trial in which we transmitted acoustic communication packets and broadband test signals from an Autonomous Underwater Vehicle (AUV), received on two separate fibre-optic (FO) cables and detected using Distributed Acoustic Sensing (DAS). The trial was conducted in the Tronsheimsfjord, using legacy FO cables and an Oceanscan Light Autonomous Underwater Vehicle (LAUV) carrying a custom external payload in a Blue Robotics acrylic housing. The payload consisted of a software-defined modem from Subseapulse (based on a Rasberry Pi platform), lithium battery, amplifier, impedance matching circuitry and an inexpensive low-frequency broadband transducer (Chelsea Instruments Sonoflex 850). The transmitted signals were in the 800Hz-5kHz band.\nThe LAUV was programmed to run along a fixed track at slow speed, approximately aligned over each FO cable, at a constant height from the seabed, until it reached its operational depth limit. The modem transmitted a set of custom-designed signals in the band 800HA-5kHz, repeated every 5s. The primary objectives were to demonstrate the ability to receive and decode acoustic communication packets transmitted by an AUV and to explore the frequency and angle dependence of DAS sensitivity to acoustic fields.\nThe LAUV also used an onboard Evologics modem to communicate with an attendant electric workboat boat, which deployed its own Evologics modem to provide status updates and ranging. These data were combined with GNSS data in post-processing to reconstruct the LAUV path more accurately than could be estimated from the onboard navigation of the LAUV.\nWe present the electrical, mechanical and software design of this simple experiment and the results of our communication packet decoding and sensitivity analysis for the two cables. We find that FO cables can be successfully used to receive acoustic communication packets at O(100)m and that DAS can be useful up to several kHz on existing FO cables.
• Corresponding author: Prof John POTTER
  Affiliation: NTNU
  Country: Norway