2025_programme: North Atlantic Right Whale Up-call Localization with a Four-Element Acoustic Array on a Slocum Glider

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  • Day: June 16, Monday
      Location / Time: D. CHLOE at 16:10-16:30
  • Last minutes changes: -
  • Session: 08b. Bioacoustics and Soundscape
    Organiser(s): Jennifer Miksis-Olds, Giacomo Giorli
    Chairperson(s): Jennifer Miksis-Olds, Giacomo Giorli
  • Lecture: North Atlantic Right Whale Up-call Localization with a Four-Element Acoustic Array on a Slocum Glider
    Paper ID: 2250
    Author(s): Michael MacGillivray, Mae Seto, S. Bruce Martin, Laird Bolt
    Presenter: Michael MacGillivray
    Abstract: North Atlantic right whales (NARW) are a critically endangered species with only an estimated 350 individuals in existence. To mitigate human-induced fatalities, vessel speed regulations and fishing closures over a 2000km^2 exclusion zone, around the position of visual or acoustic detection, are in effect for 2 weeks in Canadian sovereign waters. Passive acoustic monitoring (PAM) of NARW vocalizations provides an opportunity to localize these animals by estimating their relative bearing and range, enabling a more accurate placement of the exclusion zone. This study focuses on bearing estimations only.\n\nThis work evaluates multiple time difference-of-arrival (TDoA) bearing estimation methods for a compact volumetric array (CVA) integrated onto a Slocum glider. Underway gliders can localize a moving whale for longer intervals and perform in-water sensing to re-plan tracking missions based on in situ detections. The proposed bearing estimation methods include: maximum likelihood estimation; k-means clustering; kernel density estimation (KDE); azigram target estimation using threshold and de-speckle filtering, and a minimum difference solver. Additionally, adaptive weighting of hydrophone-pair estimates improves the bearing estimate by prioritizing pairs whose estimates have better angular resolution.\n\nSimulations were conducted in a ROS/Gazebo environment with realistic underwater acoustic noise, transmission loss, and NARW up-calls. The results suggest the KDE solver was best, with a mean absolute error (MAE) of 22.05 degrees which compared favourably with the 31.89 degrees MAE from in-water experimental validation using a moored source as a proxy for the NARW. Both simulation and experimental results indicate state estimation will improve NARW localization further.\n\nPAM using TDoA, on a mobile platform (glider) with a CVA, to localize a mobile underwater object (NARW) is novel. Multiple TDoA bearing estimation and weighting methods were evaluated. In summary, this is a notable contribution towards autonomous localization of marine mammals using robots and advances monitoring capabilities in the underwater environment.
      Download the full paper
    This paper is a candidate for the "Prof. Leif Bjørnø Best Student Paper Award (for students under 35)"
  • Corresponding author: Mr Michael MacGillivray
    Affiliation: Dalhousie University
    Country: Canada

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