2019_programme: LOW-FREQUENCY PASSIVE ACOUSTIC SURVEY OF SHIP TRAFFIC USING A GLIDER EQUIPPED WITH DIRECTIONAL SENSORS
- Session: 16. Advances in acoustic measurement systems: Technologies and applications
Organiser(s): Tesei Alessandra
- Lecture: LOW-FREQUENCY PASSIVE ACOUSTIC SURVEY OF SHIP TRAFFIC USING A GLIDER EQUIPPED WITH DIRECTIONAL SENSORS [invited]
Paper ID: 919
Author(s): Tesei Alessandra, Stinco Pietro, Dreo Richard, Micheli Michele, Garau Bartolome, Petroccia Roberto, Pinzani Diego, Grati Alberto, Maguer Alain
Presenter: Maguer Alain
Presentation type: oral
Abstract: The problem of underwater, long-term acoustic monitoring of a defined sea area has an important role in many civilian and defence applications. The concept of passive acoustic survey using a small volumetric array on board a mobile platform has been proven at CMRE since 2012 by using compact acoustic antennas installed on mobile unmanned vehicles, such as buoyancy gliders and wavegliders. Using gliders may provide covertness, quietness, persistence, wide area coverage, real-time, continuous monitoring aimed at detection and tracking of noise sources. The present activity extends the previous work by integrating in a Slocum glider, for the first time at CMRE, an acoustic vector sensor, namely the 3D GeoSpectrum M20-040. This sensor is able to provide directionality in the band from few Hz to 3 kHz, despite its limited size. The glider has been equipped also with an acoustic modem, able to communicate with a USBL deployed from a mother ship or a gateway. Through the USBL, a Control Station can get R/T measurements of the glider position and receive its detection alarms during the underwater missions, without need of surfacing.\nFirst at-sea tests of navigation, underwater communications and acoustic data collection were conducted during REP18Med trials (Palmaria Island, Italy, Oct. 2018) with one of CMRE gliders hosting an M20-040 and an acoustic modem. Estimating the smoothness of the glider navigation is fundamental to understand whether a glider is suitable to conduct passive survey with a sensor sensitive to acceleration. The USBL position measurements were compared to the estimate achieved by filtering the proprioceptive data collected on-board the glider, corrected with the available GPS fixes. Having accurate positioning of the platform is a fundamental condition to fuse data among more gliders. \nThe paper will provide a detailed analysis of the system and of the processing chain, along with at-sea results.
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- Corresponding author: Dr Tesei Alessandra
Affiliation: NATO STO CMRE
Country: Italy
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