UACE2017 Proceedings: Underwater Acoustic Modems with integrated Atomic Clocks for One-Way Travel-Time Underwater Vehicle Positioning

• Session:
  Underwater Communications and Networking
• Paper:
  Underwater Acoustic Modems with integrated Atomic Clocks for One-Way Travel-Time Underwater Vehicle Positioning
• Author(s):
  Konstantin Kebkal, Oleksiy Kebkal, Veronika Kebkal, Luís Sebastião, Antonio Pascoal, Jorge Ribeiro, Henrique Silva, Miguel Ribeiro, Giovanni Indivery
• Abstract:
  Time synchronization of the nodes of an underwater acoustic network, particularly when the nodes are autonomous underwater vehicles (AUVs) in an AUV formation, is a necessary prerequisite for the effective use of collected sensor measurements in diverse marine application scenarios. \nOne of the methods adopted to operate AUVS synchronously is to synchronize their clocks at the surface (typically by means of GPS) and then use a low drift clock for maintaining the desired precision while submerged.\nThis paper presents experimental results on the integration of a chip-scale atomic clock (CSAC), the Quantum SA.45s, into the processing electronics of an underwater acoustic modem built upon S2C technology. Since one of media access modes of the acoustic modem is based on transmission/reception of Synchronous Instant Messages, the modem with the integrated atomic clock becomes capable of precise measurements of one-way signal propagation delay (between signal source and signal recipient), and thus of precise estimation of the signal propagation distance.\nThe paper describes and discusses experimental results on the CSAC accuracy achieved during multiple field tests, includes practical recommendations for CSAC disciplining and phase synchronization with the source of common time reference (GPS time), and provides experimental results on positioning accuracy of AUVs using S2C acoustic modems for communication and position purposes\nThe work reported in the paper was done in the scope of the EC WiMUST (Widely scalable Mobile Underwater Sonar Technology) project and was made possible by a collaborative research effort among several WiMUST project partners: the Interuniversity Center of Integrated Systems for the Marine Environment (ISME), The organization of Instituto Superior Técnico for Research and Development (IST-ID, Univ. Lisbon), the Centro de Investigação Tecnológica do Algarve (CINTAL), the School of Computer Science at the University of Hertfordshire, and the companies CGG, Geo Marine Survey Systems, Geosurveys, and Graal Tech.
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Contact details

• Contact person:
  Dr Konstantin Kebkal
• e-mail:
  
• Affiliation:
  Evologics GmbH
• Country:
  Germany