Sensor networks of freely drifting autonomous underwater explorers

ABSTRACT

With the increasing sophistication of both manned and unmanned systems for remote ocean exploration, a wealth of knowledge about heretofore-unknown oceanic processes has become available. However, no technologies currently exist to observe organisms and processes without disturbing them, as they move with the natural motion of the oceans. We propose a new class of ocean sensing, whereby free-floating underwater devices operate autonomously and collaborate through an acoustic underwater network between them. This new class of sensing will provide a window into understanding the multifaceted interactions between the ocean's currents, underwater ecosystems and our impact on them. In this paper, we will present the design of our underwater vehicle, which drifts freely with the ocean currents and is equipped with a buoyancy control piston. Results from sea tests illustrate the feasibility of our design, including its depth tracking abilities.

REFERENCES

• 1: Colgan, C., "Underwater Laser Show," Explorations, Scripps Institution of Oceanograhpy, Vol.12, No.4, pp.20--27, Spring 2006.
• 2: Woods Hole Oceanographic Institution, Acoustics Communications group, "WHOI Micro-Modem," http://acomms.whoi.edu/micromodem/.
• 3: Landau, L. D. and E. M. Lifshitz, "Fluid Mechanics," Pergamon Press, 1939.
• 4: Adams, A., Hinton, O., Sharif, B., Salles, G., Orr, N., Tsiminedes, C., "An Experiment in sub-sea networks - The LOTUS Sea Trials," ECUA'00, Lyon, France, 2000.
• 5: Blandin, J., Person, R., Strout J., Briole, P., Etiope, G., Masson, M., Golightly, C., Lykousis, V., Ferentinos, G., "ASSEM: array of sensors for long term seabed monitoring of geohazards," International Symposium on Underwater Technology, pp.111--115, 2002.
• 6: Rice, J., et al, "Evolution of Seaweb Underwater Acoustic Networking," Oceans Conf., Providence, RI, pp. 2007--2017, 2000.
• 7: SNUSE: Sensor Networks for Undersea Seismic Experimentation, ISI, http://www.isi.edu/ilense/snuse/index.html, last accessed June 2006.
• 8: Underwater Acoustic Sensor Networks (UW-ASN), Georgia Institute of Technology, http://www.ece.gatech.edu/research/labs/bwn/UWASN/, last accessed June 2006.
• 9: AMOUR (Autonomous Modular Optical Underwater Robot), http://groups.csail.mit.edu/drl/underwater_robotics/amour/amour.html, Rus Robotics Laboratory, last accessed June 2006.
• 10: Distributed Surveillance Sensor Network (DSSN), SPAWAR Systems Center, San Diego, http://www.nosc.mil/robots/undersea/dssn/dssn.html, last accessed June 2006.
• 11: Statnikov, E., "Speed of Ocean Currents," The Physics Factbook, http://hypertextbook.com/facts/2002/EugeneStatnikov.shtml.

INDEX TERMS

Primary Classification:
  J. Computer Applications
  J.2 PHYSICAL SCIENCES AND ENGINEERING
      Subjects: Earth and atmospheric sciences

General Terms:
Experimentation

Keywords:
autonomous vehicles, underwater acoustic communication, underwater sensor networking