Passive and active acoustics using an autonomous wave glider

The recently developed wave glider has the potential to be an effective unmanned platform for acoustic applications. We present the results of a variety of experiments that quantify this potential. The radiated self-noise of the autonomous platform is evaluated using an integrated passive acoustic recorder during a set of field trials off the coast of Hawaii. We present the radiated noise spectra from these trials to illustrate the dependence on hydrophone location and sea state. Using the same instrumentation, we demonstrate the ability of a modified wave glider to detect marine mammals using passive acoustic monitoring techniques. We also evaluate the performance of the wave glider operating as an active acoustic gateway, highlighting the potential of this platform to serve as a navigation reference and communications relay for scientific, industrial, and military subsea assets. To demonstrate the potential of the wave glider platform to support acoustic navigation, we assess the performance of time-of-flight range estimation and seafloor transponder localization. These tests were performed using commercial off-the-shelf acoustic positioning hardware integrated with the wave glider to illustrate that the low self-noise of the wave glider makes it possible to achieve acoustic positioning performance similar to previously reported results. Finally, we show that the glider can operate as a station-keeping surface communications gateway and provide recommendations for its use. (c) 2012 Wiley Periodicals, Inc.