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In recent years there is growing concern that the use of mid-frequency (1-10 kHz) tactical sonar may be causing atypical mass stranding of some species of whales. Beaked whales form a family of 21 species of mostly deep diving whales that range from 4 to 13 meters long with a characteristic `beak' similar to dolphins. The beaked whale species common in the Mediterranean Sea, the Cuvier's beaked whale...
Mapping and profiling the ocean floor has, until recently, relied on the use of active sonar. These systems use transducers to transmit a known waveform toward the seabed, and hydrophones to listen for its reflections. In recent years, it has been shown that passive sonar systems, which use only hydrophones, can also be used for such purposes. Instead of artificial sounds, these techniques utilize...
A vertical autonomous hydrophone (VAUH) array useful for a long-term low-frequency underwater acoustic propagation study was developed at Oregon State University (OSU), North Carolina State University and the National Oceanic and Atmospheric Administration's (NOAA) Pacific Environmental Lab (PMEL). To analyze the arrival structure of the hydroacoustic signals in deep water, we needed a multichannel...
We describe field experiments in which a team of autonomous underwater vehicles cooperatively localize an acoustic source. The team implements a data fusion algorithm to enhance the localization performance of each individual vehicle and implements a decentralized motion control algorithm so that each vehicle maneuvers to minimize the joint localization error of the acoustic source. Each autonomous...
We present analytical results which quantify the effect of system mismatch and finite sample support on acoustic vector sensor array performance. One noteworthy result is that the vector aspect of the array ldquodampensrdquo the effect of array mismatch, enabling deeper true nulls. This is accomplished because the variance of the vector sensor array spatial response (due to rotational, positional...
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