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Automated open circuit scuba diver detection with low cost passive sonar and machine learning
(Massachusetts Institute of Technology, 2019)
This thesis evaluates automated open-circuit scuba diver detection using low-cost passive sonar and machine learning. Previous automated passive sonar scuba diver detection systems required matching the frequency of diver ...
Dense, sonar-based reconstruction of underwater scenes
(Massachusetts Institute of Technology, 2019)
Three-dimensional maps of underwater scenes are critical to-or the desired end product of-many applications, spanning a spectrum of spatial scales. Examples range from inspection of subsea infrastructure to hydrographic ...
Controller design for underwater vehicle systems with communication constraints
(Massachusetts Institute of Technology, 2015)
Real-time cooperation between autonomous vehicles can enable time-critical missions such as tracking and pursuit of a dynamic target or environmental feature, but relies on wireless communications. Underwater, communication ...
Robust acoustic signal detection and synchronization in a time varying ocean environment
(Massachusetts Institute of Technology, 2012)
Signal detection and synchronization in the time varying ocean environment is a difficult endeavor. The current common methods include using a linear frequency modulated chirped pulse or maximal length sequence as a detection ...
Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves
(Massachusetts Institute of Technology, 2011)
This thesis describes the physics of fully three-dimensional low frequency acoustic interaction with internal waves, bottom sediment waves and surface swell waves that are often observed in shallow waters and on continental ...
Real time bottom reverberation simulation in deep and shallow ocean environments
(Massachusetts Institute of Technology, 2015)
Due to the costs involved and time required to perform experiments at sea, it is important to provide accurate simulations of the ocean environment. Using the ray tracing code, BELLHOP, the Mission Oriented Operating Suite ...
Contributions to automated realtime underwater navigation
(Massachusetts Institute of Technology, 2012)
This dissertation presents three separate-but related-contributions to the art of underwater navigation. These methods may be used in postprocessing with a human in the loop, but the overarching goal is to enhance vehicle ...
Low frequency active sonar performance in the Arctic Beaufort Lens
(Massachusetts Institute of Technology, 2017)
A newly discovered double ducted acoustic environment present throughout much of the Beaufort Sea in the Arctic has a major effect on active acoustic transmissions. This work performs an in depth analysis of how the lower ...
Stratification on the Skagit Bay tidal flats
(Massachusetts Institute of Technology, 2012)
Estuarine density stratification may be controlled primarily by cross-shore processes (analogous to longitudinal control in narrow estuaries), or by both cross- and alongshore processes (typical of coastal plumes). Here ...
Measuring surface ocean wave height and directional spectra using an Acoustic Doppler Current Profiler from an autonomous underwater vehicle
(Massachusetts Institute of Technology, 2012)
The Acoustic Doppler Current Profiler (ADCP) is a proven technology which is capable of measuring surface wave height and directional information, however it is generally limited to rigid, bottom mounted applications which ...