Search
Now showing items 31-40 of 44
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 ...
A method for on-line water current velocity estimation using Lol-cost autonomous underwater vehicles
(Massachusetts Institute of Technology, 2020)
Advances in the miniaturization of microelectronics has greatly contributed to the proliferation of small, low cost autonomous underwater vehicles (AUVs). These affordable vehicles offer organizations a flexible platform ...
Environmental analysis and prediction of transmission loss in the region of the New England Shelfbreak
(Massachusetts Institute of Technology, 2009)
A confluence of several coastal oceanographic features creates an acoustically interesting region with high variability along the New England Shelfbreak. Determining the effect of the variability on acoustic propagation ...
A study of ocean wave statistical properties using nonlinear, directional, phase-resolved ocean wave-field simulations
(Massachusetts Institute of Technology, 2010)
In the present work, we study the statistics of wavefields obtained from non-linear phase-resolved simulations. The numerical model used to generate the waves models wave-wave interactions based on the fully non-linear ...
Demonstration of passive acoustic detection and tracking of unmanned underwater vehicles
(Massachusetts Institute of Technology, 2018)
In terms of national security, the advancement of unmanned underwater vehicle (UUV) technology has transformed UUVs from tools for intelligence, surveillance, and reconnaissance and mine countermeasures to autonomous ...
Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis
(Massachusetts Institute of Technology, 2006)
Blainville's beaked whales (Mesoplodon densirostris) use broadband, ultrasonic echolocation signals (27 to 57 kHz) to search for, localize, and approach prey that generally consist of mid-water and deep-water fishes and ...
Acoustic scattering from sand dollars (Dendraster Excentricus) : modeling as high aspect ratio oblate objects and comparison to experiment
(Massachusetts Institute of Technology, 2008)
Benthic shells can contribute greatly to the scattering variability of the ocean bottom, particularly at low grazing angles. Among the effects of shell aggregates are increased scattering strength and potential subcritical ...
Landmine detection with a standoff acoustic/laser technique
(Massachusetts Institute of Technology, 2008)
Landmines and mine-like traps are effective weapons that are difficult to detect and discriminate from a safe distance. The ability to detect landmines in their host environment at a distance and to discriminate them from ...
Emulating the fast-start swimming performance of the Chain Pickerel (Esox niger) using a mechanical fish design
(Massachusetts Institute of Technology, 2006)
Mean maximum start-up accelerations and velocities achieved by the fast-start specialist, northern pike, are reported at 120 ms-2 and 4 ms-1, respectively (Harper and Blake, 1990). In this thesis, a simple mechanical system ...
Single Transponder Range Only Navigation Geometry (STRONG) applied to REMUS autonomous under water vehicles
(Massachusetts Institute of Technology, 2005)
A detailed study was conducted to prove the concept of an iterative approach to single transponder navigation for REMUS Autonomous Underwater Vehicles (AUVs). Although the concept of navigation with one acoustic beacon is ...