Acoustic Seaglider: Planning for the Philippine Sea Experiment 2010-2011

Acoustic Seaglider: Planning for the Philippine Sea Experiment 2010-2011
Author:
Publisher:
Total Pages: 2
Release: 2011
Genre:
ISBN:

This grant covered costs associated with planning for the use of Seagliders in PhilSea10, including travel to meetings in Seattle at the Applied Physics Laboratory, in San Diego at the Scripps Institution of Oceanography, and Taipei. This planning work led to subsequent grants to cover Seaglider acquisitions (N00014-09-1-0892) and experiment execution and data analysis (N00014-10-1-0334). There are currently four Seagliders operating in PhilSea10, to be recovered in March-April 2011.

Acoustic Seaglider: Planning for the Philippine Sea

Acoustic Seaglider: Planning for the Philippine Sea
Author:
Publisher:
Total Pages: 4
Release: 2008
Genre:
ISBN:

We want to integrate acoustics across naval and oceanographic applications. On one hand active and passive acoustics are used to detect submarines. On the other hand, acoustics are used to measure and better understand the ocean environment of the detection problem. Acoustics are essential to the underwater "infrastructure" tasks of navigation, communications, and time transfer. In all cases, the detailed understanding of acoustic propagation, ocean variability, temporal and spatial coherence ambient sound and the assimilation of data in models is essential for improved systems performance and the quantification of the associated uncertainty. Within the context of the Quantifying, Predicting, and Exploiting (QPE) Uncertainty DRI activity in the Philippine Sea, Seagliders can serve as a multipurpose platform for acoustics to support research in acoustic propagation, tomography, ambient sound, navigation, and communications. Assimilating data into models will improve oceanographic and acoustic predictions; this will test many elements of the integrated end-to-end data-modeling-prediction-detection system.

North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea

North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea
Author:
Publisher:
Total Pages: 12
Release: 2009
Genre:
ISBN:

The North Pacific Acoustic Laboratory (NPAL) program is intended to improve our understanding of (i) the basic physics of low-frequency, broadband propagation in deep water, including the effects of oceanographic variability on signal stability and coherence, (ii) the structure of the ambient noise field in deep water at low frequencies, and (iii) the extent to which acoustic methods, together with other measurements and coupled with ocean modeling, can yield estimates of the time-evolving ocean state useful for acoustic predictions. The goal is to determine the fundamental limits to signal processing in deep water imposed by ocean processes, enabling advanced signal processing techniques to capitalize on the three-dimensional character of the sound and noise fields.

Underwater Acoustic Propagation in the Philippine Sea

Underwater Acoustic Propagation in the Philippine Sea
Author: Andrew W. White
Publisher:
Total Pages: 181
Release: 2013
Genre: Hydrophone
ISBN:

In the spring of 2009, broadband transmissions from a ship-suspended source with a 284 Hz center frequency were received on a moored and navigated vertical array of hydrophones over a range of 107 km in the Philippine Sea. During a 60-hour period over 19 000 transmissions were carried out. The observed wavefront arrival structure reveals four distinct purely refracted acoustic paths: one with a single upper turning point near 80 m depth, two with a pair of upper turning points at a depth of roughly 300 m, and one with three upper turning points at 420 m. Individual path intensity, defined as the absolute square of the center frequency Fourier component for that arrival, was estimated over the 60-hour duration and used to compute scintillation index and log-intensity variance. Monte Carlo parabolic equation simulations using internal wave induced sound speed perturbations obeying the Garrett-Munk internal-wave energy spectrum were in agreement with measured data for the three deeper turning paths but differed by as much as a factor of four for the near surface-interacting path. Estimates of the power spectral density and temporal autocorrelation function of intensity were attempted, but were complicated by gaps in the measured time-series. Deep fades in intensity were observed in the near surface-interacting path. Hypothesized causes for the deep fades were examined through further acoustic propagation modeling and analysis of various available oceanographic measurements.

Planning of Deployment of an Autonomous Source for Year-Round Acoustic Monitoring of the Arctic Ocean

Planning of Deployment of an Autonomous Source for Year-Round Acoustic Monitoring of the Arctic Ocean
Author: A. Gavrilov
Publisher:
Total Pages: 56
Release: 1995
Genre:
ISBN:

Planning of a year-round experiment on trans-Arctic acoustic transmission in the framework of the program Arctic Climate Observation using Underwater Sound" (ACOUS) is a complex problem involving, not only, scientific and technical issues, but requiring consideration, also, of the financial aspects. According to the ACOUS proposal, the NRAD's vertical array is one which can be used as the first receiving system for the year-round experiment, and this array should be deployed in the Lincoln Sea in the spring of 1996. Therefore, the main problem at the first stage of designing the experiment is to develop an optimum scheme for trans-Arctic acoustic transmissions to the Lincoln Sea.

Shallow Water Acoustics

Shallow Water Acoustics
Author: Jeffrey Simmen
Publisher: American Inst. of Physics
Total Pages: 0
Release: 2010-10-04
Genre: Science
ISBN: 9780735408227

Undersea acoustic applications in shallow water, to detect, communicate, navigate, monitor and measure, are dependent upon a good physical understanding of sound propagation and scattering in this highly dynamic and inhomogeneous waveguide. Achieving such an understanding requires an interdisciplinary approach encompassing acoustics, physical oceanography, marine geophysics, marine biology, ocean engineering, and signal processing, as well as the underlying physics and mathematics of the integrated theory.

Broadband Optical Modulators

Broadband Optical Modulators
Author: Antao Chen
Publisher: CRC Press
Total Pages: 555
Release: 2016-04-19
Genre: Science
ISBN: 1439825076

"provides the full, exciting story of optical modulators. a comprehensive review, from the fundamental science to the material and processing technology to the optimized device design to the multitude of applications for which broadband optical modulators bring great value. Especially valuable in my view is that the authors are internationally

Technology and Applications of Autonomous Underwater Vehicles

Technology and Applications of Autonomous Underwater Vehicles
Author: Gwyn Griffiths
Publisher: CRC Press
Total Pages: 369
Release: 2002-11-28
Genre: Technology & Engineering
ISBN: 0203522303

The oceans are a hostile environment, and gathering information on deep-sea life and the seabed is incredibly difficult. Autonomous underwater vehicles are robot submarines that are revolutionizing the way in which researchers and industry obtain data. Advances in technology have resulted in capable vehicles that have made new discoveries on how th

China's Strategic Support Force

China's Strategic Support Force
Author: John Costello
Publisher: Createspace Independent Publishing Platform
Total Pages: 84
Release: 2018-10-11
Genre:
ISBN: 9781727834604

In late 2015, the People's Liberation Army (PLA) initiated reforms that have brought dramatic changes to its structure, model of warfighting, and organizational culture, including the creation of a Strategic Support Force (SSF) that centralizes most PLA space, cyber, electronic, and psychological warfare capabilities. The reforms come at an inflection point as the PLA seeks to pivot from land-based territorial defense to extended power projection to protect Chinese interests in the "strategic frontiers" of space, cyberspace, and the far seas. Understanding the new strategic roles of the SSF is essential to understanding how the PLA plans to fight and win informationized wars and how it will conduct information operations.