INVESTIGATIONS INTO STABILITY OF THE ACOUSTIC INTENSITY VECTOR FIELD AND APPLICATION TO NAVAL SONAR
Abstract
"This work seeks to improve on the understanding and measurement of acoustic intensity in the ocean. Vectorsensor measurements made prior-to and during this effort underpin the development of a three-dimensional (3D) intensity model. Data analysis is a crucial piece of the work, both in terms of identifying shortfalls in modeling and developing applications such as environmental perception and inversion. Model development builds on a nested model approach, merging efficient analytic solutions with numerical solutions used wherever complex bathymetry or oceanography require it through maintaining continuity of the intensity vector at the solution domains. Integration of time-dependent ocean state estimates as environmental input to the model allows for study of the oceanographic processes effecting sonar performance, including tides, currents and weather events. This 3D vector intensity-based propagation model is relevant to the Navy, both for investigations into the causes of variability in signal excess and sonar performance prediction, while also being efficient enough to be included in autonomous platforms for environmental perception and awareness. In addition to the vector sensor datasets collected during ONR sponsored experiments, data streaming from 6 remote hydrophone stations of the International Monitoring System can be processed as vector intensity. This enables long term model validation with acoustic events including explosions, such as from ship shock trails, objects impacting upon the ocean surface, and active sources recorded on the network. In addition to the modeling and data analysis work, investigations will also include an assessment of emerging technologies that could greatly improve vector sensing capabilities. Ultra-low noise lightweight seismic accelerometers, which implement a force-feedback loop instead of passive measurement, have the potential to greatly expand the research space of vector sensors. Currently, vector sensors use passive transduction methods which limits the noise-floor of the system especially at low frequencies(< 20 Hz). Benchtop testing of a new generation of sensors will establish the potential of this newtechnology, and lay the ground work to create field ready systems that can enhance acoustic monitoring. Outcomes of this work will necessarily improve future naval capabilities for prediction of active and passive sonar performance in complicated and pertinent ocean environments. "
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 06, 2021
- Source ID
- N000142112228
Entities
People
- David Dall Osto
Organizations
- Office of Naval Research
- United States Navy
- University of Washington