COMPREHENSIVE DATA ANALYSIS AND MODELING OF MID AND LOW FREQUENCY SONAR IN COASTAL AND BASIN-SCALE ENVIRONMENTS
Abstract
This work seeks to determine the primary effects of oceanographic processes on both active and passive sonar target detections. This work has relevance to the Navy in that it seeks to advance understanding in the variability in signal excess, precisely our ability to distinguish targets of interest amidst clutter and propagation effects that produce false detections. To achieve this, synthesis of acoustic and oceanographic models is necessary, as acoustic fields are inherently effected by the spatial and temporal variability of the environment. Validation of this modeling effort is possible with data currently available to address two specific goals: (1) predict active mid-frequency sonar performance on the continental shelf; and (2) improve passive detection, localization and classification of low-frequency sound sources propagating across ocean basins. To accomplish these goals, a comprehensive examination of acoustic data in terms of variability in the forward field, backscatter from targets and target like bathymetric features, signal coherence (as effected by a rough sea surface), and properties of bi-static reverberation is necessary. Datasets produced through ONR sponsored experiments that contain cotemporaneous oceanographic measurements allow for correlation of signal modulations to changes in the watercolumn. Concurrent data analysis with model development will both validate and establish the required detail to address the oceanographic processes effecting sonar performance, including tides, currents and weather events. This integrated acoustic and oceanographic model is a tool to predict active sonar performance, test processing algorithms, and design future experiments. To extend the model capability in a practical sense to address long-range propagation, a nested modeling approach will be implemented through continuity of acoustic energy flux. This approach allows for both ray-based and full-wave models to be meshed into one simulation, with the preferred model operating in the regime where its resolution is sufficient to optimize computational speed. In addition to data from ONR funded experiments, data from the Comprehensive Test Ban Treaty (CTBT) hydroacoustic network will be used to verify the accuracy of this nested modeling approach. Analysis will draw from examples of acoustic events including explosions, ship-noise, objects impacting upon the ocean surface and active sources recorded over the past 15 years of CTBT operation. 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
- Jul 10, 2018
- Source ID
- N000141812219
Entities
People
- David Dall Osto
Organizations
- Office of Naval Research
- United States Navy
- University of Washington