Inversion for geoacoustic model parameters in complex shallow water environments
Abstract
"The long term objectives of this research project are to investigate simple and effective experimental methods and inversion techniques that provide estimates of parameters of geoacoustic models of the ocean bottom and their associated uncertainties. The focus is on development of model-based inversion techniques that are robust to limited knowledge of the ocean environment, and on understanding the limitations of their use. The wider context of this research is related to development of improved sonar system performance aided by greater understanding of the physics of the interaction of sound with the ocean bottom. The project investigates three aspects of model based geoacoustic inversion methods. The first is development of models of the waveform of a small explosive charge for use as a sound source in experiments to probe the ocean bottom to acquire data for geoacoustic inversion. The second aspect is related to model mismatch. Mismatch in the form of the geoacoustic model used in an inversion introduces a distortion in the estimated model parameter values. The distorted values can lead to erroneous inferences about the acoustic properties of the ocean bottom, in particular the attenuation of sound in marine sediment and its dependence on sound frequency. The second aspect is development of methods to extract the undistorted model parameter values from the estimated values in the inversion. The third aspect is to develop metrics for comparison of inversion performance of different inversion methods. The focus is on benchmarking inversions based on experimental data. Previous work completed an assessment of methods using data from the ONR Shallow Water 06 experiment. The new work extends the benchmarking to data from the Sea Bed Characterization experiment.The project will use data from previous ONR experiments. New knowledge from this project will: (1) provideconfidence in waveform modeling of sound sources used in geoacoustic inversion; (2) provide new information about the frequency dependence of sound attenuation in marine sediment; and (3) provide a means to assess the inversion performance of present day geoacoustic inversion methods."
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 15, 2021
- Source ID
- N000142112209
Entities
People
- Ross Chapman
Organizations
- Office of Naval Research
- United States Navy
- University of Victoria