Mode estimation and geoacoustic inversion in shallow water
Abstract
The ONR has organized the Seabed Characterization Experiment (SBCEX) in March 2017. This experiment took place on the New England Mud patch, which is known for complex geology and oceanography. In particular, the first layer of the seabed is mainly composed of fine-grained sediments (i.e. mud). Because acoustic propagation is poorly understood into fine-grained sediments, it is important to understand the physics driving the seabed propagation (direct problem), to estimate the seabed properties and quantify uncertainties (inverse problem), and to assess performances of the proposed methods. The proposed project focuses on low frequencies (0-500 Hz) where propagation is onveniently described by modal theory. In this context, the acoustic field is interpreted as the sum of several modal components, with each mode propagating dispersivelythrough an ocean waveguide. The main objectives of the projects are 1) developing new signal processing methods that would benefit the whole SBCEX group and 2) estimating the seabed properties, quantifying the uncertainty,and assessing performance of the proposed methods. More specifically, the project will develop signal processing methods allowing mode estimation when the source is an impulsive signal, a frequency modulated chirp or a continuous narrowband tone (task 1). Estimated modes will subsequently be used to infer the mud geoacoustic parameters (task 2), and uncertainties will be quantified using Bayesian methodology. Inversion results will be compared in order to make recommendation for future low-frequency inversion experiments (task 3). Last but not least, the opportunities provided by novel autonomous marine platforms (AUVs, gliders) will be studied (task 4).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 04, 2018
- Source ID
- N000141812783
Entities
People
- Julien Bonnel
Organizations
- Office of Naval Research
- United States Navy
- Woods Hole Oceanographic Institution