Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 3 of 3
Full-Text Articles in Engineering
Head Waves In Ocean Acoustic Ambient Noise: Measurements And Modeling, Martin Siderius, Jie Li, Peter Gerstoft
Head Waves In Ocean Acoustic Ambient Noise: Measurements And Modeling, Martin Siderius, Jie Li, Peter Gerstoft
Electrical and Computer Engineering Faculty Publications and Presentations
Seismic interferometry recovers the Green’s function between two receivers by cross-correlating the field measured from sources that surround the receivers. In the seismic literature, it has been widely reported that this processing can produce artifacts in the Green’s function estimate called “spurious multiples” or the “virtual refracted wave.” The spurious multiples are attributed to the head wave and its multiples and travels in the seabed. The head wave phenomenon is shown to be observable from both controlled active sources and from ocean ambient noise and for both vertical and horizontal arrays. The processing used is a generalization of the passive …
Passive Bottom Reflection-Loss Estimation Using Ship Noise And A Vertical Line Array, Lanfranco Muzi, Martin Siderius, Christopher M. Verlinden
Passive Bottom Reflection-Loss Estimation Using Ship Noise And A Vertical Line Array, Lanfranco Muzi, Martin Siderius, Christopher M. Verlinden
Electrical and Computer Engineering Faculty Publications and Presentations
An existing technique for passive bottom-loss estimation from natural marine surface noise (generated by waves and wind) is adapted to use noise generated by ships. The original approach—based on beamforming of the noise field recorded by a vertical line array of hydrophones—is retained; however, additional processing is needed in order for the field generated by a passing ship to show features that are similar to those of the natural surface-noise field. A necessary requisite is that the ship position, relative to the array, varies over as wide a range of steering angles as possible, ideally passing directly over the array …
Eigenvector Pruning Method For High Resolution Beamforming, Jorge E. Quijano, Lisa M. Zurk
Eigenvector Pruning Method For High Resolution Beamforming, Jorge E. Quijano, Lisa M. Zurk
Electrical and Computer Engineering Faculty Publications and Presentations
This paper introduces an eigenvector pruning algorithm for the estimation of the signal-plus-interference eigenspace, required as a preliminary step to subspace beamforming. The proposed method considers large-aperture passive array configurations operating in environments with multiple maneuvering targets in background noise, in which the available data for estimation of sample covariances and eigenvectors are limited. Based on statistical properties of scalar products between deterministic and complex random vectors, this work defines a statistically justified threshold to identify target-related features embedded in the sample eigenvectors, leading to an estimator for the signal-bearing eigenspace. It is shown that data projection into this signal …