Related Experiment Video
Updated: Mar 29, 2026

Wideband Optical Detector of Ultrasound for Medical Imaging Applications
Published on: May 11, 2014
Simultaneous localization of multiple broadband non-impulsive acoustic sources in an ocean waveguide using the array
Zheng Gong1, Purnima Ratilal2, Nicholas C Makris1
1Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Abstract:
The array invariant method, previously derived for instantaneous range and bearing estimation of a single broadband impulsive source in a horizontally stratified ocean waveguide, can be generalized to simultaneously localize multiple uncorrelated broadband noise sources that are not necessarily impulsive in the time domain by introducing temporal pulse compression and an image processing technique similar to the Radon transform. This can be done by estimating the range and bearing of broadband non-impulsive sources from measured beam-time migration lines of modal arrivals along a horizontal array arising from differences in modal group velocity and modal polar angle for each propagating mode. The generalized array invariant approach is used to estimate the range of a vertical source array and vocalizing humpback whales over wide areas from measurements made by a towed horizontal receiver array during the Gulf of Maine 2006 Experiment. The localization results are shown to have roughly 12% root-mean-squared errors from Global Positioning System measured ground truth positions for controlled source transmissions and less than 10% discrepancy from those obtained independently via moving array triangulation for vocalizing humpbacks, respectively.
Related Concept Videos
Interference and Superposition of Waves
Interference occurs in mechanical waves, such as sound waves, waves on a string, and surface water waves. Mechanical waves correspond to the physical displacement of particles. Hence,...
Propagation of Waves
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
Echo
Imagine the sound is reflected back to the ears. Assuming that the source is very close to the human, the difference between hearing the two sounds—the emitted sound and the reflected sound—may be more than the minimum time for perceiving distinct sounds. If this is the case,...
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
Sound Waves: Interference
Linear Approximation in Frequency Domain
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear....

