AOS Seminar: Dr. Heechun Song


 
10/10/2019 - 4:00pm
Location: 
Spiess Hall 330
Event Description: 
Please join us all this Thursday at 4:00pm in Spiess Hall 330 for AOS Seminar. We are excited to be hearing from Dr. Heechun Song, as detailed below: 
 
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Dr. Heechun Song, SIO
"Source localization: matched field processing, waveguide/array invariant, and blind deconvolution"
Over the last four decades, a de facto approach to source localization in underwater acoustics has been matched-field processing (MFP). MFP matches the measured field at an array with replicas of the expected field for all possible source locations, requiring accurate knowledge of the environment and/or array geometry (e.g., array tilt). As a result, MFP is inherently sensitive to environmental mismatch and has been successful mostly at low frequencies below 1 kHz. In this talk, we propose a robust, physics-based approach that requires minimal/no environmental information, called the array invariant (AI). The AI based on the beam-time migration is built upon the elegant “waveguide invariant theory that characterizes the dispersion characteristics of ocean waveguides. In addition, the AI has the capability of self-calibrating the vertical array tilt. While AI requires either a broadband impulsive source (e.g., an explosive) or Green’s function, we can extract the Green’s functions from unknown sources (e.g., ships) using a ray-based blind deconvolution. The cascade of blind deconvolution and AI has been successfully demonstrated to localize and track a surface ship using either a vertical or horizontal array in shallow water. Further, the approach has been extended to localize a weak submerged target in the presence of surface ship. MFP and AI are compared, and multiple-ship localization also is discussed.     
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There will be snacks, so please remember to bring your own dishes. We look forward to seeing you there!
For more information on this event, contact: 
Allison Ho
Event Calendar: 
Applied Ocean Science