Acoustic Systems for Classifying Underwater Ordnance
The SERDP MR Program Area is supporting a number of projects exploring how best to detect and classify submerged munitions using acoustic methods. Preliminary results have shown that acoustic methods can become a very useful tool to identify offshore munitions.
Mr. Daniel Brown is leading SERDP project ( MR-2545) at The Pennsylvania State University to design, build and demonstrate a sonar system that can produce a novel form of three-dimensional synthetic aperture sonar (SAS) imagery. Mounted on a shallow draft vessel, this system will allow the user to find proud and buried objects of interest in water less than 5 meters deep, the depth range where underwater munitions are potentially easily accessible by civilian beachgoers.
When acoustic energy strikes a munition, it generates both a characteristic reflection and a characteristic resonance. These unique responses can be the acoustic “fingerprint” needed to discriminate between submerged munitions and other subsea clutter. Dr. Steven Kargl of the University of Washington is leading a SERDP project ( MR-2505) to quantify how the environment and the scattering geometry within that environment can alter the acoustic response of an object. The research extends previous SERDP efforts ( MR-1665 and MR-2231) and will also investigate fusing low frequency (i.e., < 50 kHz) sonar techniques with high frequency imaging sonar (i.e., 100-300 kHz) to enhance detection and classification. More information can be viewed at the Webinar.
Dr. Mahmood Azimi-Sadjadi of Colorado State University worked with other SERDP researchers to develop and test a multichannel broadband coherence detection method for low frequency Synthetic Aperture Sonar systems. ( MR-2416) Additional collaboration is planned to adapt the system for differing environmental characteristics, such as partial burial of the munition, and will use an incremental training technique for classification.
A physics-based technique ( MR-2649) to isolate particular components of a predicted sonar return is being led by Dr. Lane Owsley at the University of Washington. This will combine research in basic physics and wave-direction limitations with the coupling-region approaches used in earlier research. His team will test the robustness of these techniques during separately funded sea trials.
Summaries of the research and demonstration projects discussed above can be found at the SERDP and ESTCP website. In addition, all reports originating from these efforts are available at the project web pages. Please contact the Munitions Response Program Manager if you have further questions about this research area