310 likes | 343 Views
Harbor Acoustic Monitoring Systems. John Allen University of Hawaii Department of Mechanical Engineering Honolulu, HI 96822 January 10, 2011. Harbor Environment . Threats - Swimmers, Divers, AUVs, Small Vessels System - Robust, Cost Effective, Portable. Research Approach
E N D
Harbor Acoustic Monitoring Systems • John Allen • University of Hawaii • Department of Mechanical Engineering • Honolulu, HI 96822 • January 10, 2011
Harbor Environment • Threats - Swimmers, Divers, AUVs, Small Vessels • System - Robust, Cost Effective,Portable
Research Approach Problem: A wide variety of unknown, quiet targets in different cluttered, shallow water environments Approach: Acoustic Array – Provides Beam-Forming Capabilities, Detection and Tracking (Passive, Active Acoustics) Snapping Shrimp
Deployment: Kilo-Nalu Ocean Observatory Site – 12 meter Portable Arrays -24 Channels,300 Hz-50 KHz bandwidth, 24 bit acquisition, Autonomous, 120 lbs
Deployment Small Surface Vessel, Three Divers (Portability) Leveraged Experiment – Vector Sensor Array (UCSD/Scripps), 24 Element Array (Portland State), 24 Element (UH)
Array Configuration • Horizontal Array – Bottom, Clutter Reduction • Vertical Array – Surface, Discrimination in Depth • Synchronized Data Collection cwater Receivers Target Water Sediment Sub-bottom
Horizontal Array Horizontal Array
Vertical -Modeled Data Vertical -Measured Data Direct path Surface echo Bottom echo Source Late arriving echoes are broken up in data likely due to scattering VLA Vertical Array: Performing Properly
Modeled Data Horizontal- Measured Data Direct path +bottom echo Surface + Surfacebottom echoes Time delay across array: robust measure of the source direction Source HLA Horizontal Array: Performing Properly
Acoustic Array Processing Conventional Beamforming (Horizontal Array) Extensions: Adaptive and Near Field Beamforming Combined Horizontal and Vertical Arrays
Small boat engine Engine cuts out Zoomed X-axis
Wide-band Beamforming boat REMUS
Narrow-band Beamforming
SCUBA Divers Channel 10 of Array
Channel 10 of Array Same spectrogram +14 dB white noise
Vector Sensor Array Breaking Wave Noise, Bubble Entrainment
DHS Educational Activities • Two High School Interns – Summer 2010 • Three Undergraduate Students – 2010-11 (Two Native Hawaiian) • Graduate Student -MSME (Tyler Hee-Wai, ~Spring 2012) Undergraduate Acoustic Laboratory – DHS Topic -Acoustic Characterization of RC Submarines and Boats ME 474 – Fundamentals of Acoustics (Spring 2011) Acoustical Society of America – Spring 2011 Meeting, Seattle, WA
Conclusions and On-Going Research • Deployment: Arrays (“L”,Vertical-Horizontal), Vector Sensor • Acoustic Beamforming (Conventional)– REMUS, Divers, Ships (Passive Detection and Tracking) • Combined Vertical and Horizontal Arrays • Adaptive and Near Field Beamforming • Acoustic Sources, Integration with IR Surface Detection Acknowledgements: CIMES/DHS Martin Siderius (Portland State University), Grant Deane, James Uyloan (UCSD/Scripps) Joint Array Field Deployment Jan Prins (UH Aquatic Research Lab) Kilo Nalu Observatory, University of Hawaii-Manoa IR Surface Diver Detection
Future Directions Two Array Signal Processing Acoustic Recorders – Linked Modems (Post-Doc – Alec Duncan) Collaborative DHS International Proposal Australia -2011
~25 kHz Acoustic Comms Design Freq of array(300-1500 Hz)