drdc aspects of sw06 – 2007 workshop
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Defence Research andDevelopment Canada
Recherche et développementpour la défense Canada Canada
DRDC Aspects of SW06 – 2007 Workshop
Sean Pecknold, Paul Hines, John Osler, Victor Young, and Dale Ellis
Maritime Environmental Awareness Group, DRDC Atlantic31 January, 2007
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Outline
• Data acquired
– Propagation loss
– Swath bathymetry
– FFCPt
– WBS and WARBL
• Data needed
• Anticipated output/collaborative efforts
• Other results
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Propagation loss
• Sources
– MSM
– Shipboard projector
• CWs, 200 Hz LFMs @ 1.2 and 3 kHz
• Receivers
– 2 GPS enabled SBs
– Moored UAT – 8 h/p between 22 m and 51 m depth – 24kHz sampling rate
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Propagation loss runs
38.9
39
39.1
39.2
39.3
39.4
-73.40 -73.30 -73.20 -73.10 -73.00 -72.90 -72.80 -72.70WBS (bottom)
Current moorings
New ADCP
cHIRPS
BBNs
Mooring lines
UATdep
FFCPT drops
sonobuoys
BBNs
ADCP
39.01.176N 73.03.276W
39.07.170N 73.16.638W
39.13.182N 72.54.462W
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Local measurements
Next Figure
2000 m
Reson 8125
• 455 kHz, 120 metre range
• 240 cross-track beams (0.5º)
• 1º along-track beam width
• 6 mm depth resolution
• DGPS, Gyro, pitch-roll-heave
• Pole mount on Quest
Hull mounted EdgeTech X-Star Chirp Profiler (2-16 kHz)
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
XSV Aug 1XBT Aug 1BBN Targets
Multiple drop FFCPT transectsseabed and water column measurements
0
10
20
30
40
50
60
70
80
1470 1480 1490 1500 1510 1520 1530
Sound speed (m/s)
Dep
th (
m)
.
CTD 2
CTD 3
CTD 4
CTD 5
CTD 6
CTD 7
CTD 8
CTD 9
CTD 10
CTD 11
CTD 12
CTD 13
CTD 14
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Initial scattering results from SW06
SW06 Energy Time Series – in process of calibration
Strataform ScatteringStrength Result
Hines et al., (2005)
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Wide Angle Reflection and Bottom Loss
• Bottom loss is the angle-fitted source level, calculated from direct arrival, minus received level minus theoretical transmission loss from a perfectly reflecting bottom (technique of Holland and Osler, 2000).
BL = SL - RL - TL
RECEIVER
DIRECT SOURCE
BOTTOM REFLECTED
Range
Time
1-12 kHz source
FFCPt1
FFCPt2
WBS July 24
WBS July 25
sonobuoys
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Data needed
• Sensor data from moorings (23 July – 2 August)
• Shipboard met data, CTDs/XBTs (available on DVD)
• Other acoustic data from 25 July – 2 August; ambient noise and propagation (available from WHOI)
• MSM source levels
• Sediment acoustic properties
– Chirp runs along propagation paths/WBS area (Turgut)
– Sediment mapping (Miller)
• Roughness measurements (IMP) in APL-UW area (Tang)
• Core data from FFCPt drop areas for comparison
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Anticipated output/collaborative efforts
• Scattering strengths and roughness, with Tang
• Analysis of WARBL data for bottom loss at varying angles and comparison w. Dahl
• Comparison of FFCPt measurements to inversion results (Chapman and others)
• Propagation sensitivity to oceanographic and geoacoustic parameters, with Dosso (UVic)
• Improvement of model predictions based on REA – 2007 Maritime Acoustic Symposium (CFMWC/METOc)
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
Other results
• Successful REA operation with reachback to DRDC
• Auralization data from BBN targets
• In-air vs. in-water sound levels for Convair flyover
• Ship noise levels
Defence R&D Canada – Atlantic • R & D pour la défense Canada – Atlantique
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