Presentation given at the 2014 INMARTECH Meeting in Corvallis, Oregon in November, 2014.
Highlights:
Typical Sources of Acoustic Noise:
- Machinery Noise
- Sonar Interference
- Electronic Noise
- Propeller Cavitation (Hub and Tip Vortex)
- Hydrodynamic Flow Noise
- Appendage Cavitation
- Transients
- Bubble Sweepdown
Why Acoustic Noise is Important:
- Excessive ship-related noise can degrade sonar performance
- Degraded sonar performance will impact quality of acquired sonar data
- Reduced sonar performance will increase time required on station to conduct survey operations
What is Quiet?
- Typically 49 dB is used as a quiet ship threshold for 12 kHz systems
- For shallower systems that operate at higher frequencies, the threshold is in the lower 40 dB range
- However, with more information being pulled out of sonar data (water column), the better the signal-to-noise, the better the data quality