MAC_Canadian_Hydrographic_Conference_2012_Gates
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Transcript MAC_Canadian_Hydrographic_Conference_2012_Gates
Optimizing
Multibeam Data Quality
Across the Fleet
TIM GATES (Gates Acoustic Services)
VICKI FERRINI (LDEO)
JONATHAN BEAUDOIN (CCOM-UNH)
PAUL JOHNSON (CCOM-UNH)
JOHN HUGHES CLARKE (OMG-UNB)
Background
MB workshop at NSF June 2010 in response to fleet-wide
issues with multibeam performance
Goals:
Discuss operation of the sonars
Identify common threads in documented problems
Get advice from domain experts and other MB users
Outcomes:
Identified several specific operational and technical
issues, some poorly understood, impacting multibeam
data quality
Identified a strong need to coordinate operational and
technical efforts across the fleet
UNOLS FLEET
SCRIPPS
MELVILLE
ROGER REVELLE
WHOI
KNORR
ATLANTIS
UW – THOMAS THOMPSON
UH – KILO MOANA
LDEO – MARCUS LANGSETH
Multibeam Advisory Committee
(MAC)
Fleet-wide Approach
Facilitate Communication
Community of Stakeholders
Technical Resources
Technical Teams
Shipboard Acceptance
Acoustic Noise
Quality Assurance
Best Practices
Transition into a UNOLS Committee
MAC:
Committee Planning
In-person meeting once per year
Supplement with Telecon/Web Conferencing
Review Technical Team activities & products
Prioritize ship visits
Address practical implementation of best
practices
Discuss concerns/issues from Operators
Ensure MAC is providing necessary resources
Overview of Technical Teams
ANT and SAT: help optimize
ship and system performance
QAT: help optimize the way
data is acquired
MAC:
Acoustic Noise Team
Goal: Perform acoustic noise tests to assess and
potentially improve sensor efficiency (coverage)
and data quality
Establish baseline noise levels
Help populate an archive of historical data on noise
properties of each vessel to aid in monitoring over
sensor lifetime
Anticipate 2 ship visits per year
MAC:
Shipboard Acceptance Team
Goal: Ensure all hull-mounted multibeam systems
are installed, calibrated, and configured properly
and consistently
Participate in Sea Acceptance Trials for new and/or
poorly understood existing installations
Anticipate 2 ship visits per year
MAC:
Quality Assurance Team
Goal: Ensure multibeam sonar systems are operated in
a consistent manner that maximizes data accuracy,
precision, and scientific utility
Develop and disseminate best practice documentation
Develop and deploy tools and procedures to optimize
data quality during acquisition
Technical Teams in Action
Acoustic Noise Testing
It is planned to acquire baseline acoustic signatures from
each UNOLS vessel
Signatures will be acquired from test hydrophones and
internal sonar noise routines
Results of acoustic testing will determine:
Propeller cavitation
Hydrodynamic flow noise
Machinery contributions
Bubble sweepdown impacts
Data will be archived for future comparisons and trending of
noise backgrounds
Acoustic Testing
R/V MELVILLE was tested in January
R/V KILO MOANA is scheduled for testing in June
Previous tests (prior to the MAC) have been
accomplished on:
R/V REVELLE
R/V KILO MOANA
R/V MARCUS LANGSETH
R/V ATLANTIS
Benefits of Acoustic Testing
Identify acoustic deficiencies that limit full sonar
performance
Provide corrective actions for problem areas
Develop “quiet” machinery line-ups for best
performance
Develop operational guidance to mitigate acoustic noise
issues
Recent Acoustic Findings
ATLANTIS – has a cavitating gondola
LANGSETH – quieter at 9 knots than 0 to 8 knots due to
controllable pitch propellers
KILO MOANA – Above 9 knots data is controlled by diesel
engines which limit sonar performance
MELVILLE – anti-roll system limits sonar performance
during roll cycles
REVELLE – bubble sweepdown transients limit sonar
performance in higher sea states
QAT: R/V Kilo Moana
Ship Geometry Verification
Verification of current system geometry by
establishing “chain of custody” by reviewing:
Ship drawings
Blom survey (2005): initial survey of mapping
offsets
Applanix site visit reports (2006 & 2008)
IMTEC survey (2012): survey of new EM710 installation
Independently established linear and
offsets from above documentation and
reports of configuration changes
Found and corrected errors in current
configuration:
Primary GPS location in POS/MV configuration
Pitch offset in EM710 configuration
system
angular
verbal
QAT: R/V Kilo Moana
Assessment of Documentation
Found hardcopy and softcopy operators manuals for
EM122 and EM710
Found out-dated “cookbooks” for EM1002/EM120 on
technician’s wiki
Newer “cookbooks” generated for EM710/EM122 and
focused on SIS
How to backup all system settings
How to uninstall SIS and remove the database
How to re-install SIS and import system settings to get
system back to last known good configuration
QAT: R/V Kilo Moana
Software Deployment: SVP Editor
Graphical display and editing of XBT
data: can interact with data to remove
outliers
Implements proposed best-practices:
Augment with database salinity profile
(World Ocean Atlas 2009)
Streamlined processing allows
for delivery of cast to SIS for
immediate application
Embed measured surface sound speed in
upper layer
Use database for vertical extension of cast
Server mode: automatically
delivers World Ocean Atlas sound
speed profiles to SIS while in
transit
SIS
QAT: R/V Kilo Moana
Software Deployment: BIST Logger
python script to log BIST output over network via UDP
Includes vessel position/speed and engine RPMs; reduces
requirement to embed “metadata” in filenames, e.g.
starboard_engine_200_rpm_5kts_045_heading_BIST.txt
Enables acquisition of rich acoustic noise data sets
with minimal effort
Results from acquisition of 294 BIST
noise spectrum measurements over
38 minute time span with gradual
increases in ship speed. Achieved
with one operator repeatedly
launching the appropriate BIST test;
all data and metadata were logged
automatically. Plot generated with
Matlab.
We value your input!
You can benefit: Reports and tools will be
available publicly online
You can contribute also:
Best practice documentation
Ideas
Multibeam Horror/Success stories
http://mac.unols.org/