MAC_Canadian_Hydrographic_Conference_2012_Gates

Report
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/

similar documents