UNDERWATER GLIDERS

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UNDERWATER GLIDERS
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CONTENTS

• Introduction
• Topics dealt with
• Underwater gliders
• Working of an underwater glider
• Applications
• Objective of the experiment
• Glider operations
• Future developments and applications at the
  Institute Of Ocean Technology
• ASMT
• Laboratory scale glider
• Conclusion
• Thank you

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INTRODUCTION

• Sampling of oceans has traditionally been
  conducted from ships.
• HMS challenger(1872-1876).
• Took an awesome period of 23yrs.to compile the
  results.
• Emergence of alternative technologies
• Has brought us a long way from the CHALLENGER
  CRUISE.

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TOPICS DEALT WITH

• AUVs ( Autonomous underwater vehicles)
• AOSN-2 field expt in Monterey bay, California.
• Current efforts to develop a laboratory scale
  glider.

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Underwater gliders

• Represent a rapidly maturing technology
• Large cost saving potential

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Working of an Underwater Glider

• Buoyancy engine to change their weight in water.
• Generation of hydrodynamic lift and drag forces
• Closed loop control of attitude and depth-
  performed by an on-board computer that executes a
  pre-programmed mission while submerged

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• A receiver to compare the position with the
  desired position from the mission plan
• Position error used to compute the average
  current flow encountered which is used to
  correct the dive parameters for the next dive
  cycle.
• Communication at the surface using an IRIDIUM
  satellite connection.

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• Antennaes are integrated into the gliders
• For a SLOCUM glider antennae and receiver are
  embedded within the rudder assembly.
• Glider collects data from their scientific
  sensors
• Besides CTD sensors, they even carry PAR sensors
• and Fluorometers

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APPLICATIONS

• Autonomous Ocean Sampling Network 2-Monterey Bay
  2003
• Conducted during the summer of 2003 in Monterey
  Bay, California
• Bay was chosen for its accessibility, resident
  research institutions with on site hardware
  (ships, airplanes, AUVs) and its interesting
  bathymetry.

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• A certain drawback due to additional sensors as
  well as frequent communication and shallow dives
  is
• Increase in power consumption thereby a reduction
  in mission length.

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OBJECTIVE OF THE EXPERIMENT

• To demonstrate the feasibility of an integrated
  ocean observation ,modeling and prediction system.

• This expt differs from the previous efforts
  because of its high degree of system integration

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GLIDER OPERATIONS

• Two types of gliders were available SPRAY
  gliders SLOCUM gliders
• Prior to the expt all gliders were shipped to the
  MBARI in Moss landing, California.
• Sensor data were closely monitored during the
  course of the experiment.
• Undue advantage of the different depth
  capabilities of gliders were taken

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• .communication to and from the gliders using
  IRIDIUM satellite.
• Due to more frequent inflections and higher
  sensor load SLOCUM gliders were recovered during
  the course of the experiment.
• After recovery ,gliders battery packs were
  replaced system re-ballasted, checked out and
  readied for deployment.
• A real time operational display was made
  available at the control center at MBARI.

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• The display was improved during the course of the
  expt. (display was automated)
• FINDINGS
• Gliders sometimes advanced marginally over the
  course of some several hours
• Far above its theoretical limits
• This phenomenon was observed 3-4 times

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UNDERWATER GLIDERS

• The performance of several multi-vehicle expts
  shows the potential for added value by using
  coordinated control strategies
• New tools are under development that allow for
  improved planning and monitoring of the
  observational assets which will provide a higher
  degree of autonomy during future deployments.

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FUTURE DEVELOPMENTS AND APPLICATIONS AT
THEINSTITUTEOF OCEAN TECHNOLOGY

• Newfoundland Ocean Observation, modeling and
  prediction facility (NOOMPF)
• A Team of researchers from NRC-IOT, Memorial
  University of Newfoundland (MUN) and the
  department of fisheries and oceans (DFO)
• Currently developing a plan to implement a
  regional coupled ocean observation and modeling
  system in Newfoundland (NOOMPF)
• Possible sites Conception Bay, Trinity Bay and
  Placentia Bay.

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Goal is to develop a capability for automated
coupled oceanobservation and model predictions
on a regional scale.
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• Enhance our ability to predict and manage the
  ocean
• Observations will be based on a suite of
  different sampling platforms
• Conventional observations data available from
  satellites autonomous mobile platforms.
• NRC-IOT s role is to develop the control and
  communication infrastructure necessary to direct
  and monitor the observational assets.

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ASMT

• WILL SERVE AS THE MAIN CONTROL AND MONITORIG
  SURFACE.

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LABORATORY SCALE GLIDER

• NRC-IOT is considering developing a lab. Scale
  glider
• Purpose of a lab. Scale glider is to conduct
  expts. for hydrodynamic testing and control and
  to provide a test bed for new actuation and flow
  sensing technologies
• Design alternatives and constraints of a buoyancy
  engine
• Vertical motion tests
• After completion of design of buoyancy engine
  hydrodynamic design of the glider

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CONCLUSION

• Autonomous underwater vehicles, and in particular
  autonomous underwater gliders represent a
  maturing technology with a large cost saving
  potential over current ocean sampling
  technologies for sustained (month at a time) real
  time measurements.

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THANK YOU.