a moos-based auv for magnetic signature...
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A MOOS-based AUV forMagnetic Signature Assessment
Presented by Dave Billin
University of Idaho, Moscow IdahoAt MOOS-DAWG July 21, 2011
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Team Members
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Motivation
Influence mines and torpedoes can be triggered by a ship's magnetic field.Vessel's magnetic field may be canceled or reduced using • Deperming (degaussing)• Active cancellation
Pictured:USS RAMAGE (DDG-61) at Lambert's Point deperming facility near Norfolk, VA(Robert J. Sitar 10-23-1995)
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Motivation
Challenges:Optimal field cancellation requires precise measurement.Vessel's magnetic “signature” is unique.Magnetic signature changes during travel.
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Motivation
Objective:A forward-deployable system for magnetic signature assessment
Scalable to vessel sizeMeasurement precision of 100 nTMeasurement range of 100,000 nT
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Strategy
Magnetic signature measurement using multiple AUV's
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U of I AUV
Portable, deployableSmall magnetic footprintLow Cost (approx. $19k USD)Collaborative autonomy
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AUV Instrumentation
Billingsly Aerospace triaxial fluxgate magnetometer6-channel, 200 kHz data acquisition systemGarmin GPS-18xRevolution digital compassArchangel IMU3900 MHz radio modemWHOI Acoustic Micro-modem
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AUV Measurement Pattern
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Measurement Results
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Right [m]
For
war
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Deviation from mean of 53540 [nT]Calibrated PPEkf
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Multi-AUV measurementof 448 Am2 source anchored at fixed position
Single-AUV measurementof 135 Am2 source attached to bow of a moving ship
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MOOS-based AUV Design
Legacy U of I AUVGeneration 1 MOOS AUVCurrent work (Generation 2)
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Gen.1 MOOS-based AUV
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Gen.2 Design Objectives
Reduce power consumptionEliminate redundancies and bottlenecksHardware extensibilityStreamlined integration
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Gen.2 MOOS AUV Design
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Gumstix Integration
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MOOS Software
MOOS InstrumentsFSD MOOS interfaceNavigation, support applicationsIvP Behaviors
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MOOS Instruments
iArchangelIMUiWhoiMicroModemiRevolutionCompassiYellowSubDAQiRadioModem
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Front-side controller
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libYellowSubNav
U of I AUV core navigation libraryEKF Base class and derived classes• VehicleEKF, SyncVehicleEKF • ShipEKF
Acoustic Navigation classes• LBLPositionEstimator, LBLBeacon
Unit tests for module verification
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pVehicleEKF
Estimates current AUV position Combines:
GPS, compass, acoustic navigation, IMU, pressure sensor, prop RPM
Publishes:Local Grid (East, North) locationSpeedBias-compensated yaw
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pAcousticCommsAgent
Implements acoustic TDMA controlUtilizes GPS time synchronization of AUV'sText file based configuration of time slotsActive time slot may conditionally publish to one (or more) MOOSDB variablesRuntime re-configurable
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pMissionMonitor
Monitors vehicle safety conditionsMonitor target objects “enforce” logical conditions imposed on MOOSDB variables.If monitor conditions evaluate “FALSE”, one or more variables are published to the MOOSDB.Operational even when pHelmIvP is suspendedConfiguration via text file using Behavior-like syntaxRuntime re-configurable
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IvP Behaviors
BHV_ReverseDiveImplements 3-stage sequence enabling the positively-buoyant U of I AUV to dive aft-first.
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IvP Behaviors
BHV_YellowSubReBalanceProduces objective function in speed, pitch domainsUsed when U of I AUV travels at water surface.
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Acknowledgements
Office of Naval Research
Magnetic Signature Assessment System using Autonomous Underwater Vehicles (AUVs)Phase 1 (N00014-08-1-0779)Phase 2 (N00014-09-1-0711)Phase 3 (N00014-10-1-0883)
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Acknowledgements
“Autonomous Underwater Vehicle Navigation using Moving Baseline on a Target Ship”Amanda Folk, Benjamin Armstrong, Eric Wolbrecht, Håvard Fjær Grip, Michael Anderson, and Dean Edwards
Proceedings, IEEE OCEANS 2010 Seattle, WA
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University of Idaho
TitleTeam MembersMotivation - Sea mines, torpedoesMotivation - ChallengesMotivation - ObjectiveStrategyU of I AUVAUV InstrumentationAUV Measurement PatternMeasurement ResultsMOOS-based AUV DesignGeneration 1 MOOS-based AUVGeneration 2 Design ObjectivesGeneration 2 MOOS AUV DesignGumstix Peripheral IntegrationMOOS SoftwareMOOS InstrumentsFront-side controllerAUV Navigation LibrarypVehicleEKFpAcousticCommsAgentpMissionMonitorIvP Behaviors - Reverse DiveIvP Behaviors - Re-balanceAcknowledgementsNavigation AcknowledgementsEnd Titles