Underwater Vehicles

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Overview of FAU Autonomous Underwater Vehicles : 

Overview of FAU Autonomous Underwater Vehicles Edgar An Ocean Engineering, Florida Atlantic University Collaborators: NPS, VPI, MIT, WHOI, USF, UM, SOC U.K. Funding Source: ONR

What are AUVs?: 

What are AUVs? Definition Untethered, unmanned underwater vehicles Constraints Power and data must be self-contained Missions must be executed onboard Control, navigation, guidance, planning, communication Handle what-if situations Capability determines the power and size requirements Applications Oceanographic sampling Current profiling Under ice mapping Bio nutrient / pH / salinity / temperature mapping Military Mine counter-measures Industry Oil & gas exploration survey

Limitations with Existing Oceanographic Surveys: 

Limitations with Existing Oceanographic Surveys Observational Uncertainty Most physical processes tend to vary in both temporal and spatial co-ordinates Conventional moored/bottom instrumentations are single-point time series measurements Cannot capture spatial variability (spatial aliasing) Added Error due to Platform Stability Shipboard measurements are contaminated by ship motion Towed measurements are affected by tethers Ship motion increases as sea states get worse Ship motion can be improved using a large ship at expense of operational daily cost Adverse weather data are hard to capture E.g. cold fronts, tropical storms, hurricanes Ship motion and ship safety

Arctic Research: 

Goal Measure ocean warming and global climate (CTD, ocean currents) Map Arctic ocean floor Analyze ancient plate boundaries Measure bio nutrients Typical Equipment 3D bathymetric side-scan sonar Sub-bottom profiler (200 meters below sea floor) Top-sounder high frequency sonar (measure ice draft) Existing Methods Ice breakers, on aircraft, ice camps, nuclear submarine (USS Hawkbill SCICEX-99) Challenges Navigation (no magnetic & gyrocompass) Narrow channel for maneuvering Variations in water density and temperature affect platform buoyancy Long duration and large coverage area Freezing temperature Current Estimates Arctic ice mass 20% , near surface water temperature 1 , ocean salinity 1%  Arctic Research

Hydro-Carbon Exploration: 

Hydro-Carbon Exploration Deeper Water Oil/Gas Exploration Challenges in using ROV or towed survey systems position accuracy speed (50% reduction) Cost (30 to 60% saving, typical deep water survey about $1M) Potential AUV Capabilities Increase the survey speed from 1 to 4 knots Reduce survey time during turns, run-in and run-out of vessels Existing Survey Activities Fugro Geosciences with International Submarine Engineering Racal Survey with Bluefin Robotics De Beers Marine with Maridan C&C Technologies & BP Amoco with Kongsberg Simrad Shell The use of AUVs could save the company $100 million E&P costs over the next 5 years

AUV Program Objective: 

AUV Program Objective Mission develop autonomous (unmanned and un-tethered) mobile sensor platforms and strategies to support multiple in-situ sensor payloads for cost-effective search and survey in coastal waters Platforms Ocean Explorer Morpheus Applications autonomous oceanographic sampling networks, mine reconnaissance, rapid environment assessment, ground truthing of satellite data

Ocean Explorer Sketch: 

Ocean Explorer Sketch

Ocean Explorer (OEX): 

Ocean Explorer (OEX) Mechanical Fiberglass hull, aluminum Pressure Vessels and parallel mid-body insert Ratings Depth: 300 meters, Speed: 3-5 knots, Length: variable 7 - 10 ft. Endurance: 4 - 12 hours (depending on payload and battery configuration) Range: 12 - 36 nautical miles Communications: Acoustic Modem, RF Ethernet Navigation: Doppler sonar, DGPS, dead reckoning, acoustic positioning system Modular Nose Section Dedicated to payload sensors and transducers Field re-configurable Batteries: NiCad

Existing Payloads: 

Existing Payloads CTD, ADCP/DVL (FAU Standard) HF Side Scan & Video (FAU) LF Side Scan & Sub-bottom (FAU) Turbulence (FAU) Passive Acoustic Imager (FAU) Forward Look Imaging Sonar (FAU) Laser Line Scan (USF) Laser Line Scan (Scripps) Bathymetric Side Scan Sonar (HBOI) Dual Light Sheet Particle Counter (USF) High Res Particle Imager (USF) Nutrient Sensor (USF) Trace Element Analyzer (USF) Organic Fluorescence (USF) 4 D Current (FAU, U of Miami) Bubble Cloud Sonar (FAU) (Maddog, Mini) Multi-beam Fish Finder Obstacle Avoidance Sonar Bottom Classification Albedo Package (USF) (OVII) Multi-Beam 3D Sonar (FAU)

Morpheus Diagrams REA Configuration: 

Morpheus Diagrams REA Configuration Popup DGPS and RF Modem Antennae Fairing CTD, DVL, and Drop Weight Fairing Batteries Main Computer DVL Electronics Popup DGPS and RF Modem Antennae 12 inches Tracking Transducer Acoustic Modem Navigation Module Fin Module Thruster

Morpheus AUV Configuration: 

Morpheus AUV Configuration Construction: Injection Molded Plastic Pressure Vessel Hull Modules, External Faired Cabling Ultra Modular Construction: 12” long interchangeable sections, optional 24” long double section Rapid “in the Field Reconfiguration” Wet nose, Optional Mid-body Ultem Opaque or Lexan Transparent Wet Sections Standard Sensors: CTD, DVL, Compass, 3 Axis Gyro + 3 Axis Acceleration, DGPS (popup antenna) Control Internal Buses: LonTalk + 10BT Ethernet Independent Top/Bottom Rudder, Right/Left Stern planes, & Thruster provide Depth, Altitude, Pitch, Heading, and Roll control Watch Dog Drop Weight Optional Cross Body Thruster Sections Provide Hovering Control (1kt hover) Auto-Pilot, Mission, Navigation, & Data logging Computer. PC104 + QNX OS Communications RF Modem Free-wave (115kbps max, 900 MHz popup antenna) Acoustic Modem FAU (1200 bps, 20-30 kHz) Navigation & Tracking Dead Reckoning with INS and Pop UP DGPS USBL for ship-based tracking Energy 1-4 NiMH Rechargeable Battery Sections (Optional Lithium) Ratings Range: 30-120 Km (30 km per NiMH battery section) Depth 200 M (rated) Speed 2-5 knots

Technical AUV Challenges: 

Technical AUV Challenges Research Items Multiple vehicle co-operative mission (re)planning Acoustic communication Underwater feature-based navigation (CML) Online target detection and identification Data fusion (acoustic, magnetic, optics) Endurance Manufacturing Items Low cost Rugged & reliable User friendly (pre and post-processing)

Selected Collaboration: 

Selected Collaboration MIT Sea Grant Program (Fall 1995) Odyssey and Ocean Explorer in simultaneous operation using acoustic LBL positioning Southampton Oceanographic Center, UK (Fall 1997) Autosub and Ocean Explorer in simultaneous operation for ocean currents sampling AUV Fest (Fall of 1997-1999) Organized by the US Naval Oceanographic Office (NAVO) Demonstration of AUV technology in the US (FAU, MIT, NPS, WHOI) Naval Undersea Warfare Center (Summer of 1999) Demonstrated high speed acoustic modem capability on OEX in Hawaii 4D Current (Summer of 1999) Demonstrates vertically integrated solution using AUVs, surface radar, moored sensors (FAU, UM, NOVA, NSWC, USF)

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