Download - Lesson 23: Technology II
Lesson 23:
Technology II
Strides in underwater research
• Did you know that most of the ocean (>95%) still hasn’t been explored?
• Technologies developed in recent years have made ocean navigation, research, mapping, and exploration much easier
• Today we’ll learn the basics about:• Remotely Operated Vehicles (ROV)• Autonomous Underwater Vehicles (AUV)• Hybrid Remotely Operated Vehicles (HROV)• Sonar• Electronic navigation
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How do scientists explore underwater?
Scuba diving Submersibles
Compact submarines that can explore the deep via an onboard computer system or remote operation
Explorers wear suits for diving with light, self-contained units of oxygen
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ROV: Remotely Operated Vehicle
Unoccupied underwater robots typically equipped with lights, cameras and sampling devices
Linked to a ship by cables and operated by someone on deck (tethered)
Uses:– To support science,
exploration and navigation– To investigate problems on
larger submersibles– To explore potential scuba
diving sites for safety The Institute for Exploration’s ROV Hercules, aboard a NOAA ship
Photo: NOAA
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AUV – Autonomous Underwater Vehicle
Computer-controlled, unmanned submersibles equipped with sampling technology
Self-guiding and not tethered (attached) to a ship
Technologically advanced: Highly maneuverable; Some can reach depths of 6,000 m or below.
Sample uses: – Take physical measurements
(temperature, dissolved oxygen)– Map the seafloor– Observe, take images of marine
life– Search for underwater mines
This AUV runs on solar power
Photo: NOAA/Navy
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Can operate as a tethered ROV or a programmed AUV depending on what works best for a particular mission
The Nereus is the first HROV, developed at the Woods Hole Oceanographic Institution (WHOI) Deep Submergence Lab
– It employs the most advanced sensing technology available for submersibles
– Its tether for ROV mode is much smaller and lighter than most other ROVs, allowing for better ease of movement
– In 2009, it was the first vehicle to explore the Mariana Trench since 1998
HROVHybrid Remotely Operated Vehicles
The HROV Nereus6
Sonar – SOund Navigating And Ranging
Sonar allows scientists to “see” underwater by transmitting a sound and measuring how long it takes to receive its echo
This technology allows scientists to map the sea floor, identify geological features like the Mid-Atlantic Ridge and discover underwater objects like shipwrecks
AUVs and ROVS are often equipped with sonar so they can provide images of underwater objects and habitats
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Two types of sonar
Side-scan sonar– Primary tool for obtaining details of seafloor
surface– Often used to find shipwrecks and detect
objects on seafloor– Provides high resolution data but over
smaller area
Multibeam sonar– Primary tool for seafloor mapping– Used to generate bathymetric maps (show
depths, features of seafloor)– Provides coverage over larger area but less
resolution than side-scan
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Video shows multibeam and side-scan sonar. Multibeam measures the seafloor depth (multi-colored region under boat) and side-scan identifies objects on seafloor (in back of boat). Movie Credit: U.S. Naval Oceanographic Office.
Electronic navigation
Electronic navigation allows ships to determine their exact location
In the 1960s, Loran-C (LOng RAnge Navigation) was invented to make shipping safer– Uses radio signals from two or more transmitters
to provide latitude and longitude information to within half a mile accuracy
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Electronic navigation
Global Positioning System (GPS) largely replaced Loran-C since the 1990s because it is far more accurate
GPS uses satellites to determine position within 1-100 meters depending on the sophistication of the unit
NOAA uses an advanced system of GPS receivers known as CORS (Continually Operating GPS Research Stations) to obtain positioning information accurate within less than a centimeter!
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Student activity
In today’s activity, you will undertake an activity that simulates using sonar to map the ocean floor.
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