Along with the “transfer [of] real-time video from un-tethered [submerged] vehicles” up to support vessels on the surface, “this combination of capabilities will make it possible to operate self-powered ROVs [remotely operate vehicles] from surface vessels without requiring a physical connection to the ROV,” says WHOI Senior Engineer Norman E. Farr, who led the research team. This will not only represent a significant technological step forward, but also promises to reduce costs and simplify operations, they say.
Their report will be presented Feb. 23 at the 2010 Ocean Sciences Meeting in Portland Ore.
Compared to communication in the air, communicating underwater is severely limited because water is essentially opaque to electromagnetic radiation except in the visible band. Even then, light penetrates only a few hundred meters in the clearest waters; less in sediment-laden or highly populated waters.
Consequently, acoustic techniques were developed, and are now the predominant mode of underwater communications between ships and smaller, autonomous and robotic vehicles. However, acoustic systems—though capable of long-range communication—transmit data at limited speeds and delayed delivery rates due to the relatively slow speed of sound in water.
Now, Farr and his WHOI team have developed an optical communication system that complements and integrates with existing acoustic systems to enable data rates of up to 10-to-20 megabits per second over a range of 100 meters using relatively low battery power with small, inexpensive transmitters and receivers.
The advance will allow near-instant data transfer and real-time video from un-tethered ROVs and autonomous underwater vehicles (AUVs) outfitted with sensors, cameras and other data-collecting devices to surface ships or laboratories, which would require only a standard UNOLS cable dangling below the surface for the relaying of data.
This would represent a significant advance, Farr says, in undersea investigations of anything from the acidity of water to indentifying marine life to observing erupting vents and seafloor slides to measuring numerous ocean properties. In addition, the optical system would enable direct maneuvering of the vehicle by a human.
He likens optical/acoustic system possibilities to the world opened up by “your household wi-fi.”
Co-investigator Maurice Tivey of WHOI adds that “underwater optical communications is akin to the cell phone revolution…wireless communications. The ability to transfer information and data underwater without wires or plugging cables in is a tremendous capability allowing vehicles or ships to communicate with sensors on the seafloor.
“While acoustic communications has been the method of choice in the past it is limited by bandwidth and the bulkiness of transducers,” Tivey says. “Today, sensors sample at higher rates and can store lots of data and so we need to be able to download that data more efficiently. Optical communications allows us to transfer large data sets, like seismic data or tides or hydrothermal vent variations, in a time-efficient manner.”
When the vehicle goes out of optical range, it will still be within acoustic range, the researchers said.
Because it enables communications without the heavy tether-handling equipment required for an ROV, the optical/acoustic system promises to require smaller, less-expensive ships and fewer personnel to perform undersea missions, Farr said.
This July, WHOI plans the first large-scale deployment of the system at the Juan de Fuca Ridge off shore of the Northwestern United States. The WHOI team will employ the human occupied vehicle (HOV) Alvin to deploy the optical system on a sub sea data concentrator to collect and transmit geophysical data from wellheads situated at the undersea ridge.
Ultimately, Farr says, the system will “allow us to have vehicles [at specific undersea locations] waiting to respond to an event. It’s a game-changer.”
WHOI scientists collaborating on the research with Farr—who is in the Applied Ocean Physics and Engineering (AOPE) department—and Tivey, chair of the Geology and Geophysics department, are Jonathan Ware, AOPE senior engineer, Clifford Pontbriand, AOPE engineer, and Jim Preisig, AOPE associate scientist.
The work was funded by the National Science Foundation’s Division of Ocean Sciences.
The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the oceans' role in the changing global environment.
WHOI Media Relations | EurekAlert!
UT professor develops algorithm to improve online mapping of disaster areas
29.11.2016 | University of Tennessee at Knoxville
New standard helps optical trackers follow moving objects precisely
23.11.2016 | National Institute of Standards and Technology (NIST)
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy