What ever happened to the wireline SOSUS networks of the Cold War used to detect Russian submarines? They've been replaced by the much more extensive "Seaweb" intranet based wireless network with a vast range of communications and surveillance capabilities. US and other Western submarines provide input into and communicate via the Seaweb network. A highly detailed powerpoint presentation of Seaweb’s capabilities is
here .
The vast Seaweb network uses many sensor technologies and host platforms from US and other Western defence forces. Seaweb requires a vast amount of data memory and processing power mainly provided by the US Navy. Diagram sourced from http://www.docstoc.com/docs/146099687/Seaweb )
"NPS Pioneers “Seaweb”
Underwater Sensor Networks"
Article By: Barbara Honegger
May 16, 2014
"The Naval Postgraduate School is on the cutting edge of
through-water acoustic communications technology enabling distributed
autonomous ocean sensors to operate as an underwater wireless wide-area
network.
Through a decade of engineering experiments and sea trials
in diverse maritime environments, NPS and its research partners have advanced
the “Seaweb” system to a point where it now routinely demonstrates capability
for maritime surveillance, anti-submarine warfare (ASW), oceanographic
sampling, instrument remote-control, underwater navigation, and submarine
communications at speed and depth.
“Seaweb is a realization of FORCEnet in the undersea
battlespace,” said the program’s Principal Investigator and Physics Research
Professor Joseph Rice.
The system uses through-water acoustic modems to
interconnect a scalable quantity of underwater network nodes, linking them to a
gateway node typically located at the sea surface. The gateway node is equipped
with some form of radio modem permitting bidirectional real-time digital
communications between the underwater Seaweb domain and distant command
centers.
“Seaweb is the product of interdisciplinary R&D
[research and development] involving underwater acoustic propagation, sonar
systems engineering, transducer design, digital communications, signal
processing, computer networking and operations research,” explained Rice, an
electrical engineer. “Our original goal was to create a network of distributed
sensors for detecting quiet submerged submarines in littoral waters where
traditional ASW surveillance is challenged by complex sound propagation and
high noise. But as Seaweb technology developed, its broader overarching value
became evident.”
For example, in a 2001 Fleet Battle Experiment, a U.S.
fast-attack submarine serving as a cooperative target for Seaweb ASW sensors
was itself equipped as a Seaweb node. Thus instrumented, the submarine was able
to access the deployed autonomous nodes as off-board sensors, and while
transiting at speed and depth was also able to communicate through Seaweb with
the command center and even with a collaborative maritime patrol aircraft.
“In effect, the Seaweb network served as a cellular
communications and sensor infrastructure for the submarine,” Rice said.
According to Rice, a major advantage of an undersea wireless
network is the flexibility it affords mission planners and theater commanders
to appropriately match resources to the environment and mission at hand. For
example, fixed sensor nodes can be combined with mobile Unmanned Underwater
Vehicle (UUV) nodes, which has been demonstrated in a number of Seaweb
experiments. “The UUV can serve the fixed nodes as their deployment platform,
their gateway node, or as a mule for delivering and recovering large volumes of
data,” Rice noted. “In turn, the fixed network can support UUV command,
control, communications and navigation.”
A further example of heterogeneous Seaweb networks is the
combination of surveillance sensor nodes with METOC sensor nodes to improve the
performance and relevance of both. The wireless architecture means that ASW
sensors can be sparsely distributed to cover a wide area or densely distributed
to create a tripwire or to monitor a chokepoint. In a current international
project, Seaweb is interconnecting undersea sensors from NATO nations as a
single integrated network.
“In short, Seaweb integrates undersea warfare systems across
missions, platforms, systems and nations,” Rice said.
Major attributes of Seaweb’s architecture are its low cost,
its rapid deployability from a variety of platforms, and its ability to
autonomously self-configure into an optimal network. Through a build-test-build spiral engineering
process and rigorous sea testing of diverse configurations of underwater
sensors and Seaweb modems, the effort is honing the blueprint for an
environmentally adaptive and energy efficient, expendable and cost-effective,
bi-directional wide-area-coverage undersea communications infrastructure.
“Seaweb has now been exercised in over 50 sea trials,” Rice
noted. “The system has proven to be effective in shallow waters such as the
Intracoastal Waterway and in waters up to 300 meters deep off the coasts of
Nova Scotia, San Diego, Long Island and Florida. It has been demonstrated in
the Pacific and Atlantic Oceans, in the Mediterranean and Baltic Seas, in
Norwegian fjords, and under the Arctic ice shelf.”
The experimental method involves stressing the network to
the point of failure as a means of identifying and eliminating weaknesses.
Recent multi-agency trials have engaged Seaweb at the front end of the
“observe, orient, decide, act” (OODA) loop, where the networked in situ sensors
enhance the commander’s maritime domain awareness and complement remote sensing
assets.
Last year, Rice and his students completed a two-part
“Bayweb 2009” experiment using Seaweb’s undersea communications technologies in
San Francisco Bay. The goals were to
demonstrate the network architecture and test system performance, while measuring
the strong currents around Angel Island using networked current sensors placed
near the seabed and sharing these data with oceanographers. Partnering with NPS
in Bayweb were the University of California, Berkeley; University of
California, Davis; San Francisco State University; the Monterey Bay Aquarium
Research Institute; SPAWAR Systems Center Pacific; the Office of Naval
Research; and the U.S. Coast Guard.
“Due to the high levels of shipping and wind noise and flow
noise from currents up to four knots, San Francisco Bay presented a challenging
test environment and a learning opportunity for our students,” Rice said.
Some of Rice’s students are also working on a new “Deep
Seaweb” project adapting the littoral Seaweb network to the deep ocean.
“It’s of utmost importance to the Navy to maintain submarine
communications, but all existing communication methods are severely limited
without compromising either speed or depth, or both,” said Operations Analysis
student and submariner Lt. Andrew Hendricksen. “Once deployed, Deep Seaweb is
the one option that allows stealthy, two-way submarine communications while
maintaining both depth and speed. A number of sea trials have proven Seaweb
works as a detection network, which can be expanded for two-way communications
with undersea assets – submarines and UUVs – in the deep ocean. My thesis research is developing an algorithm
that can show the best places to put it to get the coverage you want to achieve
the purposes you want for sub detection, sub communications, tsunami warning,
etc.”
Another student, Lt. Jeremy Biediger, is exploring the
advantages of deploying Deep Seaweb hydrophones in deep ocean trenches to
passively detect quiet diesel submarines, stealthy semi-submersibles carrying
contraband and surface vessels.
“The main advantages of deploying Deep Seaweb networked
acoustic sensors along deep ocean trenches for barrier or tripwire coverage of
submarines and of surface and semi-submersible vessels are reduced ambient
noise and thus relatively high signal-to-noise ratio,” explained Biediger.
“It’s great working with Professor Rice because he’s a
research professor who’s really involved with the ASW community and the system
commands, so you get to meet and work with many of the top people in those
communities,” Biediger added. “What I
learned will be of great benefit to my future career as an engineering duty
officer, especially on the acoustics side, as very few universities have
acoustics programs and the Naval Postgraduate School is unique in acoustics
with naval applications.”
“Future undersea sensor grids will enable navigation of
submarines and autonomous underwater vehicles,” Rice added. “Seaweb technology could also support
submarine communications, networked torpedo connectivity for ASW engagement
from launch platforms at long standoff, communication among unmanned underwater
vehicles in mine-countermeasure operations, and any undersea warfare system
that requires data telemetry for command and control.”
“A goal is for Seaweb technology to support the operational
community,” Rice stressed. “In the
shorter term, next year we’ll be testing against a cooperative diesel-electric
submarine in the Mediterranean Sea in preparation for NOBLE MANTA 2012, the
annual NATO antisubmarine warfare exercise.”
The NPS Seaweb program’s primary sponsor is the Office of
Naval Research, with additional support from the Office of the Secretary of
Defense. NPS Seaweb research collaborators for 2010 include SPAWAR
Systems Center Pacific; the University of Texas Applied Research
Laboratories; the NATO Undersea Research Centre; Canada’s Defense Research and
Development Center Atlantic; the Norwegian Defence Research Establishment; The
Technical Cooperation Program (TTCP), a five-nation defense R&D
collaboration involving Canada, Australia, New Zealand the United Kingdom, and
the U.S; and Teledyne Benthos, Inc.
Pete
