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Issue 1 2014
Issue 1 2014
UNDERWATER gliders that look like torpedoes and act like
mobile weather stations are providing data for computer
modelling to predict ocean conditions.
Slocum Gliders are being used by the Defence Science
and Technology Organisation’s (DSTO) Maritime Division
to evaluate the potential operational benefits of unmanned
underwater vehicles (UUVs) to acquire and transmit
oceanographic and other data to a remote location.
The off-the-shelf UUVs were most recently put to the test
in Australia’s oceans in July during Exercise Talisman
Saber in Queensland, where two “silent helpers” beamed
oceanographic information across the world to the US Naval
Oceanographic Office in Mississippi.
DSTO Maritime Division engineers Philip Jackson, James
Gourley and Jesse Passon set up a base station in Yeppoon,
near the Shoalwater Bay Training Area, to monitor the gliders
during their 10-day underwater deployment as part of the
exercise. Principal Scientist Underwater Acoustics Dr Adrian
Jones and Signal Processing Specialist Dr Mike Greening
provided support from Edinburgh in South Australia.
Philip says the gliders are shaped like a torpedo for an easy
passage through the water and can stay at sea for weeks at a
“The glider begins a voyage by retracting a piston in its nose.
This reduces the displaced volume of the glider which makes
it negatively buoyant with a nose-down trim,” he says.
“They are actually capable of traversing oceans for long
periods of time through using these buoyancy changes to
generate forward motion. Because they are shaped like a
torpedo with wings and a tail fin, they move in a similar way
as a traditional glider does through air by converting the
downward pull of gravity into forward motion.”
Philip says each glider can be thought of as the equivalent
of a mobile weather station and can be used to measure
ocean temperature and salinity at known locations. He says
Defence Science and Technology Organisation engineer James Gourley
(right) travels out to the location of a Slocum Glider off the coast of Yeppoon,
Queensland, during Exercise Talisman Saber.
determined. Each may also be fitted with an optical sensor
for determination of ocean clarity, or an acoustic sensor that
enables it to collect sound signals for both the ambient noise
and for determining the seafloor sonar properties.
In their second appearance on a Talisman Saber exercise
– the first being in 2011 – the gliders were fitted with new
battery packs and stabilised to be neutrally buoyant, and
then deployed in local waters to test their full functionality,
including their communications systems, on-board sensors
and navigation and propulsion systems.
The raw data collected was passed to the US Naval
Oceanographic Office where it went through quality control
processes before it was absorbed into numerical ocean
models by the US Naval Research Laboratory.
Results from the modelling – forecasts of conditions and
parameters applicable to undersea warfare operations – and
the quality-controlled raw data were later made available to
DSTO and the Navy.
Philip says participating in Talisman Saber exercises provides
a realistic operational environment and a great opportunity to
demonstrate new and emerging technology and the potential
capability it can offer. “As Talisman Saber is a joint Australia
and US exercise it also provides an excellent opportunity to
collaborate with US agencies,” he says.
“By applying DSTO’s knowledge and experience with the
Slocum Glider together with our knowledge of the underwater
environment and its impact on sensing, we were able to
facilitate a work program with Navy and US collaborators
to successfully demonstrate the concepts during Exercise
“Not all aspects of the technology are mature yet, but early
indications are that once it is mature it will be valuable
to maintaining a capability edge in undersea and littoral
Philip says a possible future use for the gliders is as a
platform to gather acoustic and environmental data relevant
to undersea warfare operations.
“Anti-submarine warfare can be made more effective through
understanding the structure of the immediate environment in
three-dimensional space, and the data sent by the Slocum
Glider can be vital in building this accurate picture that can
improve the overall performance of the fleet,” he says.
this data has potential for use by computer models to aid the
prediction of ocean conditions.
“The more weather stations available, or the closer you are
to a weather station, the more accurate the forecast for your
location will be,” he says.
“The ocean environment is critical in determining a sonar
system’s anti-submarine warfare capability, which can rapidly
change from good to poor in distances as short as 10km to
“Measurements from Slocum Gliders can be used to greatly
improve predictions of the overall ocean environmental
features, and therefore improve predictions of anti-submarine
The tail fin houses a GPS antenna and an Iridium satellite
antenna used for communications back to shore. The craft
periodically surfaces to upload collected sensor data via a
satellite link and to update mission parameters as required.
The gliders can be fitted with a variety of sensors for
sampling the ocean environment. The two DSTO models
are always equipped with conductivity, temperature and
depth sensors, from which sound speed in the water may be
Defence Science and
engineers Philip Jackson
(left) and James Gourley
retrieve a Slocum Glider off
the coast of Yeppoon during
Exercise Talisman Saber.
Photos: Corporal Jake Sims
The year ahead
In 2014, DSTO Maritime Division will carry out
research and liaise with relevant organisations
to assess the feasibility of routinely
assimilating glider-based measurements
of ocean sound speed profiles into the
Australian Defence Organisation “BLUElink”
This will provide more effective sonar
performance predictions for the Navy and Air
A key activity this year will be the first
multiglider deployment in Australian waters,
planned to take place in an ocean area off
Relevant organisations for liaison will
include the CSIRO Division of Marine
and Atmospheric Research, Bureau of
Meteorology, Australian National Facility for
Ocean Gliders at the University of WA, and
the University of NSW at ADFA.
The results will be communicated to the Navy
Hydro and Meteorology and Oceanography
Branch, who are responsible for the provision
of data and systems for sonar prediction to
the fleet and to the Air Force.
DSTO engineers test the ability of underwater vehicles to transmit oceanographic data
across the other side of the world during major exercises off Shoalwater Bay
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