Home' Defence Technology Review : DTR DECJAN 2016 Contents INNOVATIONS
DEFENCE TECHNOLOGY REVIEW | ISSUE 16 | DEC/JAN 2016
A key element of the US Defense Advanced Research
Projects Agency (DARPA) Anti-Submarine Warfare
Continuous Trail Unmanned Vessel (ACTUV) concept is now
in hand, with Raytheon delivering to the program its latest
Modular Scalable Sonar System (MS3) in November.
The fifth-generation hull-mounted MS3 performs active and
passive search and tracking, incoming torpedo warning and
small object avoidance for safer navigation.
Sensor data from the system is used in the anti-submarine
warfare (ASW) mission to help build a common operating
picture for ACTUV. MS3 will be integrated into an unmanned
trimaran vessel design built by Leidos, and will deliver
these capabilities in an autonomous operating environment.
Construction of the first 140 tonne ACTUV platform is around
90 per cent complete, with final software engineering and
integration currently underway.
Leveraging off the proven capabilities of earlier generation
Raytheon sonars currently in service, MS3 features a
streamlined inboard electronics suite configurable for a range
of sonar capabilities, including ASW, anti-surface warfare
and mine warfare, for most hull and bow-mounted arrays
and towed systems. It was designed and developed with an
open and modular architecture for maximum flexibility and
scalability, supporting phased upgrades over vessel life-of-
type or new construction programs.
The ACTUV program seeks to demonstrate the capability
of an unmanned vessel to employ its non-conventional
sensor technologies to achieve continuous tracking of the
quietest diesel-electric submarines over their entire operating
envelope for months at a time across thousands of kilometres
of ocean under a sparse supervisory model and severe
environmental and maritime conditions.
The requirement for ACTUV stems from the US Navy’s
(USN) concerns about the proliferation of very quiet diesel-
electric submarines around the world, the procurement
of which is forecast to grow. Even second-tier navies,
particularly in Southeast Asia, are commissioning small but
potent fleets of latest-generation diesel-electric submarines,
many of which are capable of both blue water and shallow
water/littoral operations – waters in which US carrier and
amphibious task groups could be expected to conduct
operations as strategic tensions in the Asia-Pacific region
continue to focus the attention of the Pentagon.
In addition to robust operating autonomy which complies
with international maritime laws and conventions for safe
navigation, autonomous system management for operational
reliability and autonomous interactions with an intelligent
adversary, key ACTUV technology includes advanced
software, navigation and piloting sensors, electro-optical
imagers, long and short-range radar, LIDAR (light detection
and ranging) and now the MS3 mid and high-frequency sonar.
ACTUV’s 40.2m trimaran hullform is built out of carbon-
fibre composites and designed for effective operations to Sea
State 5 and is survivable in conditions up to Sea State 7.
The USN sees ACTUV as a potential game-changer,
granting as it would a difficult-to-counter asymmetric threat to
submarines of all types. ACTUV’s unmanned modus operandi
adds significantly to its exceptionally long at-sea endurance,
enabling it to remain on station for around 90 days.
Other advantages inherent in the ACTUV concept include
greater payload and endurance than a ship-launched
unmanned surface vessel, the ability to launch from and
recover at a pier and the elimination of the need to integrate
the system with a parent ship.
According to DARPA, the estimated operating cost
for ACTUV would be around US$15,000-$20,000
(AUD$20,700-$27,600) per day, compared with
US$700,000 (AUD$967,000) per day for a large surface
ACTUV is scheduled to commence contractor sea trials in
the first quarter of 2016.
– Ian Bostock
Raytheon delivers sonar for DARPA sub hunter
Raytheon has supplied its Modular Scalable
Sonar System into the DARPA-led ACTUV
submarine hunter program. Image: DARPA
Research to validate StopRotor UAV concept
Enhanced Targeting, SA for Growler
StopRotor Technology will use a collaborative research
grant with the Royal Melbourne Institute of Technology
(RMIT) to validate the design of the former’s StopRotor
unmanned aerial vehicle (UAV).
The research project will develop the StopRotor UAV
dynamics model to validate the performance capability
of the aircraft for fixed-wing (FW) and rotary-wing (RW)
performance envelopes and commence an initial investigation
into the scalability of the aircraft at 50kg, 100kg and 200kg
maximum take-off weights.
Investigating the dynamics model, scalability of the design
and performance will uncover the actual capability of the
StopRotor UAV and identify the range of missions it may
successfully undertake, and provide a clear indication of the
minimum and maximum capability of the platform and how
these parameters can be approximated for various scales of
The RMIT Industrial Wind Tunnel will be utilised for full
scale wind-tunnel tests to gather the main steady-state
aerodynamic derivatives. Dynamic derivatives, which are
needed to model the dynamic behaviour flight behaviour, will
be acquired through a combination of engineering theory and
flight tests. The complete StopRotor UAV model will allow
various developments in its performance characteristics while
enabling the design of an appropriate control system for
autonomous or assisted control from a specialised autopilot
system. Work will commence in early 2016.
The StopRotor UAV is a novel platform that can transition in
flight between RW and FW modes by starting or slowing and
stopping its ‘RotorWing’ in flight.
The US Navy (USN) and Boeing have demonstrated
new tablet-based capabilities for the EA-18G Growler
electronic attack aircraft which enhance aircrew safety and
effectiveness through the rapid integration and distribution of
target information across multiple aircraft.
The demonstrations used an advanced targeting processor,
an open architecture, high-bandwidth data link and a
Windows-based tablet integrated for the first time with
the aircraft’s mission system and enabled the aircraft to
detect targets at longer ranges and share information more
rapidly than currently. This improved capability is considered
essential for increasingly dense threat environments where
longer-range targeting is a critical element to success.
According to Boeing, naval aviation history was made
during the USN’s fleet experimentation campaign when data
was integrated from multiple Growlers operating with an E-2
Hawkeye airborne early warning and control aircraft, which
utilised the new high-bandwidth data link and increased
speed and accuracy of target locating.
Existing USN Growlers are to be retrofitted with the
upgrades and the technology will also be included as a
standard offering on all new aircraft currently entering
– Staff Reporters
This enables the platform to take-off vertically as
a helicopter and transition to forward flight as a FW
aircraft, then transition back to RW mode for landing
vertically. StopRotor UAV can also take-off and land as a
conventional FW aircraft if required.
This, claims StopRotor Technology, combines all the
optimum design and performance characteristics and
capabilities of a helicopter (open rotor system) with those
of a FW aircraft, and enables near optimum RW and FW
performance in a single aircraft.
This combination thereby eliminates the single greatest
limitation of each type; that being the requirement for launch
and retrieval infrastructure/runways of a FW UAV, and the
limited forward flight performance of a RW UAV.
– Ian Bostock
A StopRotor SR600 UAV prototype in flight.
Image: StopRotor Technology
Tablet-based technology has provided EA-18G Growlers with
the ability to detect targets at longer stand-off distances and
disseminate that data across multiple aircraft. Image: US Navy
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