Currawong’s Song

Currawong communications system
The Network Access Module forms the central part of Australia’s Currawong battlefield communications system. This acts as the ‘clearing house’ managing incoming and outgoing line-of-sight and BLOS links.

The Australian Defence Force’s Currawong battlefield communications system provides a plethora of links to deployed forces at tactical and operational levels.

Taking its name from a specie of bird native to Australia, the Currawong battlefield communications system provides secure communications for tough and austere locations. It is being procured via the Australian Department of Defence’s Land 2072 Phase-2B initiative.

At the heart of Currawong is the Network Access Module (NAM) enclosed in a rugged case, according to documentation discussing the project. The NAM includes a power supply and housing for specific ‘bricks’ which plug into the system according to mission demands. Some bricks will always be used with the module such as those carrying the tactical edge server and tactical services router. These in turn host IP (Internet Protocol) voice, data and video networking and routing services. Likewise, mission system management software is included in the module to supervise its functions. The module’s software will identify the best bearer network for traffic depending on several factors. These include the local environment, the traffic to be carried and available links.

Capability Bricks

Boeing’s Australian subsidiary is leading the Currawong project. It told Armada via a written statement that the six ‘bricks’ cover the provision of long-haul fibre optics. This “provides high-speed, gigabit fibre optic network connections between deployed nodes”. The High-Capacity Line-of-Sight brick “provides microwave communications between nodes over long distances where terrain allows for radio line-of-sight”. A third capability provides troposcatter communications for Beyond Line-of-Sight (BLOS) communications.

Troposcatter communications use signals on frequencies of 300 megahertz up to 30 gigahertz. Transmissions are aimed towards the troposphere, a layer of the atmosphere on average about 59,000 feet (18,000 metres) above the Earth’s surface. Signals collide with the troposphere and are scattered back to Earth, being picked up by the receiving antenna. Much like high frequency radio, troposcatter communications achieve BLOS ranges by skipping over the horizon.

Currawong Radio Interface System
The Currawong battlefield communications system also hosts standard military radio networks moving traffic between these networks and across beyond line-of-sight links when needed.

An External Network Access Point (ENAP) lets users move voice and data traffic securely across public networks such as local internet services. Two Satellite Communications (SATCOM) bricks can work with the NAM. These provide access to the US and allied Wideband Global SATCOM (WGS) constellation. WGS provides X-band (7.9-8.4 gigahertz/GHz uplink/7.25-7.75GHz downlink) and Ka-band (26.5-40GHz uplink/18-20GHz downlink) SATCOM. The bricks facilitate connections with trailer-mounted and transportable satellite communications terminals carrying WGS traffic.

Towards Full Capacity

Boeing’s statement added that Currawong is intended for both tactical- and operational-level deployment “providing remote headquarter operations as well as connecting to, and extending, tactical communications infrastructure for deployed forces”. It’s Radio Interface System lets standard military transceivers be connected to the module and their traffic moved between their associated networks. Similarly, this traffic can be moved across beyond line-of-sight ranges with the fibre optic and SATCOM conduits. This is particularly useful when operationally or strategically relevant traffic needs to be transferred to higher echelons from tactical networks.

While the system’s initial operational capability was declared in April 2018, the Australian armed forces are looking forward to the full rollout of all Currawong’s capabilities. This should occur by mid-2023.

by Dr. Thomas Withington