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The
JORN receiver site located 180km south-west of Longreach
in Queensland. Photo by GPCAPT Mac Cottrell.
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By Deanna
Nott
More than 40 years
of Australian research, design and development has led to JORN
– Australia’s Jindalee Operational Radar Network.
JORN
is the $1.2 billion system that enables the Australian Defence
Force to see over-the-horizon and monitor the strategic areas
to the north and north west of Australia.
JORN,
which is set to be operationally available from early April 2003,
uses leading edge high-frequency radar technology and is capable
of detecting air and surface targets in all weather, day and night.
Group
Captain Steve Sheedy, Director of Over-The-Horizon-Radar Systems
Programs Office, said the Government determined that a network
of over-the-horizon-radars would be the most cost-effective way
to protect Australia’s sea-air gap.
“Australia
has a large coastline and a small population. This indigenous
technology will provide Australia with early warning in the event
of an imminent attack,” GPCAPT Sheedy said. “JORN will
also provide our Government with valuable information about any
illegal activities in the gap.”
With
the introduction of JORN, the Australian Defence Force is now
capable of conducting constant surveillance of a 20 million sq
km area.
JORN
can detect targets up to 2000km away from our coastline.
Receivers
and transmitters are located near Laverton in Western Australia
and Longreach in Queensland. These locations were selected for
their electronically quiet environments and because they ensure
the desired strategic coverage of Australia’s sea-air gap.
JORN’s
high-frequency radar technology is very different from the more
commonly used microwave radar. Instead of sweeping through a circular
pattern, JORN focuses on individual sectors within its arc of
coverage, between Geraldton in Western Australia and Cairns in
Queensland.
Wing
Commander Ray Cage, Commanding Officer of RAAF Base Edinburgh’s
No. 1 Radar Surveillance Unit (1RSU), the coordinating unit for
the two radars, said the radar transmitted a HF radio signal into
the ionosphere “where it is refracted back to the surface
of the earth, like light through water”.
“Any
aircraft or ships in the target region will reflect some of this
energy back along the original path to the radar receiver. Changes
in the return signal are analysed to provide track information
on those detections,” WGCDR Cage said.
Although
the radars are controlled and managed by the Australian Defence
Force, the Defence, Science and Technology Organisation developed
the capability. The radars were built by prime contractor RLM
and are maintained by the joint venture company comprising Tenix
and Lockheed Martin Corporation.
Using
specially designed computer software, about 100 Defence personnel
at 1RSU in South Australia are involved in detecting, tracking,
and analysing JORN data.
JORN
will complement and add to the OTHR capability already employed
by the ADF, through the existing Jindalee Facility at Alice Springs,
which has provided an operational platform and R&D testbed
for more than 10 years.
The
Defence Force, Customs, Coastwatch and other government agencies
use OTHR data to greatly improve the country’s knowledge
of activities in the sea-air gap, and the national surveillance
picture.
