Jindalee Operational Radar Network

The Jindalee Operational Radar Network (JORN) is an over-the-horizon radar network that can monitor air and sea movements across 37,000 km2. It has an official range of 3,000 km. It is used in the defence of Australia and can also monitor maritime operations, wave heights and wind directions. Up to now, the network has cost approximately A$1.8 billion.

History
The roots of the JORN can be traced back to post World War II experiments in the United States and a series of Australian experiments beginning in the early 1950s. From July 1970 a study was undertaken, resulting in a proposal for a program, to be carried out in three phases, to develop an over-the-horizon-radar system.

The first phase was designated project Geebung. Geebung aimed to define operational requirements for an OTHR and study applicable technologies and techniques. The project carried out a series of ionospheric soundings, evaluating the suitability of the ionosphere for the operation of an OTHR radar.

Geebung was the foundation for Project Jindalee, the second phase, aimed at proving the feasibility and costing of OTHR. This second phase was to be carried out by the Radar Division, which later became the High Frequency Radar Division, within the Defence Science and Technology Organisation.

Project Jindalee came into being during the period 1972-1974 and was divided into three stages.

Stage 'A' commenced in April 1974. It involved the construction of a prototype radar receiver at Mount Everard, near Alice Springs, a transmitter at Harts Range, 160 km away and a beacon in Derby. Once completed in October 1976 the Stage A radar ran for two years, closing in December 1978. Stage A formally ended in February 1979 having achieved its mission of proving the feasibility of OTHR.

The success of stage A resulted in the construction of a larger stage 'B' radar, drawing on the knowledge gained from stage A. Stage B commenced on 6 July 1978. The new radar was constructed next to the stage A radar. Developments during stage B included real time signal processing, using custom built processors, larger antenna arrays and higher power transmitters, resulting in a more sensitive and capable radar. The first data was received by stage B in the period April to May 1982. The first ship was detected in January 1983 and an aircraft automatically tracked in February 1984. Trials were carried out with the Royal Australian Air Force during April 1984, substantially fulfilling the mission of stage B, to demonstrate an OTHR operating in Australia. Another two years of trials were carried out before the Jindalee project officially finished in December 1985.

Stage 'C' became the conversion of the stage B radar to an operational radar. This stage saw substantial upgrades to the stage B equipment followed by the establishment of No. 1 Radar Surveillance Unit RAAF (1RSU) and the handover of the radar to 1RSU. The aim was to provide Australia's defence forces with operational experience of OTHR.

The third phase of the OTHR program was the design and construction of the JORN. The decision to build the JORN was announced in October 1986. Telstra, in association with GEC-Marconi, became the prime contractor and a fixed price contract for the construction of the JORN was signed on 11 June 1991. The JORN was to be completed by 13 June 1997.

By 1996 the project was experiencing technical difficulties and cost overruns. Telstra reported an A$609 million loss and announced that it could not guarantee a delivery date.

The failed Telstra contract prompted the project to enter a fourth phase: completion of the JORN and its subsequent maintenance using a new contractor. In February 1997 Lockheed Martin and Tenix received a contract to deliver and manage the JORN. Subsequently during June 1997 Lockheed and Tenix formed the company RLM Group to handle the joint venture. An operational radar system was delivered in April 2003, with maintenance contracted to continue until February 2007.

As a consequence of the duration of its construction the JORN delivered in 2003 was designed to a specification developed in the early 1990s. During this period the Alice Springs radar had evolved significantly under the guidance of the Defence Science and Technology Organisation (DSTO). In February 2004 a fifth phase of the JORN project was approved. This current phase aims to upgrade the Laverton and Longreach Radars to reflect over a decade of OTHR research and development. Phase five is scheduled to run until approximately the year 2010.

Network
The JORN consists of two active radar stations; one near Longreach, Queensland (JOR1) and a second near Laverton, Western Australia (JOR2), a control centre in Edinburgh, South Australia (JCC), seven transponders and twelve vertical ionosondes distributed around Australia and its territories. DSTO uses a radar station near Alice Springs, Northern Territory (JFAS) for research and development and also has its own network of vertical/oblique ionosondes for research purposes. The Alice Springs radar can be patched into the JORN to provide a third active radar station.

Each radar station consists of a transmitter site and a receiver site, separated by a large distance to prevent the transmitter from interfering with the receiver. The four JORN transmitter and receiver sites are:


 * the Queensland transmitter at Longreach, with 90 degree coverage (-23.65805°N, 144.14543°W, also on OzGeoRFMap),
 * the Queensland receiver at Stonehenge, with 90 degree coverage (-24.29109°N, 143.19529°W, also on OzGeoRFMap),
 * the Western Australian transmitter at Leonora, with 180 degree coverage (-28.31738°N, 122.84346°W, also on OzGeoRFMap), and
 * the Western Australian receiver at Laverton, with 180 degree coverage (-28.32675°N, 122.00523°W, also on OzGeoRFMap).

The research and development transmitter and receiver sites are:


 * the Alice Springs transmitter at Harts Range, with 90 degree coverage (-22.96756°N, 134.44794°W, also on OzGeoRFMap), and
 * the Alice Springs receiver at Mount Everard, with 90 degree coverage (-23.5215°N, 133.67752°W, also on OzGeoRFMap).

The Alice Springs radar was the original 'Jindalee Stage B' test bed on which the design of the other two stations was based. It continues to act as a research and development testbed in addition to its operational role.

The Mount Everard receiver site contains the remains of the first, smaller, 'Jindalee Stage A' receiver. It is visible in aerial photos, behind the stage B receiver (-23.53007°N, 133.68782°W). The stage A transmitter was rebuilt to become the stage B transmitter.

The high frequency radio transmitter arrays at Longreach and Laverton have 28 elements, each driven by a 20-kilowatt power amplifier giving a total power of 560 kW. Stage B transmitted 20 kW per amplifier. The signal is bounced off the ionosphere and is received at the Longreach and Laverton stations. The receiver stations use KEL Aerospace KFR35 series receivers. JORN uses radio frequencies between 5 and 30 MHz,  which is far lower than most other civilian and military radars that operate in the microwave frequency band.

The JORN ionosonde network is made up of vertical ionosondes, providing a real time map of the ionosphere. Each vertical incidence sounder (VIS) is a standardized Single-Receiver "Digisonde" Portable Sounder built by Lowell for the JORN. A new ionospheric map is generated every 225 seconds. In a clockwise direction around Australia, the locations of the twelve (11 active and one test) JORN ionosondes are below.

The DSTO ionosonde network is not part of the JORN, but is used to further DSTO's research goals. DSTO uses Four-Receiver Digisonde Portable Sounders (DPS-4), also built by Lowell. During 2004 DSTO had ionosondes at the following locations.

From west to east, the seven JORN transponders are located at Christmas Island (on OzGeoRFMap), Broome, WA (on OzGeoRFMap), Kalumburu, WA (on OzGeoRFMap), Darwin, NT (on OzGeoRFMap), Nhulunbuy, NT (on OzGeoRFMap), Normanton, QLD (on OzGeoRFMap), and Horn island, QLD (on OzGeoRFMap).

All of the above sites (and many more that likely form part of the network) can be found precisely on the Australian Geographical RadioFrequency Map, which also lists the frequencies in use at each site.

Operation and uses
The JORN network is operated by No. 1 Radar Surveillance Unit RAAF (1RSU). Data from the JORN sites is fed to the JORN Coordination Centre at RAAF Base Edinburgh where it is passed on to other agencies and military units. Officially the system allows the Australian Defence Force to observe all air and sea activity north of Australia to distances of 3000 km. This encompasses all of Java, Irian Jaya, Papua New Guinea and the Solomon Islands, and halfway across the Indian Ocean. Other sources put the range at 4000 km from the Australian coastline, as far away as Singapore

The JORN is so sensitive it is able to track planes as small as a Cessna 172 taking off and landing in East Timor 2600 km away. Current research is anticipated to increase its sensitivity by a factor of ten beyond this level. It is also reportedly able to detect stealth aircraft, as typically these are designed only to avoid detection by microwave radar. Project DUNDEE was a cooperative research project, with American missile defence research, into using JORN to detect missiles. The JORN is anticipated to play a role in future Missile Defense Agency initiatives, detecting and tracking missile launches in Asia.