The Jindalee Operational Radar Network (JORN) is an over-the-horizon radar network that can monitor air and sea movements across 37,000km². It has an official range of 3,000 km but depending upon certain atmospheric conditions has a range up to and including the Korean peninsula. It is used in the defence of Australia and can also monitor maritime operations, wave heights and wind directions. It was built by RLM Management ^[1], then in Burwood East in Melbourne, in partnership with Defence Science and Technology Organisation, Lockheed Martin, Telstra, BAE and Tenix Defence Systems. Up to now, the network has cost approximately $A1.8 billion. Over-The-Horizon radar (OTHR) is a design concept for radar system to overcome the problem that radio waves (a form of light) travel in a straight line, making over the horizon detection difficult. ... The Defence Science and Technology Organisation (DSTO) is a branch of the Australian Department of Defence which researches and develops technologies for use in the Australian Defence Industry. ... Lockheed/BAE/Northrop F-35 Lockheed Trident missile C-130 Hercules; in production since the 1950s, now as the C-130J Lockheed Martin (NYSE: LMT) is an aerospace manufacturer formed in 1995 by the merger of Lockheed Corporation with Martin Marietta. ... Telstra Corporation (ASX: TLS, NZX: TLS, NYSE: TLS) (formed from Telecom Australia) is an Australian telecommunications company under joint public/private ownership, holding a dominant position in landline telephone services, large share of mobile phone services, domestic consumer (including dial-up access and Broadband internet broadband cable modem, satellite and... BAE Systems plc is the worlds fourth largest defence contractor [2] and a commercial aerospace manufacturer. ... Tenix Pty Ltd is the parent company of the Tenix Group, Australia’s largest locally-owned defence and technology contractor. ...

The JORN consists of 2 active radar stations; one near Longreach, Queensland and another near Laverton, Western Australia. 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: Australian Stockmans Hall of Fame in Longreach Location of Longreach in Queensland (red) Longreach is a town and shire located in central western Queensland, Australia and is approximately 700 kilometres from the coast, west of Rockhampton. ... Laverton is a town and shire in the Goldfields-Esperance region of Western Australia. ...

• the Longreach transmitter, with ninety degree coverage (23.658047° S 144.145432° E),
• the Longreach receiver, with ninety degree coverage (24.291095° S 143.195286° E),
• the Laverton transmitter, with one hundred and eighty degree coverage (28.317378° S 122.843456° E), and
• the Laverton receiver, with one hundred and eighty degree coverage (28.326747° S 122.005234° E).

There is also an active radar system near Alice Springs in the Northern Territory, which is used for testing and was the original 'Jindalee Stage B' test bed on which the design of the other two stations was based. The two Northern Territory sites are: Alice Springs on a large scale map Alice Springs is a town in the Northern Territory of Australia located at . ...

• the transmitter at Harts Range^[2], with ninety degree coverage (22.967561° S 134.447937° E), and
• the receiver at Mount Everard^[2], with ninety degree coverage (23.521497° S 133.677521° E).

In addition 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 (23.530074° S 133.68782° E). Location of Harts Range in Northern Territory (red) Harts Range is a location in the Northern Territory. ...

The high frequency radio transmitters at Longreach and Laverton each put out a 20 kilowatt signal. The signal is bounced off the ionosphere and is received at the Longreach and Laverton stations. They use radio frequencies between about 3 and 30 MHz, which is far lower than most other civilian and military radars that operate in the microwave frequency band. High frequency (HF) radio frequencies are between 3 and 30 MHz. ... The kilowatt (symbol: kW) is a unit for measuring power, equal to one thousand watts. ... Relationship of the atmosphere and ionosphere The ionosphere is the part of the atmosphere that is ionized by solar radiation. ... Microwaves are electromagnetic waves with wavelengths longer than those of Terahertz (THz) wavelengths, but relatively short for radio waves. ...

The JORN network is operated by No. 1 Radar Surveillance Unit RAAF (1RSU). Data from the JORN sites is fed to the JORN Correlation Centre at RAAF Base Edinburgh where it is passed on to other agencies and military units. No. ... RAAF Base Edinburgh is a Royal Australian Airforce base in the northern suburbs of Adelaide, South Australia. ...

The system allows the Australian Defence Force to observe all air and sea activity north of Australia to distances of 3000km. This encompasses all of Java, Irian Jaya, Papua New Guinea and the Solomon Islands, and halfway across the Indian Ocean. The Australian Defence Force numbers about 53,000 full-time active duty personnel plus another 20,700 reservists. ...

The JORN is so sensitive it was able to track planes taking off and landing in East Timor 2600 km away. It is able to detect a Cessna 172 aeroplane and research is underway to increase the sensitivity by "up to 100 fold"^[2]. It is also reportedly able to detect stealth aircraft ^[3]; aside from the fact that most stealthy aircraft are optimized for defeating much higher-frequency radar from front-on rather than low-frequency radars from above, JORN is reputedly able to detect aircraft wake turbulence. Research is proceeding into using JORN to detect missiles, in cooperation with American missile defence research ^[4]. The Cessna 172 Skyhawk is a four-seat, single-engine, high-wing airplane. ... A missile (British English: miss-isle; U.S. English: missl) is, in general, a projectile—that is, something thrown or otherwise propelled. ... Missile defense is a term referring to the ability to intercept missiles in a given context. ...

A significant use of the JORN is the detection of boats landing on the northern shores of Australia^[2].

See also

• Ionosphere
• Over-the-horizon radar
• Imaging radar

Relationship of the atmosphere and ionosphere The ionosphere is the part of the atmosphere that is ionized by solar radiation. ... Over-The-Horizon radar (OTHR) is a design concept for radar system to overcome the problem that radio waves (a form of light) travel in a straight line, making over the horizon detection difficult. ... Traditional radar sends directional pulses of electromagnetic energy and detects the presence, position and motion of an object (such as an airplane) by analyzing the portion of the energy reflected from the object back to the radar station. ...

References

1. ^ RLM Group web site
2. ^ ^a b c d Erwin Chlanda, Nowhere To Hide When Alice's Radar Zeroes In, Alice Springs News, April 28, 2004
3. ^ Michael Sinclair-Jones, JORN assures early warning for Australia, Defence Systems Daily, 29 February 2000
4. ^ U.S. And Australia Cooperate In Missile Detection, Missile Defense Agency

External links

• The Development of Over-the-Horizon Radar in Australia - paper by D.H. Sinnott on the Australian Department of Defence website

• Defence Department Website for JORN
• Summary of the JORN system
• JORN Project History from RLM