Surveillance: What's on the horizon for JORN? | ADM Jun 08

1 June 2008

Developed to a 1990s specification and design, Australia's world beating OTH radar is today soldiering on, supported by continual improvements to its long-range surveillance and target detection capabilities.

But, in the fast moving world of computer electronics, where algorithm is king, JORN is beginning to show its age.

By Tom Muir, Canberra

So what is on the horizon for JORN?

Defence White Paper willing and an empathetic government, there are interesting developments in the wings for JORN's next generation, that would not only outstrip its current (and improving) capabilities but would establish JORN2 as this country's cornerstone ISR enabler.

But more of this later.

The Jindalee Over The Horizon Radar Network (JORN) is an extremely sensitive HF surveillance system with the range and accuracy required to monitor and detect moving objects at extreme distances from Australia's northern coastline.

The technology and subsystems used in the OTHR are continuously developed to enhance its capability for missile defence initiatives, aircraft and ship detection and tracking, plus more recently, illegal fishing activity.

This country's unique wide-range defence needs has helped to make Australia a pioneer in the development of advanced OTHR systems and is now considered a world leader in the field.

As part of necessary ongoing support arrangements for the Jindalee OTH Radar Network (JORN), contracts were signed in June last year with RLM and BAE Systems Australia, partners in the OTHR Systems Program Office (OTHRSPO), enabling them to continue their work on the development and management of this country's world beating skywave OTH radar system.

RLM's contract, worth $262 million, is for system maintenance and engineering and other support for the two JORN sites at Laverton in Western Australia and Longreach in Queensland.

The BAE Systems contract, worth $131 million, is for ongoing support of the Jindalee radar Facility at Alice Springs (JFAS).

The radars of the JORN network are an advanced development of the Australian designed radar at JFAS which is in operational use as well as being a research and development facility used by DSTO and the OTHR SPO for ongoing OTHR improvements.

While these contracts provide for the ongoing engineering, logistics and maintenance support of specialist transmitter and receiver equipment, they also include an acquisition development component, which provides for the future capability development of the OTHR network.

Ongoing work
These activities fall under Phase 5 of project JP2025, which, managed by the OTHR SPO, is building on the capabilities of the JORN system delivered in 2003.

The specifications that JORN was designed and accepted against were established in the early 1990s.

Since that time, the JFAS radar has been in operational service with the RAAF since 1992 and has evolved significantly, though continual R&D efforts by OTHR SPO, DSTO and BAE Systems and operational requirements derived from service use.

This has enabled the identification of technical and operational areas in JORN that can be readily be enhanced.

Phase 5 is introducing these developments to the QLD and WA radars, and will also progress the introduction of a common interface for all radars and the integration of JFAS into a three radar, national OTHR radar network.

Other tasks include improving the distribution of surveillance information to national agencies and undertaking further research and development into next generation OTHR technology.

And while Phase 5 does not include missile defence enhancements among the specific capabilities sought for JORN - this work is being handled quite separately by DSTO - there is not doubt that current work aimed at improving range and sensitivity, will enable it to detect incoming missiles during their early boost phase.

This point was clarified by the then Defence Minister Robert Hill when he said in 2004 that while JORN's principal objective was to see aircraft over large distances.

"Further upgrades will allow it to see much smaller objects such as missiles."

Our understanding is that there are nominally two streams of R&D activity associated with improvements to the JORN OTHR system.

One, managed by DSTO and, assuming that the Rudd Government plans to continue this research into missile defence, comes under an MOU with a 25-year framework, for Australian-US cooperation on missile defence with areas of cooperation including technological transfer, and the use of long-range OTH land-based radars in Australia.

As we have noted, the other stream, under the aegis of the OTHRSPO, builds upon the capabilities of the JORN system, but with significant developments ahead under JP 2096 or possibly a new developmental phase under JP 2025.

Missile defence
For the sake of background on a subject that has been widely associated with JORN, we reiterate here that DSTO worked with the US Ballistic Missile Defense Organisation (BMDO) in a cooperative project involving sensor/data fusion testing conducted at the Woomera Missile Range in October 1995.

This experiment correlated multiple sensors (optical and RF radar) during the boost phase of a rocket and transmitted the real-time data and imagery via satellite link to the United States.

Two years later Australia and the United States conducted a series of joint scientific experiments to investigate early detection of theatre ballistic missile launches.

Subsequent trials, led by the DSTO and conducted in April 2004 near Darwin with US officials present, examined whether Australian OTH Radar technology could improve the detection of ballistic missiles during their early boost phases, thus allowing for early interception.

In reference to this trial, then Defence Minister Robert Hill, said this was precisely the sort of work the government envisaged when committing to the missile defence program.

While there was no immediate threat to Australia from ballistic missiles, this collaborative work put Australia and its scientists at the forefront of leading edge research and development. It was also a prudent investment in potential future capabilities for the defence of Australia, Hill said.

The Darwin trials were aimed not only at detecting the target but also whether additional and more accurate information about the trajectory of the missile could be obtained using multiple digital receiving systems.

Given that missiles are a more demanding target than the target used, an aircraft in level flight, the technology was further tested using missile launches from a test range in the United States as targets of opportunity.

Subsequent work investigated the automatic detection and tracking of the missile signatures and the fusion of this information with information from other sources

Multiple digital HF receivers
The multiple receiving systems referred to are part of a suite of HF surveillance products that the Advanced Technology Group of BAES Australia developed in conjunction with the OTHRSPO and DSTO at JFAS and Edinburgh, in support of the Jindalee and JORN OTH radar programs.

These activities were funded through the OTHR SPO and BAE Systems own R&D, and include Digital HF Receivers with supporting systems that integrate the frequency management function with the radar receiver function.

BAE Systems digital OTHR receivers have been further developed and improved by DSTO with large numbers now in use for ongoing research and proofing.

They were used in further Australian experiments at the US missile range (White Sands) for the detection and tracking of missiles.

Much of this work involved the collection and analysis of launch and missile tracking data from the digital receiver systems.

Interestingly, for these trials, in a test of their sensitivity, the receivers and their arrays were sited down range within the footprint of the OTH Radar and therefore must distinguish the relatively minute returns of the target and its track in the presence of the strong direct signal from the radar illuminator, as well as other external noise and interference sources-so-called environmental noise.

The advantage of multiple digital receiver systems lies in improved system sensitivity, resolution and target registration and in the volume of data that can be stored for subsequent analysis, presumably including such valuable information as the trajectory of the missile after launch and hence an indication as to its impact point.

A paper, Forward-based Receiver Augmentation for OTHR presented by G J Frazer, at the Radar Conference, 2007 IEEE, describes an experimental multi-static HF radar that augments conventional over-the-horizon radar (OTHR) by placing multiple forward-based receiver systems within line-of-sight of targets of interest.

"With sufficient and appropriately located forward-based receiver sites the radar can generate target tracks that are independent of the uncertain ionospheric state and the system has low incremental cost compared with a complete OTHR.

"Each site in the multi-static system consists of a ten element linear array with a direct digital HF receiver per element architecture and the receiving components have sufficient dynamic range and spectral purity to operate in the footprint of the direct OTHR transmitter signal.

"The system uses custom receivers that integrate the frequency management function with the radar receiver function.

"Signal processing algorithms include real-time STAP and adaptive CFAR.

"Inter-site communications is achieved using a low-cost 802.11 b wireless communications network where the longest path in this network is 37 km.

"The system has performed beyond expectation for the desired target class."

But while it can be assumed that considerable information has been gained on the early detection and tracking by OTH radar of missiles at their launch and boost phases, it appears more work would be needed before modifications can be introduced to the JORN system to enable it to be configured for this mission, should this be desired.

And that is entirely in the hands of the present government.

Further trials?
If further trials are required one would assume that they would be performed at Woomera with rockets of opportunity.

But research into missile defence doesn't stop there. DSTO and the University of Adelaide recently signed an agreement last year to establish the Centre of Expertise in Phased Array and Microwave Radar Systems (CEPAMR) within the University's School of Electrical and Electronic Engineering.

Research outputs from the centre are expected to have significant long-term benefits for defence applications such as:

- capability development of the phased array radar on airborne platforms as well as radars proposed for future naval platforms,

- emerging Ballistic Missile Defence surveillance and tracking requirements, and

- a potential indigenous air defence radar system for Army applications.

This country's support for the US missile defence program is likely to progress little beyond the continuation of joint research and development programs with the US on the use of microwave radar in early warning systems.

This may eventually lead to the first rate JORN surveillance capability being able to detect ballistic missiles at their early boost phases at considerable distances.

If integrated into the US missile defence configuration, such information could be fused with data from satellites and other early warning surveillance systems.

Other research outputs
As Phase 5 of JP2025 continues to build on the capabilities of the established JORN radars and look at new technology capabilities for the next generation of OTHRs, so consideration needs now to be given to the development of the next generation of JORN OTHR systems and the dissemination of its data.

As the ADF-wide surveillance system expands with inputs from land-based, airborne, maritime surface and subsurface and space-based sensors, the task of managing and fusing the flow of data, disparate in form and volume, is an enormous one.

Joint Project 2096 Surveillance Enhancement will focus on the correlation and fusion of the data sourced from multiple surveillance sensors available to the Defence organisation.

According to the Defence Capability Plan a most important aspect will lie in the information management aspects including the tasking and information dissemination of the sensor outputs.

But the development of the next generation JORN is another matter.

Will JP 2025 receive further funding to move into the next developmental phase, possibly Phase 6?

Or will a new project be raised to take account of the latest advances in OTHR radar technology.

So what new capabilities are waiting in the wings for an empathetic government to seize upon and ensure this country's pre-eminence in radar technology?

First one might expect the employment of multiple digital receivers within the OTHR footprint at sites of critical national interest for their monitoring and protection against undetected incursion or attack would be an important and reasonably low cost priority to extend the capabilities of the current JORN system.

Consideration would then need to be given to updating, augmenting or replacing the JORN system to take advantage of new developments in OTHR and radar technology such as electronic scanning arrays, digital beamforming and 3D operation.

Current drawbacks include the system's inability to simultaneously detect and track different target classes, that is targets defined according to their size, speed and acceleration.

The existing JORN radars have bi-static transmit and receive array antennas separated by about 100km.

Because of their architecture, the receive arrays have no scan capability in elevation.

Our understanding is that improvements over the current OTHR capability could be achieved through the use of directional arrays electronically scanning the beam in both azimuth and elevation.

The incorporation at each site of 2D receiving arrays and 2D transmitting arrays, suitably arranged, would provide the 3D capability.

There are suggestions that rather than updating or replacing the existing large and expensive radar systems consideration should be given to augmenting them with multiple overlapping small 3D OTHRs distributed across the north and northwest, each adapted to particular target classes of interest.

Perhaps these in turn will be superceded by fully autonomous systems, adapting readily to dynamic operational environments both military and civilian.

But it remains for government to decide how far they wish to go in rebuilding JORN's capabilities--this nation's major security portal.