Page 44 - Australian Defence Magazine - June 2018
P. 44

“I think people have lost sight of how profoundly hypersonic weapons have changed the game, but OTH radars can play a role.”
receiving array; Radar Two has 960 receiv- ers, and Radar Three has 462.
Achieving a 20dB, 100-fold increase in sensitivity was a self-imposed technology challenge; Phase 6 will achieve a 10-fold increase in performance although an expen- sive technological solution for the higher end figure is available if it’s ever required.
Upgrade activities started in April with the JCC, where improved algorithms, mainly developed by DST, and a series of software builds will enhance the command and con- trol system.
The JCC will also receive an open archi- tecture Distributed Data System (DDS) that was prototyped in the radar concept demonstrators constructed during the JFSP. The DDS will ease the introduction of new applications into JORN and provide oppor- tunities for SMEs to develop new capability.
BAES is also working with Adelaide University on human factors engineering in the JCC and how to focus operators’ atten- tion on value-added tasks.
“It’s vital that we reduce the integration risk as much as possible. We’re looking to install most of the new system at a radar in parallel with the existing system,” Wynd said. “Before we take the radar down we’ll have a modification readiness review that makes sure everyone is lined up and it’s the right time to proceed with Radar One, we’ll parallel-install equipment in the bunkers and in the control room, and that will allow us to do a lot of pre-set to work and integration before we take the system offline which will increase every- body’s confidence in the timeframe to bring it back online.”
R&D history
Research and development on over-the- horizon radar undertaken by DST and its precursor organisations can be traced back to work on HF radar undertaken in the 1950s by immigrants who had earlier been involved with the UK’s Chain Home and Chain Home Low radar systems.
Even at that time it had been noted from time to time that distortion suggested the signal was no longer line-of- sight but was bouncing off
the ionosphere.
A range of studies in the
mid-to-late 1960s under Project Gebung moved to a core OTHR research proj- ect in 1970, culminating in the commissioning of the Jindalee A OTHR at Alice Springs in 1974, Jindalee B in the early 1980s, and
approval in 1986 for the design and devel- opment of the OTHR network.
After more than six decades of cutting- edge OTHR research, DST scientists are now progressing capabilities beyond those intended for Phase 6.
Project Coorong, a joint activity with Lockheed Martin, recently resulted in a ‘minimum viable demonstration’ at Woomera of a new DST-developed OTHR receiver antenna architecture technically described as a Regular Over-sampled Sparse Array (ROSA) that provides significant improvement in total sensitivity – presum- ably the expensive technical solution referred to earlier by Dr Fraser.
A full-size ROSA array would enable JORN to detect and track small, fast-mov- ing targets at extremely long ranges and at night. OTHRs typically operate at lower frequencies at night due to a diminished ionosphere, and this significantly reduces
the radar cross section of small targets such as cruise missiles.
“This has verified an idea that is now ready to go if Air Force wants to take it to the next step,” according to Dr Frazer.
A further future capability is mode selec- tive radar (MSR) that utilises four separate propagation paths through the ionosphere to and from a target. This will improve the detection of slow-moving surface ships using multi-input multi-output radar waveforms and an innovative Skewfire transmitting array that is located at an unusual angle to the receive array. DST describes the technol- ogy as a world first.
Following the success of a low-powered demonstration system in 2014, a full-scale MSR test will take place next year using a Skewfire array now under construction at RadarTwo.
The ability to evolve JORN post-Phase 6 to handle new challenges will be more straight- forward than with the present system, Dr Frazer believes.
Hypersonic challenge
Chief among his future concerns is the threat posed by hypersonics – “I think people have lost sight of how profoundly hypersonic weapons have changed the game, but OTH radars can play a role”.
Whereas ballistic missiles fly very high on a predictable trajectory and can be eas- ily seen by traditional line-of-sight radars, hypersonics fly lower and at more than Mach 6, offer propulsion in the atmosphere and can manoeuvre far more readily than current manoeuvrable missile warheads.
“We think there’s an opportunity to see hypersonic missiles at much longer ranges than line of sight radars, however advanced, and this gives you more opportunity to do something about them,” he said.
In more general terms, Dr Frazer points out that space-based surveillance assets are likely to be destroyed in a serious war, restricting surveillance to what can be physi- cally seen.
“In terms of the wavelengths we use, tar- get classes are very different from the wave- lengths other radars use so perhaps you’ll see things you might not otherwise see. If you’re not able to rely on anything to do with space, you’ve also got the standoff distance.
“Secondly, smart weapons and smart autonomous systems mean that the inherent location inaccuracy of an OTH radar is less of an issue if you’re trying to guide something to a place; you can reasonably do that now with an OTH radar.
“The fundamental concepts behind a lot of these user interfaces have not changed significantly over the years so we’re look- ing at things like eye tracking and thought processes,” Wynd said. “There’s a lot of nuances about how you operate an HF radar in terms of how you interact with the ionosphere and how the data comes back in that space.”
The radars’ upgrades will be undertaken sequentially, starting with Longreach. This site will be taken offline in 2022 with Initial Operating Capability scheduled to coincide with that of the upgraded JCC in the first quarter of 2024 following initial material release and an extensive program of opera- tional test and evaluation.
Laverton will then be taken out of service for slightly less than two years, followed by Alice Springs, where $30 million of new facilities are also programmed, and which will be offline for a full two years.
44 | June 2018 |

   42   43   44   45   46