The Australia Telescope Compact Array in Narrabri, New South Wales.
Credit: AARNet.
SYDNEY: Plans to distribute accurate time and frequency data across Australia via an existing optical fibre network could help secure a next-generation radio telescope.
The Square Kilometre Array (SKA) will comprise thousands of receptors linked electronically across a continent, but to deliver accurate astronomical observations they will need to operate with precisely synchronised timing.
"We're trying to show that Australia has a solution for one of the most challenging and potentially expensive problems, which is the need to have coordinated times at all of these different locations," said Andre Luiten, an optical physicist at the University of Western Australia in Perth.
"Accurate time signals allow us to fuse together what different telescopes across the country can see at a particular moment to give a single coherent picture," he said. Luiten is leading research into a national time and frequency network (NTFN).
Australia's SKA director Brian Boyle called the network an "innovative service" that would eliminate the need for expensive timing hardware at individual telescope sites. Australia-New Zealand and South Africa are competing to host the A$2 billion radio telescope, with a final decision scheduled for February 2012.
Helping radio astronomy, robotic surgery
Time and frequency measurements are important for a range of technologies used by industries such as telecommunications, broadcasting, commerce and IT, and could also prove vital to future scientific research.
In addition to radio astronomy, improved access to these precise measurements will support other big science projects in Australia, including AuScope - a large Earth sciences infrastructure project.
According to Luiten, time synchronicity could also have applications in everything from robotic surgery, where doctors remotely control instruments, to mobile phones, which switch-over between geographic base stations as people move around.
Real-time corrections
With $600,000 confirmed by the Australian Research Council over the next three years, a research consortium is now creating trial links to test the accurate transfer of time and frequency data. Signals are injected into an optical fibre network, sent across the fibres and reflected back to the original source. As the optical fibres change in temperature or stretch as a result of vibrations in the ground, the signals travelling through the network get disturbed.
"We use the return signal to essentially measure how the line is stretching or contracting. Once we understand how it's fluctuating around, we actively correct for that at the input to the line," said Luiten, who hopes that in two years he'll have demonstrated an accurate signal transfer more than 700 km from his lab in Perth to the proposed core site of the SKA.
