IN BRIEF
SKA FREQUENCY AND TIMING TESTING AT THE UNIVERSITY OF MANCHESTER BY PROF. KEITH GRAINGE AND DR ALTHEA WILKINSON (THE UNIVERSITY OF MANCHESTER) The Radio Astronomy Advanced Instrumentation Research (RAAIR) Laboratory at the University of Manchester is a university-industry collaboration run by the university’s Department of Physics and Astronomy and Department of Electronic and Electrical Engineering. As part of a Time & Frequency Systems project funded by the RAAIR Laboratory, engineers from Tsinghua University in China have been visiting the SKA Synchronisation and Timing (SAT) team at the University of Manchester, to develop and test potential new frequency and timing transfer systems for the SKA-Low telescope in Australia. Professor Bo Wang and his research student Yufeng Chen are working with the SAT team to test their system, developed at Tsinghua University, which provides a novel, on the fly, active phase correction to mitigate the effects produced as optical fibre expands and contracts with temperature. The team, including RAAIR Engineers Ji Zonghai and You Lu, is also integrating the White Rabbit open source hardware system so that both frequency and timing information can be transferred over a single fibre. The system is being tested as a potential prototype for the SKA pathfinder e-MERLIN telescope network (which is operated by the University of Manchester on behalf of the UK’s Science and Technology Facilities Council), which only has a single fibre available, but will also act as a test-bed for application to the SKA.
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The Tsinghua system is being tested over distances between 20 and 80 km and the results indicate a high level of accuracy, confirming that the system is working at the levels required for SKA-Low. Similar work is also being undertaken by Australian teams working on the SKA-Mid telescope. Professor Michael Garrett, Director of the RAAIR Laboratory and the Jodrell Bank Centre for Astrophysics said: “Accurate time distribution is critical to the operation of radio telescopes like the SKA, permitting signals detected by pairs of antennas to be coherently combined, enabling the array to act as an interferometer. This is at the very heart of the SKA design, since it makes the required sensitivity of the telescope feasible by allowing signals from multiple antennas to be combined, giving the telescope its power to resolve small features on the sky. This collaboration shows how much can be achieved when universities team up with industry partners – I’m absolutely thrilled by the first results.”
RAAIR team members; Ji Zonghai, Lydia Kong, Yufeng Chen and You Lu. Credit: The University of Manchester
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