The international Central Signal Processor (CSP) consortium has concluded its design work on the SKA, marking the end of five years' work comprised of 11 signatory members from 8 countries with more than 10 additional participating organisations.
Published by the editorial team, 12 February 2019
The consortium, led by the National Research Council of Canada (NRC)*, has designed the elements that will together form the "processing heart" of the SKA. The CSP is the first stage of processing for the masses of digitised astronomical signals collected by the telescope's receivers. It's where the correlation and so-called beamforming takes place to make sense of the jumble of signals, before the data is sent onwards to the Science Data Processor. At that stage, the data is ready to be turned into detailed astronomical images of the sky.
The CSP includes the Pulsar Search and Timing sub-elements, which enable astronomers to detect and characterise pulsars and fast transients. This will facilitate the most comprehensive and ambitious survey yet to detect all pulsars in our own galaxy as well as the first extragalactic pulsars. The Pulsar Search sub-element is based on a hybrid architecture of Graphics Processing Units (GPUs) and Field Programmable Gate Arrays (FPGA) computing boards. The design team was led by the University of Manchester (UK), University of Oxford (UK) and the Max Planck Institute for Radio Astronomy (Germany) supported by input from INAF (Italy), New Zealand Alliance, STFC ATC Edinburgh (UK), and ASTRON (the Netherlands). The Pulsar Timing sub-element is based on GPUs. The design team consisted of participants from Swinburne University of Technology (Australia) and the New Zealand Alliance.
As part of their work, the consortium designed the FPGA computing boards that will perform correlation and beamforming (CBF) on the signals from the SKA. The CBF for the SKA-mid telescope -to be located in South Africa- is based on Intel FPGA technology and was led by the NRC with support from MDA, a Maxar Technologies company, AUT University (New Zealand), and INAF. The CBF for the SKA-low telescope -to be located in Australia- is based on Xilinx technology and was led by CSIRO with support form ASTRON and AUT University. Hundreds of these boards are required to meet the demanding processing requirements.
The Local Monitoring and Control sub-element was led by the NRC with contributions from MDA, INAF, and NCRA (India).
The consortium was given a full pass by the review panel during the CSP Critical Design Review (CDR) in September, the first SKA engineering consortium to receive this result. With very few actions required following the review, the consortium has now concluded its work.
"Working on opposite sides of the globe could have its difficulties; planning a meeting with a 12-hour time difference was a challenge. But with modern ways of working we tackled most of the issues. For the board design it was a real benefit. We both worked on the same design during our normal working day - that meant 16 hours of work daily, which speeded up the design significantly! Working in an international team with a lot of knowledge of building instrumentation was a real benefit, we could really learn from each other to find the best solutions." Says Gijs Schoonderbeek instrument engineer at ASTRON.
The consortium was formed in late 2013 as one of 12 international engineering consortia tasked with designing the SKA, a global effort representing 500 engineers in 20 countries. Nine consortia focused on core elements, while three developed advanced instrumentation for the telescope. The nine consortia are now at CDR stage, where an expert panel examines each design proposal against the SKA's stringent requirements.
Now that its work is complete the consortium formally disbands, although the SKA Organisation will work closely with participating countries to prepare for the overall System CDR and the development of the SKA construction proposal.
"What made the design challenge so difficult are the exacting requirements for a telescope to deliver SKA telescope transformational science," said Philip Gibbs, SKA Organisation Project Manager for CSP. "The system has to meet observing requirements that may include imaging, as well as VLBI, and pulsar search and timing, all at the same time. As well as the power and space issues on site, we've naturally also been constrained by the cost involved in providing a solution."
"To reach this point is a testament to the tremendous effort of all the institutions involved in designing CSP - my heartfelt thanks go to them. We look forward to continued collaboration as we progress down the road towards construction of the SKA."
*The CSP Consortium Project Management Office was led by a collaboration between the NRC and MDA Systems Ltd, a contracted industry partner. Active consortium members (signatories) at the conclusion of the work included: Netherlands Institute for Radio Astronomy (ASTRON), Commonwealth Scientific and Industrial Research Organisation (CSIRO) (Australia), Swinburne University of Technology (Australia), Max Planck Institute for Radio Astronomy (Germany), National Institute for Astrophysics (INAF) (Italy), New Zealand Alliance (AUT University, Massey University, University of Auckland, Compucon New Zealand and Open Parallel Ltd.), the Science and Technology Facilities Council (STFC) (UK), University of Manchester (UK), and University of Oxford (UK).
Find out more about CSP's work, including photos and videos.
About the SKA
The Square Kilometre Array (SKA) project is an international effort to build the world's largest radio telescope, led by the SKA Organisation based at the Jodrell Bank Observatory near Manchester, UK. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.
The SKA is not a single telescope, but a collection of telescopes, called an array, to be spread over long distances. The SKA will be constructed in Australia and South Africa; with a later expansion in both countries and into other African countries.
Already supported by 12 countries - Australia, Canada, China, France, India, Italy, the Netherlands, New Zealand, South Africa, Spain, Sweden and the United Kingdom - the SKA Organisation has brought together some of the world's finest scientists, engineers and policy makers and more than 100 companies and research institutions in the design and development of the telescope.
About the NRC
The National Research Council Canada (NRC) is the Government of Canada's premier organisation for research and development. The NRC's Herzberg Astronomy and Astrophysics Research Centre is Canada's gateway to the universe, operating its national observatories and a national astronomy data centre, and developing advanced astronomical instruments in collaboration with industrial partners. The NRC's Herzberg has been working for more than 10 years to develop key technologies for the SKA, including correlator/beamformer signal processing, cryogenic low noise amplifiers, high-speed direct-conversion digitizers and phased array feeds.
Low CBF Water-cooled Perentie Gemini Processing Board (left), Mid CBF Air-cooled TALON-DX Processing Board (right).