Skip to ContentSkip to Navigation
About usNews and EventsNews articles

System design and wide-field imaging aspects of synthesis arrays with phased array stations. To the next generation of SKA system designers

14 December 2012

PhD ceremony: Mr. J.D. Bregman, 12.45 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: System design and wide-field imaging aspects of synthesis arrays with phased array stations. To the next generation of SKA system designers

Promotor(s): prof. W.N. Brouw, prof. H.R. Butcher

Faculty: Mathematics and Natural Sciences

This dissertation covers the art of designing an aperture synthesis radio telescope like LOFAR. Well-known design principles are combined with a vision of new solutions that are expected to materialize in the near future, due to current technological developments. The central question is how scientific users with a given budget can achieve optimum results when the final instrument becomes operational.

System design starts with an analysis of the fundamental limitations of image forming by means of aperture synthesis, and of practical limitations like the disturbance caused by the ionosphere. Such an analysis leads to the formulation of a number of scaling laws for the optimum array configuration, and for the amount of digital processing that will be required.

An aperture synthesis telescope consists of an array of stations (groups of antennas). In a station, the signals from multiple antennas are added electronically in such a way that the sensitivity is maximized in a given direction. This technology offers the flexibility of distributing a given number of antennas over an optimum number of stations.

Our research has shown that such stations must have a minimum size, to allow effective correction of ionospheric disturbances over the entire field of view. Too small stations only allow proper correction for a limited part of their large field of view. Too few stations cause additional noise that can only partly be removed by more processing.

An important practical problem is the non-trivial amount of processing that is required for image forming. Therefore, an important result of this thesis is the development of new and efficient methods, that reduce the required processing to the theoretical minimum, i.e. proportional to the area of the field of view, expressed in resolution elements. For a sufficient number of stations in an optimal configuration, it should be possible to achieve minimum noise as well as minimum processing for the new generation of giant radio telescopes, from LOFAR to SKA and beyond.

Last modified:15 September 2017 3.42 p.m.

More news

  • 17 April 2019

    Why lightning often strikes twice

    In contrast to popular belief, lightning often does strike twice, but the reason why a lightning channel is ‘reused’ has remained a mystery. Now, an international research team led by the University of Groningen has used the LOFAR radio telescope to...

  • 16 April 2019

    Still going strong after four decades

    On March 29th professor of Applied Physics Jeff de Hosson was offered a farewell symposium, a few months after his official retirement date near the close of 2018. ‘But 29 March was the 100th birthday of Jan Francken, my predecessor.’ Besides, De Hosson...

  • 11 April 2019

    Ben Feringa in orbit around the Sun

    Dozens of minor planets that used to orbit the Sun anonymously were named by the International Astronomical Union on 6 April 2019. The asteroid that used to be known as ‘minor planet 12655’ was named after Prof. Ben Feringa, winner of the 2016 Nobel...