Efficient Imaging Strategies For Next-Generation Radio Arrays

The performance goals of the Square Kilometre Array (SKA) are such thatmajor departures from prior practice for imaging interferometer arraysare required. One class of solutions involves the construction of largenumbers of stations, each composed of one or more small antennas. Theadvantages of such a “large-N” approach are alreadydocumented, but attention has recently been drawn to scalingrelationships for SKA data processing that imply excessive computingcosts associated with the use of small antennas. In this paper weexamine the assumptions that lead to such scaling laws, and argue thatin general they are unlikely to apply to the SKA situation. A variety ofstrategies for SKA imaging which exhibit better scaling behaviour arediscussed. Particular attention is drawn to field of view issues, andthe possibility of using weighting functions within an advancedcorrelator system to precisely control the field-of-view.