SKA correlators and beamformers

Major digital signal processing tasks that take place at the site of the Square Kilometre Array (SKA) telescopes are beamforming and correlation. The additional task of searching for pulsars is not discussed in detail in this paper. The combined processing, for correlation, exceeds 10 Pops/s. Input data rates are up to 66 Tb/s (SURVEY array) and output data rates are up to 34 Tb/s (LOW array). The methods used to implement these correlators are discussed. For beamforming, LOW has the highest input data rate of 3 Pb/s coupled with a compute load of 5 Peta integer arithmetic operations per second (Pops/s). The purpose of the beamformer in each antenna array is different. In one case (LOW) the beamformer reduces the field of view, in another (SURVEY) it increases it and for the third array (MID) the beamforming is used to increase sensitivity to allow for the detection of pulsars.