From antennas to multi-dimensional data cubes: The SKA data path

The SKA baseline design defines three independent radio antenna arrays producing vast amounts of data. In order to arrive at, still big, but more manageable data volumes and rates, the information will be processed on-line to arrive at science ready products. This requires a direct network interface between the correlators and dedicated world-class HPC facilities. Due to the remoteness of the two SKA sites, power as well as the availability of maintenance staff will be but two of the limiting factors for the operation of the arrays. Thus the baseline design keeps just the actual core signal processing close to the center of the arrays, the on-line HPC data reduction will be located in Perth and Cape Town, respectively. This paper presents an outline of the complete digital data path starting at the digitiser outputs and ending in the data dissemination and science post-processing, with a focus on the data management aspects within the Science Data Processor (SDP) element, responsible for the post-correlator signal processing and data reduction.