Realtime Calibration Library
This package contains the Realtime Calibration Pipeline, a SDP Receive Processors Processor that generates real-time calibration solutions for each visibility payload from the realtime receive pipeline. The solutions are then made available for subsequent real-time processing, in particular for tied-array beamforming in the Correlator & Beamformer (CBF) of the Central Signal Processor.
The payloads are SKA SDP Python-based Data Models Visibility xarrays that are sent from the Receiver via an Apache Plasma store, and the calibration solutions are sent to Kafka data queues as NumPy ndarrays of dimension (Nantenna, Nfrequency, Npolarisation=4).
Context
At a high level the realtime receive processors lie at the end of the realtime receive pipeline, each working with data written to the plasma store by the Receiver (in the Realtime-Receive-Modules repository).
The processors are responsible for performing some action on the data, for example writing to a measurement set—and in this case, for performing bandpass calibration. After calibration the antenna-based gains are re-channelised to have spectral sampling that is appropriate for CBF beamforming.
