Efficient Calibration of Radio Interferometers Using Block LDU Decomposition
Ahmad Mouri Sardarabadi (Rijksuniversiteit Groningen)
Alle-Jan van der Veen (TU Delft - Signal Processing Systems)
Leon V.E. Koopmans (Rijksuniversiteit Groningen)
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Abstract
Having an accurate calibration method is crucial for any scientific research done by a radio telescope. The next generation radio telescopes such as the Square Kilometre Array (SKA) will have a large number of receivers which will produce exabytes of data per day. In this paper we propose new direction-dependent and independent calibration algorithms that, while requiring much less storage during calibration, converge very fast. The calibration problem can be formulated as a non-linear least square optimization problem. We show that combining a block-LDU decomposition with Gauss-Newton iterations produces systems of equations with convergent matrices. This allows significant reduction in complexity per iteration and very fast converging algorithms. We also discuss extensions to direction-dependent calibration. The proposed algorithms are evaluated using simulations.