Robust Calibration of Radio Interferometers in Multi-Frequency Scenario

Abstract

This paper investigates calibration of sensor arrays in the radio astronomy context. Current and future radio telescopes require computationally efficient algorithms to overcome the new technical challenges as large collecting area, wide field of view and huge data volume. Specifically, we study the calibration of radio interferometry stations with significant direction dependent distortions. We propose an iterative robust calibration algorithm based on a relaxed maximum likelihood estimator for a specific context: i) observations are affected by the presence of outliers and ii) parameters of interest have a specific structure depending on frequency. Variation of parameters across frequency is addressed through a distributed procedure, which is consistent with the new radio synthesis arrays where the full observing bandwidth is divided into multiple frequency channels. Numerical simulations reveal that the proposed robust distributed calibration estimator outperforms the conventional non-robust algorithm and/or the mono-frequency case.

Matched and Mismatched Estimation of Kronecker Product of Linearly Structured Scatter Matrices Under Elliptical Distributions

“…To bypass this issue, we propose a new and tractable estimation procedure in the next section. Furthermore, our approach is still usable when the access to raw data is impossible, which is especially relevant in applications such as radio-astronomy [37], [38], where the data is too large to be handled and where practitioners have only access to intermediate estimates R.…”