Robust distributed calibration of radio interferometers with direction dependent distortions

Virginie Ollier (1, 2) , El Korso (3) , André Ferrari (4) , Remy Boyer (1, 5) , Pascal Larzabal (2)

1 L2S - Laboratoire des signaux et systèmes
2 SATIE - Systèmes et Applications des Technologies de l'Information et de l'Energie
3 LEME - Laboratoire Energétique Mécanique Electromagnétisme
4 LAGRANGE - Joseph Louis LAGRANGE
5 CRIStAL - Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189

In radio astronomy, accurate calibration is of crucial importance for the new generation of radio inter-ferometers. More specifically, because of the potential presence of outliers which affect the measured data, robustness needs to be ensured. On the other hand, calibration is improved by taking advantage of these new instruments and exploiting the known structure of parameters of interest across frequency. Therefore, we propose in this paper an iterative robust multi-frequency calibration algorithm based on a distributed and consensus optimization scheme which aims to estimate the complex gains of the receivers and the directional perturbations caused by the ionosphere. Numerical simulations reveal that the proposed distributed calibration technique outperforms the conventional non-robust algorithm and per-channel calibration.

Keywords: Calibration; robustness; multi-frequency; radio astronomy

Domains: Engineering Sciences [physics]; Signal and Image processing; Sciences of the Universe [physics]; Astrophysics [astro-ph]

Virginie Ollier, El Korso, André Ferrari, Remy Boyer, Pascal Larzabal. Robust distributed calibration of radio interferometers with direction dependent distortions. Signal Processing, 2018, 153, pp.348-354. ⟨10.1016/j.sigpro.2018.07.024⟩. ⟨hal-01851032⟩