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Paper: Ionospheric Corrections in AIPS++
Volume: 238, Astronomical Data Analysis Software and Systems X
Page: 411
Authors: Smirnov, O.
Abstract: The ionosphere induces significant distortion in radio astronomical measurements at lower frequencies. For polarimetric work, the most significant effect is Faraday rotation, reaching up to several turns at, e.g., meter wavelengths. Over the course of an observation, variations in the Faraday rotation can completely wash out any polarization in the signal. The effect can be corrected for only if an accurate enough estimate of the electron density distribution along the line-of-sight is somehow obtained. Campbell (1999) has experimented both with an a priori theoretical model of the ionosphere, and with GPS observations, to perform ionospheric corrections in VLBI observations. I present an extension of this approach into the AIPS++ system. AIPS++ now includes an Ionosphere module, encompassing the Parametrized Ionospheric Model (Daniell et al. 1995), and a calibration component that, given a dataset, will automatically estimate and correct for the Faraday rotation. This paper also describes some other applications of the AIPS++ Ionosphere module, such as modelling and simulation.
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