2019/02/07 by Ahmad Mouri Sardarabadi, L. V. E. Koopmans, Sardarabadi, A. Mouri +1
Computer Science · Decision Sciences · Engineering · Physics and Astronomy · #Advanced Measurement and Metrology Techniques #Advanced Wireless Communication Techniques #Digital Filter Design and Implementation #FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Radio Astronomy Observations and Technology #Scientific Measurement and Uncertainty Evaluation
paper · pdf · doi:10.48550/arxiv.1902.02482
openalex publication_date 2019/02/07 · openalex created_date 2022/09/12 · openalex updated_date 2026/07/28
Calibration is a key step in the signal processing pipeline of any radio\nastronomical instrument. The required sky, ionospheric and instrumental models\nfor this step can suffer from various kinds of incompleteness. In this paper we\nanalyze several important calibration methods, ignoring for now the ionosphere.\nThe aim is to use established statistical and signal processing tools to\nprovide a generic method to assess calibratability of an instrument. We show\nhow currently popular calibration techniques differ in their assumptions and\nalso discuss their theoretical commonalities. We also study the effect of only\nusing a sub-set of baselines on the calibration and provide theoretical methods\nto analyze excess noise and biases that it might introduce. In order to\nsimplify the physical interpretation of the results, we introduce a new signal\nprocessing model which is capable of modeling instrumental direction dependent\neffects and spectral smoothness of the individual receiver gain within a\nbeam-formed station. The statistical properties of this model are then studied\nby deriving the Cram 'er--Rao bound (CRB). We finally define a mathematical\nframework for calibratability of an instrument based on the model used which is\ngeneric and can be used to study different instruments. These theoretical\nresults are then verified using numerical simulations.\n