Robust radio interferometric calibration using the T-distribution

Sarod Yatawatta, Sanaz Kazemi, Saleem Zaroubi

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Interferometric observations used in radio astronomy are affected by errors due to the propagation medium such as the ionosphere as well as by the instrument such as the beam shape. Hence, calibration of such observations is essential in order to produce high quality data suitable for scientific endeavors. Traditional calibration implicitly relies on an underlying Gaussian noise model. However, outliers in the data due to interference or model errors would have adverse effects on processing based on a Gaussian noise model. In this paper, we propose to improve the robustness of calibration by using a noise model based on the Student's t distribution. Unlike the Gaussian noise model based calibration, traditional nonlinear least squares minimization would not directly extend to a case when we have a Student's t noise model. Therefore, we use Expectation Maximization when we have a Student's t noise model and use the Levenberg-Marquardt algorithm in the maximization step. We give simulation results to show the robustness of the proposed calibration method as opposed to traditional Gaussian noise model based calibration. We also give timing comparisons to show that robust calibration could be used with only a small additional overhead in practice.

Original languageEnglish
Title of host publication2012 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012
Pages193-197
Number of pages5
DOIs
StatePublished - 2012
Externally publishedYes
Event12th IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012 - Ho Chi Minh City, Viet Nam
Duration: 12 Dec 201215 Dec 2012

Publication series

Name2012 IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012

Conference

Conference12th IEEE International Symposium on Signal Processing and Information Technology, ISSPIT 2012
Country/TerritoryViet Nam
CityHo Chi Minh City
Period12/12/1215/12/12

Keywords

  • Radio astronomy
  • Radio interferometry
  • Robust estimation

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