Multichannel Interference Mitigation Techniques in Radio Astronomy Amir Leshem and Alle-jan Van Der Veen

Radio-astronomical observations are increasingly corrupted by radio frequency interference, and on-line detection and Ðltering algorithms are becoming essential. To facilitate the introduction of such techniques into radio astronomy, we formulate the astronomical problem in an array signal processing language and give an introduction to some elementary algorithms from that Ðeld. We consider two topics in detail : interference detection by rank estimation of short-term covariance matrices and spatial Ðltering by subspace estimation and projection. We discuss experimental data collected at the Westerbork Synthesis Radio Telescope and illustrate the e†ectiveness of the spacetime detection and blanking process on the recovery of a 3C 48 absorption line in the presence of GSM mobile telephony interference. Subject headings : instrumentation : interferometers È methods : analytical È methods : statistical