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A new leap in RFI mitigation

Submitter: Sarod Yatawatta
Description: Terrestrial radio telescopes are always affected by radio frequency interference (RFI). It is rather straight-forward to detect and mitigate strong RFI that stand well above the nominal data. However, weak RFI can remain hidden below the celestial signals and may pass undetected. Nonetheless, this weak RFI will cause problems in deep observations that accumulate many hundreds of hours of observing time.

Instead of looking at the energy of the RFI, which is already too low in weak RFI, we can look at the alignment of RFI in polarization as a detection criterion. We have combined this idea with distributed wideband spectrum sensing to develop a novel directional statistic (DS) based method of RFI mitigation. The above figure shows the performance of this method compared with two conventional RFI mitigation methods: sum-threshold (ST) and spectral kurtosis (SK). The x-axis shows the relative strength of the RFI. The y-axis shows the probabilities of RFI not being detected (missed detection) and good data being classified as RFI (false alarm). We see that the DS method can detect more weak RFI compared to conventional methods.

The details of this work are to be presented at the European signal processing conference (EUSIPCO https://eusipco2020.org/) in Amsterdam.
Copyright: Sarod Yatawatta
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