Simulating Spectral Kurtosis Mitigation Against Realistic RFI Signals

TL;DR

This paper evaluates the effectiveness of spectral kurtosis (SK) as a statistical method for detecting and mitigating realistic radio frequency interference (RFI) signals in radio astronomy, including multi-scale approaches.

Contribution

It introduces multi-scale SK techniques and assesses their performance against various realistic RFI signals, highlighting strengths and limitations.

Findings

Multi-scale SK detects over 90% of RFI signals with appropriate bin width.

High data rate signals with sidelobes are more challenging to flag.

Weak signals and those with high duty cycles are harder to detect.

Abstract

We investigate the effectiveness of the statistical radio frequency interference (RFI) mitigation technique spectral kurtosis (SK) in the face of simulated realistic RFI signals. SK estimates the kurtosis of a collection of M power values in a single channel and provides a detection metric that is able to discern between human-made RFI and incoherent astronomical signals of interest. We test the ability of SK to flag signals with various representative modulation types, data rates, duty cycles, and carrier frequencies. We flag with various accumulation lengths M and implement multi-scale SK, which combines information from adjacent time-frequency bins to mitigate weaknesses in single-scale \SK. We find that signals with significant sidelobe emission from high data rates are harder to flag, as well as signals with a 50% effective duty cycle and weak signal-to-noise ratios. Multi-scale SK with at least one extra channel can detect both the center channel and side-band interference, flagging greater than 90% as long as the bin channel width is wider in frequency than the RFI.