Simulating Spectral Kurtosis Mitigation against Realistic RFI signals

Abstract

We investigate the effectiveness of the statistical radio frequency interference (RFI) mitigation tech-nique spectral kurtosis ( (cid:100) SK ) in the face of simulated realistic RFI signals. (cid:100) 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 (cid:100) 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 (cid:100) SK , which com-bines information from adjacent time-frequency bins to mitigate weaknesses in single-scale (cid:100) 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 (cid:100) 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.