Detecting Radio Frequency Interference in radio-antenna arrays with the Recurrent Neural Network algorithm

Abstract

Signal artefacts due to Radio Frequency Interference (RFI) are a common nuisance in radio astronomy. Conventionally, the RFI-affected data are tagged by an expert data analyst in order to warrant data quality. In view of the increasing data rates obtained with interferometric radio telescope arrays, automatic data filtering procedures are mandatory. Here, we present results from the implementation of a RFI-detecting recurrent neural network (RNN) employing long-short term memory (LSTM) cells. For the training of the algorithm, a discrete model was used that distinguishes RFI and non-RFI data, respectively, based on the amplitude information from radio interferometric observations with the GMRT at $610\, \mathrm{MHz}$. The performance of the RNN is evaluated by analyzing a confusion matrix. The true positive and true negative rates of the network are $\approx 99.9\,\%$ and $\approx 97.9\,\%$, respectively. However, the overall efficiency of the network is $\approx 30\%$ due to the fact that a large amount non-RFI data are classified as being contaminated by RFI. Matthews correlation coefficient is ~0.42 suggesting that a still more refined training model is required.