Energy and polarization based on-line interference mitigation in radio interferometry
This work addresses RFI contamination for radio astronomers, but it is incremental as it builds on existing mitigation techniques with computational optimizations.
The authors tackled the problem of radio frequency interference (RFI) in radio astronomy by proposing an on-line mitigation scheme that combines energy and polarization statistics, achieving real-time detection especially for low duty-cycle or transient RFI, with results demonstrated on real data.
Radio frequency interference (RFI) is a persistent contaminant in terrestrial radio astronomy. While new radio interferometers are becoming operational, novel sources of RFI are also emerging. In order to strengthen the mitigation of RFI in modern radio interferometers, we propose an on-line RFI mitigation scheme that can be run in the correlator of such interferometers. We combine statistics based on the energy as well as the polarization alignment of the correlated signal to develop an on-line RFI mitigation scheme that can be applied to a data stream produced by the correlator in real-time, especially targeted at low duty-cycle or transient RFI detection. In order to improve the computational efficiency, we explore the use of both single precision and half precision floating point operations in implementing the RFI mitigation algorithm. This ideally suits its deployment in accelerator computing devices such as graphics processing units (GPUs) as used by the LOFAR correlator. We provide results based on real data to demonstrate the efficacy of the proposed method.