Proposed method for radio-frequency interference mitigation and signal restoration of pulsar signals

Pulsar signals obtained with radio telescopes are extremely weak. Generally, there are two primary difficulties in pulsar signal processing—one is the radio-frequency interference (RFI) mitigation, and the other one is information loss due to the preprocessing and mitigation itself.

Therefore, the innovations in RFI elimination method are meaningful to carry out further studies on the astronomical measurements, such as pulsar timing.

Using pulsar data collected by the NanShan 26-m Radio Telescope (NSRT) from 2011 to 2014, researchers from the Xinjiang Astronomical Observatory (XAO) of the Chinese Academy of Sciences have proposed a novel method called "CS-Pulsar," which carries out compressed sensing (CS) on time-frequency signals to accomplish RFI mitigation and signal restoration simultaneously.

The wavelet transform and discrete cosine transform were applied as a sparse promoting term to aid the optimization. Results showed that the sensing mechanism performed better in signal restoration for the preprocessed channels, and played a positive role in mitigating "on pulse" RFI.

In an application of pulsar timing, no systematic biases or underestimated uncertainties were caused. This method can improve the timing accuracy to a certain extent by reducing the timing residuals and the estimated errors.

The results were published in The Astrophysical Journal.