射电天文研究组知识库

射电天文已成为人类研究宇宙的重要途径。但随着人类生产、生活的发展,射频干扰信号对射电天文观测的影响越来越严重,观测数据的好坏关系到科学成果的质量甚至结论的真伪。目前广泛采用基于阈值判断射频干扰,对干扰信号直接舍弃部分观测数据的方法。此类方法存在阈值确定困难、观测带宽和时间被缩减等问题。本文针对脉冲星观测射电信号中,各干扰信号及射电信号统计独立以及呈现出的非高斯性,利用独立成分分析对混合信号进行分解;并根据观测信号中脉冲星信号和干扰信号的分布特点,识别脉冲星信号,实现干扰信号消除。使用该方法对云南天文台40米射电望远镜接收到的脉冲星观测信号进行独立成分分析,分解出独立的RFI信号和脉冲星信号,消除射频干扰信号。本文方法在干扰信号消除、射电信号保留及信噪比方面均取得良好效果。 

Radio astronomy has become an important way to study the universe. However, with the development of human production and life, radio frequency interference (RFI) has more and more serious impact on radio astronomical observation. The quality of observation is related to the quality of scientific achievements and even the authenticity of conclusions. At present, RFIdetection based on threshold is widely used, and part of the observed data is directly discarded for the interference. Such methods have difficulties in determining threshold values, and reduce observation bandwidth and time. Observed the fact that interferences and radio signals are
statistical independence and each is non-Gaussian, we propose a novel approach for radio frequency interference mitigation using independent component analysis to decompose the mixed signal, then identifies the pulsar signal according to the different distribution characteristics between the pulsar signal and RFI signals. The pulsar observations received from 40-meter radio telescope in Yunnan Observatories are processed by the new approach. The results show: RFI signals in pulsar observations are cleanly mitigated while little affecting pulsar signal and good signal-to-noise ratio is achieved.