Complex Electromagnetic Environment and RFI Mitigation at Mingantu Observing Station

Radio frequency interferences (RFI) and Electromagnetic compatibility (EMC) are common problems to all sensitive radio astronomical telescopes. Mingantu Observing Station of National Astronomical Observatories in Inner Mongolia is the site of the powerful Mingantu Spectral Radioheliograph (MUSER). Three big instruments including Meter to 10-meter Waveband Radioheliograph, Interplanetary Scintillation telescope (IPS), and Super-wide Band Spectrograph in Meridian project Ⅱ under National Infrastructure Program in China will be set up in 2019-2022. Observing data from all these radio telescopes will play important roles in solving the key problems of solar physics, space weather and solar activity prediction. The overall working frequency ranges from 1MHz to 15GHz. The complex electromagnetic environment, RFI space and spectrum distribution surveillance in double-circular polarizations are displayed and analyzed. Some anti-RFI measures and designs are introduced and discussed. RFI influences on observed data are related with many factors including the RFI sources' and the telescopes'. A RFI self-surveillance scheme using the radio telescope itself working together with omni antenna and reference antenna is proposed.