FAST所受PMT基站电磁干扰及用频防护方法综述

Review on electromagnetic interference from PMT base stations and frequency-used protection methods for the FAST

为确定500 m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)与其周边公众移动通信(Public Mobile Telecommunications,PMT)系统的电磁兼容(electromagnetic compatibility,EMC)特性,本文综合论述了FAST宁静区内中国移动、中国联通和中国电信三大运营商所属PMT基站对其产生的电磁干扰。首先,从射电天文业务的频谱划分谈起,论述了射电天文业务干扰源类型,引出了其运行保护标准,进而针对FAST详细说明了FAST宁静区的用频法规和保护要求;其次,分析了ITU-R建议电波传播预测与干扰分析方法,并通过实地测量验证了该方法的适用性,进一步针对性地分析了PMT基站的电磁辐射传播特性,综合评估了FAST宁静区内PMT基站的干扰情况:FAST宁静区域90.24%的PMT基站在一定程度上均会对FAST产生干扰,而在所选分析条件下,仅有43.14%的数据符合FAST保护要求;最后,针对PMT基站干扰信号的抑制和消除,分析了常用的射电天文射频干扰抑制方法,同时为保障FAST免受PMT基站干扰,从FAST和PMT基站的角度出发论述了可行的用频防护措施,并基于实施难度、经济成本、策略收益和通信质量4类指标建立了防护方法的评估体系,对所提防护方法进行了实例说明。上述研究成果可为保障FAST的安全观测提供技术基础。

To determine the electromagnetic compatibility characteristics of the Five-hundred-meter Aperture Spherical radio Telescope(FAST)and its surrounding Public Mobile Telecommunications(PMT)system,this paper comprehensively discusses the electromagnetic interference caused by the PMT base stations of China Mobile,China Unicom,and China Telecom,the three major operators in the FAST radio quiet zone.Firstly,this paper starts with the spectrum division of the radio astronomy service,discusses the types of interference sources in the radio astronomy service,and introduces its operation protection standards.Then it details the frequency regulations and protection requirements of its radio quiet zone for the FAST.Secondly,it analyzes the ITU-R recommended radio wave propagation prediction and interference analysis method,and the applicability of the method is verified through field measurements.Furthermore,it analyzes the electromagnetic radiation propagation characteristics of PMT base stations and comprehensively evaluates the interference caused by PMT base stations in the FAST radio quiet zone.The results show that 90.24%of the PMT base stations will interfere with the FAST to some extent.And under the selected analysis conditions,only 43.14%of the data met the FAST protection requirements.Finally,to suppress and eliminate interference signals from PMT base stations,we analyze commonly used radio frequency interference suppression methods in radio astronomy.At the same time,to protect the FAST from interference from PMT base stations,we discuss feasible frequency protection measures from the perspectives of the FAST and PMT base stations,and establish an evaluation system for protection methods from four categories of indicators,including implementation difficulty,economic cost,strategic benefits and communication quality,and provide examples to illustrate the proposed protection methods.The above research results can provide a technical basis for ensuring the safe observation of the FAST.