新疆奇台拟建的110 m全向可动射电望远镜(Qi Tai Radio Telescope, QTT)具有极高的信号捕捉能力,任何微弱的信号都会影响其高效运行,为了缓解QTT台址无线电宁静区的电磁干扰,本文提出了一种电磁干扰预测方法.首先,基于QTT台址无线电宁静区地形数据和地形特征,分析了现有电波传播模型的适用性,选取LongleyRice模型和Two-Ray模型作为QTT的电波传播模型算法,通过电波传播仿真分析,得到潜在干扰点到达射电望远镜馈源口面的路径损耗;其次,结合QTT馈源口面干扰电平阈值和天线旁瓣增益,计算得到潜在干扰点所在位置的干扰电平阈值;最后,运用该方法分析了QTT限制区内村庄典型电子设备和35 kV高压输电线路对QTT的影响.
Working in a way that passively receives electromagnetic radiation from a celestial body, a radio telescope can be easily disturbed by external radio frequency interference as well as electro- magnetic interference generated by electric and electronic components operating at the telescope site. A quantitative analysis of these interferences must be taken into account carefully for further electro- magnetic protection of the radio telescope. In this paper, based on electromagnetic topology theory, a hybrid method that combines the Baum-Liu-Tesche （BLT） equation and transfer function is proposed. In this method, the coupling path of the radio telescope is divided into strong coupling and weak cou- pling sub-paths, and the coupling intensity criterion is proposed by analyzing the conditions in which the BLT equation simplifies to a transfer function. According to the coupling intensity criterion, the topological model of a typical radio telescope system is established. The proposed method is used to solve the interference response of the radio telescope system by analyzing subsystems with different coupling modes separately and then integrating the responses of the subsystems as the response of the entire system. The validity of the proposed method is verified numerically. The results indicate that the proposed method, compared with the direct solving method, reduces the difficulty and improves the efficiency of interference prediction.
大口径射电望远镜具有极高的系统灵敏度,其建设及运行过程将引入各类电子设备,电磁干扰的有效控制是射电望远镜科学产出的重要保证.本文结合射电天文台址电子设备电磁兼容性要求,分析了现有射电天文领域及其他领域电子设备的主要电磁兼容评估标准及存在的不足,考虑到工程实施的可行性,提出大口径射电望远镜电磁兼容控制方法,涉及台址电子设备所在位置干扰电平限值量化方法、电子设备电磁兼容测量方法和测量要求、屏蔽效能测量方法及测量要求、电子设备电磁兼容控制流程等.该电磁兼容控制方法计划应用于新疆奇台拟建的110 m全向可动射电望远镜(Qi Tai Radio Telescope, QTT),确保QTT拥有良好的电磁兼容性.
