射电望远镜远场区域强干扰源规避方法研究

Research on Avoidance Method of Strong RFI of Radio Telescope in Far Field

随着频率使用率的提高,射电天文台址地面或空间存在强电磁干扰致使望远镜接收机系统处于非线性状态.为减少强电磁干扰的影响、提高天文观测效率,提出了一种基于望远镜远场区域的强干扰源规避方法.首先,通过仿真分析确定的射电望远镜远场方向图,结合望远镜与干扰源之间的位置关系,分析了强电磁干扰到达射电望远镜焦点处的功率响应,并依据接收机第2阶中频放大器性能参数,确定射电望远镜处于非饱和状态的规避角度计算方法.其次,采用该方法计算分析了民航飞机对射电望远镜的影响,若民航飞机上有主动发射的干扰源,且不经过反射等传播现象,当射电望远镜主波束轴偏开一定方向后,可有效降低对射电望远镜的干扰强度.

The strong RFI(Radio Frequency Interference)on the ground or space around the radio telescope may make the receiver system in a nonlinear state.In order to reduce the influence of strong RFI and improve the efficiency of astronomical obser-vation,a method of avoiding strong RFI based on telescope in far field is proposed in this paper.First of all,based on the far-field pattern of the radio telescope determined by simulation analysis,combined with the position relationship between the telescope and the interference source,the power response of the strong RFI reaching the focus of the radio telescope is analyzed.According to the performance parameters of the second-order intermediate frequency amplifier of the receiver,the calculation method of the avoidance angle of the radio telescope in the unsaturated state is determined.Secondly,this method is used to calculate and analyze the influence of civil aircraft on the radio telescope.For an active interference source on the civil aircraft without reflection and other propagation phenomena,the influence on the radio telescope can be effectively reduced when the main beam axis of the radio telescope deviates from a certain direction.