Faraday效应对空间目标探测雷达的影响

摘要

The influence of ionospheric Faraday rotation on space target detection radars has been analyzed in this paper.Combining the magnetoionic theory with ionospheric model and earth magnetic field model,a fast numerical model for computing Faraday rotation angle is proposed.Compared with the traditional empirical computation modules,this method is proved to be more applicable,especially in China area.During the high and low solar activity years,several typical frequencies of worldwide space target detection radars have been used to calculate Faraday rotation angles in different area,such as Haikou and Changchun which are respectively the typical areas of low and middle latitude areas in China.Simulation results have been presented and analyzed to prove that Faraday rotation effect can cause serious signal energy loss to the radars with linear polarization antenna pattern.Thus this rotation effect must be considered on the radar system perform ance so as to adopt an applicable antenna polarization mode.%分析了电离层Faraday旋转效应对空间目标探测雷达的影响.从磁离子理论出发,结合电离层模型和地球磁场模型,使用了一种快速的Faraday旋转角计算模型,并与传统使用的经验计算方法进行了比较,表明该方法普适性强,更适用于中国地区.针对当前国际上典型的空间目标探测雷达工作频段,选取我国海口(低纬地区)和长春(中纬地区)为代表,分别计算了太阳活动极大年和极小年间的Faraday旋转角,给出了仿真结果并进行分析,表明Faraday旋转效应给线极化方式雷达带来明显的回波能量损失.在进行雷达设计时,需要将该效应与雷达系统性能综合考虑,采用合适的天线极化方式.