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空地链路上的微波信号受降雨影响,会产生功率衰减和去极化效应.基于这些物理特性,本文提出利用1—10 GHz空地链路信号的降雨干扰项获取雨强的方法,并开展了相关理论研究.根据空地链路信号与雨滴复杂的相互作用,研究了空地链路信号频率为1—10 GHz时,雨强(rain rate,R)对衰减(attenuation,A)和交叉极化分辨率(cross-polarization discrimination,XPD)的影响,分别建立了A-R和XPD-R关系模型.通过数值模拟,分别分析了利用上述两个关系模型估测雨强的可行性,并系统研究了不同频率、极化方式和仰角条件下的适用性.研究结果表明,对于水平极化或圆极化,且频率较高的空地链路信号,利用A-R关系反演强降雨具有理论上的可行性;对于不同频率和极化方式的信号,XPD-R关系模型都可以用于反演雨强,并且对于1—50 mm·h-1范围内的雨强,XPD较为敏感;不同仰角条件下,A-R和XPD-R模型都适用.在4—10 GHz时,本文的XPD-R模型和国际电信联盟ITU-R中XPD预测模型的结果非常接近.所得出的结论对于下一步开展相关的验证实验,拓展卫星系统的气象应用,实时估测降雨强度,实现全球降雨观测具有重要的参考价值.
Based on these physical characteristics, this paper proposes a method to obtain rainfall intensity using the rainfall interference term of the free-space link signal of 1-10 GHz, and carries out the According to the complex interaction between the air-ground link signal and the raindrops, the effects of rain rate (R) on attenuation (A) and cross-polarization (XPD), respectively, the AR and XPD-R relational models are established respectively.The feasibility of using these two relational models to estimate the rain intensity is analyzed respectively by numerical simulation.The influences of different frequency , Polarization and applicability under the condition of elevation angle.The results show that it is theoretically feasible to inversely predict the rainfall intensity based on the AR relationship between horizontal polarization and circular polarization and the frequency of open land link signals. XPD-R relationship model can be used to inverse rain intensity and the XPD is sensitive to rain intensity in the range of 1-50 mm · h-1. Under different elevation and elevation conditions, the correlation between AR and XPD-R models are applicable The XPD-R model in this paper is very close to that of the ITU-R XPD prediction model in the International Telecommunication Union (ITU-R) at -10 GHz, and the conclusions drawn are helpful for the next step in developing relevant verification experiments, expanding the meteorological applications of satellite systems, real-time estimation Rainfall intensity, to achieve global rainfall observation has important reference value.