【作者】 尹红刚；

【导师】 董晓龙；

【作者基本信息】 中国科学院研究生院（空间科学与应用研究中心） ， 计算机应用技术， 2008， 博士

【摘要】 全球降水对全球气候与环境变化研究、人类社会的可持续发展、人们的生产生活都有重要的影响。星载降水雷达是测量全球尺度降水的有效手段和重要的遥感器,能够对降水的三维结构进行直接测量,还可以为被动微波遥感测量降水提供订正参考。本文首先分析了地表杂波对星载降水雷达测量的影响,详细研究了适用于卫星平台的降水雷达技术,包括脉冲波形设计、脉冲压缩与距离旁瓣抑制、信号处理算法、空间分辨率增强、雷达天线的选取与波束自适应扫描等。本文首次综合分析了地表杂波通过天线主瓣、旁瓣和距离主瓣、旁瓣对星载脉冲压缩雷达降水测量的干扰模型,推导出了考虑距离加权函数影响的雨水回波和地表杂波计算公式。着重分析了杂波对雷达设计的影响,指出星载降水雷达对距离旁瓣、天线旁瓣等指标的要求都要高于以往研究的结果。本文提出了一种新的脉冲压缩和距离旁瓣抑制方法,可以获得低于-110dB的峰值距离旁瓣电平。新方法避免了对LFM信号在发射阶段加权进行脉冲压缩时雷达高功率放大器只能工作在非饱和区引起的效率降低与系统检测性能下降,分析表明新方法获得的距离旁瓣性能对Doppler频移不敏感,适合于星载应用。本文全面分析了提取包括降雨强度、降雨速度、极化信息等降雨参数的信号处理方法,提出使用基于BG反演的超分辨率重建方法来提高星载降水雷达的分辨率,并用于校正雷达波束非均匀充塞造成的降雨强度估计误差。最后,本文对新一代星载降水雷达系统的参数选择进行了研究和分析。更多还原

【Abstract】 Global precipitation is very important for global climate and environment change research, sustainable development, production activities and ordinary life of human being. Spaceborne precipitation radar is a powerful tool for global precipitation measurement. It not only has the capability of directly measurementing three dimensional structure of precipitation, but also provides reference for wide swath precipitation retrieval by passive microwave readimetry.In this dissertation, key issues of the precipitation radar techniques appropriate to spaceborne application are studied, including pulse waveform design, pulse compression and range sidelobe suppression, signal processing, special resolution enhancement, attenna selection, adaptive scanning, etc.The model of surface clutter interference with spaceborne pulse-compression precipitation radar is built for the first time. Sea clutter modle with considering the effect of range weighting function is formulated.A novel technique for pulse compression with emphasis on the suppression of range sidelobes is proposed, with which the achieved peak range sidelobe level can be less then -110 dB. With this new technique, it is avoided that the high power amplifier can only operate in nonsaturated status which leads to the degradation of efficiency when compressing chirp signal. According to the results of analysis, the achieved range sidelobe is insensitive to Doppler shifts.Signal processing methods to obtain precipitation parameters including rain rate, rainfall velocity and polarimetric information are analyzed in detail. A new method—supper resolution reconstruction with BG inversion method is proposed to release the non-uniform beam-filling effects on rain rate estimations.Finally, performance parameters for future spaceborne precipitation radar are discussed.更多还原