全球地表雷达后向散射系数的特性分析及其对星载降水测量雷达系统设计的影响

全球地表雷达后向散射系数(NRCS)的统计特性分析是开展星载降水测量雷达(SPR)系统论证的基础，但大范围、长时间地表NRCS的测量难度大、费用高，目前，我国Ku频段小入射角大范围地表NRCS的测量、统计特性研究几乎还处于空白状态。该文提出利用热带降水测量计划(TRMM)卫星2011年度观测数据对全球地表NRCS进行了统计特性分析，得到了NRCS的均值、均方差等统计量与入射角的关系。在此基础上，分析了其对星载降水测量雷达的系统动态范围、天线旁瓣、脉冲压缩旁瓣、雷达定标等方面系统设计的影响，为我国星载降水测量雷达的系统指标论证和定标方法的优化选择提供了依据。

Characteristics of Surface NRCS and the Effect on theSpaceborne Precipitation Radar System Design

The analysis on the statistical characteristics of the surface Normalized Radar Cross Section (NRCS) is the foundation of the Spaceborne Precipitation Radar (SPR) system design, but it is very difficult and costly to measure the global NRCS in long time and the study results about the Ku band global NRCS at small incidence angles are very few in China. In this paper, statistical analysis on the surface NRCS measured is performed by the Tropical Rainfall Measurement Mission (TRMM) satellite in 2011. The results manifest the relations between the statistical characteristics of the surface NRCS (such as mean and standard deviation) and incidence angles. The influence of NRCS statistical characteristics on the SPR system design is analyzed in the parts of system dynamic range, range side-lobes, antenna side-lobes and radar calibration. These analysis results are the foundations of the radar system requirement analysis and radar calibration method selection.