同步轨道SAR电离层影响分析与仿真研究

针对电离层对L波段同步轨道合成孔径雷达（synthetic aperture radar,SAR）的影响,提出了一种基于四维电离层电子浓度数据进行同步轨道SAR电离层影响仿真的方法.主要针对同步轨道SAR信号相位超前导致的图像偏移、分辨率下降、脉冲展宽、峰值旁瓣比下降等成像因素进行了分析,利用IRI模型计算得到四维电离层电子浓度数据,进行不同电离层状态下的同步轨道SAR性能影响分析.给出电离层TEC缓变、阶跃变化、冲激变化、连续快速变化几种情况下同步轨道SAR成像数值仿真结果,验证理论分析的正确性,并分析每种电离层情况下是否需要校正.结果表明,电离层对同步轨道SAR距离向信号影响非常严重,对方位向信号的影响大多数情况下可以忽略.

Analysis and simulation on GEO SAR ionosphere effects

Aiming at the ionospheric effects on the L-Band Geosynchronous Synthetic Aperture Radar （GEO SAR）,a method based on the data of four-dimensional ionospheric electron density which can simulate the ionospheric effects on GEO SAR was proposed.The method analyzes the imaging factors such as image shift,decrease of resolution,pulse broadening,decrease of peak sidelobe ratio and so on which are resulting from the phase advance of the GEO SAR signal.The IRI Model was used to obtain the data of four-dimensional ionospheric electron density,and the analysis on GEO SAR performance effects in different ionospheric states was given.The GEO SAR imaging simulation results corresponding to the situations of ionospheric TEC＇s slow change,step change,impulse change,rapid continuous change were given,and the correctness of theoretical analysis was verified and then the anaysis on whether the correction was needed in every situation.The experiment results shows that the ionospheric effects on GEO SAR range signal is very serious and the effects on the azimuth signal can be ignored in most cases.