星载P波段SAR电离层效应的双频校正方法

对于高分辨星载P波段SAR系统,电离层效应对P波段SAR会带来一系列较为严重误差,包括时间延迟、法拉第旋转和色散等,这些误差与电波频率和电离层TEC值关系密切,并使得图像质量下降。如何测量与校正电离层效应误差是星载P波段SAR面临的重要问题。根据SAR系统自身的宽带特点,借鉴GPS系统采用的电离层双频测量校正方法,提出了一种基于双频SAR距离像相关的延迟误差测量方法,计算机仿真结果表明,该方法有效提高了双频回波信号的电离层延迟误差测量精度,适于低频段星载SAR系统的电离层效应测量与校正应用。

A Double Frequency Measurement and Correction Method for Ionospheric Effects in Space-Borne P-Band SAR

For high resolution spaceborne P band SAR system, ionosphere effects would cause many se- rious errors, such as time delay, Faraday rotation, dispersion, etc. These errors are relative to wave fre- quency and TEC of ionosphere and drop the image quality. How to measure and correct these errors is very important to space borne P-band SAR system. According to SAR system characteristics and the double fre- quency measurement and compensation method used in GPS system, this paper puts forward an ionosphere delay error measurement method based on double frequency SAR range profile correlation detection. The simulation result indicates that the proposed method can effectively increase ionosphere delay error measure- ment precision, and can be used in low frequency space-borne SAR system to decrease the ionospheric effect.