摘要
主要分析P波段SAR成像时,由电磁波在电离层中的传播时延引起的图像位置偏移和由电离层的色散效应导致的距离向分辨率下降问题.并在此基础上进行了点目标的成像仿真.结果表明:雷达工作频率、带宽以及路径电子总量(TEC)是影响成像质量的决定因素.TEC越大,雷达工作频率越低,信号带宽越大,图像恶化越严重.P波段的星载SAR图像中,图像偏移和分辨率扩展可达几十米.文中提出利用点目标脉冲压缩前的时域响应宽度变化量信息作为电离层定标参考函数的计算依据,实现对电离层误差的校正.
This paper analyzes the ionosphere＇s impact on imaging, which includes 1） an unknown propagation time delay which causes image shift and 2） dispersion effect which causes the mismatch in range compression, and presents the simulation of point target imaging as well. The results show that the crucial factors for imaging quality are carrier frequency, band width and TEC （total electron content）. For P band SAR, the image shift and resolution spread can reach to dozens of meters. The author proposes a method for ionospheric effect correction by utilizing the variation of time-domain response of a corner-reflector before compression to calculate the reference function used in matched filtering.
出处
《测试技术学报》
2008年第5期459-464,共6页
Journal of Test and Measurement Technology
关键词
电离层
星载SAR
P波段
成像
色散
ionosphere
spaceborne SAR
P-band
imaging
dispersion
