相控阵体制SAR系统的误差建模与补偿方法

摘要

在基于相控阵天线体制的合成孔径雷达(SAR)系统中,中央电子设备和相控阵天线的非理想特性,会引入幅相误差,造成 SAR信号幅相特性畸变,影响 SAR图像等数据产品的质量.本文建立了相控阵体制 SAR 系统误差的模型,并设计了误差校正方法.研究结果表明:雷达中央电子设备的非理想特性会引入固定的幅频、相频误差;相控阵天线的非理想特性所引入的幅频、相频误差会随着波束指向的变化而变化,该误差主要根源于有源器件在不同频点处的性能差异,并会受到 T/R模块移相衰减量的调制;可通过测量或分析计算对相控阵 SAR的系统误差进行提取,并在 SAR成像处理阶段实施误差补偿.%The non-ideal characteristics of central electronic equipment and phased array antenna in Synthetic Aperture Radar(SAR) system can introduce systematic errors, which may contribute to amplitude and phase errors of SAR signal, and hence degrades SAR images. A model is presented to derive signal errors due to non-ideal characteristics of central electronic equipment and phased array antenna, and a method is proposed to correct the errors. The model shows that the error resulting from central electronic equipment is almost invariant, while the error resulting from phased array antenna varies with the direction of the beam and is modulated by the attenuation and phase shift amount of T/R. The system error of phased array antenna SAR can be extracted by system testing or analysis calculation, and then can be compensated during SAR imaging process.