星载SAR LFM信号在轨相位预失真补偿方法

In-orbit phase pre-distortion of LFM signal for spaceborne SAR

由于空间环境下星载合成孔径雷达(SAR)系统相位误差会发生漂移,影响线性调频(LFM)信号的脉冲压缩性能,因此本文提出一种基于多项式拟合的在轨相位预失真补偿方法.通过在轨定标可获得系统相位误差,在地面对其进行多项式拟合得到相位补偿参数,上注相位补偿参数,在轨运算生成具有补偿相位的线性调频信号.给出了该方法的理论依据和实现流程,分析了星上硬件资源需求和优缺点.通过相位预失真补偿仿真和真实系统试验,并与其它方法结果进行比较,证明该方法可以有效地改善线性调频信号的脉冲压缩性能.

In spaceborne SAR（Synthetic Aperture Radar）,the pulse compression of LFM（Linear Frequency Modulated） signal would be affected by the system phase error which changes in the space environment.Therefore a method of in-orbit phase pre-distortion for LFM signal based on polynomial fitting is put forward,in which the system phase error is obtained by in-orbit calibration,the phase compensation parameters are obtained by polynomial fitting on ground,and by uploading phase compensation parameters,LFM signal with compensation phase is generated by in-orbit calculation.The basis of the theory is described,as well as the realizing flow of the method is presented.Also,hardware requirements and advantages of the method are analyzed.The method is compared with other methods,and is verified to be efficient by the simulation and experiments in real system.