基于代价函数的通道误差校正方法

摘要

Multi-channel in azimuth is a technique to achieve high-resolution as well as wide-swath in Synthetic Aperture Radar (SAR) systems. Channel error is inevitable in multi-channel systems and it induces blurring in subsequent SAR imagery. Existing compensation approaches are sensitive to system parameters as well as the imaging scenes. Uncertainty of the parameters impacts the validation of these algorithms. In this paper, an improved approach is presented to remove the channel error. Based on the error form, this approach models channel error as three parts: the range gain error, the pulse sampling clock error, and the transmission phase error. The range gain error and the pulse sampling clock error are removed alternately. Then the proposed approach uses cost function to estimate the transmission phase error so that it is independent from the imaging scene. Point target simulations are carried out to investigate the performance, and real data comparison experiments are carried out to verify this approach.%方位多通道技术是合成孔径雷达(SAR)实现高分宽测的手段之一。在多通道系统中通道失配是不可避免的，这会导致SAR图像模糊。已有的通道失配校正方法大多依赖于系统参数以及场景内容。参数的不确定性将会大大降低校正算法的稳定性。该文提出了一种改进的通道失配校正方法，根据失配产生的原因，将通道失配分为距离增益误差、脉冲采样时钟误差和传输相位误差3项。前两项误差通过交替估计进行补偿，而传输相位误差则通过代价函数给予估计。该方法对成像场景的依赖较小，基于机载多通道验证平台实测数据的实验验证了该方法的有效性。