包络相位联合自聚焦高分辨SAR运动补偿

Jointly autofocus of range shift and phase error for high resolution SAR motion compensation

提出了一种包络相位联合自聚焦运动补偿算法,解决了机载高分辨合成孔径雷达(synthetic apertureradar,SAR)成像过程中复杂的运动误差问题。该方法不但可以实现对高阶运动误差的估计,而且可以同时补偿包络和相位误差。通过对运动误差进行归一化多项式拟合建立关于运动误差多项式系数的最小熵优化方程,同时利用阻尼牛顿法对其进行求解,实现高效精确的多项式系数估计。另外,设计了交替联合自聚焦算法,以实现对较大运动误差的精确估计。最后,应用实测机载聚束SAR数据验证该方法的有效性和优越性。

The jointly autofocus algorithm of range shift and phase error for motion compensation of a high resolution synthetic aperture radar （SAR） is proposed to solve the problematic motion error in airborne SAR imaging. The algorithm focuses on the estimation of motion errors, and it can not only estimate the high order motion error but also correct the range shift and phase error simultaneously. This paper utilizes the entropy of a 2 dimensional （2-D） SAR image as the objective function, and establish the optimization function with respect to the polynomials of the motion error. Meanwhile, a damped Newton algorithm is used to solve the function for the polynomials, and both errors are compensated. Additionally, the algorithm strategy with alternate autofo- cus is designed to achieve robust motion error compensation in an accurate way. Raw data experiments validate the proposed method.