ISAR运动参数估计和补偿改进方法

在使用FFT距离多普勒算法进行ISAR成像处理时，回波相关性的减弱将加大运动补偿难度，带来较大的误差。该文在常规相邻相关法基础上，提出了一种改进的运动补偿方法。在距离向上，利用基准回波相关法与曲线拟合，克服了低回波相关性下包络对齐时出现的包络漂移、包络跳变等缺陷；在方位向上，利用DCFT变换，对目标的运动参数进行精确估计并加以补偿，减小了回波相关性降低对相位补偿的影响。仿真验证了该方法的有效性。
关 键 词 离散调频傅里叶变换; 包络漂移; 包络跳变; 二次曲线拟合

Abstract When the range-Doppler algorithm is used in inverse synthetic aperture radar (ISAR) imaging, the reduction of echo correlation will add more difficulties on motion compensation and bring more error. Accordingly, based on the adjacent-correlate compensate method used in FFT range-Doppler algorithm, an improved compensation method is presented in this paper. The traditional compensation method is modified to avoid the envelope drift and envelope jump in range align. In phase compensation, a new algorithm based on accurate target parameter estimation by use of discrete chirp-Fourier transform (DCFT) transform is presented. Finally the improve method is verified by simulation.
Key words discrete chirp-Fourier transform; envelope drift; envelope jump; 2 order polynomial fitting