在步进频率高分辨ISAR成像中,传统的参数估计方法往往不能准确地估计出运动目标的速度和加速度值,其补偿后存在的相位误差对宽带合成ISAR图像有较大的影响。因此,该文提出了一种基于相邻相关法和相位相干化的步进频率高分辨ISAR成像技术,即通过相邻相关法估计运动目标的径向运动参数,在对回波数据包络进行补偿后,利用相位相干化对各子脉冲的相位误差进行校正,再利用频带拼接技术获取目标的合成高分辨1维距离像。之后,利用RD算法实现目标的高分辨ISAR成像。该方法具有精确相位误差补偿精度和高运算效率的优点。仿真和实测数据验证了该方法的有效性。
The conventional methods for the stepped-frequency high resolution ISAR imaging are usually difficult to accurately estimate the velocity and acceleration of a moving target.Thus,the residual phase error via the motion compensation has a serious effect on an ISAR image.Consequently,a novel method based on the adjacent correlation and the coherent processing for realizing the high resolution ISAR imaging is proposed in this paper.The motion parameters can be estimated by the adjacent correlation and be used for the compensation of the range migration.Then,the phase error among all sub-pulse in a pulse team also can be obtained and compensated by the coherent processing.Thus,by the bandwidth combination in the frequency dimension and the range-Doppler algorithm,the high resolution ISAR image can be obtained.This method has some advantages of the precise phase compensation and the light computation load.Finally,the simulated and real data confirm the effectiveness of proposed method in this paper.