调频连续波逆合成孔径雷达(FMCW-ISAR)具有造价低、功耗低和重量轻的优点，因此被广泛用于对各类目标成像。FMCW信号可以看作是占空比为1的脉冲信号，其脉冲宽度相对较长，在此期间内目标的运动常常不可忽略。此时，利用传统的“走-停”模式和距离-多普勒(R-D)算法得到的ISAR像将出现距离-方位2维的模糊，导致图像分辨率下降。该文针对FMCW-ISAR对舰船目标实测数据成像时出现的模糊现象进行了研究，首先建立目标的运动模型，并分析目标在调频周期内的运动分量对距离压缩结果和最终成像结果的影响，最后提出相应的脉内补偿方法以改善图像分辨率。对比补偿前后对仿真模型与实测数据的成像结果，该文所提出的脉内补偿方法能够有效抑制1维距离像的展宽，提高FMCW-ISAR的成像质量。%Given its advantages of low cost, low weight, and low power consumption, Frequency Modulated Continuous Wave-Inverse Synthetic Aperture Radar (FMCW-ISAR) has been widely used for imaging many kinds of targets. Since the FMCW signal can be regarded as a pulse signal whose duty ratio is one and pulse duration is relatively long, the motion of targets usually cannot be neglected. In this circumstance, the stop-go assumption is not valid, so ISAR images obtained using the traditional Range-Doppler (R-D) procedure exhibit two-dimensional blurring, which results in decreased resolution. In this paper, we investigate the blur problems of FMCW-ISAR in imaging ship targets, and construct a target motion model. Then, we analyze the influence of the in-pulse motion component in range profiles and final images. We propose a corresponding in-pulse compensation method to improve the resolution of ISAR images. A comparison with the imaging results of real measured echo data verifies the effectiveness of the proposed method in diminishing the 1-D-profile broadening and improving image quality.
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