Separately Imaging for ISAR Target with Rotational Components

With the development of radar technique, radar imaging tends to be more and more clear, delicate and accurate. And as the resolution of radar imaging is growing, the two-dimension range migration caused by turntable model has influenced the effect of high-resolution ISAR imaging. What’s more, the component’s micro-motion according to target also can’t be ignored. Therefore, this paper puts forward a processing flow, which is based on processing two kinds of echoes separately, in order to image the target with rotational components delicately. First, this flow separates echoes from target’s body and rotational components by using Radon-Wigner transform with CLEAN technique. The motion parameters of turntable model could be estimated in the meantime. Then, the second-order range migration, which is resulted from turntable model, should be compensated for both echoes by adopting space-time analysis. After that, for body’s echo, Keystone transform is applied to compensate first-order migration caused by turntable model to get a focused figure. Meanwhile, inverse Radon transform is employed on the envelope curve or time-frequency distribution of components’ echoes so as to gain fine images of rotational parts. Experimental results using both simulated and measured data confirm the validity of the proposed flow.