Isar Imaging Motion Compensation Method Based On Parameter Estimation Study

The Inverse Synthetic Aperture Radar (ISAR), which can provide an all-weather, day/night capability to generate high-resolution two-dimensional images of the targets for recognition over a long range, has played a more and more important role especially in military application. Among the different imaging algorithms, the Range-Doppler FFT (R-D FFT) algorithm, based on range-Doppler theory, in which the Fast Fourier Transform (FFT) is employed to reduce compute burden, is widely used in various imaging radar because it can be easily realized in real-time application.In order to obtain high-resolution in azimuth, it's necessary to maintain the precise phase relationship between return signals. However, coherence between signals received in imaging period is always destroyed both in range and cross-range, due to the complex movement of the non-cooperative targets. Therefore, the compensation in range and cross-range towards the complex movement becomes a crucial step of ISAR imaging.The main 2 sorts of compensation algorithm are base on scatter points tracking and motion parameters estimation, respectively. In practice, it's very hard to find any ideal scatter points to track, so this thesis focuses on the motion compensation algorithm base on motion parameters estimation, which is used in R-D FFT imaging algorithm and verified by simulation. Work of this thesis contains:First analyze the signal-processing model of ISAR system in detail, and establish a 3-dimensional mathematical scattering model of moving target. Then some improvements are made on existing compensation algorithm, to get a higher image quality and reduce compute burden. In addition, research on ESPRIT (estimation of signal parameter via rotational invariance technique) super-resolution imaging technology is made to improve image quality, especially in the case of small segment of viewing angle. Afterward, a new multi-target ISAR imaging method for high-speed targets is presented. And finally, author in detail analyze the radar parameters'impact on image quality as well as the mapping between targets and image characters.There are several innovation and creativities in this work:1. In range compensation (envelope alignment), the norm-correlation method is...