Study On ISAR Imaging And Feature Extraction Of Midcourse Ballistic Target

ISAR Imaging, which can obtain two dimension feature of target, is an important means of target recognition in missile defense system. ISAR imaging for missile in midcourse of trajectory includes many key techniques, such as compensation for high resolution range profile (HRRP) and the method to choose time window length.In chapter 1, beginning with the history and actuality of ISAR, ISAR imaging and feature extraction for missile in midcourse of trajectory is presented against the background of missile defense system. The skeleton and main subjects of the thesis are also introduced.In chapter 2, after the motion characteristic of missile in midcourse being analyzed, characteristic of range profile of midcourse objects is studied by using measurement data. And then the research on effect of range profile Imaging and compensating method for target moving with high velocity is introduced.In chapter 3, base principle of ISAR imaging is presented, and a new method to evaluate range alignment with sum of weighted variance of range bins is proposed, which can evaluate range alignment directly. By analyzing image of warhead model, characteristic of ISAR image is pointed out. At last, ISAR imaging method for midcourse objects based on nutation is proposed, and the results of simulation experiment are shown.In chapter 4, according to shape of warhead, a method to extract length feature of target, which is insensitive to angle change, based on ISAR image is proposed. The result of feature extraction experiment verified the effectiveness of the feature.In chapter 5, the thesis is summarized and the new points and the further work are pointed out.