Isar Technology Research

With the development of wide-band radar technology, more attention are paid to Inverse Synthetic Aperture Radar (ISAR). During the past three decades, ISAR theory and technique have got great development and it is applied to practical system. Although ISAR technology has been studied for a long time, there are some problems remained in using the ISAR technology. In this thesis, those problems of ISAR are discussed as follows:.First, the principle of ISAR is introduced, the three steps in ISAR imaging (include envelope alignment, phase compensation and cross-focuse) are discussed in detail. Some of the practical imaging methods are discussed, and we also get ISAR map using real radar data. Then we analyze the problem in applying of ISAR, include the problem of high speed moving target imaging, spinning target imaging and multi-target imaging.(1) The problem of high moving target imaging are analyzed, we proposed the method of minimum entropy to compensate the high speed, and the computer simulation experiments are used to demonstrate its effectiveness.(2) The problem of spin target imaging are analyzed, we present a limitation for spin target imaging, and prove the result by simulation.(3) The problem of multi-target imaging is also studied. After describing the basic theories of multi-target imaging, we give a method called local-envelop alignment for range alignment. Then we use match-DFT to obtain a multi-target imagery.A simulation result to prove our method is given.(4) The problem in ISAR device is analyzed. We give some method for parameter selection that can be used by radar engineers.