ISAR Imaging And Targets Recognition

Inverse synthetic aperture radar (ISAR) is a kind of high resolution imaging radar. It can take more message than narrow-band radar. Though many outcomes have been taken out on imaging research, the reports number of applying the ISAR imaging in practice are very few. The recognition tecnique of radar targets is a urgent problem in national defence. One of the routes of recognition targets is imaging to target with ISAR. ISAR is a wide-band radar, so its price is very expensive. It is very difficult to widely use the ISAR in the near future. The tecnique of ISAR applies to nanrrow-band radar so that it has high accros-range resolution (ID imaging) to tell targets apart in nantional defenc. This thesis studies on ID imaging processing, ISAR 2D imaging in real time, and object imaging recognition. Those would extend ISAR and have important meaning not only in national defenc but also in civil.ISAR ID imaging processing, ISAR 2D imaging in real time, and object imaging recognition have been verified with field data. This thesis consists of six chapters and an appendix. The content is as follows:Chapter 1 introduces the essentials of ISAR ID imaging, ISAR 2D imaging in real time and object imaging recognition based on ISAR imaging.Chapter 2 deals with ISAR ID imaging, contains the algorithms of the range realignment, the phase compensation, single target imaging and multi-targets imaging. The method of difference phase compensation in ID ISAR is given out. The difference between quasi-inflexibility targets imaging and non-inflexibility targets imaging is analyzed. The imaging results of field data are given out.Chapter 3 studies estimation of moving target parameters. The methods of Fast ISAR ID imaging scaling and calculating the across speed of target are proposed. The distance moving rate and Doppler frequency shifting are gathered to correct the dim speed to decrease the speed error. After scaling, the scale of a target can be estimated correctly for targets resolution or target recognition.Chapter 4 proposes the idea of ISAR dynamic across 1D imaging. The calculation method and display mode of the imaging are introduced. The method of resolving targets based on the imaging and its relative problems are introduced too.Chapter 5 studies ISAR imaging in real time and image post-processing, and discusses the idea of ISAR imaging in real time and the difference with SAR imaging in real time. It introduces the method of non-overlapping ISAR imaging in real time based on software. The image post-processing includes image connectivity processing, interference stripe suppression and centroid normalization. The results are advantageous to theextraction features, and look as if optical imaging.Chapter 6 studies ATR based on ISAR imaging. The content includes explanation of four features of a target image, the algorithms of extraction features, and recognition target based on artificial neural network algorithm. The experimental results with field data verify that the methods of recognition target are efficient.Chapter 7 summrizes the whole work of this thesis and show the researches to be carried out further.Appendix introduces the field data acquisition scheme of 384 radar which is coherent and narrow-band. It introduces the calculation of the coherence error, direct shift, interference and noise of the system. The analyzing results of field data are given out.