Research On Imaging And Jamming Of Inverse Synthetic Aperture Radar

Inverse Synthetic Aperture Radar (ISAR) is a high resolution microwave imagingsystem. It has great prospects in target recognition, anti-stealth, astronomy and airtraffic control etc. It is an important research direction in radar imaging area. This dissertation focuses on the motion compensation, time-frequency imaging,multi-target imaging and interference techniques of ISAR. The models for the retumedsignal of the targets and the imaging simulations have been established. Severalimaging algorithms and interference techniques have been studied and verified bysimulations. The main contributions and conclusions of this dissertation aresummarized as follows.1. Based on the ISAR imaging principles of the moving target with ideal rotationand translation, the returned signal and the imaging principles of the complex motiontarget were studied. Simulation data were generated according to the constructedmodels for airplanes, missiles and satellites. The parameters of the radar platform,moving target and interference can be flexibly set in those models.2. The motion compensation method based on the point-scatter model has beenwidely used in ISAR. In this dissertation, the time-frequency analysis and the adaptivemethods were applied in the motion compensation of the maneuvering target. A newmotion compensation procedure using the adaptive joint time-frequency (AJTF) andmultiple prominent point processing was studied. The AJTF was used as a powerfuland automatic tool to select and track the reference point in ISAR imaging for movingtarget. The limitation of selecting and obtaining the prominent point in the prominentpoint processing technique was overcome by applying AJTF algorithm. The singleprominent point AJTF can be directly applied to the translation motion compensation.The two-prominent-point AJTF has excellent performance in compensation fornon-uniform rotation motion. The results showed the advantages of AJTF in ISARimaging for the motion compensation of maneuvering target.3. In order to suppress the cross-terms of WVD and keep the high resolutions intime and frequency domain, two modified WVD algorithms, the SMWVD and MWVD, were proposed. Compared with the images obtained by using common ISARalgorithms, the SMWVD and MWVD algorithms have been shown to have goodability in both suppressing the cross-terms and keeping the high resolutions for movingtarget imaging.4. By analyzing the imaging principle of the multiple targets of ISAR, the modelfor multiple moving targets was put forward. The images of multi-target were obtainedusing RD, WVD, SMWVD and MWVD algorithms. The results demonstrated thepriorities of MWVD algorithm in multi-target imaging.5. In this dissertation, a new signal processing algorithm, Hilbert-Huangtransform (HHT) which has been used in non-linear and non-stationary signalprocessing, was first time introduced in ISAR imaging. A new ISAR imagingalgorithm for maneuvering target and multiple targets was proposed by using HHT.First, HHT was used in the range alignment for point target and airplane target. Theimaging results validated the effectiveness and feasibility to use HHT in ISAR imaging.Based on the definition of intrinsic mode function (IMF) in HHT, multiple targetswere imaged using different components of IMF.6. The jamming models of the slant-range and cross-range of ISAR were derivedbased on the radar equations of ISAR. The frequency-modulated (FM), radiofrequency (RF) and amplitude-modulated (AM) noise jamming were studied for thejamming of ISAR imaging. A new jamming scheme which combines FM noisejamming with transmitting and shift-frequency jamming was proposed. The jammingresults demonstrated that the new scheme was much better than the FM noise jamming.It has good efficiency and is a promising technique in ISAR jamming.In summary, this dissertation has achieved some helpful research results in ISARimaging and jamming. It has constructed a strong background for the further researchin these areas. Up to now, there are still lots of opening problems in ISAR imaging andworth further efforts.