| ABSTRACTAs a new Radar model, the Invpvq" Synthetic Aperture Radar(ISAR) has highrange and azimuth reso1ution, and can get image of the moving targe q. In the recentten years, ISAR theory and technique have got great development and, furthermore, itis gradually applied to practical system. We set off our discussion and research workto the problems in ISAIL imaging with real data.1'he rotation of target relative to radar is used to form azimuth image in ISARilllaging, the rotation of target satisfies uniform rotation model in the traditional range-l)oPpler imaging method. Generally in the caJse of smooth fiigllt, it can satisfy theoryrotation model. But in the case of maneuvering flight, it is possible that the rotationof targct don't satisfy the theory model. At this time, It is difficult to obtain the imageof target tvitll hig1l quality by tl1e traditional imaging method. In this dissertation, thei[llagi11g result.s \\'it ll different quality are colnpared, and the time--frequency a11alysislll('1 1lo(l iR [lsc(l t() aIl a l}'zc tllc targct ccllos. lIl tlle case ()f prccise motion coIl1pellsatio11,1llc llOllllllifOrln rotatioIl of targct n1akcs t1lc iInage blurry. So our work empllasizcsoll the cxperiIncntal study of the influence of coInplicated motion of target to ISARilnaging and presents effective imaging method.The motion in tlle turn of fligt1t trajcctory is complicated. So this disserationbascd on tlle analysis of tl1e real data, colllparing the time--frequency distribution oftliffcrcnt range bin echos. \\7e find that the rotation of target doesn't satisfy the planell [li f()rlll r()tatioll 111odel, it is tl1rce dilllcIlsiollal rotatioll. IIl accordaIlce witll tlle tl1ree(lilllcllsiOllal rotatioll targct, tl1c three r1iInoInsioIlal rotation model of target is estab-lislled. Based on this model, the influence of the yaw' pitch' roll and the combinedrotation on imaging are discussed and analyzed. The theory result is verified by thereal data's results. In the course of maneuvering flight, the three dimensional rotationof target makes the image plane change, and then make the imaging result projectedoll tlle imaging plane change. Sometimes this change may blur the image and decreasetlle iInage quality.I:or imaging to the maneuvering target imaging, because the Doppler frequencyof scatterers echo changes and the rule of change is complicated, we can not obtainsatisfactory image by using the traditional imaging rnethod. ln accordance to the non-stationary characteristic of target scatterer ccho, the time-frequency analysis method isused to analyze the maneuvering target echoes. In the dissertation, we discuss the newitnaging method in two aspects. One aspect is on the discus8ion of imaging method fOrthe case where the target scatterer echo Doppler is linear distribution in timc -frequencydistribution, this can be regarded as theaanalysi8 of multicomponent linear modulationfrequency(LFM) signals, we present a new method where the Radon-WigTIer trans-fOrm method is used to suppress the cross terms of multicomponent LFM signal, thenwe can obtain the high resolution timesfrequency distribution witllout cross terms.The method is used to analyze the echos of target and can obtain the instantaneousilllaging result from the slice of tlle tiInofrequeIlcy distribution. CotnI)arcd with theresults of traditional method, the improvement of imaging result is obvious. On theother hand we discuss the case of the target scatterer echo Doppler being nonlinearin time-frequency distribution, this can be regarded as the analysis to multicomprynent nonlinear modulation frequency (NLFM) signal. This dissertation uses a kind ofmodified time-frequency(MTFD) where the reassignment algorithm is introduced. \Vediscuss and analyze the reassignment result of the cross signal. According to the diffenernt kind of signals, we present the principle of the selection of width of kernel. Thisreassignment tim...
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