Design Of Satellite Formation Configuration For Spaceborne Interferometric Synthetic Aperture Radar

The concept of satellite formation flying is gaining a general recognition and a thorough investigation at the present time when the satellites are being miniaturized and attached with multi-functions. One of its applications is spaceborne InSAR (Interferometric Synthetic Aperture Radar) technology. InSAR, compared with the common SAR, is able to get message containing the height of targets, and thus plays an important role in earth observation.Beginning with the principle of InSAR measure, this thesis focuses on the influences that baselines suffer from the motion of the formation, including those suffered by the baseline length, stability, orientation angles and so on, which dominate the measure precision of InSAR to a great extent.Firstly, the principle of relative motion of the satellites in the close-distance formation is studied based on the Hill equations, and especially the form of free-flying solutions derived from the relative motion equations in dynamic form is rewritten. At the same time, the former design of close-distance formation is modified correspondingly. Three special formations are designed under the new method and simulated by the mission analysis software STK (Satellite Tool Kit).Secondly, the stability of InSAR baselines is studied. The principle of InSAR height measure is introduced, and then the level baseline, vertical baseline and effective vertical baseline are defined, which dominate the measure precision. Then the concept of baseline stability is set up, and stability level is defined by the author, an index of stability which can reflect the idea of stability perfectly. Under the definition, the stability by time of all baselines is studied in some formations, including even phase formations, which is simulated and followed by some corresponding conclusions.Lastly, the variation of baseline orientation angles, an important aspect of baseline variation, is addressed. Based on the principle of InSAR height measure, the error model of absolute height in the InSAR measure is introduced, and the factors affecting the measure precision of InSAR are analyzed. At the end of the thesis, the influence of different formations on the variations of orientation angels corresponding to time is analyzed, because the orientation angels affect the measure precision.