Imaging plane characterisation for ISAR imaging of LEO space objects

For inverse synthetic aperture radar (ISAR) imaging of low earth orbit (LEO) space objects, the study of the variations in the imaging plane of the object in the entire visible arc period can acquire a more direct vision of the variations in object imaging. In this study, the ideal turntable model was extended to establish the observation geometry of LEO near circular orbit objects. Two approximations were applied to the observation model in the calculation of the imaging plane normal for near circular orbit objects. One approximation is to treat the orbit of the space object as a standard arc relative to the earth during the radar observation period. The other approximation is to omit the effect of the rotation of the earth on the observations. First, the closed-form solution of the imaging plane normal in various attitude stabilisation approaches was acquired based on geometry models. Then, the correctness of the closed-form solution for the geometric models and the effect of various attitude-stabilisation methods on ISAR imaging were confirmed by simulations.