The development of inverse synthetic aperture radar (ISAR) imaging techniques is of notable significance for monitoring,tracking and identifying space targets in orbit.Usually,a well-focused ISAR image of a space target can be obtained in a deliberately selected imaging segment in which the target moves with only uniform planar rotation.However,in some imaging segments,the nonlinear range migration through resolution cells (MTRCs) and time-varying Doppler caused by the three-dimensional rotation of the target would degrade the ISAR imaging performance,and it is troublesome to realize accurate motion compensation with conventional methods.Especially in the case of low signal-to-noise ratio (SNR),the estimation of motion parameters is more difficult.In this paper,a novel algorithm for high-resolution ISAR imaging of a space target by using its precise ephemeris and orbital motion model is proposed.The innovative contributions are as follows.1) The change of a scatterer projection position is described with the spatial-variant angles of imaging plane calculated based on the orbital motion model of the three-axis-stabilized space target.2) A correction method of MTRC in slant-and cross-range dimensions for arbitrarily imaging segment is proposed.3) Coarse compensation for translational motion using the precise ephemeris and the fine compensation for residual phase errors by using sparsity-driven autofocus method are introduced to achieve a high-resolution ISAR image.Simulation results confirm the effectiveness of the proposed method.