1. School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China; 2. Department of Electronic and Optical Engineering, Ordnance Engineering College, Shijiazhuang 050003, China
Abstract 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.
(Telecommunications: signal transmission and processing; communication satellites)
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos. 61601496 and 61401024).
Corresponding Authors:
Jun-Tao Ma
E-mail: tm0508@sina.com
Cite this article:
Jun-Tao Ma(马俊涛), Mei-Guo Gao(高梅国), Bao-Feng Guo(郭宝锋), Jian Dong(董健), Di Xiong(熊娣), Qi Feng(冯祺) High resolution inverse synthetic aperture radar imaging of three-axis-stabilized space target by exploiting orbital and sparse priors 2017 Chin. Phys. B 26 108401
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