In view of the increasing number of space objects, comprehensive high-quality space surveillance becomes ever more important. Radar is a powerful tool that, in addition to detection and tracking of objects, also enables spatially high-resolution imaging independent of daylight and most weather conditions. Together with the technique of Inverse Synthetic Aperture Radar (ISAR), very high-resolution and distance-independent two-dimensional images can be obtained. However, advanced high-performance radar imaging of space objects is a complex and demanding task, touching many technological and signal processing issues. Therefore, besides theoretical work, the Microwaves and Radar Institute of German Aerospace Center (DLR) has developed and constructed an experimental radar system called IoSiS (Imaging of Satellites in Space) for basic research on new concepts for the acquisition of advanced high-resolution radar image products of objects in a low earth orbit. Based on pulse radar technology, which enables precise calibration and error correction, IoSiS has imaged space objects with a spatial resolution in the centimetre range, being novel in public perception and accessible literature. The goal of this paper is therefore to communicate and illustrate comprehensively the technological steps for the construction and successful operation of advanced radar-based space surveillance. Besides the basic description of the IoSiS system design this paper outlines primarily useful theory for ISAR imaging of objects in space, together with relevant imaging parameters and main formulae. All relevant processing steps, necessary for very high-resolution imaging of satellites in practice, are introduced and verified by simulation results. Finally, a unique measurement result demonstrates the practicability of the introduced processing steps and error correction strategies.

中文翻译：

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太空卫星高分辨率逆合成孔径雷达成像

鉴于空间物体数量不断增加，全面、高质量的空间监视变得越来越重要。雷达是一种强大的工具，除了检测和跟踪物体之外，还能够实现独立于日光和大多数天气条件的空间高分辨率成像。与逆合成孔径雷达（ISAR）技术一起，可以获得非常高分辨率且与距离无关的二维图像。然而，空间物体的先进高性能雷达成像是一项复杂而艰巨的任务，涉及许多技术和信号处理问题。因此，除了理论工作外，德国航空航天中心（DLR）微波与雷达研究所还开发并构建了名为IoSiS（太空卫星成像）的实验雷达系统，用于获取先进高分辨率雷达的新概念的基础研究近地轨道物体的图像产品。 IoSiS 基于可实现精确校准和误差校正的脉冲雷达技术，对空间物体进行了厘米级空间分辨率成像，这在公众认知和可获取文献中都是新颖的。因此，本文的目的是全面交流和说明先进雷达空间监视的构建和成功运行的技术步骤。除了IoSiS系统设计的基本描述外，本文还概述了空间物体ISAR成像的主要有用理论，以及相关成像参数和主要公式。介绍了实际中卫星超高分辨率成像所需的所有相关处理步骤，并通过仿真结果进行了验证。最后，独特的测量结果证明了所引入的处理步骤和纠错策略的实用性。