This study presents the concept, design, and operation of a low-cost and lightweight multiple-input multiple-output (MIMO) radar system, dedicated to the characterisation of complex volumetric environments such as snow, forest, sand etc. using synthetic aperture radar tomographic focusing. The system consists of six transmitting and six receiving antennas, operated in a multi-static configuration, resulting in an equivalent mono-static vertical virtual array. Antenna positions have been set considering a trade-off between coupling effects, imaging ambiguities due to spectral folding and vertical resolution. The system also contains radio frequency signal generation and acquisition blocks and has been developed and operated at the IETR laboratory of the University of Rennes 1. An element-orthogonal frequency division multiplexing technique is proposed that avoids the use of switches for selecting transmission and reception channels, using a specific carrier for each transmit channel, and spectral analysis of each receive channel, allowing the 36 MIMO channels to be retrieved. The use of a time-domain back-projection algorithm for imaging in the elevation direction provides results that confirm the potential of the system for the characterisation of complex media.

中文翻译：

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低复杂度便携式MIMO雷达系统，用于高分辨率表征复杂环境

这项研究提出了一种低成本，轻量级的多输入多输出（MIMO）雷达系统的概念，设计和操作，该系统致力于使用合成孔径雷达表征复杂的体积环境，例如雪，森林，沙地等。层析成像聚焦。该系统由六个发射天线和六个接收天线组成，以多静态配置运行，从而形成等效的单静态垂直虚拟阵列。设置天线位置时要考虑到耦合效应，由于频谱折叠而引起的成像模糊度和垂直分辨率之间的折衷。该系统还包含射频信号生成和采集模块，并已在雷恩大学1的IETR实验室开发和运行。提出了一种元素正交频分复用技术，该技术避免了使用开关来选择发射和接收通道，避免了为每个发射通道使用特定载波以及对每个接收通道进行频谱分析，从而可以检索到36个MIMO通道。时域反投影算法在仰角方向成像的使用提供的结果证实了系统表征复杂介质的潜力。