In this work, we study the joint detection and localization of multiple delay- and Doppler-spread targets through an opportunistic radar exploiting mmWave communication signals. The problem is formulated as the identification of an unknown number of active subspaces in a large family of subspaces, accounting for the possible positions of potential targets in the delay-Doppler domain: the resulting testing problem is composite and multi-hypothesis. At first, we derive a solution based on the generalized information criterion (GIC), whose complexity is however prohibitive; then, we propose an approximated form of the GIC-based receiver and derive two iterative data-adaptive strategies, both extracting and eliminating the superimposed back-scattered subspace signals one-by-one. Leveraging the IEEE 802.11ad standard, a short-range low-mobility application is discussed to validate the merits of the proposed procedures in terms of detection and localization capabilities, robustness to multi-target interference, and achievable resolution.

中文翻译：

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使用毫米波通信信号的机会传感：一种子空间方法

在这项工作中，我们通过利用毫米波通信信号的机会雷达研究了多个延迟和多普勒扩展目标的联合检测和定位。该问题被表述为在一大类子空间中识别未知数量的活动子空间，说明延迟多普勒域中潜在目标的可能位置：由此产生的测试问题是复合和多假设。首先，我们基于广义信息准则 (GIC) 推导出解决方案，但其复杂性却令人望而却步；然后，我们提出了一种基于 GIC 的接收器的近似形式，并推导出两种迭代数据自适应策略，分别提取和消除叠加的反向散射子空间信号。利用 IEEE 802.11ad 标准，