| 摘要: |
| 针对外辐射源雷达由于采用非合作照射源而导致的目标信噪比低、易被直达波和多径等干扰掩盖等目标探测难题，该文研究可增强回波信噪比的可重构智能表面 (RIS)辅助外辐射源雷达系统和相应的目标参数估计方法。在分析建立RIS辅助的外辐射源雷达系统模型和信号模型的基础上，首先研究外辐射源雷达系统配置下RIS的设置方法，建立以提升接收信号的信杂噪比(SCNR)和保证直达波接收功率为准则的RIS反射系数优化问题，并理论推导RIS反射系数的全局最优解，从根本上解决弱目标探测问题；然后，研究RIS辅助下外辐射源雷达的信号处理方法，提出了一种基于时变RIS与稀疏重构的目标多参数估计方法，可实现对目标时延、速度和方位等参数的同时估计；最后实验验证了所提方法的有效性和优越性。 |
| 关键词: 外辐射源雷达 可重构智能表面 目标多参数估计 稀疏重构 |
| DOI： |
| 分类号:TN958.97 |
| 基金项目:国家自然科学基金(62261036),江西省自然科学基金(2022BAB202003) |
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| Signal Processing Algorithm for Echo Signal-to-noise Ratio Enhancement in RIS-Assisted Passive Radar |
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| Abstract: |
| This paper investigates the Reconfigurable Intelligent Surface (RIS)-assisted passive radar system and its corresponding target parameter estimation methods to address the challenges of low target signal-to-noise ratio (SNR), susceptibility to direct wave and multipath interference, and other detection difficulties arising from the use of non-cooperative illumination sources. By analyzing and establishing the RIS-assisted passive radar system and signal models, the study first explores the RIS configuration within the passive radar framework. An optimization problem for the RIS reflection coefficients is formulated, aiming to enhance the signal-to-clutter-and-noise ratio (SCNR) of the received signal while maintaining the direct wave"s received power. The global optimal solution for the RIS reflection coefficients is theoretically derived, providing a fundamental solution to weak target detection. Subsequently, the signal processing method for RIS-assisted passive radar is investigated, and a multi-parameter estimation technique based on time-varying RIS and sparse reconstruction is proposed, enabling simultaneous estimation of target parameters such as delay, velocity, and azimuth. Experimental results demonstrate the effectiveness and superiority of the proposed methods. |
| Key words: passive radar reconfigurable intelligent surfaces(RIS) target multi-parameter estimation sparse reconstruction |