This work studies the beamforming design in the joint proactive eavesdropping (PE) and target sensing (TS) systems. The base station (BS) wiretaps the information transmitted by the illegal transmitter and sends the waveform for TS. The shared waveform also serves as artificial noise to interfere with the illegal receiver, thereby achieving successful PE.We firstly optimize the transmitting beampattern of the BS only to maximize the eavesdropping rate or only to minimize the Cram{é}r-Rao bound, respectively. Then, the joint design of PE and TS is investigated by formulating the PE-centric, the TS-centric, and the normalized weighted optimization problems. The formulated problems are solved by the semi-definite relaxation technique and the sequential rank-one constraint relaxation method to address the complexity of the original problem. Furthermore, the scenario in which the quality of the eavesdropping channel is stronger than that of the illegal channel is considered. Numerical results demonstrate that the proposed algorithm can effectively realize PE and TS simultaneously.

翻译：本文研究了联合主动窃听与目标感知系统中的波束成形设计问题。基站一方面窃听非法发射机传输的信息，另一方面发射用于目标感知的波形。该共享波形同时作为人工噪声干扰非法接收机，从而实现成功的主动窃听。我们首先分别优化基站的发射波束方向图，以最大化窃听速率或最小化克拉美-罗界。随后，通过构建以主动窃听为中心、以目标感知为中心以及归一化加权优化问题，研究了主动窃听与目标感知的联合设计。针对原问题的复杂性，采用半定松弛技术与序列化秩一约束松弛方法求解所构建的优化问题。此外，本文还考虑了窃听信道质量优于非法信道质量的场景。数值结果表明，所提算法能够有效实现主动窃听与目标感知的同步执行。