In this paper, we investigate low probability interception (LPI) in passive phased array radars. Power control and transmit beamforming (BF) are used to minimize the received power by the interceptor. Meanwhile, desired target detection performances and the limited power budget of radar are guaranteed. The LPI problem is solved analytically and some theorems are derived for the design of optimum BF weights. Two LPI optimization problems from different perspectives are formulated and solved analytically in preparing closed-form solutions for designing transmit BF weights. LPI performance and computation time of the proposed algorithms are compared with that of the benchmark algorithms. Simulation results show that proposed algorithms not only minimize the interception probability of radar in comparison with benchmark algorithms but also satisfy desired detection performance and power budget constraints simultaneously. The proposed algorithms outperform the standard numerical Barrier algorithm in complexity and optimality.

在本文中，我们研究了无源相控阵雷达中的低概率拦截 (LPI)。功率控制和发射波束成形 (BF) 用于最小化拦截器的接收功率。同时，保证了理想的目标检测性能和有限的雷达功率预算。LPI 问题得到了分析解决，并推导出了一些用于设计最佳 BF 权重的定理。在为设计传输 BF 权重准备封闭形式的解决方案时，从不同角度制定并解析解决了两个 LPI 优化问题。将所提出算法的 LPI 性能和计算时间与基准算法的 LPI 性能和计算时间进行了比较。仿真结果表明，与基准算法相比，所提出的算法不仅最大限度地降低了雷达的拦截概率，而且同时满足了所需的检测性能和功率预算约束。所提出的算法在复杂性和最优性方面优于标准数值 Barrier 算法。