基于功率聚焦的宽带阵列信号检测算法

摘要

针对无源侦察系统的实时性应用需求,该文提出了一种基于功率聚焦的宽带阵列信号检测算法。利用均匀线阵接收信号的相位变化信息,通过改进的二重FFT算法将各阵元接收信号的功率聚焦到信号到达角(Direction Of Arrival, DOA)。在此基础上,推导了聚焦后各角度上噪声数据的概率密度函数,构造了具有恒虚警特性的检验统计量和相应的检测门限,并推导了不同虚警率和信噪比条件下的理论检测概率。该算法聚焦过程计算复杂度较小,检测过程不依赖于信号先验信息,检测结果还可为后续的精确角度测量提供初值。仿真实验表明,该算法对弱信号具有较好的检测效果。%　　Aiming at the requirement of real-time signal detection in the passive surveillance system, a wideband array signal detection algorithm is proposed based on the concept of power focusing. By making use of the phase difference of the signal received by a uniform linear array, the algorithm makes the power of the received signal focused in the Direction Of Arrival (DOA) with improved cascade FFT. Subsequently, the probability density function of the output noise at each angle is derived. Furthermore, a Constant False Alarm Rate (CFAR) test statistic and the corresponding detection threshold are constructed. The theoretical probability of detection is also derived for different false alarm rate and Signal-to-Noise Ratio (SNR). The proposed algorithm is computationally efficient, and the detection process is independent of the prior information. Meanwhile, the results can act as the initial value for other algorithms with higher precision. Simulation results show that the proposed algorithm achieves good performance for weak signal detection.