一种空-频联合最优滤波的被动宽带检测方法

常规宽带能量检测在多目标、强干扰环境下输出信噪比(SNR)降低，检测性能大幅度下降。针对此问题，该文提出一种将子阵导向最小方差(STMV)宽带空域自适应波束形成与频域Eckart滤波结合的空-频联合最优滤波宽带检测方法。该方法首先通过子阵导向最小方差波束形成进行空间自适应处理，利用自适应波束形成的干扰抑制能力在空域实现最优滤波；然后通过最大似然估计实时估计信号和噪声的功率谱，构造Eckart滤波对自适应波束形成的输出分配不同权重进行加权滤波，从而实现频域信噪比最大化。所提方法通过空-频联合最优滤波，降低空域旁瓣干扰和频带内噪声的影响，使得输出信噪比最大，从而有效地改善目标宽带检测能力，提高被动声呐的宽带检测性能。仿真和试验数据处理结果验证了该方法的有效性。

A Passive Broadband Detection Method Based on Space-frequency Joint Optimal Filtering

The output Signal-to-Noise Ratio(SNR) of conventional broadband energy detection is reduced in multi-target and strong interference environment, and the detection performance is great reduced. In order to solve the problem, a broadband detection method based on space-frequency joint optimal filtering which combines subarray STeered Minimum Variance(STMV) broadband adaptive beamforming with Eckart filtering is proposed. Firstly, the spatial adaptive processing is carried out by subarray STMV beamforming, and the optimal filtering is realized in spatial domain by using the interference suppression ability of adaptive beamforming. Then, the power spectrum of signal and noise is estimated by maximum likelihood estimation, and Eckart filter is constructed to assign different weights to the output of adaptive beamforming to maximize the output SNR in frequency domain. The influence of spatial sidelobe interference and noise in the frequency band are reduced to make the output SNR maximum by the proposed method. The broadband detection ability of the target can be effectively improved and the broadband detection performance of passive sonar is also improved. The simulation and experimental data processing results verifiy the effectiveness of the method.