有源声呐距离维波束形成方法

Active sonar range-dimensional beamforming

针对脉冲压缩处理所获得的距离分辨率和干扰抑制能力不足的问题,提出了有源声呐距离维波束形成方法。该方法从单个脉冲回波的频域输出中提取多组子带分量,每个子带分量的中心频率形成等差数列,对应的相移形成复指数等比数列(可类比于均匀直线阵的阵列流形向量)。根据这一特点,使用多组子带分量构建协方差矩阵,根据中心频率设计距离维加权向量,建立了距离维波束形成模型。给出了距离维常规波束形成和距离维自适应波束形成的表达式、处理流程,对距离分辨率和干扰抑制能力进行了分析。利用数值仿真和水池实验证明,距离维常规波束形成可获得与脉冲压缩处理类似的距离分辨率,而距离维自适应波束形成可获得更高的距离分辨率和更优的距离维干扰抑制能力。

To improve the range resolution and suppress range-dimensional interferences,we proposed a new beamformer for active sonar signal processing,which is termed as the range-dimensional beamformer.The proposed beamformer extracts several sub-band components from single echo of the active sonar.Due to the frequency gaps between these sub-band components,their phase shifts form a complex geometric series,which is similar to the array manifold vector of a uniform linear array.Accordingly,borrowing from the traditional angle-dimensional beamformer,we propose the range-dimensional beamformer which can form a beampattern in the range dimension.The corresponding sample covariance matrix is constructed directly from the sub-band components;and the scanning vector is calculated according to their phase shifts at the center frequencies.We give both the expressions and processing procedures of the rangedimensional conventional beamformer and the range-dimensional adaptive beamformer.Furthermore,we give analyses on the processing performance of the range-dimensional beamformer.Numerical simulations and a tank experiment demonstrate the effectiveness of the proposed range-dimensional beamformer.