双基地有源探测柔性水平阵阵形实时校准方法

Real-time calibration method of flexible horizontal array for bistatic active detection

双基地有源模式下接收基地搭载的柔性水平阵在运动过程中,阵形会发生实时的畸变。针对阵形误差的存在会严重影响水听器阵列探测性能的问题,本文提出一种基于发射信号为线性调频(LFM)信号,利用直达波实现阵形参数估计的方法。该方法首先利用分数阶傅里叶变换(FRFT)对LFM信号在特定阶数的分数阶傅里叶变换域上的能量聚集性,实现直达波与目标回波的分离,避免了目标回波对于阵形参数估计的影响。而后利用各阵元直达波FRFT后对应峰值点之间的相位差实现了阵形参数估计,并提出了一种基于拖曳船辐射噪声的阵形解模糊方法。计算机仿真表明该方法对于噪声及干扰影响、入射角度误差以及多普勒频移均有一定的宽容性,湖上实验验证了阵形估计方法的有效性,是一种可实时校准、高精度、稳健的柔性水平阵阵形估计算法。

The flexible horizontal array carried by the receiving base in the bistatic base of active mode has real-time array shape distortion during the motion.The detection performance of hydrophone arrays is seriously affected by the existence of array shape errors.A method is proposed in this paper to estimate the array shape parameters using direct waves based on LFM signal to solve the problem.In the method,the FRFT is firstly used to separate the direct wave from the target echo,avoiding the influence of the target echo on the array parameter estimation.The phase difference between the corresponding peak points after FRFT of each array element is used to estimate the array parameters,and an array deblurring method based on the radiation noise of the towing vessel is proposed.Computer simulation shows that the method is tolerant to noise and interference effects,incident angle errors and Doppler shifts.The effectiveness of the array estimation method is verified by the experiments on the lake,which is a flexible horizontal array estimation algorithm that can be calibrated in real time with high accuracy and robustness.