Abstract: Multi-beam fishery sonar is an indispensable equipment in marine fisheries and plays an important role in detecting fish schools. However, the directionality of such sonar is easily affected by wind, waves, and ship attitude. To address this issue, this study established a simplified attitude change model, identified the factors that affect beam stability error, and proposed a beam stability algorithm based on Kalman filtering and digital beamforming technology: first, filter and interpolate the attitude values to obtain smoother and higher sampling rate attitude data; By using coordinate rotation to compensate for the target pointing of the beam, stable and accurate pointing of the sonar beam can be achieved. This study implemented a beam stabilization module based on FPGA (Field Programmable Gate Arrays). The shaking table test shows that under the fourth level sea state, the application of this module can ensure that the maximum deviation of the pointing angle of each beam does not exceed ±1.8°, which is basically consistent with the simulation results. This study has been applied to multi-beam fishery sonar, greatly improving the fishing efficiency of fishing vessels.

Key words: fishery sonar, kalman filter, digital beamforming, beam stabilization 

摘要： 多波束渔用声呐是海洋渔业中不可或缺的设备，在探测鱼群方面发挥着重要作用。然而此类声呐的指向性容易受到风浪和船舶姿态的影响。为了解决这个问题，本研究建立了简化的姿态变化模型，指出了影响波束稳定误差的因素，并提出了一种基于卡尔曼滤波和数字波束形成技术的波束稳定算法：先对姿态值做滤波及插值处理，获得更平滑、采样率更高的姿态数据；再使用坐标旋转的方式对波束的目标指向进行补偿，从而实现声呐波束的稳定而精确的指向。本研究基于FPGA（现场可编程门阵列）实现了波束稳定模块。摆台模拟试验结果表明，在四级海况下，应用本模块可保证各波束指向角度最大偏差不超过±1.8°，与仿真结果基本一致。本研究已应用在多波束渔用声呐中，大大提高了渔船捕捞效率。

关键词: 渔用声呐, 卡尔曼滤波, 数字波束形成, 波束稳定