船舶航行辐射噪声的主动控制方法研究

船舶航行辐射噪声控制对于环境保护和军事应用均具有重要意义。根据船舶的航行轨迹和接收点建立了自适应噪声抵消模型，从船舶外部对其产生的特定低频线谱进行主动控制，实现局部自由声场静区。针对低频线谱信号，在船舶上布设自适应次级声源，进行了不同信号频率的仿真，研究其在特定空间内产生的降噪效果。仿真显示当船舶在特定区域内航行时，次级声源的开启能够在接收点处实现特定低频线谱信号的有效抵消。针对仿真结果，理论推导了有效声抵消区域半径的计算公式。由此得到了一种可能的船舶航行辐射噪声低频线谱主动控制方法:首先计算有效声抵消区域半径，当船舶进入或离开该区域时，动态开启或关闭次级声源，从而实现噪声的有源控制。 

On the Active Control of Vessel Navigation Noises

Controlling vessel navigation noise’s intensity has great significance to both the protection of marine animals and military operations. An adaptive active noise cancellation model is given where both sound sources and receiver are constantly moving, by which vessel navigation noise can be controlled outside the ship hull to generate a quiet local free space. With respect to specific low frequency linear spectrum of those noises, a study is conducted to investigate the effects of noise reduction within some constrained space by the installation of an adaptive secondary cancelling noise source. Simulation experiments are then conducted with various low frequency linear spectrum signals as inputs. Simulation results show that when vessel is navigating in certain region the activation of secondary noise source do cancel some noises in the receiver. Besides, the calculation formula of the region’s radius is deduced, which is consistent with the simulation results. Hence, a possible method to actively control vessel navigation noises is got. The method starts by the calculation of effective noise cancellation region’s radius and then activates or deactivates the secondary noise source depending on whether vessel is in that region.