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.