Acoustics and Sustainability : How should acoustics adapt to meet future demands ? Cyclostationarity for Passive Underwater Detection of Propellor Craft : A Development of DEMON Processing
Acoustics and Sustainability : How should acoustics adapt to meet future demands ? Cyclostationarity for Passive Underwater Detection of Propellor Craft : A Development of DEMON Processing
复制标题
声学与可持续性：声学应如何适应未来的需求？
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
R. Emslie
中科院分区：
文献类型：
--
作者：
D. Hanson;J. Antoni;Graham Brown;R. Emslie
当螺旋桨的叶片通过水时，它们会产生特征调幅随机噪声信号，可以用声纳检测到。利用这些声纳信号对水面舰艇进行被动声探测的一种流行的经验技术是DEMON(检测对噪声的包络调制)处理。顾名思义，恶魔处理寻求检测调制的频率，即轴和叶片的通过频率。它的工作原理是隔离对操作员来说调制最明显的频带，取此滤波噪声频带的包络并生成瀑布谱图。与螺旋桨旋转部件相关的谐波将在瀑布中显现，从而使船只能够被识别。然而，恶魔处理有几个缺点，最重要的是在选择噪声频段时对操作员技能的要求。本文介绍了正在进行的工作的初步结果，以提供经验恶魔处理技术的数学形式。这种形式化是基于观察到的，即恶魔处理不知不觉地利用了螺旋桨信号的循环平稳特性。循环平稳信号处理是一种最近在涉及旋转机械的机械系统中得到应用的技术，它提供了对检测问题的深入了解，并有可能克服恶魔处理的弱点，并将其能力扩展到包括频率和幅度调制。
As the blades of a propeller pass through the water they produce characteristic amplitude modulated random noise signals which can be detected using sonar. A popular empirical technique for passive acoustic detection of surface ships from submarines using these sonar signals is DEMON (Detection of Envelope Modulation on Noise) processing. As the name suggests, DEMON processing seeks to detect the frequencies of modulation, i.e. the shaft and blade pass frequencies. It works by isolating the frequency band in which the modulation is most distinct to the operator, taking the envelope of this filtered noise band and producing a waterfall spectrogram. Harmonics associated with the rotating components of the propeller will be manifest in the waterfall, allowing the vessel to be identified. DEMON processing has several drawbacks however, most importantly the requirement for operator skill in the selection of the noise band. This paper presents the preliminary findings of work underway to provide a mathematical formalisation of the empirical DEMON processing technique. This formalisation is based on the observation that DEMON processing unknowingly exploits the cyclostationary properties of the propeller signals. Cyclostationary signal processing, a technique which has recently found application in mechanical systems involving rotating machinery, offers great insight into the detection problem, and has the potential to overcome the weaknesses of DEMON processing as well as expanding its capability to include frequency as well as amplitude modulation.