线谱非平稳性分析和利用干涉谱测距

Nonstationarity analysis of line spectrum and range estimation by spectrum interference

研究运动舰船辐射噪声线谱的非平稳性的规律并利用其来提高声呐的检测性能和实现目标测距测深功能是本研究的目的。线谱的非平稳性有3个方面来源,线谱声源的不稳定、传输途径和目标与接收点的相对运动。通过对大量的运动目标辐射噪声进行的时频分析,总结出运动目标辐射噪声线谱的非平稳性谱图的典型表现。对不同形态的线谱应用不同的处理和检测方法,对频率稳定的连续线谱可以用长积分的最佳检测方法进行,对多普勒变化的线谱可用Dopplerlet方法处理并用于目标测距和测速,对时断时有的线谱得可用卡尔曼跟踪对付断裂的特性。从理论上分析了钟型的“线谱群”的产生原因,证明了此现象是反射声和直达声之间的谱干涉引起的。利用谱干涉现象中的干涉谷之间的关系可实现目标测距测深的目的,最后给出某一实际海上运动目标距离和深度的测量结果。

The purpose of the research is to investigate the line spectrum nonstationarity of radiated noise produced by moving vessels, and to use the features to improve sonar detection performance and to realize the ranging function. The line spectrum nonstationarity comes from 3 aspects: instability of sound source, propagation path and relative movements of sound source and receiver. Several typical patterns of line spectrum are summarized after the time-frequency analysis of a large amount of samples. Different patterns have different processing methods, taking a long time-integral for a stable line pattern, using Dopplerlet for a varying line pattern by relative movements of sound source and receiver, using Kalman filter for intermissive line pattern. A theory analysis is made for a phenomenon of 'line group' which is bell shaped, and the spectrum interference between direct path sound and reflected sound is revealed. One kind of ranging method that employs the superimposed interference pattern is utilized to find moving vessel range. Finally the range and depth estimation of a moving vessel is given using this method.