浅海环境中矢量水听器角度谱特性

The characteristics of frequency-time azimuth spectrum estimation by a vector hydrophone in shallow water

为探明远场舰船噪声和近场平台噪声声能流相互作用的机制对矢量水听器角度谱特性的影响,基于简正波矢量场理论,构建舰船平台噪声声场模型,获得与海上实验结果相符的声能流角度谱特性,声能流方向均随频率变化。对远场舰船噪声声能流和近场平台噪声声能流相互作用进行仿真,两者声能流强度的此消彼长使角度谱出现4种条纹,与海上实验获得的角度谱特性一致,导致目标方位估计出现误差,且不同频带上的结果不一致。说明两个声能流相互作用时,影响合成能流角度谱特性的主要因素是两者的声压级之差,为浅海中同时存在多个声源时的目标方位估计提供参考。

The impact of mechanism of interaction between the energy flow of the far-field ship noise and the near-field platform on the characteristics of frequency-time azimuth spectrum is discussed. Description of acoustic vector fields of normal modes theory is used to model the energy flows of radiated noise generated by the near-field platform. The characteristics of frequency-time azimuth spectrum are the same with the investigation by the vector hydrophone in shallow water. The azimuth of the energy flow changes with frequency. The interaction between the energy flow of the far-field ship noise and the near-field platform is simulated. The frequency-time azimuth spectrum turns up four kinds of stripes when the sound intensity of the energy flows change against each other, which is the same with the investigation of sea trial. The results of direction of arrival estimation appear inaccuracy, and vary with frequency. The main factor that affects the characteristics of frequency-time azimuth spectrum of resultant energy flow is the difference of sound pressure level. The estimation of the direction of arrival in shallow water when a number of sources exist benefits from this.