基于首达波与次达波到达时差的深海浅层移动声源定位

为克服海洋环境不确定性、信号接收及处理偶然误差对定位精度的影响，基于单水听器多途声到达时差，利用扩展卡尔曼滤波（EKF）算法对深海浅层移动声源进行定位研究。结合Butterworth带 通滤波算法及Bellhop射线模型识别水声试验数据中的多途到达波，对比分析各到达波间的相对能量大小，并确定信噪比较大的首达波与次达波为研究对象；以单频信号作为匹配序列，计算时域相关性大小，得到首达波与次达波的声到达时差；以首达波与次达波的声到达时差为观测值，构建EKF声源定位模型，得到移动声源的深度、水平距离及速度等信息。研究结果表明：在深海水声信道中，当声源和水听器都位于浅表水层时，直达波与海面反射波重合，首达波与第1次 海底反射波能量相对较大；滤波结果与实测数据吻合较好，验证了EKF算法可较好地实现对水下移动目标定位。

Localization of Moving Acoustic Source in Shallow Layer of Deep Ocean Based on the Time Difference of Arrival between theFirst and Second Waves

In order to eliminate the effects of the ocean environmental uncertainty, the accidental errors due to acoustic signal receiving and processing on positioning accuracy, the localization of a moving sound source is realized using EKF method based on the time difference of arrival between the first and second arrival waves. The acoustic waves arriving from multiple paths are identified using Butterworth band pass filtering method and Bellhop ray model, and their relative energies are also compared. And the first and second arrival waves with bigger signal-to-noise ratio (SNR) are studied. The time difference of arrival between the first and second arrival waves is calculated using time domain correlation method by taking single frequency signal as a matched sequence. The time difference of arrival is set to be a measured value, and the acoustic source is localized based on extended Kalman filter (EKF) method, thus obtaining the depth, horizontal range and speed of the moving acoustic source. When the acoustic source and hydrophone are on the surface layer in deep water acoustic channel, the direct and reflected waves overlap each other, and the energies of the first arrival wave and the first wave reflected from the bottom of the sea are higher than the others. The research work shows that the calculated results are in good agreement with the experiment data, which proves that EKF method is well fit for the localization of the underwater moving acoustic source.