Detection and Parameter Estimation of Solitary Internal Waves Using Distributed Acoustic Sensors

A method to detect solitary internal waves passing through the sensors area in shallow water and estimate their parameters is proposed in this paper using distributed acoustic sensors. The proposed detection method is based on cross correlation of the (envelop of) channel impulse responses estimated from broadband signals transmitted between the sensor nodes with the reference impulse responses in the absence of solitary internal waves. An iterative sequential parameter estimation method is proposed based on time domain matching of the measured channel impulse responses with modeled impulse responses. Simultaneous parameter estimation can be obtained using a global search method such as the matched field inversion. Simulation studies are carried out using environmental acoustic data collected in the northern South China Sea. The results show that the proposed method can effectively detect the existence of passing SIWs, and their parameters can be estimated with reasonable accuracy even under low signal-to-noise ratio conditions.