Abstract：The horizontal variations of sound speed profile and water depth have a significant effect on acoustic propagation in shallow water. This paper presents a method for calculating travel time based on ray theory in unstratified ocean.An efficient algorithm was applied to seek eigen rays arriving at hydrophone.The sound speed profile can be described approximately by empirical orthogonal functions (EOF) with proper precision.The coefficient of the EOF will scale linearly with horizontal distance in certain sea area.The ray method can calculate travel time rapidly with higher precision.The method can be used for fast inversion of sound speed profile in the ocean.
2015, Vol. 34 
