Research on position location in three-dimensional and echolocation click sound source levels of dolphins in shallow water

A location method in shallow water with a single hydrophone and a multi-hydrophone array was introduced in detail in the present study and the time delay difference among different receiving channels was used to calculate spatial coordinates.Combining with the experimental data,the three-dimensional spatial coordinates of dolphins in water and the sound source level of echolocation clicks were calculated.The analysis of dolphin movement track was also carried out.The results show that the broad application range and working conditions of the multi-hydrophone array are more satisfactory and more accurate relative to the single hydrophone,but there are high requirement to synchronization and hardware connection of acquisition equipment.The error analysis shows that the positioning error of the hydrophone array can be reduced to less than 5% at a distance greater than 3 meters.The results of this study provide a technical support for the accurate calculation of click source level of dolphins and the research of dolphin sonar performance and behavior.