Experiment and analysis on cross-ice bearing estimation for underwater acoustic source in the Arctic

In order to obtain the bearing information of the acoustic source beneath the Arctic ice,by placing the geophones on the ice surface and dropping the acoustic bomb into the water under-ice,the experiment of the bearing estimation by the division frequency band for the acoustic source beneath the Arctic ice was carried out.The results show that the error and accuracy of bearing estimation are related to the received signal frequency(or the signal frequency of underwater sound source)of the geophone.When the received signal in low frequency band was used for bearing estimation,the accuracy was high and the mean error was small.When the frequency of the received signal was less than and equal to 250 Hz,the accuracy of bearing estimation can reach 72.9%.On the contrary,when the received signal in high frequency band was used for the bearing estimation,the accuracy was low and the mean error was large.When the received signals of different frequency bands were used to estimate the bearing of the under-ice sound source,the estimation error was related to the variation of the reflection coefficient of the water ice interface in the same frequency band.If the change of the reflection coefficient was great,the bearing estimation error was large.Otherwise,the bearing estimation error was small.