Evaluation of sound speed profile estimation by single sonar

It is almost always said that the sound speed profile is principle in the underwater acoustic measurements. The profiles affect propagation ranges, target depression angles and so on. Therefore the sonar operation is useless without them for the severe requirements like security usages. Usually, they are estimated based on temperature and salinity distribution measurements with expendable probes like XBTs. However, it is not appropriate for frequent measurements which are sometimes required in the highly secure applications. On the other hand, this is also true for acoustic tomography of which scale is sometimes too large for small sized applications. To solve this frequent estimation problem a new approach is proposed. The new approach needs only single sonar and it is based on a layered model of ray propagations. This method is found to be effective by simulations. However, required computational times are laid on the table for consideration.