Optimal frequency in acoustic location

In acoustic location the problem of choice of operating frequency arises. Usually it is found with the help of a compromise agreement. High frequency means high accuracy and directivity. On the other hand, low frequency means weak oscillations in the media under the sonar frequency. In the paper the optimal frequency for hydrolocation is found: in a marine and river media. As an optimal criterion, we have taken the ratio of intensity of echo signal to the sum of noise intensity and reverberation.