Depth sounding systems
The first section of this chapter deals with the characteristics and problems that arise from the need to propagate energy in seawater.
2.2 The characteristics of sound in seawater Before considering the problems of transmitting and receiving acoustic energy in seawater, the effects of the environment must be understood. Sonar systems rely on the accurate measurement of reflected frequency or, in the case of depth sounders, a precise measurement of time and both these parameters are affected by the often unpredictable ocean environment. These effects can be summarized as follows.