Physical constraints in sonar design

Abstract

The dynamic range and processing gains achievable within a simple passive sonar will be reviewed. It will be demonstrated that the constraints of modern electronic hardware components do not necessarily limit the performance of a passive sonar system when compared with the physical constraints of the acoustic channel. By contrast it will be demonstrated that the pulse design of an active sonar places significant limitations on the capability of the system. For example, range resolution, Doppler resolution, range sidelobes, ambiguities and reverberation performance all depend on the design of the sonar transmission. Techniques available to the designer for suppressing range sidelobes and pulse designs with both range and Doppler sensitivity will be reviewed. The constraints imposed by the transducer will be considered, particularly in relationship to ultrahigh range resolution capabilities. Finally, a comparison between an early 1960s sonar and a modern equivalent will be made in terms of performance, power consumption and size.