Tutorial introduction and historical overview of the need for heading sensors in sonar applications

The development of sonar systems is closely coupled to the evolution of the submarine. By the beginning of the twentieth century, the threat of a submarine force to commercial and naval shipping was starting to be appreciated. It is no coincidence that experiments using underwater sound were also taking place at this time. The development of sonar systems has progressed throughout the twentieth century, with increased activity being occasioned by events such as two world wars, the cold war and the exploitation of off-shore oil reserves