Acoustic position measurement systems

Progress made over the past 2 decades in acoustic measurement technology is finding important application in dynamically positioning drill ships for offshore oil exploration. This paper quickly traces the history of this technology, examines in general terms the basic underwater tracking problem, describes approaches taken to its solution, and identifies the factors which affect the designer´s choice of systems. Comparisons are made between the basic types of tracking systems and between the conventional and newly developed signal processing techniques.