Abstract
The autonomous underwater vehicle mounted on the forward obstacle avoidance sonar is developed to investigate ocean environments such as that of the Arctic Ocean. In order to obtain real time, high efficiency and clear acoustic images, the acoustic lens sonar system has been adopted. Usually, the design of the acoustic lens as well as that of the optical lens is based on geometrical optics theory. In this paper, the acoustic characteristics of the acoustic lens are studied by using the two- and three-dimensional parabolic equation methods.