Obstacle avoidance sonar-an analysis of system requirements and detection performance during near-bottom operation

An obstacle avoidance sonar (OAS) is designed to provide spatial information concerning the underwater environment, through an interface, to the guidance and control subsystem of an autonomous underwater vehicle (AUV). An OAS sensor system requirements analysis for near-bottom operation is presented using characteristic environmental and operational parameters. The analysis shows that higher spatial resolution (beam patterns and shortened pulse lengths) is needed to provide effective obstacle detection when operating near the bottom. Simple modifications to an existing obstacle avoidance sonar provide these features and result in an effective obstacle avoidance sonar for near-bottom operation. Detection performance calculations for the unmodified and modified versions of the obstacle avoidance sonar are presented