High Resolution Imaging And Mapping Of The Seabed Using Synthetic Aperture Sonar

Detailed information of the seabed at large depths is increasingly important in many fields such as marine biology, marine geology, offshore constructions and installations, and military applications. With the advent of unmanned autonomous underwater vehicles (AUV) capable of operating at large depths, there is a need for high performance imaging sensors. Synthetic aperture sonar (SAS) is becoming a tool of choice for very high resolution imaging and mapping of the seabed. The Norwegian Defence Research Establishment (FFI) has an ongoing long-term collaboration in research and development of the HUGIN AUV and the HISAS interferometric SAS with Norwegian company Kongsberg Maritime. The specified image resolution is better than 5 x 5 cm and the mapping rate is 2 km2/hour. In this paper, we give an overview of the SAS technology including the challenges involved. We show example images to illustrate the achievable performance.