The SENSOTEK Synthetic Aperture Sonar - results from HUGIN AUV trials

The Norwegian Defence Research Establishment (FFI) and Kongsberg Maritime have an ongoing programme to develop synthetic aperture sonar (SAS) technology for the HUGIN autonomous underwater vehicle (AUV). As part of this programme, a wideband multi-aspect interferometric SAS, named SENSOTEK, has been developed. The system was installed on FFIs own research vehicle HUGIN I in 2005, and has been tested on numerous trials in various conditions and water depths from 10 m to 200 m. The SENSOTEK SAS has a theoretical resolution that approaches 1 cm, which is radically better than conventional sidescan sonar technology. The system is also equipped with two full-length receiver antennas, giving the ability of seafloor mapping in the same swath as the high resolution imaging. The system is used for prototyping of SAS signal processing software, sonar design and technology demonstrations. It is also the prototype in the HISAS product series manufactured by Kongsberg Maritime. In 2007, the Royal Norwegian Navy will receive their second HUGIN 1000, equipped with a HISAS 1030 system. This is a second generation SAS system heavily based on the learnings from the SENSOTEK system. This report describes the SAS system in detail, and shows example imagery of various targets on the seafloor.