Development of a Sonar forUnderwater Sensor Platformsand Surface Vehicles

Abstract: In the frame of a thesis project the authors have developed software and methodologies for a sonar prototype. The ultimate goal is the installation of the sonar prototype on the department’s sensor platforms, which include AUVs and ASVs. The thesis presents the intelligent sampling algorithms and DSP tools, e.g. a matched filter, that have been implemented. The sonar was successfully configured to work as an echo sounder. Tests were performed in the underwater laboratory at FOI and in-situ in the Stockholm archipelago. It was found that the sonar is capable of measuring distances with an average error of less than 1 cm in controlled experiments. The in-situ experiments in Baggensfjärden showed a echo detection rate of ≈90 %. Unfortunately, due to hardware limitations, attempts to implement DVL functions have failed. However, background theory and methodologies for velocity measurements, communication and positioning are briefly explained to provide a basis for future work. The electronics currently are subject to improvements and a new version is expected to be ready for use soon. Future work will include analysis and integration of velocity sensing, communication protocols and positioning concepts.