Motion compensation of AUV-based synthetic aperture sonar

To date, ocean-going synthetic aperture sonar (SAS) systems have been deployed exclusively in a configuration where the sonar instrument is housed in a towed body that receives power from and exchanges information with the vessel to which it is attached. Meanwhile, recent years have witnessed the beginnings of maturity with respect to both SAS and autonomous underwater vehicle (AUV) technologies. In order to move away from the towed sonar paradigm, the Coastal Systems Station has recently taken delivery of and begun using the first AUV-based SAS. The AUV was manufactured by Blue n Robotics and the sonar used on this vehicle is the existing CSS LF/HF SAS. This transition is not without its challenges, however, as the operation and dynamic behavior of an AUV is different from that of a towed body. In general, the AUV configuration makes the problem of unwanted platform motion more severe and more difficult to solve. This paper discusses motion compensation in the context of initial evaluations of the performance of the CSS AUV-based SAS system.