“Inverted” acoustic navigation system also measurers sound speed at towed vehicle

An “Inverted” acoustic navigation system (AMSNAV) is being developed jointly by Acoustic Marine Systems and Seafloor Surveys International to provide reliable position information for deep towed sonar survey operations. The acoustic navigation signal is also used for accurately determining sound speed at the towed vehicle, eliminating errors caused by sound speed uncertainties when converting the measured phase angles to tow vehicle bearing. The measured sound speed also allows for increased sonar data accuracy, especially important for bathymetric mapping