Today, measuring of water and underwater vehicles speed is important, needed for navigation, and as an input to navigation systems. Water vehicles speed is also used as an input to fire control systems on military vessels. Therefore, the need for an accurate speed measuring device that measures water vehicle speed relative to the sea bed is apparent. All non-acoustic velocity logs measure water vehicle speed relative to the water, and the absolute water vehicle speed can only be estimated if a knowledge of water currents is available. An acoustic velocity log that provides an absolute measure of water vehicle speed at limited operating depths is the Doppler velocity log. For deep water, the Doppler velocity log measures speed relative to the water and it is thus affected by currents. The acoustic correlation velocity log has acoustic beams similar to a conventional depth-sounder, with a vertically downward propagation direction and a broad beamwidth. Compared to the Doppler velocity log, it is affected less by water vehicle roll and pitch due to its broad beamwidth, and the velocity is virtually independent of the velocity of sound and is referred to the sea bed to a greater depth. In this dissertation, our aim is to eva‎luate the fundamentals, principles, and challenges related to the correlation velocity log. We attempt to solve the challenges using some novel technique or signal processing method so that they have not been used in correlation velocity log yet. Finally, inspired by the experiences yielded by the mentioned investigations, we propose a new velocity log with appropriate capability.

محمدرضا تابان

مهدي امامي

اصغر غلامي