ABSTRACTThe technique of estimating a vessel's speed over the ground by measuring the Doppler frequency shift of an acoustic pulse reflected from the bottom has been successfully employed by the oceanographic community for many years. A system based on this principle may act as a precise dead‐reckoning navigation device, or may provide an accurate velocity reference for other types of navigation systems. Despite the history of success of the Doppler sonar to date, improvements in marine technology and more stringent operational requirements have placed new demands on system accuracy. The study of Doppler sonar navigator error growth and error prediction suggests that significant improvements in the performance of existing systems may be achieve