Abstract: A system and method operate a Navigation Sonar System in an Alert Velocity Submode, receive sonar data during the operation of the Navigational Sonar System in the Alert Velocity Submode, and use the sonar data to compute depth data used to calculate a Bathymetric Fix.

Abstract: A method of finding a vertical velocity of a vehicle by first forming two cost functions from three pulse return times. An independently determined approximate vertical velocity and a Fletcher-Powell estimation technique are used on the first cost function, to select a minimum velocity of the first cost function. The selected minimum velocity, two calculated velocities from the selected minimum velocity, and a Fletcher-Powell estimation technique are used on the second cost function, to select a minimum velocity of the second cost function. The selected minimum velocity of the second cost function is taken as the vertical velocity of the vehicle.

Abstract: A method of correcting errors in in inertial navigation system, without imposing restrictions on the ships course, utilizing bathymetric data collected during the Ocean Survey Program (OSP). As the ship is in transit in or crosses an OSP swath, sonar transmissions commence and continue only to acquire bottom data within data areas of predetermined dimensions. Depth gates and transmission power levels are established in accordance with OSP provided bottom data and depth is determined by an autocorrelation process. A virtual linear map is established with the OSP data in the predicted locations of data collection areas. The collected data is then compared to corresponding OSP data to determine inertial navigation system corrections.