Improvement on Seafloor Positioning Analysis Method: Constraint on Acoustic Velocity Estimation and Evaluation

Abstract

The current analysis method in this study simultaneously estimates positions of seafloor transponders and temporal variation of acoustic velocity based on horizontally stratified structure of acoustic velocity. However, according to the result of numerical experiment using this method, the positioning might be affected by bias error using travel-time dataset made under the temporal variation of acoustic velocity with dual-period. The most probable cause of the bias error was misestimation of acoustic velocity with its uneven location in space. Thus to avoid misestimation, a constraint is added on the estimate of the acoustic velocity to the current analysis method. With this constraint, the result in numerical experiment showed that the positioning by the improved method has high repeatability in three components. As the constraint, for instance, the continuous measurement of temperature and pressure in seawater can be applicable.