DVL-Based Odometry for Autonomous Underwater Gliders

Autonomous underwater gliders (AUGs) are capable of traversing basin scale distances but lack sufficient localization accuracy to operate without periodic surfacing to obtain GPS fixes and constrain localization drift. Conventionally, AUGs use a dynamic flight model with depth averaged current correction (DACC) to dead-reckon their position while subsurface. However, these flight models become unstable at shallow pitch angles and DACC is inaccurate in dynamic and highly sheared water column currents. We present a method and preliminary results from field trials for improved real-time AUG localization using a Doppler Velocity Logger to estimate vehicle velocity and dynamically profile water column currents. This improved localization reduces the need for periodic surfacing, while independence from a dynamic flight model makes it particularly suited for shallow-yo profile missions.