Model-Aided Localization and Navigation for Underwater Gliders Using Single-Beacon Travel-Time Differences

Area of Science:

• Robotics
• Oceanography
• Navigation Systems

Background:

• Accurate localization and navigation are crucial for autonomous underwater vehicles (AUVs) in underwater environments.
• Underwater gliders face challenges in modeling and measurement due to limited maneuverability and payload capacity.
• Existing methods often struggle with the complexities of underwater glider dynamics.

Purpose of the Study:

• To propose an enhanced extended Kalman filter (EKF)-based method for improved underwater glider localization.
• To develop a modified kinematic model that accounts for underwater glider motion dynamics.
• To integrate a novel measurement approach using travel-time differences for robust position estimation.

Main Methods:

• Modified underwater glider kinematic model incorporating attack and drift angles and depth-averaged currents.
• Utilized travel-time differences from a single beacon as measurements, bypassing synchronization needs.
• Integrated the Rauch-Tung-Striebel (RTS) smoothing method with the EKF to minimize estimation errors.

Main Results:

• The proposed RTS-EKF method demonstrated improved position estimation performance compared to traditional motion model estimates.
• Significant performance gains were observed, particularly a 46% improvement at inflection points in simulations.
• The method effectively handles the unique challenges of underwater glider navigation.

Conclusions:

• The developed EKF-based method with a modified kinematic model and RTS smoothing offers a more accurate solution for underwater glider localization.
• The novel measurement strategy using travel-time differences enhances reliability in underwater navigation.
• This research contributes to advancing the capabilities of autonomous underwater vehicles in complex marine environments.