Estimation of State for GPS-Denied Navigation of Autonomous Underwater Vehicles (AUVs) in Underwater Exploration

During the AUV mission, localization and Navigation are crucial. AUVs use various methods of Navigation, such as Vision- Based Navigation, INS, Doppler Velocity Logs (DVL), and depth sensors to estimate their position and orientation. This information guides the A UV along the planned path and maintains accurate positioning. Before deploying the AUV, a mission plan is created. This plan includes the survey area, waypoints, and mission objectives. The survey area is typically defined based on the desired coverage and specific areas of interest. Autonomous underwater vehicles (AUVs) have gained significant attention in marine exploration and research due to their ability to operate in challenging environments without direct human intervention. However, accurate Navigation of AUVs remains a critical issue, particularly in scenarios where GPS signals are unavailable or unreliable such as underwater missions. This paper presents a novel state estimation method to enable GPS-denied Navigation for AUVs in marine environments. This proposed method combines sensor data, including IMU, Doppler velocity log, and pressure sensors, to accurately estimate the vehicle's position, orientation, and velocity. We employ EKF and UKF framework to perform the state estimation process, which fuses the different sensor measurements and models the system's uncertainties.