Loosely Coupled GNSS and IMU Integration for Accurate i-Boat Horizontal Navigation

Global Navigation Satellite System (GNSS) has been widely utilized as a navigation solution for mobile vehicle, yet stand-alone GNSS is unable to achieve sufficient accuracy in some applications. For example, aquatic environment, the position of Unmanned Surface Vehicle (USV) affected by wind, current, and waves dynamics. In this case, integration Inertial Measurement Unit (IMU) an approach that can be used support USV localization accurate solution. This study integrates IMU using Extended Kalman Filter (EKF) process loosely coupled integration. The results show estimated x-position 0.3058 m accurately y-position 0.2780 m. Then, EKF were compared with Unscented (UKF) simulation previous studies. produces higher RMSE value 2D attitude angle than UKF Scenario I. However, due smoothing process, provide visually smoother trajectory UKF, although it significant difference from observed trajectory. On other hand, linear velocity shows better stability both I II.