A low-cost underwater navigation system for remotely operated underwater vehicle — Design, system-integration, and implementation

This paper presents a low-cost underwater navigation system for Remotely Operated Underwater Vehicles (ROUVs). The navigation uses an on-board IMU signal together with intermittent GPS signal to provide real-time localization. This GPS-aided Inertial Navigation System (INS) estimates latitude and longitude of the ROUV using Kalman filter. A dedicated navigation software with a GUI is built to simulate the orientation of the ROUV and also is able to acquire near real-time data as it does not require post-data analysis. The software is able to access Google Maps and thus plot the live trajectory. This makes the system user-friendly for people with bare minimum knowledge in mathematics of navigation. The navigation system is first tested on ground where reception of GPS signal is good to ensure proper functioning. This is followed by testing with a custom-built ROUV in swimming pools surrounded by high raise-building where the GPS signal is distorted or poor. The navigation system is able to localize the ROUV with an accuracy of 2 to 3 metres. The system is also designed to store the data on-board as well as on surface to facilitate ease-of-search, and to initialize the search operation in the event of loss of communication.