A Real-Time Autonomous Gravity Measurement Method for Underwater Gravity-Aided Navigation

Underwater gravity-assisted navigation is typically employed by submarines as a navigation method when external navigation information is not easily available, which necessitates the acquisition of gravity information through autonomous measurement. However, underwater gravity measurement research currently relies heavily on high-precision external navigation information, such as acoustic positioning, and lacks autonomy. Therefore, there is a contradiction between the existing underwater gravity measurement technology and the underwater gravity-assisted navigation application scenario. To solve this problem, a real-time, autonomous gravity measurement method specifically designed for underwater gravity-assisted navigation is proposed in this study. The proposed method achieves real-time, autonomous underwater gravity measurement with mGal-level precision by integrating classical gravity measurement principles, which involves a gravimeter, an electromagnetic log (EML), and a depth gauge (DG). To evaluate the proposed method’s effectiveness, a semi-physical simulation was conducted through vehicle testing. The experimental results demonstrated that the proposed method achieved a precision of 1.01 mGal at 0.0033 Hz within the repeated measuring line.