Experimental Study on Underwater Moving Gravity Measurement by Using Strapdown Gravimeter Based on AUV Platform

Abstract Autonomous underwater vehicle (AUV) can be controlled autonomously and cable-less, which can reduce the cost and has good applicability for underwater gravity measurement. Based on airborne gravity measurement, the basic principle of underwater moving gravity measurement is studied, and the mathematical model of AUV underwater moving gravity measurement is established, which based on the data obtained by the gravimeter with a fibre optic inertial navigation system (INS), short baseline underwater acoustic positioning (SBL), Doppler velocity log (DVL) and depth gauge (DG). Underwater experimental verification system of moving gravity measurement consists of the reformed BQR800 Unmanned Underwater Vehicle and dg-M strapdown gravimeter. Mulan Lake in Wuhan was selected as the experimental site. Experimental scheme and processing flow of underwater moving gravity measurement data was designed. Data obtained by strapdown gravimeter, DG, DVL, SBL and other equipment was analysed, and the data calculation was completed. Moreover, the repetition lines are selected to evaluate the repeatability of gravity measurement. The experiment al verification of gravity measurement for three return trips were carried out from January 7 to 8, 2020. The accuracy of repetition line reached 0.42 mGal, which verified the feasibility of underwater moving gravity measurement.