Analysis and Reflections on the Development of Underwater Gravity-Aided Inertial Navigation Technology in the United States and Russia

Objectives The development of underwater gravity-aided inertial navigation technology in China is coming to a critical period and faces many difficulties and challenges. There are both cognitive problems in research ideas and “stuck neck” problems in key technologies, which require us to concentrate our wisdom and make creative thinking, and to find ways to solve these problems.

Methods First, we clearly define the connotation of gravity-aided navigation technology as the general term for two types of the aided navigation technologies: gravity compensation and gravity correction. Second, we analyze and review the development strategies, planning layout, development ideas, research and development paths, innovation results, test applications and some development trends worthy of attention in this research field in the United States and Russia, summarize the technical characteristics and successful experiences at diffe-rent stages of the research and development process of the two countries.

Results The characteristics of technological development in the United States include: (1) The demand for gravity compensation has been leading the development of gravity data modelling technology. (2) The demand for gravity compensation has been leading the development of gravity equipment technology. (3) The progress of gravity equipment technology has been promoting the development of gravity correction technology. The technological development characteristics in Russia include: (1) The military requirement has been dominating the development of sea and air gravity equipment technology. (2) The special attention has been paid to the researches on the correction algorithms of inertial navigation system parameter using gravity information. Finally, we compa-ratively analyze the differences and gaps research process between China and the two countries, and put forward five aspects of countermeasure and suggestion based on China's national conditions, involving directional issues such as research ideas, development focus, and priority arrangements.

Conclusions The purpose is to attract ideas, exchange in-depth, reach consensus, and provide reference for decision-making departments to deploy the next work. Our specific countermeasures and suggestions are: (1) Give priority to the first task of gravity compensation. (2) Urgently promote detail gravity measurements in the key sea areas and gravimeter development for polar region. (3) Focus on the development of nonlinear filtering technology and filtering algorithms for gravity correction. (4) Give priority to the development of practical software-based gravity-aided inertial navigation systems. (5) Strengthen the requirement demonstration and top-level design for gravity-aided inertial navigation.