The accurate navigation of the underwater vehicle plays an important role in the process of the ocean utilization and development. The problem of restraining the accumulation errors of the underwater navigation over time was discussed and analyzed in detail. Firstly, the development history of the inertial devices was briefly described. Secondly, the advantages and disadvantages of each navigation system were compared in detail, the research status of the gravity-aided navigation at home and abroad were introduced, and the demand for the high-precision navigation of the underwater vehicles and the scientific problems of insufficient spatial resolution of the global marine gravity reference map were analyzed. Finally, the idea and technical route of obtaining the high spatial resolution and high precision global marine gravity reference map by GNSS-R altimetry constellations are proposed in order to improve the accuracy of the underwater gravity-aided navigation.