Development Status and Influencing Factor Analysis of Underwater Matching Navigation Based on Gravity Field Products

Due to the characteristics of high accuracy and passivity, underwater matching navigation technology has become one of the main development directions of underwater vehicle navigation. To analyze the problems in gravity matching navigation, this paper introduces the development status of matching na-vigation based on gravity field products, and then discusses the constraints for positioning accuracy, including matching variables, gravity measurement precision, suitable matching areas and grid size. Gravity anomaly and gravity gradients of the two study regions are calculated by the spherical harmonic function based on a highly accurate gravity field model. And the influence of the grid size and the accuracy of gravity field pro-duct on the matching algorithm is evaluated. According to different kinds of indexes on gravity field characteristics in the two study regions, it is easy to find that the study region of the South China Sea has much more abundant gravity field information and is more suitable for matching navigation than the Pacific Ocean. The gravity assisted matching navigation techno-logy is more suitable for use in the areas with obvious va-riations in gravity characteristics. If the grid size of the gravity field products is l, the highest precision of the matching navigation is \frac\sqrt6l6 .