Long Range Underwater Localization and Navigation using Gravity-Based Measurements

This paper reports on work to assess the feasibility of gravity-based long range underwater navigation and localization. As a first step, this is explored in simulations with RAO-Blackwellized particle filter simultaneous localization and mapping (SLAM). When implemented on an autonomous underwater vehicle it can operate submerged for extended periods without the use of an active sensor, thus widening the variety of AUV missions. Additionally, this work applies information theory to navigate through a region such that the SLAM data association, and thus the localization, performance is improved. The results also indicate that characteristic values for a region can be used as a SLAM metric for the region. Combining the characteristic value with information theory techniques improves the localization performance at extended ranges and is a first step towards long range underwater localization using gravimeters. Future work will optimize the particle filter, explore more sophisticated loop closures as well as hardware-in-the loop tests.