Long-Range Gravity-Aided Autonomous Underwater Vehicle Navigation
Abstract
Autonomous underwater vehicles (AUV) are a mobile platform for underwater sensing, an environment relatively unexplored. Georeferencing measurements is difficult due to the challenge of AUV localization. The rapid attenuation of radio frequencies underwater restricts AUVs from using the global position system (GPS), the above-water solution to localization. Underwater localization relies on dead-reckoning, the integration of vehicle inertia measurements to arrive at a position estimate. However, the dead-reckoned position error is unbounded. This error can be bounded using a source of position feedback. Terrain aided navigation (TAN) - using georeferenced geophysical terrain maps can provide that feedback. TAN shows significant promise as a method for long-range, passive underwater AUV navigation, especially gravity-aided navigation (GAN). This thesis presents a TAN algorithm that uses a gravity gradiometer and gravity gradient maps to successfully limit dead-reckoning error by a factor of 25 over a 500 km long AUV mission, with a localization accuracy of 1 km. The TAN algorithm exploits the correlation between terrain and the gravity anomaly to use a global database of bathymetry maps (GEBCO) with 400 m resolution. The mission was simulated in the AUV navigation testbed (ANT), a collection of tooling developed during this thesis to accelerate research in TAN. Among the contributions made by the ANT, is a inertial navigation system (INS) that emulates the uncertainty characteristics of a commercial navigation grade INS (Kearfott Seanav) \textemdash~to simulate dead-reckoning error growth. Parts of the ANT have been released to the research community as open-source, and are being used by researchers in the Intelligent Systems Laboratory (ISL) at Dalhousie University.
Subject
Collections
Related items
Showing items related by title, author, creator and subject.
-
Long Range Underwater Navigation using Gravity-Based Measurements
Pasnani, Parth (2020-04-30)The aim of this thesis is to demonstrate feasibility of a gravity-based system for long range underwater localization. Such a system is demonstrated, in simulations, with the use of particle filter-based localization and ... -
Need for Navigation and Utilization of Cancer Patient Navigators (CPNs) among Breast Cancer Patients in Nova Scotia
Miller, Sally (2019-09-03)Background: The Cancer Patient Navigator (CPN) program aims to reduce burdens of care coordination, emotional stress and logistical challenges on cancer patients in Nova Scotia (NS). There is concern that some patients ... -
The mean surface circulation of the North Atlantic subpolar gyre: A comparison of estimates derived from new gravity and oceanographic measurements
Higginson, S.; Thompson, K. R.; Huang, J.; Veronneau, M.; Wright, D. G. (2011-08)A new mean sea surface topography (MSST) is used to estimate the surface circulation of the subpolar gyre of the northwest Atlantic. The MSST is produced using a new geoid model derived from a blend of gravity data from ...