Underwater robotic terrain-relative navigation using acoustic shadows in sonar imagery
Abstract/Contents
- Abstract
- This thesis presents a new underwater Terrain-Relative Navigation (TRN) method that provides a vehicle position estimate with respect to a prior seafloor topography map. This method uses imaging sonars rather than profiling sonars, and is to the knowledge of the author the first TRN work that correlates imaging sonar measurements with topography maps for localization. Imaging sonars are commonly found on operational underwater vehicles, due to their large area ensonification and low size, weight, power, and cost. However, the nature of imaging sonars makes their use with topography maps challenging. Imaging sonars measure the intensity of surface reflections versus time of flight, as opposed to directly measuring the shape of the reflecting surface as profiling sonars do. As such, comparing imaging sonar measurements to a seafloor topography map is not straightforward. An innovation of this work is the use of acoustic shadows in sonar imagery as the information source, as acoustic shadows are primarily geometric in nature, and thus predictable from a topography map. By enabling TRN with imaging sonar through the use of acoustic shadow data, this work introduces a TRN capability for typical operational underwater remotely-operated vehicles (ROVs) that has been largely unavailable to date, and can augment TRN performance for autonomous underwater vehicles (AUVs) in areas where the vehicle is operating over locally flat terrain, but where there is terrain information to the sides, and/or at low altitudes. The methods presented in this thesis are validated through field demonstrations on ROVs and AUVs operated out of the Monterey Bay Aquarium Research Insitute (MBARI). Meter-level localization accuracy is demonstrated on ROV trials using a mechanically-scanned imaging sonar, where the ROV was held motionless during sonar image formation. Further, meter-level localization accuracy is demonstrated on AUV trials using sidescan sonar, where the AUV was moving as the measurements were made. The results presented here are the first demonstrations of successful localization with respect to prior topography maps using imaging sonar measurements.
Description
Type of resource | text |
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Form | electronic; electronic resource; remote |
Extent | 1 online resource. |
Publication date | 2017 |
Issuance | monographic |
Language | English |
Creators/Contributors
Associated with | Padial, Jose | |
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Associated with | Stanford University, Department of Aeronautics and Astronautics. | |
Primary advisor | Rock, Stephen | |
Thesis advisor | Rock, Stephen | |
Thesis advisor | Close, Sigrid, 1971- | |
Thesis advisor | Enge, Per | |
Advisor | Close, Sigrid, 1971- | |
Advisor | Enge, Per |
Subjects
Genre | Theses |
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Bibliographic information
Statement of responsibility | Jose Padial. |
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Note | Submitted to the Department of Aeronautics and Astronautics. |
Thesis | Thesis (Ph.D.)--Stanford University, 2017. |
Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Jose Antonio Padial
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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