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- Title
Two-Step Correction Based on In-Situ Sound Speed Measurements for USBL Precise Real-Time Positioning.
- Authors
Zhao, Shuang; Liu, Huimin; Xue, Shuqiang; Wang, Zhenjie; Xiao, Zhen
- Abstract
The ultra-short baseline (USBL) positioning system has been widely used for autonomous and remotely operated vehicle (ARV) positioning in marine resource surveying and ocean engineering fields due to its flexible installation and portable operation. Errors related to the sound speed are a critical factor limiting the positioning performance. The conventional strategy adopts a fixed sound velocity profile (SVP) to correct the spatial variation, especially in the vertical direction. However, SVP is actually time-varying, and ignoring this kind of variation will lead to a worse estimation of ARVs'coordinates. In this contribution, we propose a two-step sound speed correction method, where, firstly, the deviation due to the acoustic ray bending effect is corrected by the depth-based ray-tracing policy with the fixed SVP. Then, the temporal variation of SVP is considered, and the fixed SVP is adaptively adjusted according to the in situ sound velocity (SV) measurements provided by the conductivity–temperature–depth (CTD) sensor equipped at the ARV. The proposed method is verified by semi-physical simulation and sea-trail dataset in the South China Sea. When compared to the fixed-SVP method, average positioning accuracy with the resilient SVP be improved by 8%, 21%, and 26% in the east, north, and up directions, respectively. The results demonstrate that the proposed method can efficiently improve the adaptability of sound speed observations and deliver better performance in USBL real-time positioning.
- Subjects
SOUND measurement; SPEED measurements; OCEAN engineering; MARINE resources; SPEED of sound; HYDROGRAPHIC surveying
- Publication
Remote Sensing, 2023, Vol 15, Issue 20, p5046
- ISSN
2072-4292
- Publication type
Article
- DOI
10.3390/rs15205046