Improvement of GPS/acoustic seafloor positioning precision through controlling the ship's track line
Improvement of GPS/acoustic seafloor positioning precision through controlling the ship's track line
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DOI：
10.1007/s00190-013-0649-9
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发表时间：
2013-09-01
影响因子：
4.4
通讯作者：
Asakura, T.
中科院分区：
文献类型：
--
作者：
Sato, M.;Fujita, M.;Asakura, T.
全球定位系统/声学海底定位的精度得到提高，2008年3月引入了船体安装系统，使我们能够对沿预定航迹线航行的船只进行声波测距测量，而2008年前的早期系统只能采用不可控的漂移观测。通过对平行进行的风帆和漂流观测结果的比较，首先证实了由于过渡而产生的定位结果的连续性。利用2008年以来近3年的观测资料，对风帆观测定位的重复性进行了评估，其水平分量的均方根精度约为2 cm，明显优于早期的漂移观测。定位精度的提高可能是通过控制航迹线改善了水声测距数据的几何分布。结果还表明，航海观测可以用较少的数据量获得可靠的结果。不同海区的定位结果比较表明，南开海槽沿岸海域的定位精度高于日本海沟沿岸海域，这可能是由于日本海沟沿岸海域经常观测到复杂的海水声速结构所致。此外，高程测定的精度也得到了提高，这使得我们预计，通过数据的积累和进一步的技术发展，未来将可以探测到地壳垂直运动。
The precision of GPS/acoustic seafloor positioning was improved by introducing a hull-mounted onboard system in March 2008, which allows us to conduct acoustic ranging measurements with the vessel sailing along the pre-determined track lines, while the early system before 2008 could only adopt the uncontrollable drifting observation. The continuity of the positioning results due to the transition was first confirmed through the comparison between results from sailing and drifting observations conducted in parallel. Using the data acquired for about 3 years since 2008, the repeatability of the determined position for the sailing observation was evaluated to be about 2 cm in root mean squares in the horizontal component, significantly better than that for the early drifting observation. The improvement of positioning precision probably resulted from the improvement of geometric distribution of acoustic ranging data by controlling the track lines. It was also shown that the sailing observation allows to obtain reliable results with a smaller amount of data. Comparison between the results in different sea regions suggests that positioning precision is better in the region along the Nankai Trough than in the region along the Japan Trench, probably because of the complicated acoustic velocity structure of seawater often observed in the latter. Furthermore, the precision of height determination was also improved, which leads us to expect that vertical crustal movement will be detectable in the future through accumulation of data as well as further technology development.