排序方式: 共有45条查询结果,搜索用时 609 毫秒
41.
介绍了在短基线状态下利用单频单历元双差载波相位定位时模糊度固定的基本理论.结合正则化理论和阻尼矩阵的思想,提出了一种用改进的正则化方程来改善法方程病态性的方法.算例分析表明,应用改进的正则化算法可以改善法矩阵的病态性,得到更加精确的浮动解,利用LAMBAD方法搜索可得到准确的整周模糊度解. 相似文献
42.
Estimation of the surface and mid-depth currents from Argo floats in the Pacific and error analysis 总被引:2,自引:0,他引:2
With the large deployment, the Array for Real-time Geostrophic Oceanography program has great potential for measuring the ocean currents both on the surface and at mid-depth. However the positioning error of fixes in a trajectory varies from 150 m to 1000 m, and thus created difficulty for accurate estimations of the surface and mid-depth currents. Also the reliability of the estimated surface and mid-depth currents requires accurate error estimations.In this study a new sequential method of Argo float surface trajectory tracking and extrapolating is proposed based on Kalman Filter (KF), under the presumption that a surface trajectory of Argo float is dominated by a constant current plus inertial oscillation. This trajectory tracking and extrapolating method is able to reduce the positioning uncertainties of Argo surface trajectories and provides error estimations. When this method was applied to extrapolate the positions when float resurfacing and descending, the estimation error of the mid-depth currents can be reduced. Utilizing this method in the Pacific, surface and mid-depth currents were estimated from surface trajectories of Argo floats from 2001 to 2004, along with their detailed error estimations. The average error for surface currents is about 4.4 cm s− 1 which is equivalent to the accuracy order (5 cm s− 1) of the Surface Velocity Program drifters. The estimation error of the mid-depth currents at 1000 db is reduced to about 0.21 cm s− 1 without considering the effect of vertical shear.This study shows that the surface trajectory from Argo float provides a new means to measure surface circulations in the global ocean at real time, and that the estimated mid-depth current could be one of the important sources to improve the understanding for ocean dynamic. 相似文献
43.
44.
通过技术创新采取了一系列措施,将2孔64m单线下承式钢桁梁拼装连接成1孔128 m钢桁梁,通过将拼装后的梁体整体反拖拉与顶推相结合的方式,顺利完成了架设施工任务,取得了较好的经济效益和社会效益,为同类型钢桁梁架设施工提供了一些值得借鉴的经验. 相似文献
45.