CODAS系统在厦门湾走航ADCP观测资料质量控制中的应用     

沈俊强 《台湾海峡》2014,(4):472-480

CODAS系统搭配相应质量控制参数,用以识别ADCP在复杂测流环境下测得的可疑或错误流速单元和剖面.通过水跟踪和底跟踪,CODAS系统可有效获取仪器自带数据处理软件vmdas、winriver无法修正的系统误差.本研究采用该系统对厦门湾走航ADCP测量数据做后续质量控制,所得相应系统误差如下：旋转角度偏差ΔФ=3.2°,幅值修正因子β=0.98.此外,以底跟踪测得流速为准确值,参考GPS数据经过系统误差订正后,流速精度显著提高,平均误差订正前后分别为28.9cm/s和11.6 cm/s.最后,结合现场数据采集工作与数据质量控制过程,总结数据质量问题一般特征并提出改进建议.  相似文献   

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王霞迎  秘金钟  张德成  李兵 《大地测量与地球动力学》2014,34(3):164-168

???????????????????????????????????10 d????λ?á???????????????????????????????????С??2 m????????????????????С??8 ns????????????С??0.5 m/s??????????С???2.5 m?????????2006?????????????????????????????  相似文献   

可变模糊理论与模糊粗糙集在地下水污染评估中的应用     

马荣  石建省  刘继朝 《吉林大学学报(地球科学版)》2012,(4):1130-1138

传统的地下水污染评估方法需检测多项地下水化学变量,成本较高且无法考虑水质指标区间量值的影响。为此,笔者利用可变模糊理论对地下水污染进行综合评估,在此基础上通过模糊粗糙集理论挖掘关键变量,并利用生成的最小决策规则库对样品点的污染综合指数进行预测。将该方法应用于洛阳盆地,对其有效性进行验证,计算结果表明:As、Hg、Se、I、NH3-N对研究区地下水污染分类起控制作用。通过与实测的13种化学变量所计算的地下水污染综合指数相比,测试数据中7组样品的相对误差为0.104 0～0.172 5;剩余15组样品的相对误差为0.001 5～0.093 7,基本满足地下水污染评估的要求。可变模糊集与模糊粗糙集理论能够通过较少的化学变量对污染综合指数进行预测,从而降低地下水污染评估成本,为后续的地下水污染控制与修复提供可靠的数据来源。  相似文献   

Robust sliding mode control of a mini unmanned underwater vehicle equipped with a new arrangement of water jet propulsions: Simulation and experimental study     

《Applied Ocean Research》2016

This paper presents dynamical modeling and robust control of a Mini Unmanned Underwater Vehicle (MUUV) equipped with a new arrangement of water jet propulsion. The water jet propulsion includes some advantages comparing with a propeller one, such as, reducing the number of required motors, desired number and arrangement of the propulsions, removing adverse torque and cavitation due to propeller rotation and etc. In order to model the proposed MUUV, the gray box method is used in such a way that the dynamical equation of motion is derived analytically by Euler-Lagrangian method, and then the hydrodynamic coefficients (such as added mass and drag coefficients) are derived by performing some tests in a Computational Fluid Dynamic (CFD) software. The dynamical model is used to simulate the MUUV system and also to design the proposed controllers, which are Feedback Linearization Controller (FLC) and Sliding Mode Controller (SMC). In order to investigate and compare the performance of the MUUV and the applied controllers, three types of tests including a desired signal tracking case and two desired path tracking cases are designed. To do so, a method is presented to obtain the desired signals from a desired path under predetermined conditions. Then, an MUUV prototype is designed and constructed in order to investigate the performance of the proposed water jet propulsions and controllers for regulation and tracking desired signal purpose, experimentally. As it is expected, the simulation and experimental results show better performance of the SMC compared to FLC. Furthermore, the experimental results reveal that the water jet propulsion is implementable to practical prototypes and also can be produced in an industrial level.  相似文献   

影响地面三维激光扫描仪数据质量的因素分析     

张洪栋  刘翔  时振伟 《东北测绘》2014,(2):183-186

三维激光扫描技术使传统的工程测量从静态的单点测量发展到动态的跟踪测量与三维立体测量领域。从用户角度出发,简要介绍了地面固定式三维激光扫描仪的基本原理、主要特点、性能指标,阐述了获取高精度三维扫描数据成果的过程。不是利用详尽的公式和实验进行精度分析,而是着重分析从采集数据到点云数据处理过程中数据质量的误差来源,详细分析其中原因,并且在已有研究分类的基础上,重新进行归类,最后介绍了国内外产品。  相似文献   

基于选权迭代法的抗差整体最小二乘及其应用     

杨勇喜  贾东振  何秀凤 《测绘工程》2014,23(12):56-59

在测量数据处理中,观测向量与系数矩阵同时存在偶然误差时,整体最小二乘法能够得到更高精度的参数解,但整体最小二乘法无抗差能力,观测向量中的粗差将对参数求解产生较大影响。为解决上述问题,采用拉格朗日极值法推导了基于选权迭代法的抗差整体最小二乘计算公式,通过三维坐标转换参数求解实例对3种选权迭代法进行分析。结果表明,IGG法在抗差整体最小二乘解法中抗差效果最好。  相似文献   

A variationally consistent hyperstatic reaction method for tunnel lining design     

Hoang-Giang Bui  Jelena Nini&#x;  Ngoc-Anh Do  Daniel Dias  Günther Meschke 《国际地质力学数值与分析法杂志》2022,46(1):205-217

In this technical note, a consistent finite element formulation of the Hyperstatic Reaction Method (HRM) for tunnel linings design is proposed by introducing a variational consistently linearized formulation. It permits to consider a nonlinear interaction between a lining structure and the surrounding ground. Recent advances of the HRM in regard to the consideration of the nonlinear response of the segmented tunnel lining exposed to design loads use an iterative algorithm for solving the nonlinear system of equations. In the proposed Variationally consistent Hyperstatic Reaction Method (VHRM), a distributed nonlinear spring model representing the interaction between the lining and the ground soils is considered in a variationally consistent format. Computing the tangential spring stiffness via consistent linearization, and using Newton-Raphson iteration, requires significantly smaller number of iterations as compared to the original HRM model based on nodal springs. Furthermore, the method is applicable for simulations using solid finite elements (2D and 3D), as well as beam or finite shell elements, respectively.  相似文献