共查询到18条相似文献,搜索用时 109 毫秒
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井径仪、井温仪有相似的测量原理和计算方法。由于仪器测量原理的限制,许多因素均可产生误差。本文根据历年工作经验,从仪器测量原理入手,分析了误差产生的各种原因,探讨了这些误差因素对测量值的影响,提出了提高仪器测量精度的具体措施。井径、井温的测量是煤田测井中必不可少的重要内容。但是在实际测量和校验时,常产生很大的误差;因此,如何保证两种方法的测量精度是一个值得研究的问题。本文拟分析煤田测井规程所规定的仪器精度,分析影响测量精度的因素以及提高测量精度的相应措施。 相似文献
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遥感水深反演是水深测量的一种重要技术和手段.以美济礁水深反演为例,选择WorldView-02高分影像为数据源,在辐射定标和大气校正的基础上,构建BP(Back Propagation)和RBF(Radial Basis Function)人工神经网络水深反演模型,以遥感影像8个波段为输入层,通过tansig、logsig、高斯函数和purelin函数变换实现从输入层到隐含层、隐含层到输出层的转换,以便反演水深.最后对反演水深与实测水深采用回归分析,求解决定系数(coefficient of determination,R2)、平均决定误差(Mean Absolute Error,MAE)、均方根误差(Root Mean Square Error,RMSE)等进行比较,评价2种模型的精度.结果表明,RBF神经网络模型结构更简单,对样本要求更低,反演精度达到0.995,更适合遥感水深反演. 相似文献
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将芬兰VTI公司生产的SCA100T双轴倾角传感器应用于钻孔测斜仪,其体积小,能提高倾角测量的稳定性和精度。双轴倾角传感器测量角度会引起算法校正问题,采用测得的标定数据得出倾角值的回归模型,测量倾角的实验结果和推算结果存在一定的误差,通过应用误差补偿方法来减小实际测量误差。理论分析和仿真计算表明,采用此法补偿后得到的均方差最大为0.15258,而没有补偿的结果最大均方差为4.81104。 相似文献
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多波束系统横摇、纵倾参数的校正方法 总被引:3,自引:0,他引:3
多波束水深测量系统以条幅式测量为特点,比较传统单波束测深发生了巨大的变化,能够进行实时声速、船体姿态等参数的改正.多波束系统换能器安装时存在的纵倾角度偏差(pitch bias)和横摇角度偏差(roll bias)是产生水深测量系统误差的重要来源之一.分析两个参数对水深测量精度的影响,并根据其误差在地形剖面上的表现形式,讨论实测法和剖面重合法两种参数测试的方法,特别是针对剖面重合法参数测试,制作可视化操作界面,大大方便了野外和室内参数调整.测试获取的纵倾、横摇参数输入多波束系统中进行实时水深校正.在室内资料处理中,利用参数校正方法,能够对野外采集资料进行再处理,提高资料质量. 相似文献
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孔位测量数据是见煤点定位计算的起始数据,当然精度要高,但又应该经济合理。本文拟通过分析计算,论证孔口测量误差对见煤点误差的影响程度,并提出一点个人看法。 笔者认为,见煤点定位中误差(M_C)由孔口测量中误差(M_s)与见煤点测井定位中误差(M_L)组成,即 M_c~2=M_s~2 M_L~2 测井误差包括测斜仪误差与电缆深度误差(本文以孔深丈量误差代替)。目前测斜仪倾角的标定误差(M_α_1)为±1°,读数误差(M_α_2)为± 0.5°;方位角的标定 相似文献
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免仪器高全站仪高程测量及其应用 总被引:1,自引:0,他引:1
免仪器高、免棱镜高全站仪测量技术是根据在实地测量时不改变仪器高和棱镜高为前提,设置仪器时,根据测量高差时前视减后视的原理,利用系统自身自行消除公式中的仪器高和棱镜高。根据免仪器高、免棱镜高法测量中误差计算公式,此测量技术可有效地减少全站仪三角高程法测量中仪器高和棱镜高的测量误差对高差计算的影响。同时也减少了以后计算时的工作量。从算例可以看出,距离在100m,竖直角在28°以内时,采用免仪器高、免棱镜高法进行高程测量,中误差小于±1.0mm,足以满足水准控制测量的精度要求。 相似文献
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JSP-1型虹吸校正翻斗雨量计研制与特点 总被引:1,自引:0,他引:1
翻斗式雨量计因雨强影响会产生很大的误差,虹吸雨量计不能数字化降雨过程,并需要人工测量虹吸水量进行虹吸订正.本研究成果利用翻斗计量降雨过程,用精确的虹吸计量值智能校正翻斗的误差,综合了翻斗计量和虹吸计量的优点,将分辨率为0.1mm的翻斗雨量计的测量误差从±15%减小到±2%.因此,JSP-1型虹吸校正翻斗雨量计具有很高的精度. 相似文献
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以实例介绍了三维地震勘探测量中各项作业限差的关系、复测校差的关系以及测点坐标系转换关系.依照规范及限差控制标准,讨论了控制点布设、导线布设的精度计算以及作业方法.通过对极坐标法误差的计算论证了放样点误差主要是由测角误差引起. 相似文献
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Neil K. Ganju Steven E. Suttles Alexis Beudin Daniel J. Nowacki Jennifer L. Miselis Brian D. Andrews 《Estuaries and Coasts》2017,40(1):22-36
Geomorphology is a fundamental control on ecological and economic function of estuaries. However, relative to open coasts, there has been little quantification of storm-induced bathymetric change in back-barrier estuaries. Vessel-based and airborne bathymetric mapping can cover large areas quickly, but change detection is difficult because measurement errors can be larger than the actual changes over the storm timescale. We quantified storm-induced bathymetric changes at several locations in Chincoteague Bay, Maryland/Virginia, over the August 2014 to July 2015 period using fixed, downward-looking altimeters and numerical modeling. At sand-dominated shoal sites, measurements showed storm-induced changes on the order of 5 cm, with variability related to stress magnitude and wind direction. Numerical modeling indicates that the predominantly northeasterly wind direction in the fall and winter promotes southwest-directed sediment transport, causing erosion of the northern face of sandy shoals; southwesterly winds in the spring and summer lead to the opposite trend. Our results suggest that storm-induced estuarine bathymetric change magnitudes are often smaller than those detectable with methods such as LiDAR. More precise fixed-sensor methods have the ability to elucidate the geomorphic processes responsible for modulating estuarine bathymetry on the event and seasonal timescale, but are limited spatially. Numerical modeling enables interpretation of broad-scale geomorphic processes and can be used to infer the long-term trajectory of estuarine bathymetric change due to episodic events, when informed by fixed-sensor methods. 相似文献
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J. N. Carter 《Mathematical Geology》2004,36(2):187-216
When the parameters of a numerical model are adjusted, so that the predictions of the model match measurements from the real system, we need to take account of two sources of errors. These being measurement errors and modelling errors. Measurement errors are commonly considered, and a number of different approaches are in general usage, the most common being the weighted sum of squares method. In this paper the standard Bayesian equation, used for inverse problems, is reformulated so as to make it more intuitive to use. This allows the inclusion of both a modelling error and correlations between measurements to be carried out easily. The results are tested on a simple one-parameter numerical model and a cross-sectional model of a petroleum reservoir. In the first case the proposed error model appears to work well. In the second case it appears that the objective function is multimodal, leading to multiple acceptable solutions. The results of this paper are important to those whose numerical models are thought to contain significant modelling error. This encompasses many areas of modelling related to earth science and engineering. 相似文献
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在考虑了异常体的形态、异常体和围岩的电性差异、供电极和接收极测量误差、供电电流误差、仪器测量精度,以及外界干扰等因素的基础上,提出了用电位异常来描述电阻率剖面法中探测深度的定义。通过编程,计算得到各向同性均匀半空间中球体异常,在电阻率剖面法中的电位异常,得出在特定条件下的探测深度。定量分析了联合剖面法中探测深度与电极距AO、供电电流和外界干扰的关系。制作并完成了软件的各种正演计算,可以为电阻率剖面法野外施工前的电极距大小、供电电流的设计等提供参考。 相似文献