手持式GPS定位误差的校正方法

在野外进行地质调查时，许多单位采用麦哲伦公司的手持式GPS卫星定位导航仪进行位置定位，为了在野外方便地将调查点的位置上到地形图上，普遍要求使用大地坐标(UTM)。但是，手持式卫星定位导航仪在定位大地坐标(UTM)时存在明显误差，水平定位的最大误差超过2km。该文根据GPS的参数设置，总结出一套手持式GPS定位大地坐标的误差校正方法，使野外调查点水平定位误差小于100m。     

差分GPS实现探地雷达图像地形校正方法研究

针对在地形起伏较大的区域探地雷达获取的图像不能表达地形变化的缺点,通过探地雷达与差分GPS同步采集记录数据,实现探地雷达图像与GPS数据时间同步,选择某一标准水准面为参考面,根据时间位移和线性插值方法,将探地雷达数据进行时深转换,从而实现探地雷达地形校正。探地雷达图像地形校正前后对比表明此方法在保留地下介质体水平方向分布特征的同时,实现了探地雷达图像在垂直方向的精确校正,对地下目标的解译和精确定位有很大的帮助,对浅层活动断层探测具有一定的实际意义。      

用解方程法确定手持式GPS的校正参数

在地质野外测量中,正确校正手持式GPS,以便保证其测量精度,在工作区内均匀选择2、3个控制点,正确输入中央经度、DX、DY、DZ、DA、DF等校正参数即可完成。笔者总结出GPS的显示坐标X、Y变化量与校正参数DX、DY、DZ的变化量的比值（即变化率）在某一地区有一定的线性关系,通过此种线性关系用解方程法可快速准确地确定DX、DY、DZ参数,且只要满足该方程组解的不同组合的DX、DY、DZ,均可作为该地区正确的校正参数,从而可准确校正GPS。     

数字化地质中的误差校正

分析数字化过程中图形数据输入时引起误差的原因,说明了误差校正的原理,通过几何变换、最小二乘法线性校正、分块校正等方法对图形数据进行校正,经过仿射变换、双线性变换、平方变换、双平方变换、立方变换、四阶多项式变换等对图像进行校准。实践表明MAPGIS提供的误差较正功能模块进行图形校正,在地质图件的应用中效果很好。     

GIS数据的误差分析与校正

本文主要介绍了GIS数据的误差类型、传播过程、产生的原因、误差控制以及误差校正的方法,并简要阐述了MAPGIS中的误差校正问题。     

MAPGIS误差校正的方法及应用

本文介绍在矢量图件时需扫描TIF影像,MAPGIS软件对扫描TIF影像进行误差校正的使用方法及期特点.     

煤矿井下随钻测斜仪误差联合校正方法

为降低煤矿井下随钻测斜仪随钻测量钻孔姿态角参数的误差,建立基于递推最小二乘的误差补偿数学模型,采用椭球拟合法、点积不变法和旋转平面拟合法的联合校正方法对随钻测斜仪进行误差补偿校正。对研发的随钻测斜仪进行数值仿真和双轴转台实验,用联合校正方法对实验数据进行误差补偿校正,校正前俯仰角和方位角的最大绝对误差分别为4.7°和5.1°,校正后为0.8°和0.9°,校正后测量精度满足随钻测斜仪要求。实验结果表明,该方法可以对煤矿井下随钻测斜仪进行有效的误差补偿校正。     

GPS在测量中的应用及误差分析

简述了全球定位系统（GPS）的基本结构和特点,总结了GPS用于工程测量所具有的特点,介绍了GPS在工程测量中的应用实例及体会。简述了GPS系统的定位误差直接影响着GPS定位精度,按其产生的来源、性质及对系统的影响等进行了介绍和初步分析,提出了相应的措施以便消除或削弱它们对测量结果的影响。     

GPS测量的误差来源及其改正措施

根据有关资料概述了GPS测量误差的主要来源和它的改正措施.     

浅谈影响GPS测量的误差因素及分析

本文简述的GPS在测量中产生的误差源,并进行了分析及提出消除和削弱对测量影响的措施。     

Investigation of the lithosphere beneath the Vogelsberg volcanic complex with P-wave travel time residuals

With the aim of investigating the P-wave velocity structure below the Tertiary volcano Vogelsberg, a network of 10 mobile short period seismograph stations was installed in May 1987 for a period of 20 months. P-Wave travel time residuals relative to the station Kleiner Feldberg/Taunus (TNS) were determined for 168 seismic events using the Jeffreys - Bullen travel time tables. At all stations the relative residuals showed a positive sign, indicating a low velocity zone beneath the Vogelsberg. Maxima were found in the northern part of the Vogelsberg (station VAD +0.5 s) and in the region of the Amöneburger Basin (station RAU +0.28 s).The travel time residuals were inverted using the tomographic inversion method of Aki et al. (1977). The slowness perturbations of the single blocks were calculated relative to a crustal and upper mantle model of the Rhenish Massif. The results show an intracrustal low velocity body (about –9%) striking in a Variscan direction and underlying the north-eastern part of the Vogelsberg, and another velocity minimum (about – 6%) in the region of the Am6neburger Basin. In the lower crust and the upper mantle the velocities are reduced by about 4% relative to the starting model.The Variscan alignment of the low velocity zone under the Vogelsberg correlates with results of other geological studies. It can be assumed that during the rifting phase of the Upper Rhinegraben Variscan lineations have been reactivated, favouring uprising of magma along these old structures. The position and extension of the low velocity zone correlate with the assumed sediment distributions in the area of investigation. This may account for about one-half of the observed anomaly. The reason for the velocity reduction of about 4% in the entire underground region of the Vogelsberg down to a depth of about 70 km can be explained by the intensive fracturing of the lithosphere, caused by thermal and pressure gradients during the magma eruption process.     

Analysis of travel time,sources of water and well protection zones with groundwater models

This study compares numerical models with analytical solutions in computing travel times and radius of protection zones for a pumping well located in an unconfined aquifer with uniform recharge and in a semi-confined aquifer. Numerical models were capable of delineating protection zones using particle tracking method in both cases. However, protection zones defined by travel time criterion can only protect small percent of source water to the well; large percent of source water is not protected which may pose a risk of pollution of source water to the well. The case study of Leggeloo well field in the Netherlands indicates that although a well field protection area was enforced in 1980s, elevated nitrate concentration has been monitored in the abstracted water since 1990s. The analysis of protection areas shows that the current protection area only protects 37.4% of recharge water to the well field. A large protection area must be adopted in order to safeguard the sustainable water supply for the local community     

双毛细管在线干扰校正-电感耦合等离子体发射光谱法测定含铀地质样品中微量铅

应用电感耦合等离子体发射光谱法测定地质样品中的铅时,基体元素的干扰会使测量结果偏低。本文用氢氟酸、硝酸、高氯酸、盐酸溶解样品,采用等径双毛细管在线干扰校正的方法测定了含铀地质样品中的微量铅。首先通过双毛细管确定了样品溶液中的Fe、Al对铅有负干扰,而一定浓度的U、Ba、Ti、Ca、Mn、K、Mg、Na等基体元素没有干扰或可以忽略,由此在线双毛细管根据样品中Fe、Al的含量使用不同的校正试液建立标准曲线,测定未知样品时同步进行稀释,降低了Fe、Al的基体效应。方法检出限为1.5μg/g,精密度(RSD)小于5%。与普通干扰校正法相比,双毛细管在线干扰校正法可根据不同基体的样品使用不同的干扰校正试液,快速建立标准曲线进行复杂样品的测定,且避免了二次稀释,节省试剂,适合测定基体成分接近的批量样品。