The Accuracy of GIS Tools for Transforming Assumed Total Station Surveys to Real World Coordinates

Most surveying works for mapping or GIS applications are performed with total station. Due to the remote nature of many of the sites surveyed, the surveys are often done in unprojected, local, assumed coordinate systems. However, without the survey data projected in real world coordinates, the range of possible analyses is limited and the value of existing imagery, elevation models, and hydrologic layers cannot be exploited. This requires a transformation from the local assumed to the real world coordinate systems. There are various built-in and add-in tools to perform transformations through GIS programs. This paper studies the effect of using Georeferencing tool, Spatial Adjustment tool (Affine and similarity) and CHaMP tool on the precision and relative accuracy of total station survey. This transformation requires real-world coordinates of at least two control points, which can be collected from different sources. This paper also studies the effect of using geodetic GPS, hand-held GPS, Google Earth (GE) and Bing Basemaps as sources for control points on the precision and relative accuracy of total station survey. These effects have been tested by using 111 points covered area of 60,000 m2and the results have shown that the CHaMP tool is the best for preserving the relative accuracy of the transformed points. The Georeferencing and spatial adjustment (similarity) tools give the same results and their accuracy are between 1/1000 and 1/300 depending on the source of control points. The results have also shown that the cornerstone to preserve the precision and relative accuracy of the transformed coordinates is the relative position of the control points despite their source.

Variability and Long-Term Trend of Total Cloud Cover in China Derived from ISCCP, ERA-40, CRU3, and Ground Station Datasets

Total Cloud Cover （TCC） over China deter- mined from four climate datasets including the Interna- tional Satellite Cloud Climatology Project （ISCCP）, the 40-year Re-Analysis Project of the European Centre for Medium-Range Weather Forecasts （ERA-40）, Climate Research Unit Time Series 3.0 （CRU3）, and ground sta- tion datasets are used to show spatial and temporal varia- tion of TCC and their differences. It is demonstrated that the four datasets show similar spatial pattern and seasonal variation. The maximum value is derived from ISCCE TCC value in North China derived from ERA-40 is 50% larger than that from the station dataset; however, the value is 50% less than that in South China. The annual TCC of ISCCP, ERA-40, and ground station datasets shows a decreasing trend during 1984-2002; however, an increasing trend is derived from CRU3. The results of this study imply remarkable differences of TCC derived from surface and satellite observations as well as model simu- lations. The potential effects of these differences on cloud climatology and associated climatic issues should be carefully considered.

Technical specification for GPS total station surveying

The redundant observation, error tolerances, adjustment and precision estimation are the methodology of surveying technology, which are used in the procedure of survey engineering. Based on a redundant observation magnitude of experiments, a guideline system of precision for GPS total stations is established to prescribe the methods of redundant observation, the computation formulas of error tolerances and standard errors. Moreover, a series of precision indexes for GPS total station measurements and results are also acquired from the comparative experimentations and study on the observation data between GPS total station elevation and direct leveling.

Monitoring Bridge Deformation Using Auto-Correlation Adjustment Technique for Total Station Observations

Bridges are omnipresent in every society and they affect its human, social, ecological, economical and cultural aspects. This is why a durable and safe usage of bridges is an imperative goal of structural management. Measurement and monitoring have an essential role in structural management. The benefits of the information obtained by monitoring are apparent in several domains. In deformation analysis, the functional relationship between the acting forces and the resulting deformations should be established. If time depending observations are given, a regression could be used as a functional model. In case of stochastic model uncorrelated observations with identical variance are assumed. Due to the high sampling rate, a small time difference arises between two observations. Thus the assumed stochastic model is not suitable. The calculation has to be effected by means of auto-correlated observations. This paper investigates an integrated monitoring system for the estimation of the deformation (i.e., static, quasi-static) behavior of bridges from total station observations and studies the effect of autocorrelation technique on the accuracy of the estimated parameters and variances. The results have shown that autocorrelation technique is reduced the standard deviation of X&Y-direction about 6.7% to 29.4% and 6.5% to 15.5% of the original value, respectively, but the situation was differ in Z direction;the standard deviation in vertical component Z was increased.

Estimation of the Gauging and the Calibration Time Interval for the Modern Total Stations

The modern TSs （total stations） have reached a very high level in the provided reading and reliability （accuracy and precision） of their measurements. The evolution of the digital technology has helped in this direction. Thus, the TSs can support all requirements for the stake out and monitoring of modern survey engineering and constructions projects. Their complicated manufacturing process and the sensitivity of their components require gauging, adjusting and calibration at certain time intervals. This appears to be the only way in order to assure the precision of measurements provided by the manufacturer and the reliability of the works they are used for. The goal of this paper is to propose a method for the estimation of the gauging time interval for modern YSs. which could be used by any user. More specifically, the indispensable need for the TSs gauging is elevated and documented. All the parameters that influence their operation are registered. A model expressed by a scale of grades is defined, leading thus to an equation for the calculation of the time interval for the next needed gauging and calibration.

SmartStation定位模型及精度测试

介绍一种全新的测量仪器—SmartStation。分析SmartStation定位模型的特点,研究影响精度的主要因素,由定位模型得出这种测量方式的便捷性。根据影响精度的主要因素进行了精度测试,通过测试结果得出SmartStation应用的相关结论。

Adjustment of precipitation measurements using Total Rain weighing Sensor(TRwS)gauges in the cryospheric hydrometeorology observation(CHOICE)system of the Qilian Mountains,Northwest China

Precipitation is one of the most important indicators of climate data,but there are many errors in precipitation measurements due to the influence of climatic conditions,especially those of solid precipitation in alpine mountains and at high latitude areas.The measured amount of precipitation in those areas is frequently less than the actual amount of precipitation.To understand the impact of climatic conditions on precipitation measurements in the mountainous areas of Northwest China and the applicability of different gauges in alpine mountains,we established a cryospheric hydrometeorology observation(CHOICE)system in 2008 in the Qilian Mountains,which consists of six automated observation stations located between 2960 and 4800 m a.s.l.Total Rain weighing Sensor(TRwS)gauges tested in the World Meteorological Organization-Solid Precipitation Intercomparison Experiment(WMO-SPICE)were used at observation stations with the CHOICE system.To study the influence of climatic conditions on different types of precipitation measured by the TRwS gauges,we conducted an intercomparison experiment of precipitation at Hulu-1 station that was one of the stations in the CHOICE system.Moreover,we tested the application of transfer functions recommended by the WMO-SPICE at this station using the measurement data from a TRwS gauge from August 2016 to December 2020 and computed new coefficients for the same transfer functions that were more appropriate for the dataset from Hulu-1 station.The new coefficients were used to correct the precipitation measurements of other stations in the CHOICE system.Results showed that the new parameters fitted to the local dataset had better correction results than the original parameters.The environmental conditions of Hulu-1 station were very different from those of observation stations that provided datasets to create the transfer functions.Thus,root-mean-square error(RMSE)of solid and mixed precipitation corrected by the original parameters increased significantly by the averages of 0.135(353%)and 0.072 mm(111%),respectively.RMSE values of liquid,solid and mixed precipitation measurements corrected by the new parameters decreased by 6%,20% and 13%,respectively.In addition,the new parameters were suitable for correcting precipitation at other five stations in the CHOICE system.The relative precipitation(RP)increment of different types of precipitation increased with rising altitude.The average RP increment value of snowfall at six stations was the highest,reaching 7%,while that of rainfall was the lowest,covering 3%.Our results confirmed that the new parameters could be used to correct precipitation measurements of the CHOICE system.

基于全站仪定位的辐射场测量方法研究

在核设施检修或退役中,往往需要对现场的辐射剂量场进行测量。传统的剂量率仪不支持空间坐标测量,需要额外的坐标测量工具,且剂量测量和坐标测量不同步,使得测量效率受到限制。针对该问题,提出了一种基于全站仪定位的测量方法,可同时测量剂量率和对应的空间坐标,定位精度为mm级,研制了测量系统样机。使用样机对某个水泥固化放射性废物桶进行了测试实验,与蒙特卡罗计算结果进行对比,测量值与模拟值的相对偏差遵循正态分布,平均偏差为12.8%,标准偏差为9.37%,数量大约占96%的测量点位的相对偏差在[-30%,5%]的范围内,体现了较高的测量精度。对某核设施厂房的另外两个较为复杂的场景进行辐射场测量,使用对数变换普通克里金方法对离散的测量点进行辐射场插值计算,三维辐射场重构结果的平均相对偏差可控制在50%左右。结果表明通过基于全站仪的辐射场测量系统可对现场的三维辐射场进行重构,精度可以满足三维辐射场的应用需求。

基于点云切片算法的铁路钢桁拱桥线形分析

铁路桥梁线形测量对于桥梁健康检测与确保铁路安全运营具有重要作用。为提高运营铁路钢桁拱桥线形测量效率,以某3跨钢桁拱桥为例,运用地面激光扫描(TLS)技术对桥梁杆件进行整体化扫描,从桥梁线形测量精度、扫描完整性、点云个数等3方面,分析出最佳的桥梁扫描测站数为10个。运用3DNDT点云配准算法将各测站一一配准,桥梁点云配准精度为2 mm,将桥梁点云投影至xoy平面,用半径滤波器进行噪声点的去除,得到完整“纯净”的桥梁点云模型。提出点云等距切片与点云平面切片算法提取桥梁线形,并将线形点云数据导出在AutoCAD中拾取坐标。将点云切片法提取的TLS测量值、全站仪法测量结果与原始成桥线形做比较分析,结果表明:在桥面线形分析中,两方法均在跨中处A5点测量出最大变形,分别为12.69 mm、10.29 mm,两方法的最大相互较差R为2.4 mm,相关系数优于99.93%;在拱轴线线形分析中,点云切片法与全站仪法在主桁上弦跨中B4点位测量的最大变形为6.2 mm、3.9 mm,在主桁下弦跨中B10点位测量的最大变形为5.9 mm、3.5 mm,两方法的最大互相较差R为3.2 mm,相关系数优于99.87%,验证了点云切片算法的有效性与TLS测量的高精度性。拱轴线横向线形未出现明显侧移,点云等距切片得到的19个吊杆垂直度保持良好,未发生扭转与偏移。该成果对于运营铁路钢桁拱桥的线形分析与点云处理方法可提供相应的思路和参考,具有重要的实用价值。

普速铁路控制网测量技术方法探讨

为改善普速铁路有砟轨道长期运营后容易变形、损坏,线位逐年变化导致维修难度和维修成本增高等难题,对引入坐标控制的相关可行性方案进行探讨,并对测量费用、测量精度、测量效率及技术前景等进行分析。研究表明:直接引入高速铁路CPⅢ控制网测量方法,必将导致精度有余而效率不足等适用性问题。基于全站仪免置平测量的三维平差技术对控制网进行整体施测和整体平差,为控制网测量与线路测量合二为一创造了条件,数据资源利用率大幅提高,有利于测量效率的提升;避开了高程异常的解算,为高程测量精度的提高另辟蹊径;为全站仪工程测量坐标系统、卫星测量地心坐标系统的统一提供一种新的思路和方法。因此,不宜直接引入高速铁路CPⅢ控制网测量方法,而基于全站仪免置平测量的三维平差技术与方法在诸多方面都具有良好特性和应用前景,值得研究和推广。

基于无人机正射影像的基坑位移观测精度研究

基坑水平位移变化是基坑变形监测的重要参考指标,快速、精确的获取基坑位移变化量对基坑安全评价十分重要。常规监测方法利用全站仪、GNSS等手段获取监测点的坐标,通过各期数据对比,反映基坑的位移变化。但是这些常规方法工作强度大、自动化程度低,在某些不易到达的监测点,难以有效发挥作用。本文通过合理设置无人机飞行参数,采用摄影测量的方法生成高精度的基坑正射影像,获取监测点的平面坐标,实现了基坑水平位移变化的快速获取,并与全站仪测得的精确数据进行比较,验证了该方法的可行性。结果显示:当飞行高度为50 m时,所获取点位和距离的均方根误差分别为14.3 mm和14.9 mm;当飞行高度为20 m时,所获取点位和距离的均方根误差为7.2 mm和5.6 mm。因此,当无人机贴近飞行时,基于无人机正射影像获取的基坑监测点平面坐标精度较高,基本能够反映出基坑的位移变化,满足三等水平位移监测误差的要求。

广东省小水电绿色全要素智能管理存在的问题及对策

广东省农村小水电资源丰富,省内有近万座小水电,数量占居全国之首。小水电在解决农村用电、促进农村经济发展方面发挥了重要的作用,但是,随着技术进步和国家产业政策的调整、生态文明建设的推进,广东省小水电面临绿色转型、强化管理等需求,因此有必要分析小水电在绿色全要素智能管理方面存在的问题及对策。研究表明,广东省小水电存在安全生产有隐患、生态流量保障不足、运行管理自动化程度低、监管难等问题,可以通过建立安全生产标准机制、落实生态流量、促进小水电绿色转型、开展全要素智能管理等措施加以解决。

单目标旋转摄影方法标定图像全站仪相机

为了实现图像全站仪望远镜相机和广角相机的高精度标定,采用单目标旋转摄影法推导了旋转摄影模式下图像全站仪的相机标定模型,并对模型参数展开相关性分析,针对其中存在的参数耦合问题,提出了双盘观测法进行参数解耦;对单目标旋转摄影方法的可行性进行了实验验证,取得了图像全站仪望远镜相机和广角相机的高精度标定结果。结果表明,标定得到的相机参数可用于不同摄影距离的图像测量,望远镜相机标定点重投影误差平均为1.0 pixel,对应图像角分辨率达2.0″;望远镜相机定焦摄影时标定点重投影误差平均为0.15 pixel,对应图像角分辨率达0.3″;广角相机标定点重投影误差平均为0.6 pixel,对应图像角分辨率达13.3″。该研究对提高图像全站仪的图像测量精度及拓展其相关应用有一定参考意义。

全站仪气象改正公式优化研究

为了提高全站仪长距离测距精度,提出一种全站仪气象改正公式的优化方法。对气象改正公式进行了分析,发现存在一定误差和优化的空间。为了降低改正公式引起的残余误差,以最小化残余误差之和为优化目标,将气象公式系数调整转化为最优化问题。借助野外长基线上部署的密集环境参数传感器阵列,实时记录全站仪长时间连续测距时的环境参数;利用测距数据构造优化函数,对改正公式系数的不同组合进行优化调整和验证,实验数据分析结果表明:优化后,测距误差均值可减小99.8%,误差的标准偏差减小81.2%。为验证所提出方法的有效性,将优化系数后的改正公式应用于其他测量时间段的测距补偿,结果显示,残余误差也同样得到有效降低,优化幅度达到37%以上。表明气象改正公式系数优化是显著降低野外测距误差的有效方法。

基于神经网络的测量机器人大坝监测观测值折光修正

测量机器人在水库大坝自动化监测中应用广泛,为确保监测结果的可靠性,需对原始观测值进行折光修正。结合测量机器人自动化监测可提高监测频率、提供大量观测数据的特点,在分析观测值折光影响因素的基础上,构建了神经网络折光修正模型来对原始观测值:垂直角、斜距、水平角进行修正。并利用某水电大坝自动化监测系统展开了试验与验证,选取评价指标对模型修正后观测值精度进行分析。结果表明,对于以垂直角为基础的垂直位移修正,基于神经网络的方法相对于传统的K值修正公式效果明显,最高可提升垂直位移的精度约2 mm。对于斜距修正,基于神经网络的方法有一定的效果,显示出距离越远效果越明显的趋势。对于水平角修正,数据结果表明水平角观测值受折光影响较小,使用神经网络进行修正并不能进一步提高观测值的精度。

空间坐标映射下的大型高炉炉壳钢结构吊装位移三维高精度控制方法

为保障大型高炉吊装工程的安全性与可靠性,提出空间坐标映射下的大型高炉炉壳钢结构吊装位移三维高精度控制方法。采用Revit软件建立高炉本炉BIM模型,对高炉本炉体建造过程分析,实施高炉本炉安装模块化设计。运用所构建的BIM模型确定高炉框架安装节点空间坐标,框架安装模块安装节点由梁柱节点调整为柱柱节点,由此将高炉BIM模型坐标投射到拼装平台上的标准柱上;在此基础上,使用高精度免棱镜全站仪对高炉框架模块的空间坐标进行精确控制,保证大型高炉炉壳钢结构吊装位置三维精度。实验结果显示该方法有效实现模型中高炉模块划分,且各部分吊装位移均控制在技术要求之内,顺利实现高炉模型的安装。

基于陀螺全站仪的地铁贯通定向分析应用

地铁隧道工程的开挖掘进由于缺少可靠的检核条件,导致控制导线的精度较低,大大影响了隧道的贯通精度。本文采用高精度的陀螺全站仪通过逆转点方法对地铁隧道进行加测陀螺定向边,并对陀螺仪的定向原理进行分析利用,结合相应的计算公式进行优化分析,得到精确的导线边方位角。通过验证确保了成果的可靠性,有效提高了控制网的精度,减小了导线网的测角误差积累及地下导线测量最弱边对地铁贯通的影响,保障地铁隧道顺利贯通。

面向自动驾驶的车道级道路电子地图制作

高精度车道级道路电子地图是实现车道级导航与监控的基础地理信息数据和必要条件,未来在自动驾驶系统方面具有广阔的应用空间。该文使用全站仪、RTK进行野外测量,生产符合要求的车道级道路路网数据,包括车道数、车道宽度等属性数据,并进行地图编译,输出OpenDrive格式数据,供自动驾驶系统测试使用。

基于全站仪的风力发电机组塔架挠度测量研究

风力发电机组塔架上无法布设观测点,常规的边角测量方法无法对其挠度进行测量。为实现对塔架挠度的测量,利用全站仪测量风力发电机组塔架挠度的原理,研究提出了一种基于全站仪实现对风力发电机组塔架挠度测量的方法,该方法包括了工艺流程、测站布设和观测计算方法、步骤,分析了测量误差的来源及应对措施。结果表明:该方法流程清晰、技术可行、成本可控,弥补了利用角度观测实现风机塔架挠度测量的技术空白,具有较强的实用性和推广价值。

高速磁浮轨道(梁)安装测控平面控制网测量技术实验研究

首先提出高速磁浮轨道(梁)安装测控平面控制网的精度要求,然后建立了小范围的CFⅢ平面控制测量实验网,在实验网中分别进行了基于高精度智能型全站仪和激光跟踪仪的观测实验,并对观测数据进行了处理与分析,以验证用这2种仪器及其对应的测量方法建立高速磁浮轨道安装测控平面控制网的精度及其可行性。实验结果表明,利用激光跟踪仪进行高速磁浮轨道(梁)安装测控平面控制网测量是可行的,且能够满足平差后方向改正数≤±1.5″、距离改正数≤±1 mm、相邻点的相对点位中误差≤±0.5 mm的精度要求。