单波束测深数据的插值精度分析

基于误差传播定律,对稀疏的离散水深点内插值进行了精度分析,建立了单波束水深内插值中误差表达的数学模型,利用我国南方某海岸带的3个试验区的进行了试验。试验结果表明,反距离加权法、Shepard法和线性插值三角网法,辅以自适应搜索半径法,内插水深值粗差比例普遍低于5%,质量与效率上为较优的插值模型;内插值精度与数据源精度有关,但与数据源密度关系不大;在给定深度测量极限误差情况下,建议在制定有关数字水深模型标准时,对水深在20 m以内的格网点水深值极限误差可设置为0.4 m。     

TWO NOTES ON SHORT TERTIARY BASES

Abstract

During recent years a light apparatus has been made up in the Survey of India to provide a basis for minor triangulation. The idea originated with the writer when executing rough triangulation under war conditions, when the need was felt for checking work which had become liable to development of considerable error. The terrain was not such as to allow the measurement of an ordinary base of such a length as half a mile; nor were other facilities present. Accordingly a length of 200 feet was marked out, with the help of a 100-foot steel tape, on a fairly smooth site on rolling ground; and its subtended angle at a distance of about 1500 feet was measured carefully with numerous repetItIons. This 1500-foot length was in turn extended in a similar way to a 3-mile side of the triangulation. No great accuracy was looked for, but enough to rule out the possibility of gross mistake in the irregular triangulation.     

导线近似平差计算

随着红外线测距仪的普及以及全站仪的广泛应用,量距精度也逐步提高,导线测量逐步取代了传统的三角测量,成为一种日益流行并深受广大测量工作者青睐的平面控制测量方法。本文基于此设计了在Visual Basic （VB）平台上对附和导线,闭合导线和支导线进行编程解算的软件。     

特大型桥梁平面变形监测设计与实践

本文根据某特大型桥梁平面监测实际,提出了分段分级布设监测网的方案。在同时顾及精度、可靠性和工作量的情况下,利用机助法对直伸边角网进行了优化设计,提出了最优布网方案和观测方法。经过几年的观测实践证明,该设计方案是可行的,符合实际情况,满足了工程要求。     

浅谈提高空中三角测量数据成果质量的3个关键环节

空中三角测量数据主要是为摄影测量提供定向框架数据,其质量决定最终产品的质量。笔者结合生产实践中遇到的实际问题,对提高空中三角测量数据成果质量的3个关键环节——航外控制测量,航内控制点量测,外业控制点的残差分析、空中三角测量成果检查及评定的重要性进行了阐述。     

VirtuoZo AAT+PATB空三成果输出工艺研究

VirtuoZo AAT采用PATB软件进行空三平差,是目前国内使用广泛的空三软件。生成的文件内容尽管十分详尽,但没有一目了然地表达控制点、检查点、外业点及接边情况,无法满足后续航测生产对空三成果的要求。故本文通过加密生成对文件进行分析、归纳和提取,将其重新整合,输出成新的空三成果文件,很好地满足了后续航测生产的要求。     

手持测距仪快速定位测量装置的研制

目前,国内外测绘业使用的手持测距仪主要用于房屋室内测量,测距大多在70～80m以内。在室外较长距离的测量中,手持测距仪存在着测距精度低、测距对点慢和准确率低等情况。手持测距仪快速定位测量装置旨在拓展手持测距仪应用范围,为室外较长距离测量提供了一种经济适用,简便快捷的测量方法。     

一种基于区域分割的三角划分方法

基于三维重建中物体截面轮廓边缘序列中相邻轮廓基本相似的事实，提出了一种物体截面轮廓线点集之间的三角划分的快速算法。该算法首先寻找轮廓线的控制点，对每两条相邻轮廓线的控制点进行配对，其次将这样两条轮廓线之间的三角划分的任务分配在多个小的曲线段对之间进行，并且由于事先的控制点匹配，在每个小的区域中就能够进行简化快速的三角划分。通过试验验证了本算法的有效性。     

THE LAY-OUT OF THE EAST AFRICAN ARC

Abstract

The only essential difference between geodetic triangulation and any other of the fifteen “orders” of triangulation—which were once proposed, and happily rejected, at an International Conference—is that steps are taken to secure the high degree of accuracy necessary over the large areas to be covered. Some of the steps taken to secure increased accuracy may well be used to insure economy in secondary work, as for instance the use of fewer readings of a large instrument, or the use of luminous signals in conditions of poor visibility; while any surveyor may at any time have to connect his work to a geodetic triangulation, using much the same methods.     

空三加密更新测量在大比例尺数字化成图中的应用

介绍空三加密更新测量实际上就是利用已成图的旧控制成果资料,在将要更新成图与新飞的航片上,利用原有的旧像控点成果再适当布测少部份新像控点,通过现有的自动空三选点量测AAT3.4及光束法区域网平差PATB-NT软件系统进行空三加密更新量测、平差、解算作业的过程。本方案在是否能达到航测大比例尺1∶1000的数字化成图的精度要求上进行了实际探讨与论述。     

精密单点定位技术在1:25000航测成图中的应用

基于精密单点定位技术的GPS辅助航测技术的推广应用,节约了传统像片控制测量的作业成本,优化了传统空三加密工序的技术流程,缩短了航测成图周期。以1∶25000地形图测绘生产为例,介绍了并进行基于精密单点定位的GPS辅助空三试验,分析并比较了空三方法的加密精度,得出了基于精密单点定位的GPS辅助摄影进行中小比例尺航测成图时新的像控布点、像控测量以及GPS辅助空三加密的方法。     

THE GEODIMETER: AN INSTRUMENT FOR THE ACCURATE MEASUREMENT OF DISTANCES BY HIGH-FREQUENCY LIGHT VARIATIONS

Abstract

During the last few years a method of measuring accurately the lengths of lines of moderate length by means of high-frequency variations in the intensity of light emitted by a special transmitter, which promises to have many important applications in triangulation and precise traversing, has been devised by Mr. E. Bergstrand, of the Geographical Survey of Sweden. In principle, the method has certain resemblances to the apparatus invented and used by Fizeau for measuring the velocity of light, Bergstrand's instrument having been designed in the first place for the measurement of the same constant. In Fizeau's apparatus, it will be remembered, a ray of light was directed through the cogs of a revolving toothed wheel towards a distant mirror, and, when the wheel reached a certain angular velocity, the ray reflected from the mirror was intercepted by the cogs, so that an observer stationed on the same side of the wheel as the light source no longer saw the reflection of the light in the mirror. The angular velocity of the wheel being known or observed, the time taken for the cogs to obliterate the reflected image could be calculated, and twice the distance to the mirror divided by this time gave the velocity of light. In the Bergstrand apparatus, which is called the “geodimeter”, light pulses of known frequency and varying intensity are directed to the end station of the line whose distance is required, and, after reflection by a mirror at that station, are received back in a special receiving apparatus alongside the transmitter. Here they are converted into small electric currents, which, when the required distance is a certain function of the wave length of the transmitted and reflected pulses, can be made to give zero deflection on a sensitive galvanometer. In this way, the distance to be measured can be determined in terms of the wave length of the pulses. Experiments so far carried out with this apparatus have been successful up to distances of about 36 kilometres. Even with the latest model, however, as we shall see later, it is necessary to know the approximate distance to within 1½ km.     

基于5G技术的实时三角测绘在测绘信息中的应用

本研究基于5G技术的实时三角测绘在测绘信息中的应用案例。通过瀑布式开发模型,本文在明确使用三角控制测量法的前提下,使用5G技术及其带来的分布式计算技术和自适应组网技术,对基于5G技术的实时沉降三角测绘系统进行了开发,通过组网测试,发现该系统的测量精度与使用全站仪人工测量精度相当,且系统部署过程并未对原有的IDC核心节点增加任何设备,系统稳定性、可靠性良好,与原有IDC设施的兼容性良好。所以,本文认为,5G技术在沉降控制测量任务中具有极大的技术优势。     

A NEW METHOD FOR THE ADJUSTMENT OF A NETWORK OF TRIANGULATION

Abstract

A problem frequently encountered by surveyors in carrying out a system of triangulation, is the adjustment of a network of lower order triangulation to make it geometrically consistent with an existing triangulation of a higher order. For example, in Fig. 1 it will be assumed that the positions of the stations A, B, and C have already been determined and that it is now required to determine the positions of the stations a, b, c, d, e and f from the measured values of the internal angles of the network of triangulation shown. In practice, several different solutions have been suggested, ranging from rigorous least squares methods to semi-graphical solutions. The method described in this article is believed to be original and may prove of interest to surveyors.     

UWB TW-TOA测距误差分析与削弱

针对室内环境下UWB TW-TOA测距精度受标准时间偏差和NLOS误差影响明显的问题,采用4阶多项式拟合模型对标准时间偏差进行标定,设计了一种新的基于偏移卡尔曼滤波的NLOS误差鉴别与抑制方法。该方法将测距残差与卡尔曼滤波结合,鉴别出NLOS误差,并将残差值加入到卡尔曼滤波的迭代中,修正卡尔曼滤波的异常值,得到消除NLOS的测量值。利用实测试验对以上算法进行验证,结果表明经过标准时间偏差标定及NLOS误差的鉴别与抑制后,在LOS环境下,UWB TW-TOA测距精度可达到毫米级;在NLOS环境下,测距精度可由原来的0.5m缩小至0.2m,证明了本文方法的正确性和可行性。     

THE USE OF AIRBORNE AUXILIARY DATA IN THE RIGOROUS LEAST SQUARES ADJUSTMENT OF A BLOCK OF AERIAL TRIANGULATION

The problem of incorporating airborne auxiliary data into an aerial triangulation block adjustment is considered. The conclusion is reached that this problem can be most readily solved by the use of a fully rigorous adjustment method. The first order adjustment equations for all types of airborne auxiliary control are developed and the method of incorporating these equations into the block solution is demonstrated. The general computing problems of the aerial triangulation block adjustment are briefly discussed and a method outlined for the incorporation of tie strips, at any angle across the block, into the adjustment without unduly increasing the storage requirements for the solution. The problem of correctly weighting the different types of available data is discussed. The paper concludes with a demonstration of the improved accuracy possible if precise aerial triangulation data are combined with apparently crude absolute airborne data.     

测量机器人ATR智能测量程序研制

依据我国三角测量、工程测量等行业测量规范的有关规定,以GeoC++为开发平台,研究开发了三角网野外数据采集的智能化测量程序,可用于控制网建立过程中的数据自动采集、超限数据的自动判别与重测,有效提高了数据采集的效率和数据处理的自动化程度。     

大范围倾斜多视影像连接点自动提取的区域网平差法

提出了一种大范围倾斜多视影像自动连接点提取和光束法区域网平差算法。首先利用POS数据对倾斜影像进行矫正并预测候选像对,使用SIFT特征进行影像匹配;然后利用并查集数据结构实现多视影像间连接点对应关系的快速确定;最后将POS数据和控制点数据作为带权观测值进行平差解算。选取3种典型的倾斜相机系统(组装轻量级倾斜相机、国产SWDC-5相机、微软UltraCam相机)进行了试验,结果表明,本文算法能够适应国内外流行的倾斜摄影系统,且一次性可处理的影像数目超过2000张;在相同条件下倾斜影像光束法区域网平差的整体精度优于传统垂直摄影情形,实际精度可以达到水平方向0.75 GSD,高程方向2.0GSD。     

CORRECTION OF PLANE-TABLE HEIGHTS FOR CURVATURE OF THE EARTH AND ATMOSPHERIC REFRACTION

Abstract

Most text-books on surveying limit their discussion of the correction of vertical angles for curvature of the earth and atmospheric refraction to the correction of angles taken with a theodolite during triangulation and omit any reference to those taken with a clinometer. This is rather illogical, as in well-observed triangulation, with all vertical angles measured in both directions, no correction for these effects is necessary, whilst in plane-tabling on small scales where sketching at considerable distances is frequently employed the application of corrections for these effects is essential.     

椭球面三角形外心的地图代数解法

椭球面三角形外心到3个相邻顶点的大地线距离都相等。面向椭球面空间的外心大地坐标的求解对于椭球面Voronoi图的生成和椭球面Delaunay三角网的构造具有重要作用。利用基于地图代数理论的矢栅结合方法,首先基于地图代数测地变换建立高精度椭球面空间距离场,再通过边界跟踪配对确定外心所在的栅格范围,最后通过数值计算内插生成初始等距点并不断逼近外心的精确大地坐标。试验结果表明,采用本文方法求解的椭球面三角形外心大地坐标,在103~104 km跨度内其定位误差小于0.001m,且算法非常适用于海量空间数据的高精度快速计算。