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1.
The concepts of “confining structure” and structure light are illuminated in this paper. A laser theodolite with three freedoms of rotation, which is aimed at “confining structure”, is developed. Various scanning modes and their mathematical models based on laser theodolite with three freedoms of rotation are discussed. According to the features of a huge object the structure light engineering surveying based on laser theodolite with three freedoms of rotation is determined as the main method in an actual application. The observation of four sound concrete posts and forced centering plates. Subsequently, it is transformed into the huge object coordinate system. The scanning mode with plumb plane is selected as the main mode in the whole work. And other assistant methods, such as close range photogrammetry and the method of using reflection sheet, are applied to the work of “scanning dead angle”. At last, a surveying accuracy estimation of this method is done and a surveying accuracy test is finished. It can be concluded that the structure light engineering surveying based on laser theodolite with three freedoms of rotation is considered to be an effective and applied method, and has many superiority to some other surveying methods in the work of surveying “confining structure”. 相似文献
2.
基于三旋转自由度激光经纬仪的结构光工程测量原理与应用 总被引：4，自引：0，他引：4
围绕具有三旋转自由度的激光经纬仪,阐述它在封闭构筑物测量中应用的优越性,提出结构光工程测量中各种扫描关系式的解算式,并用实例证明所述理论的正确性与高效率。 相似文献
3.
FENGWenhao 《地球空间信息科学学报》2004,7(3):157-161
This paper is to advance some relevant techniques to set up a three-dimensional industrial surveying system of “building blocks type“, making use of the electronic theodolite, standard ruler and portable computer. 相似文献
4.
非正交系坐标测量系统原理及进展 总被引：16，自引：0，他引：16
非正交系坐标测量系统是近十几年来发展的一类移动、便携式的测量系统，一般分为电子经纬仪测量系统、全站仪测量系统、数字近景摄影测量系统、激光跟踪测量系统、激光扫描测量系统和关节式坐标机等6类，通过间接测量边长和角度来确定测点的三维坐标值。本文将这6类测量系统归纳为球坐标测量法、三角测量法、三边测量法和导线测量法4种测量方法，讨论了其测量原理，简单介绍了其应用和发展。 相似文献
5.
The traditional approach to geologic mapping consists of sketching, taking orientation and thickness measurements with compass
and tape, and noting positions of features on topographic maps or photos. These methods are time consuming, often difficult
to realize in rough terrain, and poorly constrain lateral variations in sedimentary facies in relatively flat lying strata.
We describe a case study that captures the three-dimensional architecture of sandstone bodies and key geological surfaces
such as stratigraphic boundaries and faults using digital capture techniques. The Ferron sandstone in Utah is a superbly exposed
ancient delta deposit that provides an improtant outcrop analog to fluvio-deltaic subsurface reservoirs. It has been the focus
of many traditional outcrop studies, but here we use a methodology (“cybermapping”) based on GPS with offsets from a continuous
ranging mode reflectorless laser rangefinder (“laser sketch”) for collection and analysis of basic stratigraphic and structural
data in a relatively remote area. We also show hos this data can be analyzed and visualized in three dimensions. The study
area was mapped in two days, which included hiking several kilometers into the area. One-the-fly and rapid static post processing
of GPS surveying was used for positioning the reflectorness laser rangefinders; 60,000 points were acquired mapping sedimentological
and structural features, terrain, and control points. The resultant quantitative 3D model of the geology and terrain allowed
robust geometric visualization and analyses. ? 2001 John Wiley & Sons, Inc. 相似文献
6.
Very Long Baseline Interferometry (VLBI) is one of the new techniques which will probably dominate geodesy and geophysics
in the near future. Its main advantage lies in the fact that it brings the accuracy of direction measurements to a level previously
possible only for range measurements. This closes the gap between powerful range determination techniques such as laser ranging
and the much less accurate determination of directions through photographic tracking of artificial earth satellites.
The technique is geometric in the sense that the relevant observations are independent of the gravity field of the earth.
However, the “orbits” of the observed extragalactic radio sources with respect to an earth-fixed system are dominated and
perturbed by the rotation of the earth with respect to inertial frame. This allows the determination of polar motion, precession-nutation
and length-of-the-day variations, and the technique becomes also “dynamic” in this respect.
The capability of determining the geometry of a network of stations within a short time interval and with a centimeter level
accuracy also allows the study of the variation of network geometry with time caused by earth tides and other periodic or
secular station drifts.
The main objective of the present work is the exploration of the capabilities of VLBI for the recovery of earth rotation and
network geometry parameters. For this purpose, a number of characteristic experimental designs based on present and candidate
for the near future station locations is chosen. The results from the analysis of simulated observations for each particular
design are presented in the paper.
Presented at IAG International Symposium on “Optimization of Design and Computation of Control Networks”, Sopron, Hungary,
4–10 July 1977. 相似文献
7.
Assessment of long-range kinematic GPS positioning errors by comparison with airborne laser altimetry and satellite altimetry 总被引：3，自引：0，他引：3
Long-range airborne laser altimetry and laser scanning (LIDAR) or airborne gravity surveys in, for example, polar or oceanic
areas require airborne kinematic GPS baselines of many hundreds of kilometers in length. In such instances, with the complications
of ionospheric biases, it can be a real challenge for traditional differential kinematic GPS software to obtain reasonable
solutions. In this paper, we will describe attempts to validate an implementation of the precise point positioning (PPP) technique
on an aircraft without the use of a local GPS reference station. We will compare PPP solutions with other conventional GPS
solutions, as well as with independent data by comparison of airborne laser data with “ground truth” heights. The comparisons
involve two flights: A July 5, 2003, airborne laser flight line across the North Atlantic from Iceland to Scotland, and a
May 24, 2004, flight in an area of the Arctic Ocean north of Greenland, near-coincident in time and space with the ICESat
satellite laser altimeter. Both of these flights were more than 800 km long. Comparisons between different GPS methods and
four different software packages do not suggest a clear preference for any one, with the heights generally showing decimeter-level
agreement. For the comparison with the independent ICESat- and LIDAR-derived “ground truth” of ocean or sea-ice heights, the
statistics of comparison show a typical fit of around 10 cm RMS in the North Atlantic, and 30 cm in the sea-ice region north
of Greenland. Part of the latter 30 cm error is likely due to errors in the airborne LIDAR measurement and calibration, as
well as errors in the “ground truth” ocean surfaces due to drifting sea-ice. Nevertheless, the potential of the PPP method
for generating 10 cm level kinematic height positioning over long baselines is illustrated. 相似文献
8.
Arcsecond-level accuracy of NASA's ICESat (Ice, Cloud, and land Elevation Satellite) satellite laser altimeter beam pointing
angle is required to satisfy the scientific goal of detecting centimeter-level elevation changes, over time, in the Greenland
and Antarctic ice sheets. Two different approaches, termed “topographic inferred” and “direct detection”, were examined for
calibrating the laser pointing angle (that is, detecting and removing pointing determination bias) at the 1.5-arcsec level,
using information independent of the onboard pointing instrumentation. Both approaches entail estimating the beam pointing
by differencing the three-dimensional position of the altimeter instrument and the laser-beam spot (or “footprint”) location
on the ground. Analytical assessments of the two approaches are discussed, along with recommendations for the ICESat pointing
determination calibration strategy.
Received: 28 April 2000 / Accepted: 6 November 2000 相似文献
9.
Atmospheric Angular Momentum Time-Series: Characterization of their Internal Noise and Creation of a Combined Series 总被引：1，自引：0，他引：1
The atmosphere induces variations in Earth rotation. These effects are classically computed using the “angular momentum approach”. In this method, the variations in Earth rotation are estimated from the variations in the atmospheric angular momentum (AAM). Several AAM time-series are available from different meteorological centers. However, the estimation of atmospheric effects on Earth rotation differs when using one atmospheric model or the other. The purpose of this work is to build an objective criterion that justifies the use of one series in particular. Because the atmosphere is not the only cause of Earth rotation variations, this criterion cannot rely only on a comparison of AAM series with geodetic data. Instead, we determine the quality of each series by making an estimation of their noise level, using a generalized formulation of the “three-cornered hat method”. We show the existence of a link between the noise of the AAM series and their correlation with geodetic data: a noisy series is usually less correlated with Earth orientation data. As the quality of the series varies in time, we construct a combined AAM series, using time-dependent weights chosen so that the noise level of the combined series is minimal. To determine the influence of a minimal noise level on the correlation with geodetic data, we compute the correlation between the combined series and Earth orientation data. We note that the combined series is always amongst the best correlated series, which confirms the link established before. The quality criterion, while totally independent of Earth orientation observations, appears to be physically convincing when atmospheric and geodetic data are compared 相似文献
10.
激光扫描技术在规划竣工测量中的应用 总被引：1，自引：1，他引：0
规划监督测量包括验线测量和竣工测量两个阶段,本文以竣工测量为研究对象,结合实际工程项目,研究探讨三维激光扫描技术在规划监督测量中应用的可行性,具体流程、质量控制等关键技术。 相似文献
11.
12.
J. A. Weightman 《Journal of Geodesy》1967,41(3):237-247
Summary A datum change between two geodetic systems with points in common may be derived in three stages; slight adjustments of coordinates
to make the networks of common points geometrically similar in the two systems; a scale factor to make them geometrically
congruent; finally, an orthogonal transformation to swing them into coincidence.
The geometrical concept is developed of a “datum screw”, not arbitrarily chosen as is the “origin” or “datum point” of a geodetic
survey, but intrinsic to the geometry. The conditions under which it degenerates to a simple “datum shift” are discussed.
Differential and other formulae for changes of spheroid and of datum are given, together with a set of tables of coefficients. 相似文献
13.
LIQi CAOJian 《地球空间信息科学学报》2004,7(2):101-103
This paper is to construct a “digital local, regional, region“ information framework based on the technology of “SIG“ and its significance and application to the regional sustainable development evaluation system. First, the concept of the “grid computing“ and “SIG“ is interpreted and discussed, then the relationship between the “grid computing“ and “digital region“ is analyzed, and the framework of the “digital region“ is put forward. Finally, the significance and application of “grid computing“ to the “region sustainable development evaluation system“ are discussed. 相似文献
14.
移动激光扫描技术是从上世纪90年代初逐步发展起来的一门测绘技术,也是当今测绘界最为前沿的技术之一,可用于工程测量和制图等诸多领域。地面3D激光扫描仪具有测量速度快,精度高等优点。本文以奥地利RIEGL公司的地面三维激光扫描仪VZ400为例,研究将其作为移动测量系统的主要传感器所涉及的关键技术,包括联机控制、时间基准统一和空间基准统一三个方面:解析了激光扫描仪的接口定义,并结合联机控制的开发库——RiVLIB实现的仪器的联机控与数据通信;给出了基于GPS秒脉冲信号的时间同步原理,实现了系统时间基准的传递与统一;分析了移动测量系统中的坐标系,并根据地面三维激光扫描仪的实际情况,构建了单站的参数标定模型。通过本文的研究与实验,使测量系统实现常见移动测量的二维帧扫描模式以及针对重点区域的三维全景扫描模式,同时,当它闲置时还可将激光扫描仪拆卸进行静态的扫描,丰富了系统的测量方式,提高了系统的适应性与使用效率。 相似文献
15.
3维激光扫描是基于近景扫描获取物体3维景观模型的一种新的激光测量技术,但在应用其扫描所得的点云数据使用配套软件Cyclone建立3维空间模型中又遇到了许多技术性问题,本文就此问题进行了探讨,并提出点云数据在MicroStation下处理的一些参考性方法。 相似文献
16.
王汉顺 《测绘与空间地理信息》2020,(3):169-172
三维激光扫描技术是目前最先进的测绘数据获取方式之一,它采用非接触主动测量方式直接获取高精度的三维数据,能够对任意物体进行扫描,快速将现实世界的信息转换成计算机可处理的三维数据信息,与传统测绘技术相比,除了速度快、精度高的优势外,更有获取对象信息更全面、提供的测绘成果更丰富更直观的突出技术特点。本文以宁化天鹅洞改造测量项目为例,探讨了三维激光扫描技术在地下溶洞改造测量工作中的应用原理、工作流程、成果类型及其技术优势,希望对同类工程项目应用有一定借鉴作用。 相似文献
17.
Experiments photographing satellite reflected laser pulses have been made to demonstrate the feasibility of using an earth-based
light source to illuminate satellites. The reflection was also recorded photoelectrically for range information. The reflections
are photographed against stellar backgrounds from which the angular positions of the satellites relative to the laser site
can be determined. With the angular information and the range data from the laser-illuminator, the position of the satellite
in space is uniquely determined. When other widely separated laser-camera sites make simultaneous observations, the location
of these sites relative to the “control” site can be found. 相似文献
18.
The round-trip travel time measurements made by spacecraft laser altimeters are primarily used to construct topographic maps
of the target body. The accuracy of the calculated bounce point locations of the laser pulses depends on the quality of the
spacecraft trajectory reconstruction. The trajectory constraints from Doppler and range radio tracking data can be supplemented
by altimetric “crossovers”, to greatly improve the reconstruction of the spacecraft trajectory. Crossovers have been used
successfully in the past (e.g., Mars Orbiter Laser Altimeter on Mars Global Surveyor), but only with single-beam altimeters.
The same algorithms can be used with a multi-beam laser altimeter, but we present a method using the unique cross-track topographic
information present in the multi-beam data. Those crossovers are especially adapted to shallow (small angle) intersections,
as the overlapping area is large, reducing the inherent ambiguities of single-beam data in that situation. We call those “swath
crossovers”. They prove particularly useful in the case of polar-orbiting spacecraft over slowly rotating bodies, because
all the non-polar crossovers have small intersection angles. To demonstrate this method, we perform a simplified simulation
based on the Lunar Reconnaissance Orbiter (LRO) and its five-beam Lunar Orbiter Laser Altimeter. We show that swath crossovers
over one lunar month can independently, from geometry alone, recover the imposed orbital perturbations with great accuracy
(5 m horizontal, < 1 m vertical, about one order of magnitude smaller than the imposed perturbations). We also present new
types of constraints that can be derived from the swath crossovers, and designed to be used in a precision orbit determination
setup. In future work, we will use such multi-beam altimetric constraints with data from LRO. 相似文献
19.
The extraction of points on the bare earth from point clouds acquired by airborne laser scanning is one of the most important
steps for the generation of digital terrain models (DTM). This process is called “filtering”. However, most of the current
filters erode the bare earth in steep sloped landscapes and at discontinuities, and they retain low vegetation. Therefore,
a new filtering method for extracting ground points based on a distance limit is proposed in this paper. The angle criterion
is used to assure the robustness of the algorithm. The experimental results show that the proposed filtering method can effectively
derive the ground points from point clouds in complex urban areas.
Supported by the Program for Changjiang Scholars and Innovative Research Team in University (No.0438), the National 863 Program
of China (No. 2006AA12Z151). 相似文献
20.
Feng Wenhao 《地球空间信息科学学报》2013,16(4):66-72
The purpose, classification, required accuracy and surveying methods of control work for close range photogrammetry have been briefly stated. The different methods for definition of space, object coordinate system are also reviewed. It is suggested that the habitu-ally-practised rotation angle system for aerophotogrammetry in China should be used for the future teaching and resaarching work in the close range photogrammetry, and that the rotation angle system for terrestrial deformation photogrammetry should be left out in order to avoid the confuse and reduce the amount of expanse for making softwares. It has been emphasized that there are three improtant aspects in the close range control work with high accurary using the conventional method of engineering surveying: the use of standard scale for measurement of distance between two general stations, the accurate determination of start direction line between two general stations and the handling method of influence of 2C change. A method for setting up industrial surveying control net with extra-high accuracy ±(0.05–0.20) mm is presented by the author. This kind of industrial control net is necessary for batch process of large industrial components with purposes of measurement, inspect and lofting. There are some special methods of control work in the close range photogrammetry, including two methods presented by the author. 相似文献