Future developments and synergism of space geodetic measurement techniques

1993 ◽  
pp. 21-25 ◽  
Author(s):  
Thomas A. Herring ◽  
Michael R. Pearlman
Keyword(s):  
Measurement Techniques ◽  
Geodetic Measurement ◽  
Future Developments

scholarly journals Modern Geodetic Measurement Techniques in Gravimetric Studies on the Example of Gypsum Karst in the Siesławice Region

2018 ◽  
Vol 35 ◽  
pp. 03002 ◽  
Author(s):  
Sławomir Porzucek ◽  
Monika Łój ◽  
Karolina Matwij ◽  
Wojciech Matwij
Keyword(s):  
Laser Scanning ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Digital Terrain Model ◽  
Field Studies ◽  
Surface Zone ◽  
Three Dimensional Model ◽  
Geodetic Measurement ◽  
Near Surface ◽  
Gypsum Karst

In the region of Siesławice (near Busko-Zdrój, Poland) there are unique phenomena of gypsum karst. Atmospheric factors caused numerous gypsum outcrops, canals and underground voids. The article presents the possibility of using non-invasive gravimetric surveys supplemented with geodetic measurements to illustrate karst changes occurring around the void. The use of modern geodetic measurement techniques including terrestrial and airborne laser scanning enables to generate a digital terrain model and a three-dimensional model of voids. Gravimetric field studies allowed to map the anomalies of the gravitational field of the near-surface zone. Geodetic measurement results have made it possible to accurately determine the terrain correction that supplemented the gravimetric anomaly information. Geophysical interpretation indicate the presence of weathered rocks in the near surface zone and fractures and loosened zones located surround the karst cave.

scholarly journals The Impact of Modern Topo-Geodetic Technologies on Positioning Techniques

2021 ◽  
Vol 78 (2) ◽  
pp. 1
Author(s):  
Mircea Emil NAP ◽  
Petre Iuliu DRAGOMIR ◽  
Silvia CHIOREAN ◽  
Jutka DEAK ◽  
Ioan LUPUȚ ◽  
...  
Keyword(s):  
New Technologies ◽  
Measurement Techniques ◽  
Machine Building ◽  
Measuring Instruments ◽  
Primary Research ◽  
Geodetic Measurement ◽  
Vast Number ◽  
Current State ◽  
The Impact ◽  
Permissible Deviation

The field of constructions has evolved extraordinarily in terms of measurement techniques, requiring increasing accuracy. This has led to the creation of new specific technologies, and implicitly measuring instruments. The range of classical geodetic measuring instruments has been completed with new high precision instruments, even in the field of physics or machine building. The use of geodetic measurement methods in the field of Engineering Topographic Measurement Techniques involves, in addition to ensuring precision requirements, the choice of appropriate devices and technologies. This choice is imposed both by the previous precision calculations, starting from a maximum permissible deviation given, and by the knowledge of the execution and assembly technologies. The purpose of this paper was to study the effect and also the impact that new technologies had on the main measurement activities, and of course on measurement techniques. This review article summarizes, analyzes and discusses the current state of primary research in terms of the impact of current or developing technologies on geodetic techniques. The global corpus of primary research is growing at an unprecedented rate. It is difficult for most researchers to grasp the state of the art of a topic. A vast number of bibliographic references were taken into account, on which analyzes were performed.

scholarly journals The Development of the Temporal Measurements for Ultrashort Laser Pulses

2020 ◽  
Vol 10 (21) ◽  
pp. 7401
Author(s):  
Yi Cai ◽  
Zhenkuan Chen ◽  
Xuanke Zeng ◽  
Huangcheng Shangguan ◽  
Xiaowei Lu ◽  
...  
Keyword(s):  
Measurement Techniques ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Time Frequency ◽  
Development Status ◽  
Spectral Interferometry ◽  
Future Developments ◽  
The Past ◽  
Status Characteristics ◽  
Ultrashort Laser

In the past three decades, ultrafast pulse laser technology has greatly progressed and applied widely in many subjects, such as physics, chemistry, biology, materials, and so on. Accordingly, as well as for future developments, to measure or characterize the pulses temporally in femtosecond domain is indispensable but still challenging. Based on the operation principles, the measurement techniques can be classified into three categories: correlation, spectrogram, and spectral interferometry, which operate in time-domain, time-frequency combination, and frequency-domain, respectively. Here, we present a mini-review for these techniques, including their operating principles, development status, characteristics, and challenges.

scholarly journals STUDIES ON EXTERNAL GEOMETRY OF A PLANE WITH PHOTOGRAMMETRIC METHODS AND LASER SCANNING

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 459-464
Author(s):  
S. Mikrut ◽  
J. Brzęczek
Keyword(s):  
Laser Scanning ◽  
Measurement Techniques ◽  
Measurement Methods ◽  
Medium Size ◽  
Geodetic Measurement ◽  
Structure Framework ◽  
Photogrammetric Method ◽  
Cloud Of Points ◽  
Small Models ◽  
Selection Of

Abstract. The authors of the paper were looking for a simple methods of the examination the airframe structure framework as part of the scientific and research project. The main tasks were: carrying out tests and analyses in defining external geometry of a selected plane with three independent methods i.e., geodetic (surveying), photogrammetric and laser scanning and selection of one of these methods as fast and acceptable accurate (below 3 mm) measurement applied to examine plane geometry. The carried out experiments were mainly aimed at answering the question if tested measurement methods give satisfying and acceptable results in case of works referring to the objects such as plane and if the assumed accuracy is realistic to be achieved by these measurement techniques. The authors testing the available on the market methods of the measuring the geometry of planes in the aspect of the selection of most accurate, but at the same time, fast measurement method. Thus three independent methods were tested: classical geodetic measurement, laser scanning by means of two independent scanners and photogrammetric method (based on the generated cloud of points). Experiments carried out so far in various centres worldwide usually included measurements of single elements or small models of planes. In surveying measurements of large objects, mainly buildings are predominant (e.g. surveying or photogrammetry in the inventory of historic architectural monuments, studies of the geometry of engineering constructions, etc.). The objective of the experiment carried out by the authors was to find good solution somewhere in the middle, i.e., apply geodetic measurement methods, but apply them for so-called medium-size objects such as planes.

Reference Coordinate System Requirements for Geophysics

1975 ◽  
Vol 26 ◽  
pp. 87-92
Author(s):  
P. L. Bender
Keyword(s):  
Coordinate System ◽  
Polar Motion ◽  
Main Part ◽  
Measurement Techniques ◽  
Reference Points ◽  
Angular Motion ◽  
Coordinate Systems ◽  
Axis Of Rotation ◽  
The Earth ◽  
Fixed System

AbstractFive important geodynamical quantities which are closely linked are: 1) motions of points on the Earth’s surface; 2)polar motion; 3) changes in UT1-UTC; 4) nutation; and 5) motion of the geocenter. For each of these we expect to achieve measurements in the near future which have an accuracy of 1 to 3 cm or 0.3 to 1 milliarcsec.From a metrological point of view, one can say simply: “Measure each quantity against whichever coordinate system you can make the most accurate measurements with respect to”. I believe that this statement should serve as a guiding principle for the recommendations of the colloquium. However, it also is important that the coordinate systems help to provide a clear separation between the different phenomena of interest, and correspond closely to the conceptual definitions in terms of which geophysicists think about the phenomena.In any discussion of angular motion in space, both a “body-fixed” system and a “space-fixed” system are used. Some relevant types of coordinate systems, reference directions, or reference points which have been considered are: 1) celestial systems based on optical star catalogs, distant galaxies, radio source catalogs, or the Moon and inner planets; 2) the Earth’s axis of rotation, which defines a line through the Earth as well as a celestial reference direction; 3) the geocenter; and 4) “quasi-Earth-fixed” coordinate systems.When a geophysicists discusses UT1 and polar motion, he usually is thinking of the angular motion of the main part of the mantle with respect to an inertial frame and to the direction of the spin axis. Since the velocities of relative motion in most of the mantle are expectd to be extremely small, even if “substantial” deep convection is occurring, the conceptual “quasi-Earth-fixed” reference frame seems well defined. Methods for realizing a close approximation to this frame fortunately exist. Hopefully, this colloquium will recommend procedures for establishing and maintaining such a system for use in geodynamics. Motion of points on the Earth’s surface and of the geocenter can be measured against such a system with the full accuracy of the new techniques.The situation with respect to celestial reference frames is different. The various measurement techniques give changes in the orientation of the Earth, relative to different systems, so that we would like to know the relative motions of the systems in order to compare the results. However, there does not appear to be a need for defining any new system. Subjective figures of merit for the various system dependon both the accuracy with which measurements can be made against them and the degree to which they can be related to inertial systems.The main coordinate system requirement related to the 5 geodynamic quantities discussed in this talk is thus for the establishment and maintenance of a “quasi-Earth-fixed” coordinate system which closely approximates the motion of the main part of the mantle. Changes in the orientation of this system with respect to the various celestial systems can be determined by both the new and the conventional techniques, provided that some knowledge of changes in the local vertical is available. Changes in the axis of rotation and in the geocenter with respect to this system also can be obtained, as well as measurements of nutation.

Electron microscopy of niobium and tantalum hydrides

1978 ◽  
Vol 36 (1) ◽  
pp. 644-645
Author(s):  
T. Schober
Keyword(s):  
Electron Microscopy ◽  
Heat Storage ◽  
Measurement Techniques ◽  
Metal Hydrides ◽  
Detailed Understanding ◽  
Storage Devices ◽  
Unit Cells ◽  
Endothermic Reactions ◽  
Hydrogen Reactions ◽  
New Phase

Nb, Ta and V are prototype substances for the study of the endothermic reactions of H with metals. Such metal-hydrogen reactions have gained increased importance due to the application of metal-hydrides in hydrogen- und heat storage devices. Electron microscopy and diffraction were demonstrated to be excellent methods in the study of hydride morphologies and structures (1). - Figures 1 and 2 show the NbH and TaH phase diagrams (2,3,4). EM techniques have contributed substantially to the elucidation of the structures and domain configurations of phases β, ζ and ε (1,4). Precision length measurement techniques of distances in reciprocal space (5) recently led to a detailed understanding of the distortions of the unit cells of phases ζ and ε (4). In the same work (4) the existence of the new phase η was shown. It is stable near -68 °C. The sequence of transitions is thus below 70 %.

Legal Update: North Dakota Supreme Court: Third Edition of Guides is “Most Current”

1999 ◽  
Vol 4 (1) ◽  
pp. 6-7
Author(s):  
James J. Mangraviti
Keyword(s):  
Internal Rotation ◽  
External Rotation ◽  
Measurement Techniques ◽  
Fourth Edition ◽  
Hip Motion ◽  
The Difference ◽  
The Right ◽  
Hip Flexion ◽  
Hip Rotation ◽  
Hip Extension

Abstract The accurate measurement of hip motion is critical when one rates impairments of this joint, makes an initial diagnosis, assesses progression over time, and evaluates treatment outcome. The hip permits all motions typical of a ball-and-socket joint. The hip sacrifices some motion but gains stability and strength. Figures 52 to 54 in AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, illustrate techniques for measuring hip flexion, loss of extension, abduction, adduction, and external and internal rotation. Figure 53 in the AMA Guides, Fourth Edition, illustrates neutral, abducted, and adducted positions of the hip and proper alignment of the goniometer arms, and Figure 52 illustrates use of a goniometer to measure flexion of the right hip. In terms of impairment rating, hip extension (at least any beyond neutral) is irrelevant, and the AMA Guides contains no figures describing its measurement. Figure 54, Measuring Internal and External Hip Rotation, demonstrates proper positioning and measurement techniques for rotary movements of this joint. The difference between measured and actual hip rotation probably is minimal and is irrelevant for impairment rating. The normal internal rotation varies from 30° to 40°, and the external rotation ranges from 40° to 60°.

Eye-movement measurement techniques.

1975 ◽  
Vol 30 (3) ◽  
pp. 315-330 ◽  
Author(s):  
Laurence R. Young ◽  
David Sheena
Keyword(s):  
Eye Movement ◽  
Measurement Techniques
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