Reference Ellipsoid Misalignment, Deflection Components and Geodetic Azimuth

1985 ◽  
Vol 39 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Petr Vaníček ◽  
Galo Carrera
Keyword(s):  
Coordinate System ◽  
Geodetic Network ◽  
Reference Ellipsoid ◽  
Coordinate Systems ◽  
Misalignment Effect ◽  
Terrestrial System ◽  
The Earth ◽  
Geocentric Coordinate System

Whichever way the geodetic reference ellipsoid, used as a horizontal datum, is oriented within the earth it is theoretically never exactly aligned with the geocentric coordinate system (called here Conventional Terrestrial System). It is then important to know just how much the misalignment affects the pertinent geodetic quantities in the horizontal geodetic network: the azimuth and the deflection components. The misalignment effect on these geodetic quantities must be accounted for to maintain the consistency of all the involved coordinate systems and transformations between them.

Geocentric Coordinate Systems and Actual Problems of Modernization of the State Geodetic Network

2018 ◽  
Vol 931 ◽  
pp. 687-691
Author(s):  
Anastasia E. Dudnik ◽  
Oksana V. Germak ◽  
Maksim G. Govorukhin ◽  
Galina K. Tupoleva
Keyword(s):  
Coordinate System ◽  
Russian Federation ◽  
Geodetic Network ◽  
The State ◽  
Coordinate Systems ◽  
The Russian Federation ◽  
Geodetic Coordinate System ◽  
Geocentric Coordinate System

The article describes the state of the geocentric coordinate system of the Russian Federation. Current problems of the geodetic coordinate system are described, and a method for solving this problem is proposed.

scholarly journals Reference Coordinate Systems for Earth Dynamics: A Preview

1980 ◽  
Vol 56 ◽  
pp. 1-22 ◽  
Author(s):  
Ivan I. Mueller
Keyword(s):  
Coordinate System ◽  
Coordinate Systems ◽  
Inertial Coordinate System ◽  
Terrestrial System ◽  
The Earth ◽  
Earth Dynamics

AbstractA common requirement for all geodynamic investigations is a well-defined coordinate system attached to the earth in some prescribed way, as well as a well-defined inertial coordinate system in which the motions of the terrestrial system can be monitored. This paper deals with the problems encountered when establishing such coordinate systems and the transformations between them. In addition, problems related to the modeling of the deformable earth are discussed.

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.

Chinese Geodetic Coordinate System 2000 and its Comparison with WGS84

2014 ◽  
Vol 580-583 ◽  
pp. 2793-2796 ◽  
Author(s):  
Hou Pu Li ◽  
Shao Feng Bian ◽  
Zhong Mei Li
Keyword(s):  
Coordinate System ◽  
Normal Gravity ◽  
Three Dimensional ◽  
Vertical Gradient ◽  
Coordinate Systems ◽  
Present Measurement ◽  
Three Dimensional Coordinate ◽  
Geodetic Coordinate System ◽  
International Measurement ◽  
Geocentric Coordinate System

It is a general trend to adopt the geocentric coordinate system as a geodetic datum for the international measurement community. The definition and realization of Chinese geocentric three-dimensional coordinate system (CGCS2000) which has been employed since July 1st, 2008 were introduced in detail. The defining parameters and derived constants of the reference ellipsoid used were given. The comparison between CGCS2000 and WGS84 was carried out. The differences of geodetic coordinates of a point between the two coordinate systems, normal gravity and vertical gradient of normal gravity on the two ellipsoids caused by the change of the flattening of the ellipsoid were analyzed. The results show that these differences could be neglected in view of present measurement accuracies.

scholarly journals The Effect of Using Multiple Coordinate Systems and Datum Transformations on the Calculated Coordinates in Palestine

2020 ◽  
Vol 19 (1) ◽  
pp. 31-41
Author(s):  
Ghadi Younis
Keyword(s):  
Coordinate System ◽  
Spatial Data ◽  
Service Providers ◽  
Local Coordinate System ◽  
Geodetic Network ◽  
Coordinate Systems ◽  
The West ◽  
Transformation Methods ◽  
Gnss Data ◽  
Gis Software

AbstractThe recent developments in spatial data collection, management and software require the availability of proper geodetic infrastructures for integrating different types and sources of coordinates without causing effective changes in positions. Nowadays, positions are mostly collected by GNSS data collectors based on WGS84/ITRF reference systems. The data are then subjected to transformations and projections to a locally used system. Another possibility is direct data collection based on the local coordinate system by classical surveys using land surveying, photogrammetry, laser scanning, etc. The spatial data management is commonly operated using Geographic Information Systems (GIS) software for mapping, analysis, planning, and other services. The conversions between different coordinate systems should be well defined to guarantee the consistency of the coordinates on all systems and tools. In Palestine, the classical and local surveys are all based on the local coordinate system Pal1923Grid for engineering, cadastral and planning applications. The different GNSS RTK-service providers use different definitions and transformation methods between WGS84 or the International Terrestrial Reference Frames (ITRF) and the local Palestine1923Grid, whereas the Land authority has adopted a group of parameters to be implemented on the Global Navigation Satellite Systems (GNSS) data collectors, which do not fit with Palestine1923Grid properties. Additionally, different transformation methods are used in GIS applications for converting the coordinates between the different systems using WGS84 as an intermediate system. Here, the coordinates of a group of the geodetic network in the West Bank of Palestine are used to assess the accuracy of the different transformations and systems by comparing the transformed coordinates using the GNSS system and the originally registered coordinates. Furthermore, a grid of points covering the coordinate system extents is used to describe the differences between the transformations and systems. It was found that the parameters provided by GNSS service providers have results that are consistent with each other and the geodetic network in the West Bank of Palestine compared to GIS-software parameters. By contrast, all systems have extremely deteriorated coordinates in the Gaza strip and the further parts of the Pal1923Grid extents.

Nature of the Requirements for Reference Coordinate Systems

1975 ◽  
Vol 26 ◽  
pp. 49-62
Author(s):  
C. A. Lundquist
Keyword(s):  
Rigid Body ◽  
Coordinate System ◽  
Equations Of Motion ◽  
Inertial Reference Frame ◽  
Earth System ◽  
Coordinate Systems ◽  
Dynamical Equations ◽  
The Earth ◽  
Measurement Uncertainties ◽  
Rotational Motions

AbstractThe current need for more precisely defined reference coordinate systems arises for geodynamics because the Earth can certainly not be treated as a rigid body when measurement uncertainties reach the few centimeter scale or its angular equivalent. At least two coordinate systems seem to be required. The first is a system defined in space relative to appropriate astronomical objects. This system should approximate an inertial reference frame, or be accurately related to such a reference, because only such a coordinate system is suitable for ultimately expressing the dynamical equations of motion for the Earth. The second required coordinate system must be associated with the nonrigid Earth in some well defined way so that the rotational motions of the whole Earth are meaningfully represented by the transformation parameters relating the Earth system to the space-inertial system. The Earth system should be defined so that the dynamical equations for relative motions of the various internal mechanical components of the Earth and accurate measurements of these motions are conveniently expressed in this system.

Determining the parameters of a local coordinate system with a non-standard longitude of the central meridian. Analysis of existing methods

2020 ◽  
Vol 960 (6) ◽  
pp. 2-12
Author(s):  
A.V. Vinogradov
Keyword(s):  
Coordinate System ◽  
Local Coordinate System ◽  
Geodetic Network ◽  
Systematic Errors ◽  
Central Meridian ◽  
Coordinate Systems ◽  
Preliminary Calculation

Processing the results of topographic and geodetic works is performed in local coordinate systems. The parameters of the local coordinate systems were established on the basis of SK-42 or SK-63 systems. At present, it is necessary to set new communication parameters with coordinate systems SK-95 and GSK-2011. In many MCSs, the central meridians do not coincide with the origin, and the coordinates of the starting points were obtained from the catalogs of the preliminary calculation geodetic network. To establish the new communication parameters, it is necessary to determine the longitude of the central meridian MCS in SK-95 and GSK-2011 systems. To find the errors in calculating the longitude of the central meridian, MCS the models were constructed with different positions of the central meridian relative to the origin. The longitude was calculated using well-known and new formulas and methods. Errors in calculating the longitude of the MSC are systematic. An increase in the calculation volume does not exclude the influence of systematic errors, reaching 4ʺ. For some lines, they make 8ʺ.

scholarly journals Origin and Scale of Coordinate Systems in Satellite Geodesy

1980 ◽  
Vol 56 ◽  
pp. 239-250
Author(s):  
J. B. Zieliński
Keyword(s):  
Coordinate System ◽  
Inner Core ◽  
Center Of Mass ◽  
Point Of View ◽  
Satellite Geodesy ◽  
Coordinate Systems ◽  
Scale Problem ◽  
The Earth ◽  
Geocenter Motion

AbstractThe center of mass of the Earth is commonly taken as origin for the coordinate systems used in satellite geodesy. In this paper the notion of the “geocenter” is discussed from the point of view of mechanics and geophysics. It is shown that processes in and above the crust have practically no impact on the position of the geocenter. It is possible however that motions of the inner core may cause variations of the geocenter of the order of 1 m. Nevertheless the geocenter is the best point for the origin of a coordinate system. Mather’s method of monitoring geocenter motion is discussed, and some other possibilities are mentioned. Concerning the scale problem, the role of the constant GM and time measurements in satellite net determinations are briefly discussed.

2.1. Working Group 1: Requirements for Coordinate Systems for Earth Dynamics

1975 ◽  
Vol 26 ◽  
pp. 15-20
Keyword(s):  
Coordinate System ◽  
Working Group ◽  
Global Scale ◽  
Coordinate Systems ◽  
Tectonic Plates ◽  
The Earth ◽  
International Projects ◽  
The Subject ◽  
Earth Dynamics ◽  
Group 1

As initial guidance for its deliberations, Working Group 1 accepted the objective implied in the Colloquium title and the more explicit description contained in the First Circular announcing the Colloquium:Earth dynamics is currently the subject of intensive world-wide research efforts. As a consequence of the new insights into Earth dynamics and acceptance of the hypothesis of moving tectonic plates, as well as the ability to measure crustal motions on a global scale with a precision of a few centimeters, a number of national and international projects have been organized to pursue these investigations. In all these efforts, a common feature is the necessity for a very well defined coordinate system to which all observations can be referred and in which theories can be formulated. At this time there is no widely accepted coordinate system in the Earth or in space which is defined with the precision needed for ongoing geodynamics research.

scholarly journals On the Absolute Orientation of the Selenodetic Reference Frame

1981 ◽  
Vol 63 ◽  
pp. 281-286
Author(s):  
V. S. Kislyuk
Keyword(s):  
Coordinate System ◽  
Center Of Mass ◽  
The Moon ◽  
Coordinate Systems ◽  
Inertial Coordinate System ◽  
Reference Coordinate System ◽  
The Earth ◽  
Principal Axes ◽  
The Mean ◽  
Selection Of

The selection of selenodetic reference coordinate system is an important problem in astronomy and selenodesy. For the purposes of reduction of observations, planning and executing space missions to the Moon, it is necessary, in any case, to know the orientation of the adopted selenodetic reference system in respect to the inertial coordinate system.Let us introduce the following coordinate systems: C(ξc, ηc, ζc), the Cassini system which is defined by the Cassini laws of the Moon rotation;D(ξd, ηd, ζd), the dynamical coordinate system, whose axes coincide with the principal axes of inertia of the Moon;Q(ξq, ηq, ζq), the quasi-dynamical coordinate system connected with the mean direction to the Earth, which is shifted by 254" West and 75" North from the longest axis of the dynamical system (Williams et al., 1973);S(ξs, ηs, ζs), the selenodetic coordinate system, which is practically realized by the positions of the points on the Moon surface given in Catalogues;I(X,Y,Z), the space-fixed (inertial) coordinate system. All the systems are selenocentric with the exception of S(ξs, ηs, ζs On the whole, the origin of this system does not coincide with the center of mass of the Moon.

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