Ideal Reference Frames, Concepts and Interrelationships

AbstractMany problems of geodynamics depend on spatial relationship of points and their temporal variations. To solve these problems it is convenient, but not necessary, to use a reference frame. To use a reference frame, a scheme is needed by which the coordinates of any point expressed in this frame could be obtained. Coordinates are hardly ever measured directly. Instead, they are computed from measurements of other quantities within the framework of a theory that relates the measured quantities with the coordinates. Such a scheme will be called a reference system. Reference systems have been realized using simple theories and reducing the measurements with the best available, but not always complete, theories. This geometric (static) method has been used to a great extend to define astronomic reference systems (star catalogues) and geodetic reference systems (geodetic datums), With space techniques, a method can be used based on dynamic principles. A space object moving according to a certain theory (assumed to be known) defines in a time dependent way the representative points. A reference system of this type is the WGS 72.

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Reference Frames

Symposium - International Astronomical Union ◽

10.1017/s0074180900127871 ◽

1996 ◽

Vol 172 ◽

pp. 455-460

Author(s):

Jean Kovalevsky ◽

Martine Feissel

Keyword(s):

Reference Frame ◽

Present State ◽

Reference Frames ◽

The State ◽

Reference Systems ◽

Short Introduction ◽

Hipparcos Catalogue

After a short introduction on the definition and the construction of a reference frame, the presentation concentrates on the actual construction of the new IAU conventional reference frame. The 1991 IAU resolutions on reference systems is reviewed and the present state of the implementation of these resolutions is discussed. The IERS extragalactic reference frame is described and we show that it fulfills the IAU requirements. The Hipparcos catalogue will be linked to this frame before the end of this year. The state of advancement of this job is presented.

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Deformation detection through the realization of reference frames

Journal of Applied Geodesy ◽

10.1515/jag-2019-0056 ◽

2020 ◽

Vol 14 (2) ◽

pp. 133-148

Author(s):

Nestoras Papadopoulos ◽

Melissinos Paraskevas ◽

Ioannis Katsafados ◽

Georgios Nikolaidis ◽

Euagelos Anagnostou

Keyword(s):

Reference Frame ◽

Reference System ◽

Reference Frames ◽

Satellite System ◽

Geodetic Reference System ◽

Deformation Model ◽

Navigation Systems ◽

International Gnss Service ◽

Tectonically Active ◽

Global Navigation Satellite

AbstractHellenic Military Geographical Service (HMGS) has established and measured various networks in Greece which constitute the geodetic infrastructure of the country. One of them is the triangulation network consisting of about 26.000 pillars all over Greece. Classical geodetic measurements that held by the Hellenic Military Geographic Service (HMGS) through the years have been used after adjustment for the state reference frame which materializes the current Hellenic Geodetic Reference System of 1987 (HGRS87). The aforementioned Reference System (RS) is a static one and is in use since 1990. Through the years especially in the era of satellite navigation systems many Global Navigation Satellite System (GNSS) networks have been established. The latest such network materialized by HMGS is ongoing and covers until now more than the 2/3 of the country. It is referenced by International GNSS Service (IGS) permanent stations and consists a local densification IGS08 Reference Frame. Firstly, this gives the opportunity to calculate transformation parameters between the two systems and a statistical analysis of the residuals leads to intermediate conclusions. After that and in conjunction with existing past transformations, tectonic deformations and their directions are concluded. Moreover past GPS observations on the same pillars in compare to the newer ones give also a sense of tectonic displacements. Greece is one of the most tectonically active countries in Europe and the adoption of a modern kinematic or semi-kinematic geodetic datum is a necessity as it should incorporate a deformation model like 3d velocities on the reference frame realization. The detection of geodynamic changes is a continuous need and should be taken into consideration at each epoch.

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Nutation and reference frame

Highlights of Astronomy ◽

10.1017/s1539299600011072 ◽

1995 ◽

Vol 10 ◽

pp. 228-231

Author(s):

N. Capitaine

Keyword(s):

Perturbation Theory ◽

Reference Frame ◽

Euler Equations ◽

Coordinate Transformation ◽

Earth Rotation ◽

Reference System ◽

Reference Frames ◽

Fundamental Importance ◽

Terrestrial Reference System ◽

Celestial Reference System

The reference frames are of fundamental importance in all kinds of the precession and nutation studies involving the theory, the coordinate transformation and the observations. The aim of this paper is to review all the frames used in such studies and to lead to a better consistency between them in order that theory and reductions of observations be referred, as close as possible, to the frames to which observables are actually sensitive.The equations of Earth rotation can be expressed either as Euler equations in the Terrestrial Reference System (TRS), or as perturbation theory in the Celestial Reference System (CRS) (Kinoshita 1977). Euler equations are transformed to the CRS in the astronomical approach (Woolard 1953) and solved by the method of variation of the parameters, whereas, in the geophysical approach (Melchior 1971), the solutions, first obtained in the TRS, are transformed to the CRS and then solved by an integration with respect to time.

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Improvements to Reference Systems and Their Relationships

Symposium - International Astronomical Union ◽

10.1017/s007418090022826x ◽

1995 ◽

Vol 166 ◽

pp. 309-314

Author(s):

P. K. Seidelmann

Keyword(s):

Reference Frame ◽

Reference Frames ◽

Three Dimensional ◽

Reference Systems ◽

Basic Frame ◽

Dynamical Time ◽

Optical Wavelengths ◽

The Difference ◽

The Relationship ◽

Optical Radar

Reference Systems include the reference frames and their relationships, time arguments, ephemerides, and the standard constants and algorithms.The extragalactic, or radio, reference frame will be the basic frame. Achieving milli to microarcsecond accuracies at optical wavelengths will reduce the disparity between optical, radar, and radio reference frame determinations. Thus, the relationships and identifications of common sources should be much more accurate. Another significant change should be the ability to determine distances, and thus space motions on a three-dimensional basis, rather than the current two-dimensional basis of proper motions.Improvements in ephemerides provide the opportunity to investigate the difference between atomic and dynamical time, the relationship between the dynamical and extragalactic reference frame and the values of precession and nutation.Also, the relationships between the bright and faint optical catalogs, the infrared, and extragalactic reference frames should be better determined. Reference frames at other wavelengths will become determinable.

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Using the Hubble Space Telescope to Relate the HIPPARCOS and Extragalactic Reference Frames

Symposium - International Astronomical Union ◽

10.1017/s0074180900134916 ◽

1988 ◽

Vol 129 ◽

pp. 335-336

Author(s):

P. D. Hemenway ◽

R. L. Duncombe

Keyword(s):

Reference Frame ◽

Solid Body ◽

Reference System ◽

Reference Frames ◽

Hubble Space Telescope ◽

Inertial Reference Frame ◽

Body Rotation ◽

Space Telescope ◽

Solid Body Rotation ◽

Instrumental System

The HIPPARCOS satellite will produce positions, motions and parallaxes of celestial objects with previously unattained accuracy. This HIPPARCOS Instrumental System, however, will have an unknown solid body rotation with respect to an inertial reference frame. One aspect of our program of astrometric observations with the Hubble Space Telescope is to determine the rotation of the HIPPARCOS reference frame with respect to an extragalactic reference system.

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The U.S. is replacing NAD83 with NATRF2022: what this means for Canada

GEOMATICA ◽

10.1139/geomat-2019-0021 ◽

2019 ◽

Vol 73 (3) ◽

pp. 74-80

Author(s):

Caroline Erickson ◽

Geoff Banham ◽

Ron Berg ◽

Joey Chessie ◽

Michael Craymer ◽

...

Keyword(s):

Reference Frame ◽

North American ◽

Reference System ◽

Reference Frames ◽

Terrestrial Reference Frame ◽

The U.S

In 2022, the U.S., as part of its reference system modernization, will replace its North American Datum of 1983 (NAD83) with a new North American Terrestrial Reference Frame (NATRF2022), creating 1.3 to 1.5 m horizontal coordinate differences at the Canada–U.S. border with respect to Canada’s NAD83(CSRS). Never before have such significant differences existed between our two countries’ reference frames. This paper reviews why the U.S. is making this change and then looks at Canada’s situation with respect to reference frames. There are compelling reasons for Canada to follow suit and move to NATRF2022 within a decade, but there are also major challenges. Whether or not Canada follows the same path, there is much work to be done to prepare Canada for the U.S.’ move to NATRF2022. This paper is intended as a first step to inform the Canadian geospatial community of the U.S.’ move to NATRF2022 and what it means for Canada.

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An All-in-One Application for Temporal Coordinate Transformation in Geodesy and Geoinformatics

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi9050323 ◽

2020 ◽

Vol 9 (5) ◽

pp. 323

Author(s):

Antonio Banko ◽

Tedi Banković ◽

Marko Pavasović ◽

Almin Đapo

Keyword(s):

Reference Frame ◽

Coordinate Transformation ◽

Reference System ◽

Plate Tectonics ◽

Reference Frames ◽

Spatial Scales ◽

Global Navigation Satellite Systems ◽

Tectonic Plate ◽

Kinematic Models ◽

Terrestrial Reference System

Over the years, Global Navigation Satellite Systems (GNSS) have been established in the geosciences as a tool that determines the positions of discrete points (stations) on the Earth’s surface, on global to local spatial scales in a very simple and economical manner. Coordinates obtained by space geodetic measurements ought to be processed, adjusted, and propagated in a given reference frame. As points on the Earth’s surface do not have a fixed position, but rather, are moving with associated velocities, it is inevitable to include those velocities in the coordinate transformation procedure. Station velocities can be obtained from kinematic models of tectonic plate motions. The development and realization of an all-in-one standalone desktop application is presented in this paper. The application unifies coordinate transformation between different realizations (reference frames) of the International Terrestrial Reference System (ITRS) and European Terrestrial Reference System 1989 (ETRS89) following European Reference Frame Technical Note (EUREF TN) recommendations with temporal shifts of discrete points on the Earth’s surface caused by plate tectonics by integrating no-net rotation (NNR) kinematic models of the Eurasian tectonic plate.

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4 Ephemerides (Ephemerides)

Transactions of the International Astronomical Union ◽

10.1017/s0251107x00009731 ◽

1991 ◽

Vol 21 (1) ◽

pp. 1-6

Keyword(s):

Working Group ◽

Reference System ◽

Reference Frames ◽

General Assembly ◽

Reference Systems ◽

The Earth ◽

Astronomical Constants ◽

Future Reference

This report covers the period from 1 July 1987 to 30 June 1990. The ephemerides that have been published during this period have made use of the system of astronomical constants adopted at the 16th General Assembly of the IAU in Grenoble. At the same time that the use of the FK5 system on the J2000 epoch is increasing and catalogues are becoming available for that system, there is an IAU Working Group on Reference Systems with subgroups on astronomical constants, nutation of the Earth, time and reference frames/origin. The purpose is to define a future reference system and resolve some of the difficulties that occur in the system. It is anticipated that this Working Group will develop recommendations for consideration at the 21st General Assembly of the IAU.

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Ultrastructural evidence for mast cell-macrophage interrelationships in the dura mater of the rat: Infrequent mast cell-nerve associations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159308 ◽

1990 ◽

Vol 48 (3) ◽

pp. 352-353

Author(s):

Ruth V.W. Dimlich

Keyword(s):

Mast Cell ◽

Mast Cells ◽

Dura Mater ◽

Spatial Relationship ◽

Potassium Phosphate ◽

Plasma Extravasation ◽

Close Spatial Relationship ◽

Male Wistar Rats ◽

Headache Pain ◽

Relationship Of

Mast cells in the dura mater of the rat may play a role in cerebral pathologies including neurogenic inflammation (vasodilation; plasma extravasation) and headache pain . As has been suggested for other tissues, dural mast cells may exhibit a close spatial relationship to nerves. There has been no detailed ultrastructural description of mast cells in this tissue; therefore, the goals of this study were to provide this analysis and to determine the spatial relationship of mast cells to nerves and other components of the dura mater in the rat.Four adult anesthetized male Wistar rats (290-400 g) were fixed by perfusion through the heart with 2% glutaraldehyde and 2.8% paraformaldehyde in a potassium phosphate buffer (pH 7.4) for 30 min. The head of each rat was removed and stored in fixative for a minimum of 24 h at which time the dural coverings were removed and dissected into samples that included the middle meningeal vasculature. Samples were routinely processed and flat embedded in LX 112. Thick (1 um) sections from a minimum of 3 blocks per rat were stained with toluidine blue (0.5% aqueous).

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Allocentric to Egocentric Spatial Switching: Impairment in aMCI and Alzheimer's Disease Patients?

Current Alzheimer Research ◽

10.2174/1567205014666171030114821 ◽

2018 ◽

Vol 15 (3) ◽

pp. 229-236 ◽

Cited By ~ 8

Author(s):

Gennaro Ruggiero ◽

Alessandro Iavarone ◽

Tina Iachini

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Reference Frame ◽

Reference Frames ◽

Memory Task ◽

Spatial Representations ◽

The Novel ◽

Spatial Memory Task ◽

Switching Condition ◽

Normal Controls

Objective: Deficits in egocentric (subject-to-object) and allocentric (object-to-object) spatial representations, with a mainly allocentric impairment, characterize the first stages of the Alzheimer's disease (AD). Methods: To identify early cognitive signs of AD conversion, some studies focused on amnestic-Mild Cognitive Impairment (aMCI) by reporting alterations in both reference frames, especially the allocentric ones. However, spatial environments in which we move need the cooperation of both reference frames. Such cooperating processes imply that we constantly switch from allocentric to egocentric frames and vice versa. This raises the question of whether alterations of switching abilities might also characterize an early cognitive marker of AD, potentially suitable to detect the conversion from aMCI to dementia. Here, we compared AD and aMCI patients with Normal Controls (NC) on the Ego-Allo- Switching spatial memory task. The task assessed the capacity to use switching (Ego-Allo, Allo-Ego) and non-switching (Ego-Ego, Allo-Allo) verbal judgments about relative distances between memorized stimuli. Results: The novel finding of this study is the neat impairment shown by aMCI and AD in switching from allocentric to egocentric reference frames. Interestingly, in aMCI when the first reference frame was egocentric, the allocentric deficit appeared attenuated. Conclusion: This led us to conclude that allocentric deficits are not always clinically detectable in aMCI since the impairments could be masked when the first reference frame was body-centred. Alongside, AD and aMCI also revealed allocentric deficits in the non-switching condition. These findings suggest that switching alterations would emerge from impairments in hippocampal and posteromedial areas and from concurrent dysregulations in the locus coeruleus-noradrenaline system or pre-frontal cortex.

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