ISO 19161-1-2020 pdf free.Geographic information — Geodeticreferences — International terrestrial referencesystem(ITRS).
This document provides the basic information and the requirements related to the InternationalTerrestrial Reference System (ITRS), its definition, its realizations and how to access and use theserealizations.
This document:describes ITRS following the definitions and terminology adopted by the International Union of
GeodesyandGeophysics(1UGG),the InternationalAssociation ofGeodesy(IAG)andthe InternationalAstronomical Union (IAU);
describes different categories of ITRSrealizations its primary realization,labelled the InternationalTerrestrial Reference Frame (ITRF), other existing realizations of reference systems that aremathematically derived from the ITRS, and realizations that are aligned to the lTRF, such as GNSS-specific reference frames;categorizes procedures for realizing the ITRS.
geocentric terrestrial reference system GTRS:system of geocentric space-time coordinates within the framework of General Relativity, co-rotatingwith the Earth and related to the Geocentric Celestial Reference System by a spatial rotation whichtakes into account the Earth’s orientation parameters.
computational process that determines,directly from measurements,the geodetic coordinates ofpoints (absolute positioning), or that derives geodetic coordinates of points from previously determinedgeodetic coordinates (relative positioning)
numerical representation of the trajectory of the centre of mass of an Earth orbiting artificial satelliteexpressed in an Earth centred terrestrial reference frame (3.5)
realization of a terrestrial reference system (TRS)(3.6), by specifying its origin, orientation, scale, andits time evolution
Note 1 to entry:The realization is achieved through a set of physical points with precisely determined coordinatesin a specific coordinate system(3.1), which may include the rate of coordinate change.
Note 2 to entry: The realization is called static when no rates of coordinate change are defined, and kinematicwhen rates of coordinate change are defined without considering the underlying forces causing the motion.Therealization may be called dynamic when these external forces are considered.”Dynamic” is also used colloquiallyto describe both the dynamic and kinematic cases without distinction.terrestrial reference systemTRS:set of conventions defining the origin, scale, orientation and time evolution of a spatial reference systemco-rotating with the Earth in its diurnal motion in space
Note 1 to entry: The abstract concept of a TRS is realized through a terrestrial reference frame(3.5).
Note 2 to entry: In such a system, positions of points attached to the solid surface of the Earth have coordinateswhich undergo only small variations with time, due to geophysical effects (tectonic or tidal deformations).Inthe Newtonian framework, the physical space is considered as a Euclidean affine space of dimension 3, with anorigin, a scale and an orientation.ISO 19161 pdf download.