# [Volute] r4914 - trunk/projects/time-domain/time-series/note

Volute commit messages volutecommits at g-vo.org
Tue Apr 10 15:51:47 CEST 2018

Author: lmichel
Date: Tue Apr 10 15:51:47 2018
New Revision: 4914

Log:

Modified:

==============================================================================
--- trunk/projects/time-domain/time-series/note/appendixAda.tex	Tue Apr 10 15:51:12 2018	(r4913)
+++ trunk/projects/time-domain/time-series/note/appendixAda.tex	Tue Apr 10 15:51:47 2018	(r4914)
@@ -19,7 +19,7 @@
GPS   & (Global Positioning System) runs (approximately) synchronously with TAI; GPS $\approx$ TAI - 19 s\\
TCG   & (Geocentric Coordinate Time) TT reduced to the geocenter, corrected for the relativistic effects of the Earth rotation and gravitational potential; TCG runs faster than TT at a constant rate.\\
TCB   & (Barycentric Coordinate Time) derived from TCG by a 4-dimensional transformation, taking into account the relativistic effects of the gravitational potential at the barycenter (relative to that on the rotating geoid) as well as velocity time dilation variations due to the eccentricity of the Earth orbit, thus ensuring consistency with fundamental physical constants; Irwin \& Fukushima (1999) provide a time ephemeris.\\
-TDB   & (Barycentric Dynamical Time) runs slower than TCB at a constant rate so as to remain approximately in step with TT; runs therefore quasi-synchronously with TT, except for the relativistic effects introduced by variations in the Earthâ€™s velocity relative to the barycenter; when referring to celestial observations, a pathlength correction to the barycenter may be needed which requires the Time Reference Direction used in calculating the pathlength correction.\\
+TDB   & (Barycentric Dynamical Time) runs slower than TCB at a constant rate so as to remain approximately in step with TT; runs therefore quasi-synchronously with TT, except for the relativistic effects introduced by variations in the Earth velocity relative to the barycenter; when referring to celestial observations, a pathlength correction to the barycenter may be needed which requires the Time Reference Direction used in calculating the pathlength correction.\\