Transformation coordinate M from the international terrestrial reference system (ITRF) to the international
celestial reference frame (ICRF) : Celestial coordinates
( X Y Z) = M x Terrestrial coordinates ( x y z )
from 1962 to the current week the matrix can include the EOP of the
IERS combined series C04 (time resolution for EOP fluctuations is about
6 days), as well as diurnal and semidiurnal variations in UT1 and polar
motion produced by oceanic tides (IERS 2000 conventions). Accuracy is
0.0001", corresponding to 5 10-10 rad.
current week to 6 months afterthe matrix
is computed from the prediction of the polar motion and UT1-UTC.
outside the range
[1962, current week+ 6 months prediction]
the rotation matrix is restricted to the diurnal rotation and the precession-nutation
model IAU 2000
digit (12) of the matrix element corresponds to the pico radian level.
time resolution for the matrix variation is 14 nano seconds.