Compute the Earth rotation matrix  


updated on December 2007

Include combined EOP C04 (1962 - today + 6 months prediction) :
Celestial pole offsets   UT1 - UTC   Polar motion

Include diurnal and semidiurnal variations produced by ocean tides in polar motion and UT1 (IERS conventions 2000)

Civil date :     year   month   day

UTC :       h   min   s

Real time
stop   yes 




                               2012 5 20     16 h 33 min 13 s   UTC 
                 
-0.600054079259    -0.799958492301     0.001229861818 
 0.799959080231    -0.600054555381    -0.000022838411 
 0.000756253967     0.000970134847     0.999999243459

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.

  • from the 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

  • The last digit (12) of the matrix element corresponds to the pico radian level. Corresponding time resolution for the matrix variation is 14 nano seconds.