BACK
HOME SHOW THIS PAGE

IERS-OP WEB SERVICE



Warning : The web service clients given below only works under Linux with PHP installed


1- Leap second WebService

   This webservice gives the current value of UT1-UTC, the date of the last leap second 
   and the date of the next leap second. If no leap second is scheduled, then it ouputs 
   "Not scheduled". This webservice relies on the information of the last Bulletin C and the 
   current date.


  - Address of the webservice server: 
  
      http://hpiers.obspm.fr/eop-pc/webservice/leap_second_server.php	

      Name of the function : LeapSecond
      Input variables      : No variable input
      Output variables     : UT1_TAI (UT1- TAI), Last_leap_second, Next_leap_second 


  - Exemple of a client using this webservice: 
  	
      http://hpiers.obspm.fr/eop-pc/webservice/leap_second_client.php


  - How to use this webservice :

      * download the php client on your computer : leap_second_client.php
	
      * download nusoap.php : http://hpiers.obspm.fr/eop-pc/webservice/nusoap.php
	
      * execute within your program or at your terminal the command : php leap_second_client.php



2- Earth orientation parameters from civil date (combined series C04 - click here for description)
- Address of the webservice server : http://hpiers.obspm.fr/eop-pc/webservice/server_EOP2.php Name of the function : C04fromDate Input variables : theyear (YYYY), themonth (MM), theday (DD) Ouput variables : MJD, x("), y" , UT1UTC(s), LOD(s), dX("), dY("), xerr("),yerr("), UT1UTCerr("), LODerr(s), dXerr("), dYerr(") - Exemple of a client using this webservice: client_EOP2.php - How to use this webservice : * download this php client on your computer: client_EOP2_cmd.php * download nusoap.php: nusoap.php * execute inside your program or in your terminal this command example (change the date): php client_EOP2_cmd.php 2011 12 31
3- Earth Orientation Matrix at a given instant - see also
- Address of the webservice server: http://hpiers.obspm.fr/eop-pc/webservice/server_MATRICE_EOP.php Name of the function : MATRICEfromDate Input variables : year(YYYY), month(1-12), day(1-31), hour(0-23), minute(0-59), second(0-59), pm (0-1), ut (0-1), nut (0-1), tides (0-1) Ouput variables : MJD, x("), y(") , UT1UTC(s), LOD(s), dX("), dY("), xerr("),yerr("), UT1UTCerr("), LODerr(s), dXerr("), dYerr (") - Example of a php client calling this webservice: http://hpiers.obspm.fr/eop-pc/webservice/files/client_MATRICE_EOP.php - How to use this webservice: * download this php client on your computer: client_MATRICE_EOP_cmd.php * download nusoap.php: nusoap.php * execute inside your program or in your terminal this command example (change the values): php client_MATRICE_EOP_cmd.php 2011 12 31 23 59 59 1 0 1 0
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 ) We use the FORTRAN CODE of the VLBI analysis Software GLORIA developped by Anne-Marie Gontier (Paris Observatory), and compatible with the IAU 2000 resolutions
  • from 1962 to the current week the matrix can include the whole EOP set of the IERS combined series C04 (daily step, 0hUTC, time resolution for such EOP fluctuations is about 6 days), as well as diurnal and semi-diurnal effects produced by ocean tides, which amount about 0.001". Accuracy is 0.0001", corresponding to 5 10-10 rad. In turn the time resolution of the matrix can reach approximatively 6 hours. Bewteen two dates at 0hUTC the EOP are interpolated according to a cubic spline.
  • from the current week to 6 months after the 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.
  • Components of the instantaneous rotation vector are deduced from the orientation matrix and its time derivative.