****************************************************************************** dorismail 16-Apr-2009 09:07:31 Message No 0596 ****************************************************************************** Author: "H. Fagard" Subject: Antenna centering control at Kerguelen Dear Colleagues, The antenna of the DORIS station at Kerguelen had to be replaced on November 26, 2008 because of a power loss on the 400 MHz channel (see DORISMail #0565). This change was carried out by the host agency, without supervision by a geodesist. The possible antenna offset was therefore unknown, until an IGN surveyor recently travelled to Kerguelen (on her one month boat trip starting at La Réunion and calling at Crozet, Kerguelen and Amsterdam). The 2 GHz phase center of the new antenna was found 3 mm west, 3 mm south of the initial position. The antenna verticality was then adjusted on March 31, 2009. All three antenna positions are identified by the same acronym (KETB) and the same DOMES number (91201S005). The vector from the initial (April 2007) position to the new, current position is: dE = 0.001 m ; dN = 0.001 m ; dh = 0.001 m. Hence the ITRF2005 @2000.0 coordinates for the current KETB position, derived from those published in the DORISMail #0569: X = 1406334.620 m Y = 3918142.539 m Z = -4816185.301 m (sigma: 2 mm for each component) I remind you the ITRF2005 velocities for this site: VX = -0.0054 m/y VY = 0.0000 m/y VZ = -0.0019 m/y SigVX = 0.0001 m/y SigVY = 0.0001 m/y SigVZ = 0.0001 m/y Here is a summary of the operation periods for each antenna location: Code DOMES Start End Comment KETB S005 2007-04-11 2008-11-26 Initial position KETB S005 2008-11-26 2009-03-31 New antenna, slightly offset KETB S005 2009-03-31 - Same antenna, vertical Best regards, Herve Fagard -- ====================================================================== Herve FAGARD e-mail : herve.fagard@ign.fr Institut Geographique National 94165 SAINT-MANDE CEDEX PHONE : + 33 1 43 98 81 48 FRANCE FAX : + 33 1 43 98 84 50 ====================================================================== Please do not reply directly to this message, but send comments and suggestions to IDS.central.bureau@cls.fr