****************************************************************************** dorismail 25-May-2007 13:47:58 Message No 0497 ****************************************************************************** Author: "H. Fagard" Subject: Antenna raising at Amsterdam Dear Colleagues, The DORIS antenna at Amsterdam (TAAF = French Antarctic and Austral Territories), installed on a concrete pillar, was raised by 15 cm in order to remove the N-type bent adaptors located at the base of the antenna. The antenna moving took place on April 17, 2007, but transmissions could not be activated immediately because of a failure of the beacon's screen lighting, which is now solved. The acronym for the new reference point is AMUB. The DOMES number for the new antenna reference point is 91401S004. The vector from AMTB (initial position between March 29, 2001 and November 24, 2005 - see below) to AMUB is exactly dE = dN = 0; dh = 0.151 m. Hence the ITRF2000, 1997.0 coordinates for AMUB: X = 1086063.032 m Y = 4927948.669 m Z = -3887840.068 m (sigma: 2 cm) Because the ITRF2000 velocities were biased by the antenna tilt which affected the AMSB antenna, here are the ITRF2005 ones: VX = -0.0109 m/y VY = 0.0039 m/y VZ = -0.0031 m/y SigVX = 0.0005 m/y SigVY = 0.0004 m/y SigVZ = 0.0004 m/y The former antenna - AMTB - 2 GHz phase centre was found slightly offset (6 mm east, 5 mm south) following an antenna change which took place in November 2005, without any centring control at that time. As the antenna history has been somewhat eventful at this site, the following summary may be useful to the analysis centres: Code DOMES Model Start End Comment AMSA S001 Alcatel 1987-02-01 1997-04-21 AMSB S002 Starec 1997-04-21 2001-03-28 Progressive tilt (1) AMTB S003 Starec 2001-03-29 2005-11-24 Stable and centred AMTB S003 Starec 2005-11-24 2007-04-17 Stable and offset (2) AMUB S004 Starec 2007-04-17 (current) Raised by 15 cm (1) 2 GHz phase centre: 4 mm towards north, 64 mm towards west at the end of this time period, see DORISMail #0128 (2) 2 GHz phase centre 7 mm towards south-east, see above. 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