****************************************************************************** dorismail 02-Mar-2015 15:12:48 Message No 0963 ****************************************************************************** Author: "Soudarin Laurent" Subject: New 4-letter code ending with letter C for DORIS ground station Dear colleagues Here are some details on the recently deployed antennas whose 4-letter codes end with the letter C. In the frame of permanent performance validation and improvement of the DORIS system, a characterization of DORIS STAREC ground antennae was performed over years 2013 and 2014. This leads to a new phase law correction that was provided (http://ids-doris.org/analysis-documents.html#phaselaw). During this characterization, it appeared that there was a dispersion in mechanic mounting of STAREC antennae. This dispersion implies an increase of the error budget link to the phase law correction. To improve the error budget, a work has been performed with the antenna manufacturer. The manufacturing process has been consolidated and thus, the budget error has been improved. (Cf. http://ids-doris.org/images/documents/report/ids_workshop_2014/IDS14_s2_Tourain_DORISgroundAntennasCharacterizationAndImpact.pdf ) DORIS STAREC antenna are produced since 2014 July with this consolidated process. This means that they have the same characteristics, but with an improved error budget. In order to clearly indicate sites equipped with those antennae, it has been decided to name those sites with a 4-letter code ending with letter C. So now there are 3 types of 4-letter codes : XXXA : site equipped with Alcatel antenna (no longer used) XXXB : site equipped with STAREC antenna, former error budget XXXC : site equipped with STAREC antenna, improved error budget. But it is important to note that there is no design difference between type "B" and type "C", they have the same specifications.=20 The distance between the 2 Ghz phase center and the DORIS reference plan stays unchanged (see ftp://ftp.ids-doris.org/pub/ids/stations/antennas.pdf ). Such antennae with improved error budget are being deployed on the network. The first four are PDNC (Ponta Delgada), OWEC (Owenga), ROWC (Rothera), KEUC (Kerguelen). They will progressively replace the type "B" antennas. Cédric Tourain and Laurent Soudarin