[IGSMAIL-6507] igs08_1667.atx: Update including GLONASS-M satellite R746

[Robert Khachikyan]

Dear IGS colleagues!

The absolute IGS antenna correction file (igs08_wwww.atx) has been
updated. The new release is called 'igs08_1667.atx'. It contains the
following changes:

1) A single GLONASS-M satellite launched on 28 November 2011 was added
with a preliminary z-offset value of 245 cm:

R746 (R17)

2) A decommission date for the following satellite has been added:

R714 (R17): 19 December 2011

According to the Information-Analytical Centre, R746 replaced R714 this
morning:

> According to GLONASS System control center- a planned commissioning into constellation of Glonass-M satellite №746 (orbital slot №17) will begin at 01:00 (MT) 20.12.2011. The Glonass-M SC №714 will be transferred into orbital reserve.
http://www.glonass-ianc.rsa.ru/en/content/news/?ELEMENT_ID=217

Further information is given by Richard Langley:
https://listserv.unb.ca/cgi-bin/wa?A2=ind1112&L=CANSPACE&T=0&F=&S=&P=40347

The updated antenna correction model is available at
ftp://igs.org/pub/station/general/igs08_1667.atx
or
ftp://igs.org/pub/station/general/igs08.atx

With best regards,
Ralf Schmid and Robert Khachikyan
on behalf of the IGS Antenna Working Group