[IGSMAIL-6676] igs08_1710.atx: Update including reactivated Block IIR-M satellite SVN49/PRN27

[Robert Khachikyan]

Dear IGS colleagues!

The absolute IGS antenna correction file (igs08_wwww.atx) has been 
updated. The new release is called 'igs08_1710.atx'. It contains the 
following changes:

1) According to NANU 2012064 BLOCK IIR-M satellite SVN49 "will resume 
transmitting L-band utilizing PRN27 on approximately 18 OCT 2012". 
Therefore, the following satellite has been added to igs08.atx:

G27 (G049)

Source:
> NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2012064 NANU TYPE: GENERAL
> *** GENERAL MESSAGE TO ALL GPS USERS ***
> On approximately 18 OCT 2012 SVN49 will resume transmitting L-band 
> utilizing PRN27.  At L-band activation, SVN49/PRN27 will be unusable 
> until further notice.  Additionally, no broadcast almanacs will 
> include SVN49/PRN27.  Future NANUs will inform users of any changes to 
> the above-stated status.
http://cgls.uscg.mil/pipermail/nanu/2012-October/001449.html

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

G27 (G027): 17 October 2012

Although officially removed from the GPS constellation on 6 October 
2012, SVN27 didn't stop signal transmission before 17 October 2012 
according to the IGS tracking statistics provided by CODE 
(ftp://ftp.unibe.ch/aiub/igsdata/odata_gnss_day.txt).

Source:
> GPS SATELLITE SVN27 (PRN27) WAS UNUSABLE AS OF JDAY 280 (06 OCT 2012)
>      AND REMOVED FROM THE GPS CONSTELLATION ON JDAY 280 (06 OCT 2012).
http://cgls.uscg.mil/pipermail/nanu/2012-October/001448.html


The updated antenna correction model is available at
ftp://igs.org/pub/station/general/igs08_1710.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