[IGSMAIL-7249] igs08_1884.atx: Update including Block IIF satellite G070

[Ralf Schmid]

Dear IGS colleagues!

The absolute IGS antenna correction file (igs08_wwww.atx) has been 
updated. The new release is called 'igs08_1884.atx'. It contains the 
following change:

The twelfth and last Block IIF satellite launched on 5 February 2016 and 
already active since 10 February 2016 has been added:

G32 (G070)

The following PRELIMINARY phase center offset (PCO) values were assigned:

PCO_X =  39.4 cm
PCO_Y =   0.0 cm
PCO_Z = 160.0 cm

NANU message 2016011:
> NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2016011
> SUBJ: SVN70 (PRN32) LAUNCH JDAY 036
> 1. NANU TYPE: LAUNCH
> NANU NUMBER: 2016011
> NANU DTG: 051404Z FEB 2016
> SVN: 70
> PRN: 32
> LAUNCH JDAY: 036
> LAUNCH TIME ZULU: 1338
>
> 2. GPS SATELLITE SVN70 (PRN32) WAS LAUNCHED ON JDAY 036.
> A USABINIT NANU WILL BE SENT WHEN THE SATELLITE IS SET ACTIVE TO SERVICE.
http://www.navcen.uscg.gov/?Do=gpsShowNanu&num=2016011

losangeles.af.mil: Final GPS IIF satellite joins constellation
http://www.losangeles.af.mil/news/story.asp?id=123468882


The updated antenna correction model is available at
ftp://ftp.igs.org/pub/station/general/igs08_1884.atx
or
ftp://ftp.igs.org/pub/station/general/igs08.atx
A separate release without the MGEX extension is no longer provided.

As regards the naming of GLONASS satellites, the following was 
recommended by the IGS Workshop in Sydney:
"In order to guarantee unique IGS space vehicle numbers for GLONASS, 
GLONASS numbers "701..." (GLONASS-K) and "750..." (GLONASS-M) are 
converted to "R801..." and "R850...", respectively."

According to that recommendation, the following two satellites will be 
renamed with the next release of igs08.atx:
R754/R18 (2014-012A) --> R854
R755/R21 (2014-032A) --> R855
If you expect a problem that deserves closer attention, please let me know!

Sorry for the delay in adding G070 to igs08.atx!

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