[IGSMAIL-7124] igs08_1853.atx: Update including Block IIF satellite G072

[Ralf Schmid]

Dear IGS colleagues!

The absolute IGS antenna correction file (igs08_wwww.atx) has been 
updated. The new release is called 'igs08_1853.atx'. It contains the 
following changes:

1) The tenth Block IIF satellite launched on 15 July 2015 has been added:

G08 (G072)

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 2015068:
> NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2015068
> SUBJ: SVN72 (PRN08) LAUNCH JDAY 196
> 1. NANU TYPE: LAUNCH
> NANU NUMBER: 2015068
> NANU DTG: 151857Z JUL 2015
> SVN: 72
> PRN: 08
> LAUNCH JDAY: 196
> LAUNCH TIME ZULU: 1536
>
> 2. GPS SATELLITE SVN72 (PRN08) WAS LAUNCHED ON JDAY 196.
> A USABINIT NANU WILL BE SENT WHEN THE SATELLITE IS SET ACTIVE TO SERVICE.
http://www.navcen.uscg.gov/?Do=gpsShowNanu&num=2015068

spaceflightnow.com: Atlas 5 delivers GPS satellite 11,000 miles up
http://spaceflightnow.com/2015/07/15/recap-story-atlas-5-delivers-gps-satellite-11000-miles-up-2/

2) Two robot calibrations provided by Shanghai Huace Satellite 
Navigation Technology Ltd. have been added:

CHCC220GR       CHCD
CHCC220GR2      CHCD

The updated antenna correction model is available at
ftp://ftp.igs.org/pub/station/general/igs08_1853.atx
or
ftp://ftp.igs.org/pub/station/general/igs08.atx

The announced update with satellite antenna corrections for the new GNSS 
(Galileo, BeiDou, QZSS, IRNSS) will follow at the beginning of next week.

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