[IGSMAIL-6185] Preliminary version of IGS08

[Paul Rebischung]

Dear Colleagues,

Following the release of ITRF2008, a preliminary version of the future IGS08
has been designed. 241 current and former IGS stations from ITRF2008 were
retained as potential IGS RF stations.

The main selection criteria were:
- Geographical location
- "ITRF2008 quality" (data span, number of discontinuities, velocity
accuracy, residual time series...)
- Equipment (type of antenna calibration, GLONASS capability, atomic clock,
collocation with other techniques...)
- Belonging to IGS05

A table with information on all IGS stations in ITRF2008 can be found at:
ftp://igs-rf.ign.fr/pub/IGS08/ITRF2008-IGS.xls
Stations are classified into 4 groups:
1 - "Selected without reserve"
2 - "Selected with reserve" (stations selected in spite of one or more
unsatisfied criteria)
3 - "Rejected with reserve" (stations which could have been selected but
were left aside in favour of other neighbour stations)
4 - "Rejected without reserve" (stations which could not be selected because
of a poor "ITRF2008 quality")

A list of selected stations as well as illustrations can be found in the
same ftp directory:
- IGS08.txt: List of the 241 retained stations (SINEX SITE/ID block)
- IGS08.png: Map showing the selected stations among all IGS stations in
ITRF2008
- IGS08_glonass.png: Map showing the distribution of GLONASS capable
stations among selected stations
- IGS08_hourly.png: Map showing the distribution of hourly stations among
selected stations
- IGS08_availability.pdf: Maps showing the availability of selected stations
over years

We want to stress the preliminary nature of this selection. Comments and
revisions were already made within IGS, but the discussion is still open.
Please feel free to make any comments!

Best regards,

Paul Rebischung, Bruno Garayt,
igs-rf at ign.fr