Subject: [IGSMAIL-1475] 6th IGS Governing Board Meeting in Paris (Oct 96)
From: G. Beutler
Date: Tue, 12 Nov 1996 23:59:20 PST

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IGS Electronic Mail      Tue Nov 12 23:59:20 PST 1996      Message Number 1475
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Author: G. Beutler
Subject: 6th IGS Governing Board Meeting in Paris (Oct 96)

Dear colleagues,

The 6th meeting of the IGS Governing Board took place on Wednesday, October
16, 1996 at the Obervatoire de Paris, France. The meeting was attached to
the 1996 IERS Workshop.

Let me try to summarize the highlights discussed at the 6th Governing Board
Meeting.

IGS Annual Report for 1995, Proceedings of the
1996 IGS Analysis Center Workshop
----------------------------------------------
In the Central Bureau Report Ruth Neilan circulated copies of the 1995 IGS
Annual Report, covering the second official year of IGS operations. The
new Annual Report was again edited by J.F. Zumberge et al. The IGS
Governing Board was very much pleased by this second annual report, which
again contains most valuable information about the IGS and which gives
an excellent overview of the remarkable progress made in 1995 (and early
1996). The IGS Governing Board was impressed by the consistent document
and the early availability of the document which we owe to Jim Zumberge
and his editorial team of JPL.

Ruth Neilan also mentioned that the proceedings of the 1996 IGS Analysis
Center Workshop (Silver Spring, March 1996) are more or less ready for
mailing. As some of us may remember the Silver Spring meeting really
deserved the label "workshop" because a lot of work was accomplished in
Silver Spring (IGSMail, No. 1266) and afterwards at the IGS Analysis
Centers in order to implement all the the agreed upon changes and
improvements, which actually were incorporated to the greatest extent by
all the IGS Analysis Centers.

IGS as a FAGS Service
---------------------
Some time ago the IGS applied to become an official FAGS Service
(Federation of Astronomical and Geophysical Data Analysis Services). In a
letter dated May 10, 1996 the IGS was informed that the FAGS Council, at
its meeting on April 22, 1996 in London, had decided to give FAGS
recognition to the IGS beginning with January 1st, 1996 (!). This means
that the IGS is an official FAGS Service from now on.

In the same letter we were informed that Dr. David Pugh, Southhampton
Oceanographic Centre, was designated as the FAGS representative to the IGS
Governing Board. This created a minor problem because, according to the
IGS Terms of Reference, there is just one slot for an IAG/FAGS
representation in the IGS Governing Board. It is well known that Prof.
Ivan I. Mueller was appointed by IAG at the IUGG General assembly in
Boulder, 1995 to fill this position for 1995-1999. The problem was solved
in an unbureaucratic way by the Board by considering both, Ivan I. Mueller
and David Pugh as Governing Board members untill 1999, when IAG/FAGS will
delegate only one person to the IGS Governing Board. The IGS Governing
Board unanimously accepted this unconventional proposal and was very much
pleased that Ivan I. Mueller was willing to continue serving on the IGS
Governing Board.

Elections into the Governing Board by the End of 1997
-----------------------------------------------------
In order to have a good blend of both, continuity and new ideas, the
elected IGS Board members were given staggered terms, which is why
elections have to be organized every two years. The next elections will
have to be organized in 1997 for those members whose terms will start on
January 1st, 1998. In addition the Chairman reminded the Board that his
term will elapse on 31 December, 1997 and that (due to other committments)
he is not available for a second term.

According to the IGS Terms of Reference the elections (of the Governing
Board members and of the Chairperson) will be conducted by a nominating
committee of three members, the chair of which is appointed by the Chair of
the IGS Governing Board. This appointment is expected to take place at the
IGS Business meeting attached to the AGU Fall meeing 1996.

AC Coordinator Report
---------------------
Although Dr. Jan Kouba, the IGS Analysis Center Coordinator, was not able
to attend the 1996 Analysis Center Workshop he was the key responsible for
the organization and implementation of the changes and to watch the
implementation deadline (30 June, 1996, begin of GPS Week 860). He
reviewed the work that had to be accomplished (new definition of Rapid IGS
Products (delay 24 hours) and Final IGS Products (delay maximum of 10
days), transition from ITRF93 to ITRF94, use of an agreed upon models for
daily and sub-daily terms for earth rotation, use of JGM-3, adoption of
SINEX 1.0, etc.) and pointed out that these changes would undoubtedly lead
to a more consistent set of solutions but that there is always "real work"
involved with such strategic decisions. The Board thanked the AC
Coordinator for his great work and asked him in term to pass on the
appreciation of the Board for the accomplished work to the IGS Analysis
Centers.

The Coordinator then gave an overview over the Pilot Project on the
"Densification of the ITRF using Regional GPS Networks" which started in
Fall 1995 and which entered into a new phase on 30 June 1996:  Since
that time new IGS Associate Analysis Centers submit their solutions to the
IGS Global Network Analysis Centers (GNAACs). Two GNAACs, University of
Newcastle (Geoff Blewitt and Phil Davies) and MIT (Tom Herring) regularly
analyse the IGS AC and AAC results every week. Jan Kouba recommended to
extend the Pilot phase beyond the end of 1996 in order to gain more
experience with the AAC solutions. The Board shared this opinion and
decided to continue the Pilot project "Densification of the ITRF using
Regional GPS Networks" at least till mid 1997.

Another highlight in the AC Coordinator's report was was a short review of
yet another very promising AC activity, namely the generation of predicted
orbits. It became obvious that reliability is THE key issue in this
"business" and that several contributions are required to generate a
reliable IGS product in future. At present there are three Analysis Centers
regularly producing 1- and 2- day predictions with accuracies clearly
better than that of broadcast orbits. The AC Coordinator continues to
monitor these predicitons (remember that he was given the task "to study
options leading to the production of an official IGS predicted orbit").

Data Center Report
------------------
Carey Noll, Data Center Representative on the Board, gave an impressive
report of the performance of the IGS Data Centers. The Analysis Centers
heavily rely on the timely availability of the data stemming from the IGS
network. From the re-definition of Rapid and Final Products, which are
available much earlier since 30 June 1996 (see comments above) and from the
availability of predictions based on data which often are not older than 12
hours one must conclude that the IGS Data Centers are performing very well.
The Board thanked Carey for her personal effort and asked her to pass on
the Board's appreciation to all IGS Data Centers.

Additional work needs to be done on the Quality Control (QC) Routines
routines, at what level they should be executed, and what actions should be
taken when data fails a test (warning, removal, etc.). A close interaction
between the Central Bureau and the Data Centers is reqired.

Carey Noll reminded the board that 36 sites were identified in IGS-Mail
No. 1318 for which a (very) rapid delivery was required. The success was
not overwhelming, so far, and it seems that more work has to be done.

Carey Noll mentioned that problems occasionally showed up at individual
Data Centers, when key persons were "out of town". Such difficulties
should no longer occur (a corrective plan was worked out by the centers).
Also, Carey Noll was concerned that even today (after more than four years
of IGS operations) the header information in the IGS Rinex files has not
yet reached the level of reliability of the IGS products. The IGS Central
Bureau together with the IGS Data Centers and the IGS Analysis Centers must
work together to remove such problems.

NASA Request to IGS Support Role for Space Missions
---------------------------------------------------
With a letter dated July 2, 1996 John Labrecque from NASA Headquarters
asked the IGS Governing Board to review and identify its position in the
field "GPS receivers on Low Earth Orbiters".

The request was passed on in July from the Governing Board to the (already
existing) working group consisting of Bill Melbourne, John Dow and Chris
Reigber asking it to come up with a position paper for the 6th Governing
Board Meeting. This team, together with Mike Watkins and John Labrecque
came up with a document called "IGS White Paper on Low Earth Orbiting GPS".
When reading this paper it becomes crystal-clear that space-borne
applications of the GPS will become rather common in future and that the
scientific implications, within and outside the scope of space geodesy, are
remarkable.

The white paper concluded by asking the IGS to consider:

1. Broaden the participation within the IGS and its Governing Board to
   include atmospheric and navigation agencies and institutions ...
2. Encourage the enhancement of the IGS constituent facilities including
   the IGS Global Network, the Analysis Centers and the Data Centers  to
   provide optimum support to spacebased applications.
3. Encourage the participants of the various groups developing satellites
   to carry the appropriate GPS receiver hardware.
4. Encourage the development of GPS occultation science through workshops,
   the development of standards, data exchange formats, data policy, etc.

The "IGS White Paper" was discussed at length at the GB Meeting. Short
statements by the Analysis Center Representatives present at the Board
Meeting revealed that there indeed is great interest in spaceborne
applications. The general opinion within the board clearly favours at
least some of the developments recommended above.

On the other hand, it was recognized that such developments are a major
undertaking and that there is a lot of work involveld for the existing IGS
structures, which are under considerable pressure already now. It was
therefore decided that the paper should first be made available to the key
IGS components (Data Centers, Analysis Centers, etc.) and that specific
questions should be asked (level of anticipated involvement, etc.). The
topic should then be brought on the agenda (perhaps with 1-2 sessions) at
the next IGS Analysis Center Workshop (spring 1997). Based on the feedback
from the IGS components and on the outcome of the next IGS workshop the
Governing Board should be in a position to get a clearer picture, not only
of the policy to follow but also of the next concrete steps to be taken in
this field of GPS applications.

Atmosphere Issues
-----------------
A closer contact with the atmosphere community, with UCAR (University
Consortium of Atmospheric Research, Boulder, CO) in particular, could be
established by defining points of contacts within the IGS (Dr. Gerd Gendt
from GFZ Potsdam) and within UCAR (Dr. Chris Rocken from University of
Colorado in Boulder) to optimize the estimation of the precipitable water
content using the IGS network. We hope that this will lead to an optimized
routine procedure to deal with ground based GPS meteorolgy within the
IGS, in future.

The activities to coordinate ionosphere resarch within and outside IGS were
continued as well. John Dow, who is coordinating these activities at
present, informed the Board that the new Data Exchange Format IONEX is
being developed by a rather active group and that ionosphere models are
routinely produced by some groups.

Closing Remarks
---------------
The above summary can only give an incomplete picture of the discussions
which took place at the GB Meeting. Many more issues which may become of
interest in the near future (like the availability of the Russaian GLONASS)
were mentioned, but, in view of more urgent business, not thoroughly
discussed. Looking back at the Governing Board meeting and at the
developments that took place within the last few months one must conclude
that the IGS is a very healthy organization still in a rather rapid
development. It will be of greatest importance not to endanger a healthy
development by exhausting the essential IGS components.

                                                    Gerhard Beutler
                                                    Chair,
                                                    IGS Governing Board

[Mailed From: Gerhard Beutler <[email-masked]>]