[IGSMAIL-1683] 7th IGS Governing Board Meeting in Rio de Janeiro

[G.]

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IGS Electronic Mail      Sun Sep 14  7:26:47 PDT 1997      Message Number 1683
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Author: G. Beutler
Subject: 7th IGS Governing Board Meeting in Rio de Janeiro

Dear Colleagues

The 7th IGS Governing Board meeting took place in the Copacabana Palace
Hotel in Rio de Janeiro on Friday, 5 September 1997.  The meeting took
place during the Scientific Assembly of the International Association of
Geodesy (IAG) from September 3 to 9, 1997. A very rich agenda asked for a
full day meeting of the IGS Governing Board.

Let me try to pick out and comment the essential agenda items of the
Governing Board Meeting without making the attempt to give a complete
report.

GPS time transfer proposal from US Naval Observatory
----------------------------------------------------
With a letter dated August 6, 1997 Dr.  Kenneth Johnston, Scientific
Director of the United States Naval Observatory (USNO), asked the IGS
Governing Board to present the proposal "IGS Pilot Project for Precise Time
Comparisons" to the IGS Governing Board at its Rio meeting.  The topic was
put on the agenda of the 7th IGS GB Meeting and Dr. Dennis McCarthy from
USNO was invited to present and comment the proposal to the Board.  In
essence USNO proposed to (quoted from the proposal)

"" ...
 * establish a UTC(IGS) realization that is a reliable reference
   time source to which all station and satellite clocks within the
   IGS can be accurately related and which is traceable to known
   timing standards such as UTC(USNO);

 * organize time transfer programs at other national timing
   laboratories and facilities to investigate the capabilities of
   GPS by comparison with independent techniques;

 * prepare and distribute regular reports on time transfer results
   obtained;

 * investigate the possibility of coordinating international time
   standardization using GPS.
  ...
  USNO proposes to organize and coordinate an international network of GPS
  receivers installed at national timing laboratories for the purpose of
  time transfer and comparison.  A working group (WG) consisting of
  representatives from the agencies involved would be formed to supervise
  the operations of the network and other activities.  Data from all the
  sites will be made available to the IGS community and some of these
  stations could also be considered primary fiducial clock sites for the
  IGS tracking network.
  ...
  USNO would plan that the pilot phase of this Project run until the end
  of 1999.  A final report would be prepared by USNO and other members of
  the WG and be submitted to the IGS Governing Board at its meeting
  closest to 31 December 1999.  In addition, an interim report would be
  submitted around late 1998 to describe progress achieved to that point.
  At the end of the pilot phase, possible future activities in this area
  will be considered.
  ...
  The point of contact for this proposal is Dr. McCarthy, USNO Director of
  Time.  The operational activities would be conducted by USNO staff from
  the Time Service Dept.  (Dr. Demetrios Matsakis, Head) and from the Earth
  Orientation Dept. (Dr. Jim Ray, Head).
  ..."

The IGS Governing Board viewed this proposal as a very positive and
constructive document. It fully endorses the project and proposes its
components (the Analysis Centers in particular) to contribute to the pilot
project.

It was stated in particular that the additional workload for IGS Analysis
Centers is minimal (at least at first sight) which is important, as
well.  The Governing Board expects that the pilot experiment will include
the entire "timing community", in particular the BIPM in Paris.  Assuming
that the USNO proposal is acceptable to this community the IGS Governing
Board is willing to formally establish the pilot project at its next
meeting in December in San Francisco.  (The complete text of the proposal
is available through the USNO).

Directions of the IGS: An IGS Retreat?
--------------------------------------
More and more proposals and pilot projects are proposed to the IGS GB
(e.g., the above timing proposal, the densification project, the LEO
project, the meteorology experiments (groundbased and space borne), the
GLONASS project (see below)). So far these projects were discussed one by
one by the IGS components and the IGS GB. Ivan Mueller proposed that the
IGS should establish a general policy in the area "directions of the IGS".
It was proposed to organize a one day "IGS Retreat" with a very limited
group of IGS Governing Board Members and Associates with the goal to come
up with a plan which then may be discussed by the entire IGS community and
the Board. A small comittee consisting of Ivan Mueller, Yehuda Bock, Bill
Melbourne and Ruth Neilan are setting up the agenda for this retreat by mid
October. Ruth Neilan is to set up the meeting and the chairman thinks of
ways how to give some input to this important committee ...

AC Coordinator Succession
-------------------------
Jan Kouba, IGS Analysis Coordinator, informed me by e-mail on July 30, 1997
that he was "approved for an Early Retirement Initiative" and that he would
retire on 31 March 1998. The IGS Governing Board was informed immediately
of this important development. At the GB meeting Jan Kouba told the
Governing Board that the Geodetic Survey Division of Natural Resources
Canada (NRCan) is willing to continue in its capacity as a Coordinating
Center for the IGS till the end of 1998 to facilitate a smooth transition
to another Cordinator resp. Coordinating Center.

Jan Kouba also pointed out that "the job" requires important "human
resources":  Yves Mireault is taking care more or less full time of the
daily workload, whereas Jan Kouba uses a good part of his time to actually
coordinate the work of analysis centers and to monitor the progress of
projects like, e.g., the pilot project on densification, or the transition
from ITRF94 to ITRF96, etc.

The chair first asked Jan to pass on the Governing Board's thanks to NRCan
for its offer to contribute to a smooth transition to a new coordinator.
The following procedure was proposed and accepted:

- According to the IGS Terms of Reference "the responsibilities for the
  Analysis Coordinator shall rotate between the Analysis Centers with
  appointments and terms specified by the Governing Board".

- A Call for Proposals will be sent out in September 1997 to the seven IGS
  Analysis Centers (in alphabetic order: COD, EMR, ESA, GFZ, JPL, NGS, SIO)
  to obtain a list of candidates by mid November (due date for the
  proposals).

- The received proposals are distributed to the GB Board members at least
  two weeks prior to the 8th IGS Governing Board Meeting in the week of
  December 8-12 in San Francisco (precise date and time not yet fixed).

- The new coordinator is elected at the IGS GB Meeting in December. The
  new and the old coordinator will work out a program to guarantee a smooth
  transition of IGS AC coordination in 1998.

- The responsibility for the coordination will remain at NRCan till the end
  of 1998. The new coordinator will take over on January 1, 1999.

The Call for Proposals is sent out to all Analysis Centers and all IGS
Analysis Centers (including NRCan) are encouaged to send in proposals.  The
chair expressed the Governing Boards feelings by pointing out how very much
pleased the Board and the entire IGS community is by the performance of the
current Analysis Coordinator and his team.  Analysis Coordination is one
of the crucial and essential tasks within the IGS.  The board hopes to find
a coordinator with a similar profile.

Elections to the IGS Governing Board / Election Procedure for a new Chair
-------------------------------------------------------------------------
The Governing Board positions currently held by Geoff Blewitt, Bjorn Engen,
and Carey Noll are open in the next election,  i.e., the 1997 election.

Ivan Mueller was asked to organize these elections at the GB Business
Meeting in December 1997.  He informed the board that meanwhile the list of
Associate members (the electing body for the board) was reviewed and
updated and that soon (in October 1997) the nomination procedure would be
conducted by e-mail.  "Normally" (i.e., if there are no tie situations) the
new members should be known before the December meeting of the board in San
Francisco. The new members will be confimed at the 8th GB meeting in SF.

At the same meeting, according to the IGS Terms of Reference, two other
members of the Governing Board will be elected upon recommendation of the
Central Bureau (positions currently held by Bob Schutz and Gerry Mader).

The current chairman of the Governing Board was telling everybody who
wanted to know (as a matter of fact also those who did not ask) that his
term as chairperson elapsed on 31 December 1997 and that, due to other
committments, he would not be available for a second term (see e.g. IGS
Mail, Message No. 1475).

Ivan Mueller pointed out that due to the circumstance that five GB members
are up for elections in December and that consequently the composition of
the board is not known at present it seemed not a straight forward matter
to start the nomination procedure for the position of the chair right now.
He and others also raised the concern that it would not be wise to have
a new IGS chairman "so to speak" simultaneously with the Analysis
Coordinator (see above topic).

In order to avoid such situations now and in future Ivan Mueller proposed
to re-elect the current chairman for exactly one more year (till 31
December 1998) and to allow it to elect the next (and this time actually
new) chairperson at the end of 1998 for four years.  This procedure would
allow it to elect the IGS Chairperson in years when there are (normally) no
Governing Board elections not only in 1998 but in future, as well.

After having stated that he would be avaliable for this limited time period
the chairman was asked to leave the room.  It seems that the Board
unanimously accepted this proposal -- which is why the inauguration party
for the new IGS Chair is postponed for one year.

AC Coordinator Report
---------------------
In his report Jan Kouba pointed out that the significant number of changes
performed on June 30, 1996 worked out very well.  The community is
meanwhile heavily relying on the availability of rapid orbits within 24
hours and on the final IGS products after only 11 days.  This change of
procedures obviously implied the addition of a daily cycle for the
coordinator, a significant increase of the workload and the "stress" for
analysis coordination.

In addition two new products have been introduced:  the IGS 2-day orbit
prediction (IGP) and the IGS LOD/UT1 combination.  The 2-day prediction is
in the average much better than the broadcast ephemerides.  With 30 to 50
cm rms the quality of IGP ephemerides is, as a matter of fact, for the
"normal" satellites (i.e., those not manoeuvred and not in eclipse)
probably very close to the quality of the final IGS orbits in the year
1992.

In collaboration with Jim Ray from USNO the analysis coordinator worked out
a procedure for using the LOD estimates of individual IGS Analysis Centers
to produce (more or less) unbiased combined daily IGS LOD estimates which
in turn may be used to extrapolate UT1-UTC (by integrating the LOD values).
A similar procedure was also developed by Daniel Gambis from the IERS
Central Bureau. Such algorithms seem to work very well -- in particular to
facilitate the IERS rapid products. After all: GPS-derived LOD values seem
to be considered useful! I personally believe that the same developmnet
will take place for GPS-derived nutation drift values -- but this would be
another story.

The IGS chair once again thanked Jan and his team from NRCan for his
excellent work in 1996/97. The IGS Annual Report for 1996 gives an
excellent and more copmprehensive overview of the Analysis Coordinator's
recent activities.

Central Bureau Report
---------------------
Ruth Neilan mentioned that the 1996 IGS report is very close to completion.
We all hope that it will be available by the end of September. This report
gives an excellent insight into the really very smooth functioning of the
service. For the first time the work of the regional IGS Associate Analysis
Centers is documented in this report. It is impressive to see what
progress was made in this pilot project in very short time.

Moreover the proceedings of the 1997 Analysis Center Workshop (held at JPL
in spring 1997) and the proceedings of the sea-level workshop are
approaching completion.  It is assumed that both documents will be
available by the end of this year.

Apart from that new IGS brochures in English and in Spanish were prepared and
distributed at the IGS booth in the exhibition hall of the symposium. It is
only fair to say that the IGS was well presented to the general scientific
community here and at other symposia.

Ruth also reported that some of the IGS network monitoring and engineering
duties are right now transferred from JPL to UNAVCO. This monitoring of
course has to be seen as a Central Bureau contribution to the IGS. It is
understood that monitoring is required for the entire IGS network, not only
for a subset of stations implemented by a particular organization.

Hatanaka Compression
--------------------
Werner Gurtner from the CODE analysis center and Yuki Hatanaka from GSI,
Japan were asked at the IGS business meeting in spring to organize and
coordinate tests with the new Hatanaka compression format.  The report
was presented by the chairman, a written version was distributed to the GB
members.

The report states that the RINEX compression scheme developed by Yuki
Hatanaka from GSI, Japan has been extensively tested by CDDIS, SIO, IGN,
IfAG, CIGNET, GSI, ESA, and CODE.  The new compression scheme reduces the
data volume (as compared to the normally compressed files) by a factor of
2-3, which considerably reduces the volume of data shipped around the world
by the IGS.

It seems that no serious problems were encountered during the very extended
test phase. That the tests were/are really extensive is (among other)
underlined by the fact that the CODE Analysis Center completely switched to
the Hatanaka format for its data analysis since June 1997, a change which
did not affect the quality of CODE results.

In the discussion it was mentioned that the Hatanaka compression scheme is
based on a "delta-format" which inherently bears some risks. This is
counterbalanced by a reduction of transmission times due to the shorter
files. Based on the experiences gained so far it was decided to proceed
along the lines proposed in the report:

- Werner Gurtner will send out through the IGS Report Series a report
  covering the experiences gained in the test phase and by making generally
  available the addresses where the current version for the new
  (de-)compression software for different computer platforms may be
  obtained. In the same e-mail other IGS centers are invited to join the
  test phase.

- The test will be evaluated a next time end of November 1997, an updated
  report will be prepared for the GB meeting end of November. In particular
  the approval of Analysis Centers and the Analysis Coordinator is
  required.

- Based on this report the GB will decide at its December meeting whether
  or not to switch the new scheme.

Assuming that the decision is made to switch to the new format:

- The new compressed RINEX files are used by all global and regional IGS
  data centers for data transfer starting February 1st, 1998 at the
  latest.

- The new compressed RINEX format is used for data transfer between
  individual stations and regional/operational centers starting March 1st,
  1998 at the latest.

- Finally, by May 1st, 1998 the availablility of standard compressed RINEX
  files may be terminated at Global Data Centers.

It is clear that the procedure must be stopped if unexpected difficulties
should occur.

The Board asked the chairperson to thank Yuki Hatanaka and Werner Gurtner
for their effort.

IGS Pilot Project on Densification
----------------------------------
Starting with Erathostenes (about 284 to 202 B.C.) Geoff Blewitt presented
a report prepared by him and P.B.H. Davies, C. Boucher, M.B. Heflin, T.
Herring and J. Kouba leading to the conclusion that the coordinate file
prepared by the three Global Associate Analysis Centers (University of
Newcastle (G. Blewitt and P.B.H. Davies), JPL (M.B. Heflin) and MIT (T.
Herring) are not only better (in the sense of an improved repeatability)
than the original contributions from the seven IGS Analysis Centers and the
RNAACs (regional associate ananlysis centers)) but also more reliable.
The paper was also presented at the IAG Scientific Assembly. It will be
published in the proceedings, but it is also available through G. Blewitt).

G. Blewitt also concluded that the pilot project is now sufficiently
stable to proceed to the next step, i.e., to terminate the pilot phase and
to establish a service-like activity.

It is required for this transition to
- ask the GNAACs to continue their work
- to define a unique, easy to understand official IGS product of the
  activity.

The chairman and the Analysis Coordinator were asked to send a letter to
the three GNAACs exploring the level of committment of the three GNAACs,
a small working group of the Governing Board consisting of Geoff Blewitt,
C. Boucher and J. Kouba were asked to define this unique IGS product and to
come up with a procedure how this product shall be generated.

The chairman pointed out that he is ferociously determined NOT to terminate
the pilot phase unless the rather long list of discrepancies published
every week by Jan Kouba will have zero entries! It really would be a shame
if "such a simple problem" could not sorted out on the IGS level. (It is
of course well known that in modern Space Geodesy it is easy to bridge
distances of a few thousand kilometers with accuracies of a few
millimeters -- it seems to be utterly difficult to really know where these
highly accurate points really are).

LEOs and the IGS
----------------
At the business meeting of the Governing Board in spring 1997 an IGS/LEO
working group was formed.  The Board confirmed its interest in the issue.
In view of the upcoming satellite missions involving GPS the issue will
become a burning one for many IGS institutions.  Coordination is required
and it is expected that the working group is taking care of that in the
near future.  The scheduled LEO workshop in Munich (see below) also is an
indication of the Governing Board's wish to have an active involvement of
the IGS in LEO matters.

Troposphere Activities
----------------------
Chris Reigber reported that troposphere estimates delivered by the IGS
processing centers are now regularly analysed at GFZ in Potsdam. The
results are interesting and stimulating for a continuation of the effort.
GFZ and a few additional institutions regularly make available RINEX-met
files for a considerable number of IGS stations.  It is highly desirable
that more institution follow the example.  It is clear, moreover, that a
concentrated effort should be made now to deploy high quality met equipment
in the IGS network.

GLONASS Activities
------------------
Again the chairman could present a short report prepared by Werner Gurtner
from CODE. The following activities related to the Russian GLONASS took
place within the IGS:

 - Since October 1995 the IGS CBIS is maintaining a compilation of the
   "Notice Advisory of Glonass Users (NAGUs)" (IGS Mail 1088).
 - In April 1997 the RINEX format was extended to properly include GLONASS
   observation and and broadcast orbit files (IGS Mail 1577).
 - In April 1997 the Global Data Center at IGN set up an area
   on one of their anonymous ftp accounts to accomodate GLONASS
   observations and/or combined GPS/GLONASS files.
   The information in these areas is publicly available.
 - Several institutions (like e.g., AIUB, IfAG, and Neustrlitz)
   gained considerable experience related to permanent observation and
   analysis of the GLONASS.

Werner Gurtner's report concludes with the recommendation to organize a
global GLONASS test campaign in 1998 using IGS sites or sites which are
collocated with the IGS network.

In the discussion it became clear that such a test campaign in 1998 must be
of a very experimental nature (in particular due to the uncertainties
associated with receiver and satellites availability).  It seeemed not wise
to ask the IGS components to spend too much time in such an experiment.  It
was said, however, that the IGS would strongly recommend its members to
work together with other groups willing to organize such an experiment.

Gerhard Beutler, in his capacity as president of CSTG (IAG/COSPAR
Commission on the Coordiantion of Space Techniques for Geodesy and
Geodynamics), proposed in CSTG Bulletin No. 13 (pages 12ff.) a
collaboration of CSTG and IGS for GLONASS-related activities.  The proposal
to ask CSTG to prepare a CSTG/IGS-proposal for a GLONASS test campaign in
late 1998 and to discuss the IGS-related aspects of the proposal at the
December Governing Board meeting was unanimously accepted.

IGS Network Performance
-----------------------
At the 1997 Analysis Center Workshop the Analysis Centers demonstrated that
some of the Global Stations of the IGS network did not perform on the
expected accuracy level, that even today the IGS recommendations for sites
(including data transmission) were not always followed by some stations.
Data latency become a much more important issue after June 30, 1996, when
the rapid IGS products became available after 24 hours. It still seems that
data availability can be much improved within the IGS. It was therefore
decided that a very small group consisting of Yehuda Bock (chair), Werner
Gurtner, Ruth Neilan, and a UNAVCO representative (t.b.d.) should study the
infrastucture-related problems of the IGS network and prepare a report in
fall 1997. The group is somewhat smaller than originally planned (in spring
1997), but it seems that this small group will be able to gather in the
September/October 1997 timeframe at JPL.

IGS AC Meeting/LEO Meeting
--------------------------
Finally it was agreed that the next IGS Analysis Center Workshop will be
held at ESOC in Darmstadt February 9-11, and that a LEO worshop will take
place immediately afterwards from February 12 to 14 at the DLR facilities
in Oberpfaffenhofen (near Munich).  The chairman thanked John Dow from ESA
and Chris Reigber from GFZ to organize these IGS gatherings.


[Mailed From: Gerhard Beutler <BEUTLER at aiub.unibe.ch>]