[IGSMAIL-5064]: FW: Call for ITRF2004 and supplementation of IERS CPP
"Ferland, Rémi"
RFerland at NRCan.gc.ca
Tue Dec 21 15:13:41 PST 2004
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IGS Electronic Mail 21 Dec 15:47:34 PST 2004 Message Number 5064
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Author: R. Ferland
Dear IGS Colleagues,
For those interested, I have included below a (reformatted/text only)
copy of the
IERS Call for participation for ITRF2004 and the Combination Pilot Project.
For those interested, could you inform Gerd and myself about the potential
extent
of your participation.
Season's Greetings,
Best Regards,
Remi,
-----Original Message-----
From: Schwegmann, Wolfgang [mailto:wolfgang.schwegmann at bkg.bund.de]
Sent: December 21, 2004 3:48
To: IERS Central Bureau; 'John Dow (E-Mail)'; "Schl=FCter, Dr. Wolfgang";
'Werner Gurtner (E-Mail)'; 'Hermann Drewes (E-Mail)'; 'Zuheir Altamimi
(E-Mail)'; 'Remi Ferland (E-Mail)'; 'Boucher, Claude (E-Mail)'; 'Chao,
Benjamin F. (E-Mail)'; 'Fagard, Herve (E-Mail)'; 'Feissel-Vernier, Martine
(E-Mail)'; 'Gambis, Daniel (E-Mail)'; 'Gendt, Gerd (E-Mail)'; 'Ma, Chopo
(E-Mail)'; 'McCarthy, Dennis D. (E-Mail)'; 'Noomen, Ron (E-Mail)';
'Nothnagel, Axel (E-Mail)'; Peter Schwintzer (E-Mail); 'Petit, Gerard
(E-Mail)'; 'Pugh, David (E-Mail)'; IERS CB Richter, Bernd; 'Rothacher,
Markus (E-Mail)'; 'Shelus, Peter (E-Mail)'; 'Souchay, Jean (E-Mail)';
'Vondrak, Jan (E-Mail)'; 'Wilson, Clark R. (E-Mail)'; 'Wooden, William
(E-Mail)'; 'Zhu, Sheng Yuan (E-Mail)'
Subject: RE: Call for ITRF2004 and supplementation of IERS CPP
Dear Colleagues,
Please note, that the call for long time series of weekly SINEX files
for ITRF2004 contains a wrong e-mail address for the Central Bureau.
The correct e-mail address of the Central Bureau to submit a time series
of SINEX files is:
central_bureau at iers.org
Copies should be submitted to:
ITRF PC: itrf at ensg.ign.fr
Markus Rothacher: rothacher at bv.tum.de
Claude Boucher: cbpro at club-internet.fr
Attached to this e-mail is a corrected version of the original call.
With best regards
Wolfgang Schwegmann
<<CfP_ITRF2004_CPP_211204.doc>>
-----Original Message-----
From: IERS CB Richter, Bernd On Behalf Of IERS Central Bureau
Sent: Friday, December 17, 2004 6:59 PM
To: John Dow (E-Mail); Schl=FCter, Dr. Wolfgang; Werner Gurtner (E-Mail);
Hermann Drewes (E-Mail); Zuheir Altamimi (E-Mail); Remi Ferland (E-Mail);
Boucher, Claude (E-Mail); Chao, Benjamin F. (E-Mail); Fagard, Herve
(E-Mail); Feissel-Vernier, Martine (E-Mail); Gambis, Daniel (E-Mail); Gendt,
Gerd (E-Mail); Ma, Chopo (E-Mail); McCarthy, Dennis D. (E-Mail); Noomen, Ron
(E-Mail); Nothnagel, Axel (E-Mail); Peter Schwintzer (E-Mail); Petit, Gerard
(E-Mail); Pugh, David (E-Mail); Richter, Bernd (E-Mail); Rothacher, Markus
(E-Mail); Shelus, Peter (E-Mail); Souchay, Jean (E-Mail); Vondrak, Jan
(E-Mail); Wilson, Clark R. (E-Mail); Wooden, William (E-Mail); Zhu, Sheng
Yuan (E-Mail)
Cc: IERS Central Bureau
Subject: Call for ITRF2004 and supplementation of IERS CPP
Dear Colleagues,
Enclosed you find the call for long time series of weekly
SINEX files for ITRF2004 and a supplementation of the IERS
Combination Pilot Project.
With best regards
Bernd Richter
CALL FOR LONG TIME SERIES OF "WEEKLY" SINEX FILES for
ITRF2004 and a supplementation of the IERS Combination Pilot
Project
December 16, 2004
Background
Long time series of weekly (session-wise for VLBI) SINEX solutions from
the various space geodetic techniques are very important for two types
of activities planned by the IERS:
1. ITRF2004: the generation of a new ITRF solution by the ITRF
Combination Centers under the responsibility of the ITRF Product
Center
2. IERS Combination Pilot Project Supplementation: it has become
evident, that long time series are essential for the rigorous
combination of the space techniques based on "weekly" solutions.
The long time series of SINEX files obtained as a result of this call will
be used for both activities.
ITRF2004
The most recent realization of the ITRF, namely ITRF2000, has been
performed in the year 2000 based on solutions of the space geodetic
techniques available at this time. Since that time quite some changes
can be noticed:
- A few years of additional data have become available
- New sites have joined the global network
- The processing strategies of the individual techniques have improved
- Velocities of more recent sites are not available or poorly
determined
in ITRF2000, which leads to the point that the individual techniques
start to use their own TRF realizations
- Some station positions are no longer valid because of events
(earthquakes, equipment changes creating discontinuities in the time
series, local tie updates, etc.).
- With the combination of "weekly" SINEX files a much more rigorous
combination of the space techniques is now possible, allowing for
more consistent IERS products and time series analysis, especially
through a better detection of discontinuous position changes.
- Experience in rigorous combination strategies has been or is gained
through the IERS SINEX Combination Campaign and the IERS
Combination Pilot Project (CPP).
In view of these circumstances it is a necessity to compute, with a high
priority in time, a new realization of the ITRS, which is taking benefit of
these new developments.
The ITRS/ITRF Product Center, together with the ITRF CCs is planning
to generate a new ITRF solution (ITRF2004) and solicits inputs from the
IERS Technique Services and their related Analysis Centers.
Unlike the previous ITRF solutions, ITRF2004 will be based on the
combination of time series of station positions and EOPs. The latter
should cover as long a time interval as possible but at least 6 years (say
1999-2004), a period over which we expect to have solutions containing
EOPs from all the techniques. This new ITRF solution will include all
available data for station positions, such as for instance VLBI and SLR
data since the eighties. Weekly or (daily VLBI) solutions will allow better
monitoring of non-linear motions of stations and other kind of
discontinuities in the time series.
IERS CPP Supplementation:
The combination centers taking part in the IERS CPP came to the
conclusion, that the weekly SINEX solutions now routinely generated by
the Technique Centers are not sufficient to generate combined inter-
technique solutions in a consistent way over many weeks. To
complement the IERS CPP routine activities with solutions of the past,
the IERS therefore asks for long term series. If possible, these series
should be consistent with the IERS CPP solutions.
If quasar coordinates can be included in the VLBI series, this would be
very welcome, too.
The IERS CPP supplementation should be a further step towards the
ultimate goal, namely a future rigorously combined, consistent IERS
product series, which we may call IERS200x:
"Integrated Earth orientation parameters, Radio sources, and Site
coordinates 200x"
and which can be represented by the formula
IERS200x =3D ITRF200x + EOP200x + ICRF200x
It will probably not be feasible to already obtain an IERS2004 solution,
including more than the ITRF2004, but the ITRF2004 is the most urgent
part and thus a planned product in any case.
The time series to be submitted by the Technique Centers (or individual
Analysis Centers) will give the material to test such an approach.
Depending on whether some SINEX file submissions will contain quasar
coordinates or no, the ICRF part will play no or only a minor role in the
analyses.
Long Time Series Contributions
Contributed time series (weekly/daily) solutions to be included in the
ITRF2004 and IERS CPP analyses should be provided in SINEX format
and comply with one of the following constraint categories:
- Solutions with removable constraints
- Loosely constrained solutions (constraint level: s > 1 m)
- Solutions with TRF minimum/inner constraints
- Free normal equations
The SINEX files have to follow the SINEX Version 2.0 format standard
and should contain for one week (Sunday to Saturday) - a session in
the case of VLBI - site coordinates, a set of EOPs for each day (offsets
and rates fitted over 24-hr intervals for polar motion, UT1-UTC, and
nutation, where only VLBI provides UT1-UTC and nutation offsets), and,
if possible, quasar coordinates. If the SINEX files contain the variance-
covariance matrix (eventually except minimal constraints or loose
constraints), all constraints applied to the solution should be given in the
a priori variance-covariance matrix.
Solicited solutions to be considered are of three types:
A) Official single-technique combined solutions from the Technique
Centers
B) If solutions of type A are not available, or for specific reasons
(longer time span, more stations, more homogeneous processing,
..) individual Analysis Center solutions are solicited under the
coordination of the corresponding Technique Center.
C) Solutions that result from a combination of various techniques at
the observation level may be submitted as well.
A description file
should be submitted together with the SINEX files.
Long Time Series Analyses and Results:
The ITRF Combination Centers (CCs) and all participants of the IERS
CPP will have access to the SINEX file time series to perform various
types of analyses.
ITRF2004 Analyses and Results:
The ITRF CCs, led by the ITRS/ITRF PC, are are in charge of the
generation of the ITRF2004 solution. Each CC should generate solutions
to be compared and validated among each other. The detailed
computation process will be agreed between the CCs in the frame of the
ITRF PC. The IERS Analysis Coordinator expertise is required for the
final product quality assurance.
The analysis strategy planned by the ITRS/ITRF PC will consist of the
following steps:
- Remove original constraints (if any) and apply minimum constraints
equally to all constrained solutions
- Use as they are the minimally constrained solutions
- Perform per-technique combinations (TRF + EOP) of each individual
time series: rigorously stacking the weekly solutions. The outputs of
this step will be full SINEX file per technique/AC, containing station
positions, velocities and daily EOPs.
- Identify and reject outliers and properly handle discontinuities,
using
break-wise approach
- Combine if necessary all solutions of a given technique into a
unique solution
- Combine the per-technique combinations adding local ties in
collocation sites. This global combination will constitute the
ITRF2004 solution.
The expected main results will be:
- Positions and velocities for a global network of tracking stations
and
related markers of the four techniques (VLBI, SLR, GPS, DORIS)
- Fully consistent EOPs: daily polar motion and their rates, UT1 and
LOD
- Per-technique solutions of station positions and velocities and daily
EOPs, with full variance/covariance information provided in SINEX
format.
- Residual time series as result from the per-technique time series
combinations
- Geocenter offset time series from satellite solutions (SLR, GPS,
DORIS)
>From the results mentioned above, a set of new official IERS products
will be selected
The IERS Directing Board will have to approve these selected official
products.
IERS CPP Analyses and Results:
Based on the long time series of SINEX files the IERS CPP participants
should come up with long time series of rigorously combined weekly and
multi-year SINEX solutions using different strategies. These solutions
should be validated by those groups that sent a proposal for the
validation step of the IERS CPP. The long time series should
complement the routine IERS CPP submissions and allow the
combination centers to study all their combination strategies and results
over long time intervals.
Instructions
The Technique Centers and individual Analysis Centers that intend to
contribute their long time series of "weekly" SINEX files should submit
these series by February 28, 2005 at the latest. Earlier submissions are
most welcome and very much encouraged !
To submit a time series of SINEX files please send an e-mail to:
IERS Central Bureau: central_bureau at iers.org
with a copy to:
ITRF PC itrf at ensg.ign.fr
Markus Rothacher: rothacher at bv.tum.de
Claude Boucher: cbpro at club-internet.fr
The e-mail should contain the detailed instructions on where the
solutions can be downloaded, their present naming convention, etc. The
submitted SINEX files will be archived in the IERS information and
database system and the ITRF PC.
Schedule:
December 2004 Dissemination of the Call for Participation
February 28, 2005 Deadline for solution submissions by
Technique/Analysis Centers
March 13, 2005 Start of feed back to contributors
May 15, 2005 Submission of ITRF solutions by the ITRF CCs, start
of comparison and validation phase
August 5, 2005 Final ITRF2004 solution ready after comparisons and
validations; various results available from the IERS
CPP.
Presentation of the new ITRF2004 and the IERS
CPP results at the IAG Scientific Assembly 2005
(Cairns, Australia)
October 2005: IERS Workshop 2005; evaluation of the CPP and
discussions concerning the transitions to new IERS
products; IERS Directing Board Meeting for
decisions.
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