| Date: | 2004-12-23 17:31:00 | |
| Sender: | Zuheir Altamimi <Schwegmann, Wolfgang [mailto:wolfgang.schwegmann@bkg.bund.de]> | |
| Subject: | [SLR-Mail] No. 1286: Call for ITRF2004 and supplementation of IERS CPP | |
| Author: | Zuheir Altamimi | |
| Content: | ******************************************************************************** SLR Electronic Mail 2004-12-23 17:31:00 UTC Message No. 1286 ******************************************************************************** Author: Zuheir Altamimi Subject: Call for ITRF2004 and supplementation of IERS CPP Subject: RE: Call for ITRF2004 and supplementation of IERS CPP Subject: Call for ITRF2004 and supplementation of IERS CPP Dear IDS, ILRS and IVS Colleagues, For your consideration, I draw your attention to the IERS call for participation for ITRF2004 and the Combination Pilot Project. Please find below the formated text of the call issued by the IERS Central Bureau. Happy Christmas and my best wishes for the New Year 2005. Regards Zuheir -- ---------------------------------------------------------------------- Zuheir Altamimi Email : altamimi@ensg.ign.fr Institut Geographique National Phone : 33 1 64 15 32 55 ENSG/LAREG FAX : 33 1 64 15 32 53 6-8 Avenue Blaise Pascal 77455 Champs-sur-Marne, FRANCE ---------------------------------------------------------------------- -----Original Message----- From: Schwegmann, Wolfgang [mailto:wolfgang.schwegmann@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@iers.org Copies should be submitted to: ITRF PC: itrf@ensg.ign.fr Markus Rothacher: rothacher@bv.tum.de Claude Boucher: cbpro@club-internet.fr Attached to this e-mail is a corrected version of the original call. With best regards Wolfgang Schwegmann < -----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 ofthis 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@iers.org with a copy to: ITRF PC itrf@ensg.ign.fr Markus Rothacher: rothacher@bv.tum.de Claude Boucher: cbpro@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. From: Zuheir Altamimi From: Schwegmann, Wolfgang [mailto:wolfgang.schwegmann@bkg.bund.de] From: IERS CB Richter, Bernd On Behalf Of IERS Central Bureau ******************************************************************************** |