Dear Colleagues, As you may have read in the IVS Newsletter already the IVS Directing Board has decided to go ahead with preparations for augmenting the list of IVS products with time series of baseline lengths. Please find below the 'call for proposals' for IVS Analysis Centers and Associate Analysis Centers to contribute to this series. Yours sincerely, Axel Nothnagel IVS Analysis Coordinator Call for Proposals for participation in IVS Pilot Project: Time Series of Baseline Lengths Axel Nothnagel, IVS Analysis Coordinator August 18, 2003 Abstract IVS Analysis Centers and Associate Analysis Centers are asked to submit proposals for regular generation and submission of station coordinate results in SINEX files. From these files the IVS Analysis Coordinator's office will produce baseline length series and make them available in the IVS Data Centers. Proposals are due by October 15, 2003, a pilot project will start on January 1, 2004, and the project is planned to be phased into routine operation sometime in 2004. At a later stage, time series of station coordinates may be published as well. Motivation Users of VLBI results have often asked for time series of station coordinates and histories of baseline lengths. The use of this type of time series is manifold. Time series of station coordinates may be used for a detailed analysis of periodic and aperiodic variations related to individual VLBI sites caused by various geophysical phenomena. Baseline length series can be inferred by coordinate lists and provide valuable insight into scale variations. Both types of information can also be compared with results of other techniques. In addition, time series of coordinates and baselines produced by different VLBI analysis software packages may help to investigate systematic errors of these packages. Call for Proposals In order to satisfy this demand, IVS Analysis Centers and Associate Analysis Centers are asked to submit proposals for regular generation and submission of station coordinate results. In order to keep the submissions in a form which a) is suitable also for augmented applications b) uses a format which is accepted already c) will keep software development efforts at a minimum it is mandatory to submit results in SINEX format (http://alpha.fesg.tu-muenchen.de/iers). The details of the mandatory contents of the SINEX files for this purpose are stated below. Regular contributions of a number of IVS Analysis and Associate Analysis Centers are required containing session-wise coordinate results specifically for the purpose of coordinate and baseline length time series. In order to provide complete time series, all IVS VLBI sessions of approximately 24 hour duration should be processed but subsets of 24 hour sessions are also acceptable if complete series are maintained. The time requirement for the submission of the SINEX files is 8 weeks after correlation. IVS baseline length files are planned to be updated quarterly. >From the input files combined baseline length results with their formal errors will be computed and uploaded to the IVS Data Centers on the basis of one file per baseline. Pilot Project Group A group will be set up to coordinate all activities within the PP and to discuss all steps that should finally lead to operational products. One person of each Analysis Center submitting input files should be part of the Pilot Project Group. The director of the IVS Coordinating Center will become ex-officio member of the PP Group. Other colleagues interested in this type of product are welcome to join the group but the number of members should be kept at a reasonable number. Names of the members will be provided after Analysis Centers have responded to the call for proposals. The computations of the baseline lengths from the input data and the combination will be done by staff at the IVS Analysis Coordinator's office at the Geodetic Institute Bonn (Project leader: Axel Nothnagel). Details The IVS Analysis Centers participating in the project will submit their data in SINEX Version 2.0 (see http://alpha.fesg.tu-muenchen.de/iers). In order to permit transformations of the coordinates at a later stage, the EOP (pole coordinates and UT1) applicable on the respective day for the specific data set have to be included in the SINEX file (in the SOLUTION/APRIORI block if fixed). Ideally the EOP epoch should match the station coordinate parameter epoch. However, if this requires extraordinary efforts any EOP epoch within the session will do. The treatment of EOP and station coordinates of a fixed reference station as described below (including the reference station in SITE/ID, SITE/ECCENTRICITY, SOLUTION/APRIORI ...) still has to be discussed with and approved by the IERS Analysis Coordinator, Markus Rothacher. So, the following specifications are only preliminary. Please refer to SINEX 2.00 specifications in general. Mandatory blocks for the purpose of generating time series of baseline lengths (station coordinates) are the following. %=SNX 2.00 BKG 03:169:83402 BKG 03:149:66713 03:150:66242 R 00032 2 S * Please refer to SINEX 2.00 specifications for contents of this line * Solution contents should be "S" * +FILE/REFERENCE DESCRIPTION Organization CONTACT Name of Person -FILE/REFERENCE *mandatory +FILE/COMMENT Should contain a detailed description of your solution. Please specify all models which may have any effect on the baseline lengths (station positions) and signatures of the time series. General headlines are sufficient. N.B.: In order to keep this section small, general aspects of the solution which are identical for all SINEX files of a specific series may also be included in a general .txt file (see file name convention below). -FILE/COMMENT *mandatory for the purpose of baseline length time series +SITE/ID *Code PT Domes____ T Station description___ Approx_lon_ Approx_lat_ App_h__ 7225 A 40408S002 R GILCREEK Gilmore Creek 212 30 08.9 64 58 42.3 333.2 7298 A 40424S007 R KOKEE Kokee Park, K 200 20 05.6 22 07 35.9 1177.4 .... -SITE/ID *mandatory * * All sites included in the solution have to be listed here * +SITE/ECCENTRICITY *Code PT SOLN T Data_Start__ Data_End____ typ Apr --> Benchmark (m)_______ 7225 A 1 R 03:188:61284 03:189:60373 XYZ 0.0000 0.0000 0.0000 7298 A 1 R 03:188:61284 03:189:60373 XYZ 0.0000 0.0000 0.0000 .... -SITE/ECCENTRICITY *mandatory * * All sites included in the solution have to be listed here * +SOLUTION/EPOCHS *Code PT SOLN T Data_start__ Data_end____ Mean_epoch__ 7225 A 1 R 03:188:61284 03:189:60373 03:189:20152 7298 A 1 R 03:188:61284 03:189:60373 03:189:21152 7243 A 1 R 03:188:61284 03:189:60447 03:189:18930 7209 A 1 R 03:188:61530 03:189:60099 03:189:20141 7224 A 1 R 03:188:70453 03:189:60447 03:189:22382 -SOLUTION/EPOCH *mandatory * * All sites included in the solution have to be listed here * +SOLUTION/APRIORI *Index Type__ CODE PT SOLN Ref_epoch___ Unit S Apriori_value________ Constraint_ 1 STAX 7225 A 1 03:189:20152 m 2 -2.28154744959240D+06 0.00000D+00 2 STAY 7225 A 1 03:189:20152 m 2 -1.45364510604036D+06 0.00000D+00 3 STAZ 7225 A 1 03:189:20152 m 2 5.75699309196696D+06 0.00000D+00 4 STAX 7298 A 1 03:189:21152 m 2 -5.54383768988341D+06 0.00000D+00 5 STAY 7298 A 1 03:189:21152 m 2 -2.05456744861528D+06 0.00000D+00 6 STAZ 7298 A 1 03:189:21152 m 2 2.38785213311849D+06 0.00000D+00 .... 16 XPO ---- - 1 03:189:21152 mas 2 1.53774229520449D+02 9.84707D-02 18 YPO ---- - 1 03:189:21152 mas 2 5.28723119335481D+02 1.20715D-01 20 UT1 ---- - 1 03:189:21152 ms 2 -3.23641970112338D+04 2.37730D-03 -SOLUTION/APRIORI *mandatory * * * All sites included in the solution have to be listed here including fixed * reference stations * plus XPO, YPO, UT1 applicable at the reference epoch (for example * as fixed in the solution). * The number of parameters in the SOLUTION/APRIORI block and in * the +SOLUTION/ESTIMATE block need not be identical. However, * index numbers should match. Therefore, it is recommended to * put the reference station and EOP at the end of the list. * +SOLUTION/ESTIMATE *Index TYPE__ CODE PT SOLN Ref_epoch___ Unit S Total_value__________ Formal_erro 1 STAX 7225 A 1 03:189:20152 m 2 -2.28154749130444D+06 1.53186D-03 2 STAY 7225 A 1 03:189:20152 m 2 -1.45364514745397D+06 1.06504D-03 3 STAZ 7225 A 1 03:189:20152 m 2 5.75699308890249D+06 2.60085D-03 4 STAX 7298 A 1 03:189:21152 m 2 -5.54383768528991D+06 3.10717D-03 5 STAY 7298 A 1 03:189:21152 m 2 -2.05456743437212D+06 1.99017D-03 6 STAZ 7298 A 1 03:189:21152 m 2 2.38785213764529D+06 1.33263D-03 ... -SOLUTION/ESTIMATE *mandatory * * All sites estimated in the solution have to be listed here * +SOLUTION/MATRIX_ESTIMATE L COVA * Ind1 Ind2 Covariance(ind1,ind2) 1 1 2.34659227440684D-06 5.98793655687025D-07 1.13430588727378D-06 1 4 -1.85793593558410D-06 ... ... 22 22 3.32139978698741D-03 ... ... -SOLUTION/MATRIX_ESTIMATE L COVA *mandatory +SOLUTION/STATISTICS NUMBER OF OBSERVATIONS 2084 NUMBER OF UNKNOWNS 862 WEIGHTED SQUARE SUM OF O-C 2.78502744698645D+14 SQUARE SUM OF RESIDUALS (VTPV) 1.51350820848453D+03 VARIANCE FACTOR 1.00886553765208D+00 -SOLUTION/STATISTICS * * Recommended if available * %ENDSNX In the IVS Data Centers a file structure appropriate for this type of results will be set up in cooperation with the IVS Coordinating Center, as will be submission procedures. The proposed file name convention for the data files is ddddddddd_aaasssss_bl.snx where ddddddddd data base name aaa analysis center code sssss solution code bl code for baseline pilot project and for any text files aaasssss_bl.dsnx.txt Initial submissions should contain at least data starting at 2002.0 with a clear plan for completing the data backwards in time. ---------------------------------------------------------------------- The proposals should at least contain: Name of institution: Name of responsible scientist: Sessions/series to be processed: Time table for submissions of results prior to 2002.0: ---------------------------------------------------------------------- -- Dr. Axel Nothnagel Email: nothnagel@uni-bonn.de Geodetic Institute of the University of Bonn Nussallee 17 Tel.: ++49 (228) 733574 D-53115 Bonn Fax: ++49 (228) 732988 Germany