****************************************************************************** DORIS Electronic Mail Sat Mar 7 14:37:49 WET 1998 Message Number 0038 ****************************************************************************** Author: Pascal Willis, Gerhard Beutler, Werner Gurtner, Gunther Hein, Ruth Neilan, Jim Slater Subject: International Call for Participation (GLONASS IGEX-98 campaign) Dear colleagues, we would like to organize a international campaign of GLONASS observation (Sep 20 - Dec 20, 1998) (see attached document). We are looking forward receiving positive answer to this Call for Participation? All groups will be welcome. People already participating in the IGS Service are expected to answer to this proposal. If you ihave received this document through several channels, please accept our apologizes in advance. Best regards ======================================================================== FINAL VERSION (March 6, 1998) The International GLONASS Experiment IGEX-98 Sept 20 - Dec 20, 1998 document prepared by Pascal Willis, Gerhard Beutler, Werner Gurtner Guenter Hein, Ruth Neilan, Jim Slater ------------------------------------------------------------ 1. IGEX-98: Description of the Experiment -------------------------------------- 1.1 Sponsoring Organizations 1.2 The GPS, the GLONASS, and IGS Involvement 2. Call for Participation ---------------------- 2.1 IGEX-98 Coordinating Center 2.2 Observing stations 2.3 Data Centers 2.4 Data Analysis 2.5 Evaluation 2.6 Instructions to Answer the Proposal 1. General Description of IGEX-98 ------------------------------ 1.1 Sponsoring International Associations ------------------------------------- The International GLONASS EXperiment (IGEX) is an international campaign sponsored by: - the International Association of Geodesy (IAG) Commission VIII, International Coordination of Space Techniques for Geodesy and Geodynamics (CSTG), - the International GPS Service for Geodynamics (IGS), - The Institute of Navigation (ION), and - The International Earth Rotation Service (IERS). CSTG is a commission of IAG (International Association of Geodesy) and a subcommission of COSPAR (COmmission for SPAce Research) and IGS is an approved service of IAG and a FAGS-Service (Federation of Astronomical and Geophysical Data Analysis Services) The CSTG Subcommission on "Satellite Microwave Systems" (Chair, Pascal Willis) is coordinating the project, as it was proposed at the 7th IGS Governing Board Meeting in September 1997 in Rio de Janeiro (see IGS-Mail Message 1683). The ION is a non-profit professional society dedicated to the art and science of navigation including air, space, marine, land navigation and position determination. ION organized a GLONASS-GPS Interoperability Working Group in 1996 to facilitate solutions to problems related to coordinate and time reference frames, precise ephemerides, and hardware and software implementations. The IERS is a Service of IUGG (International Union of Geodesy and Geophysics) and IAU (International Astronomical Union) and an approved service of FAGS. All GLONASS satellites are equipped with arrays of LASER reflectors allowing the SLR community to range easily to the GLONASS satellites. It is thus natural to closely coordinate the IGEX-98 with the SLR Subcommission of CSTG. Werner Gurtner from the IGEX-98 steering committee is at present considered as "liaison officer" of the IGEX-98 with the SLR Subcommission of CSTG 1.2 The GPS, the GLONASS, and IGS Involvement ----------------------------------------- There are many common aspects of the IGEX-98 and the 1992 IGS Test Campaign: - The GLONASS and the GPS are close relatives from the technical point of view (dual-frequency microwave systems in the L-band). - At present GLONASS is not fully operational (nor was the GPS in 1992, although it was more fully developed). - Only the broadcast GPS orbits and precise ephemerides from the U.S. Department of Defense were available in 1992, while only broadcast GLONASS orbits are currently available. - GPS orbits were referenced to WGS 84 in 1992 but not to the ITRF; GLONASS orbits are referenced to neither WGS 84 nor the ITRF. For the IGEX campaign, the IGS infrastructure can be exploited to the extent possible. In particular, the IGS global network of tracking stations, its experience with data acquisition and orbit production, and its ties to the ITRF can be used to support the IGEX. With this in mind,the Terms of Reference and the Call for Participation for the following experiment were presented to and approved by the IGS Governing Board on February 11, 1998. 1.2 Objectives ---------- The main purpose of IGEX-98 is to conduct the first Global GLONASS Observation Campaign for geodetic and geodynamics applications and to evaluate the results in an international workshop in 1999. The campaign duration of three months is intended to simulate an operational environment, i.e., observations, data transfer, and data analysis have to be performed in a service-like manner (as opposed to a campaign-oriented strategy). The main objectives of IGEX-98 are: - set up a global GLONASS observation network, - test GLONASS data processing software, - determine GLONASS orbits of meter-quality or better in a well-defined Earth-fixed reference frame (namely, the ITRF), - gain insight into GLONASS orbit modeling peculiarities (solar radiation pressure, attitude, etc.), - study common GPS/GLONASS processing strategies, - engage the collaboration of the SLR community to evaluate the accuracy of the determined GLONASS orbits, - determine transformation parameters between the GLONASS operational reference frame and ITRF and WGS 84 (the GPS operational reference frame), - connect the GPS and GLONASS time systems, - compare receiver equipment performance, - compare and contrast the separate and combined satellite systems on a global basis, and - foster participation and cooperation with Russian agencies and organizations. 1.3 IGEX-98 Schedule ---------------- February 1998 Distribution of IGEX-98 Call for Participation May 29, 1998 Proposals due June 1998 Evaluation of proposal by Steering Committee Review/approval of the schedule Designation of the Oversight Commitee (including Chair) Campaign Planning Meeting September 20, 1998 Campaign begins December 20, 1998 Campaign ends early 1999 IGEX-98 Evaluation Workshop 1.4 IGEX-98: Organizational Aspects ------------------------------- The CSTG Subcommission on Microwave systems is coordinating IGEX-98 with Pascal Willis as coordinator. The Steering Committee of IGEX-98 consists of Pascal Willis(IGN) (chair), Gerhard Beutler (AIUB), Werner Gurtner (AIUB), Ruth Neilan (JPL), Guenther Hein (UbM), Jim Slater (NIMA). The Steering Committee prepares and sends out the Call for Participation, evaluates and answers the proposals received. After this evaluation, IGEX-98 will be coordinated by a broad-based International Organizing Committee consisting of participants in IGEX-98. The steering committee will be dissolved. Participation in the IGEX-98 is requested for the following activities: - Observing station(s) - Data Center(s) - Analysis Center(s) - Evaluation of Results Additional information may be found below and in the following Web sites: http://lareg.ensg.ign.fr/IGEX http://www.ion.org/workgroup.html 2. CALL FOR PARTICIPATION ---------------------- The Steering Committee of the IGEX-98 is seeking participants for the 1998 International GLONASS Experiment. The description of the campaign is contained in Section 1 of this document. In particular, we are seeking - IGEX-98 Observing Sites - IGEX-98 Data Centers - IGEX-98 Data Analysis Groups - IGEX-98 Evaluation Groups 2.1 Observing Sites --------------- 2.1.1 Receivers --------- Only geodetic-type receivers (capable of collecting pseudorange and carrier phase observations) may be used in IGEX-98. Receivers must be able to track at least four GLONASS satellites simultaneously and, if combined with a GPS receiver, at least four GPS satellites simultaneously. In particular, and in sequence of preference, the following receiver types may be used in IGEX-98: - Combined dual-frequency GPS/GLONASS receivers - Dual-frequency GLONASS receivers - Combined single-frequency (L1) GPS/GLONASS receivers - Single-frequency GLONASS receivers Receivers must be colocated with or tied to sites that have well-determined ITRF coordinates. IGS sites are preferable. The ITRF coordinates should have an accuracy of 1-5 cm. In cases where there are no suitable ITRF coordinates available at a site, a dual-frequency geodetic-quality GPS receiver must be colocated with the GLONASS receiver to collect sufficient GPS data during the experiment to compute ITRF coordinates for the site at the specified accuracy. This may be done by relative positioning to a nearby IGS site or by absolute positioning. In the case of single-frequency GLONASS receivers, it is absolutely mandatory that a dual-frequency geodetic-quality GPS receiver is operating during the whole campaign on the same site on a marker with known or determinable ITRF coordinates (within a distance of less than a few hundred meters from the GLONASS receiver). The local ties between the two antennae should be available with an accuracy of less than 1 cm (in ITRF). A GLONASS Site Information Report must be available at the IGEX-98 Coordination Center prior to the observation campaign (format identical to IGS site documentation form, available at the IGS Central Bureau Information System, see ftp://igscb.jpl.nasa.gov/igscb/resource/blank.log). If the IGEX-98 receiver is driven by an accurate external clock (rubidium, cesium or hydrogen standard), this information should be included in the proposal. 2.1.2 Operational considerations -------------------------- The IGEX-98 will be based on a 30s sampling rate. The data must be forwarded to an IGEX data center within 48 hours from the end of the UT day on which it was collected. The exchange file format is the RINEX format (see ftp://igscb.jpl.nasa.gov/ igscb/data/format/rinex2.txt). The following naming conventions will be followed: A 4-character acronym for each receiver operated during the campaign should be proposed to and approved by the IGS Central Bureau (igscb@igscb.jpl.nasa.gov). For each marker, a DOMES number (a globally unambiguous marker number used by ITRF) has to be requested from the ITRF Section of the IERS Central Bureau (see http://lareg.ensg.ign.fr/ITRF/domesreq.html, e-mail contact: domes@ensg.ign.fr). The proposal should specify what quality control will be performed before sending the data to a data center. Detailed guidelines for the data handling will be provided together with the approval of the proposal. 2.1.3 Local Geodetic Ties ---------- The local geodetic ties between the GLONASS equipment and all geodetic equipment in the vicinity (GPS, DORIS, SLR, VLBI, PRARE,..) must be performed, documented and made available before the start of IGEX-98. They have to be reported as Cartesian coordinate differences (delta X/Y/Z) parallel enough to the earth-centered ITRS to maintain the accuracy of a few millimeters. 2.2 Data Centers ------------ The proposal should describe the maximum number of stations from which data can be received, stored and made available for anonymous ftp access. Data upload from the stations to the data center should be performed through ftp (anonymous or by user account/password), too. However, it will be the responsibility of the data centers to coordinate the data upload with the observing sites. The data should be available online within hours after reception from the observing organizations and for at least 3 months after the campaign. Offline availability upon request should be maintained for at least 2 years. Data centers should fill out a data center description form available at ftp://igscb.jpl.nasa.gov/igscb/center/data/BLNKFORM.DCN. 2.3 Data Analysis ------------- Data Analysis Groups will process the GLONASS IGEX-98 data. It is expected that after some time they may be able to produce results on a daily or a weekly basis. They should make them available for comparisons (or combinations) as early as possible. IGEX-98 Data Analysis Groups should briefly describe planned analysis. It is expected, however, that GLONASS ephemerides and GLONASS satellite clock information will be the main result. In the response to the Call for Participation, the Analysis Groups should indicate which of the following items they plan to produce: - precise GLONASS ephemerides (in SP3-Format, see ftp://igscb.jpl.nasa.gov/data/format/sp3.txt) and/or - GLONASS satellite clocks and/or - Earth rotation parameters and/or - stations coordinates (in SINEX files, see ftp://igscb.jpl.nasa.gov/igscb/datga/format/sinex.txt) and/or - other information (e.g., ionosphere, troposphere, etc.) 2.4 Data Evaluation ------------------ In IGEX-98 we envisage that two kinds of orbit/clock evaluations will be done (1) Comparison of results (obtained by the various Analysis Groups) similar to those routinely performed by the IGS Analysis Coordinator (2) Evaluation based on independent techniques, i.e., SLR observations. We are seeking participation in both domains. In case (1) we would prefer a proposal from an IGS- and/or and IGEX-Analysis Group, in case (2) a proposal from an SLR Analysis Center. 2.5 Instructions for Submitting a Proposal ----------------------------------- Proposals submitted in response to the Call for Participation should contain: - a cover letter signed by an official representative of the organization - the attached cover sheet - a detailed plan describing the activities proposed by the organization It should be clear in the proposal which organizations are cooperating or assumed to contribute and whether the organization(s) would consider continuing their activities after the end of the observation campaign (Dec 20, 1998). Send proposals to: Pascal Willis Institut Geographique National ENSG/LAREG Phone: 33-(0)1-6415-3254 6-8 Avenue Blaise Pascal FAX: 33-(0)1-6415-3253 Cite Descartes, Champs-sur-Marne e-mail: pascal.willis@ensg.ign.fr 77455 Marne-la-Vallee, France --------------------------------------------------------- Proposal Submitted in response to the Call for Participation International GLONASS Experiment (IGEX-98) Proposing Organization: Point of Contact: Name Address Telephone FAX email Authorizing Official Name Address Telephone FAX email signature Proposal for Stations Observations Data Management Data Analysis Evaluation For Joint proposals: Collaborating institutions Contacts Detailed proposal (see attached requirements) ------------------------------------------------------- ---------------------------------------------------------------------- Pascal Willis ---------------------------------------------------------------------- Institut Geographique National ENSG/LAREG Phone: 33-(0)1-6415-3254 6-8 Avenue Blaise Pascal FAX: 33-(0)1-6415-3253 Cite Descartes, Champs-sur-Marne Email: pascal.willis@ensg.ign.fr 77455 Marne-la-Vallee, France WWW: http://lareg.ensg.ign.fr ---------------------------------------------------------------------- [Mailed From: Pascal Willis ]