Date: Mon, 24 Feb 2003 16:55:02 -0500 (EST) From: Carey Noll Reply-To: Carey Noll To: igs-dcwg@igscb.jpl.nasa.gov Subject: [IGS-DCWG-6] Data Center Requirements Documentation Message-ID: Sender: owner-igs-dcwg Precedence: bulk ****************************************************************************** IGS-DCWG Mail 24 Feb 13:55:04 PST 2003 Message Number 6 ****************************************************************************** Author: Carey Noll/CDDIS Dear Colleagues, Please forgive the long delay in getting in touch with the IGS Data Center Working Group. I have been quite late in getting activity going. Included below in this email is an IGS data center requirements document written a couple of years ago. Data center requirements were discussed briefly at the IGS governing board meeting in December and I realized we never "formalized" the requirements. I would ask that you review this document and provide any feedback in the next couple of weeks. I envision adding this document to the IGS website as a reference for future data center inquiries. As you may know, there will be several IGS working group meetings in Nice during the EGS/AGU joint assembly. Right now, they are planned for Saturday, April 5. I would like to find out how many people will be in Nice and could make a meeting of the data center WG. Perhaps if we have alot of people coming to the EGS who had not planned to be there on Saturday we could meet briefly during the week sometime. Let me know! Best regards, Carey. +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ Ms. Carey Noll Manager, Crustal Dynamics Data Information System (CDDIS) Secretary, ILRS Central Bureau Code 920.1 E-mail: Carey.E.Noll@nasa.gov NASA GSFC Voice: (301) 614-6542 Greenbelt, MD 20771 Fax: (301) 614-5970 USA WWW: http://cddisa.gsfc.nasa.gov/cddis_welcome.html +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ IGS Data Centers Requirements Carey Noll/CDDIS IGS data centers fall into three categories: Operational, Regional, and Global Data Centers. The Operational Centers are in direct contact with the tracking sites. Their tasks include data validation and monitoring, suitable data reformatting into a uniform format (RINEX), compression of data files, maintenance of a local archive of the tracking data in its original receiver and reformatted format, and the electronic transmission of data to a Regional or Global Data Center. The Operational Center must download data from the receivers located at IGS stations on a timely basis (either hourly or daily), without interruption. Operational Centers typically do not allow users direct access to their data holdings. The Regional Data Centers reduce traffic on electronic networks by archiving data from sites in a limited geographic region (e.g., Europe, Australia, etc.) or agency network (e.g., JPL). They collect reformatted tracking data from several Operational Centers, maintain a local archive of the data received, provide on-line access to these data to the user community of the region, and transmit data from a subset of their sites (minimally IGS global stations) to the Global Data Centers. The Global Data Centers are the main interfaces to the Analysis Centers and the user community in general. They receive/retrieve, archive, and provide online access to tracking data provided by the Operational/Regional Data Centers. At a minimum, Global Data Centers archive data from IGS sites identified as global stations. The Global Data Centers also archive and provide online access to IGS products generated by the IGS Analysis and Associate Analysis Centers. Finally, the IGS Global Data Centers backup and secure their holdings of IGS data and products, exchanging data between other data centers in order to ensure equalization of data holdings. Data centers at all levels should perform routine quality control on incoming data in order to detect bad or corrupt data prior to making these data available to the user community. The online archive of GPS data available through the IGS Global Data Centers should include: o Daily files of GPS data (minimum all IGS global stations) at a 30-second sampling rate (minimum of one year online); includes daily files of GLONASS data in support of the IGS GLONASS Pilot Project (IGLOS-PP) as GPS/GLONASS stations are made official IGS sites o Hourly files of GPS data at a 30-second sampling rate (minimum of three days online) All data should be available in RINEX format, both Hatanka and Z compressed. Data archive should also include broadcast ephemeris, meteorological, and other auxiliary files identified by the IGS as an analysis center requirement. The online archive of IGS products available through the IGS Global Data Centers should include: o Weekly solutions of classic IGS products from the IGS Analysis Centers o Combined weekly solution from the IGS Analysis Center Coordinator o Daily rapid and sub-daily ultra-rapid solutions from the IGS Analysis Center Coordinator o Combined station coordinates and velocities from IGS Reference Frame Coordinator o Associate Analysis Center products as they are approved by the IGS Governing Board as Pilot Projects or Working Groups, including: o Regional and Global Network Analysis Center solutions in SINEX format from the Pilot Project for the Densification of the ITRF o Zenith path delay files from the Troposphere Working Group o Ionosphere parameters from the Ionosphere Working Group