CDDIS Bulletin - December 1998
Volume 14 No. 2

In this issue:

• Cover: IGS Sites Providing Hourly Data to the CDDIS
• Articles:
  • IGS Network Systems Workshop
  • Access to SLR Data through the CDDIS
  • Access to GPS Data and Products through the CDDIS -- Update
• Data Bits and Bytes:
  • Permanent GPS Network Update
  • IGEX-98 Network Update

About the cover: The map on the cover of this issue of the CDDIS Bulletin shows the IGS sites currently supplying hourly data in near real time to the CDDIS. Currently 32 sites are providing data in hourly increments.

IGS Network Systems Workshop

Nearly 100 IGS colleagues gathered in Annapolis Maryland, November 2 through 5 to attend a workshop dedicated to the infrastructure of the IGS collaborative international organization. NASA Goddard Space Flight Center, through the Crustal Dynamics Data Information (CDDIS), an IGS Global Data Center, in conjunction with the IGS Central Bureau, sponsored the IGS Network Systems Workshop. This workshop provided a great opportunity for people working within the various components of the IGS to meet and discuss current configurations, problems and resolutions. A good deal of time was devoted to understanding the many future requirements and how to begin incorporating these into our existing infrastructure.

The final day of the workshop, November 6, was a summary session for the program committee to pull together the recommendations of the workshop. These recommendations will be reviewed by the Governing Board at its December meeting where approval will be sought for the appropriate items. A workshop proceedings document is in progress and will be available on the web as well as in limited hardcopy publications. The final result of the workshop is intended to become a Network Operations Plan for the IGS Network System.

In brief, the workshop was considered to be productive and engaging, both in the workshop meetings as well as during the discussions, breaks, social receptions and dinners. The web site (http://cddisa.gsfc.nasa.gov/igs_netws/netws_home.html) has been updated to include the workshop summary, recommendations, and photos. This site also includes the archive of pre-workshop materials developed for planning purposes.

Access to SLR Data through the CDDIS

The CDDIS staff is pleased to announce that the SLR data archiving and processing activities are now operational on the UNIX platform, a Digital AlphaServer 4000:

Host name: cddisa.gsfc.nasa.gov
Host number: 128.183.204.168
Access: anonymous ftp and web

All data filenames are in lower case, with the exception of the .Z indicating a compressed file. Below is a directory tree structure for these data.

As of December 1, 1998 the host cddisa.gsfc.nasa.gov was operational for SLR data archiving. For the next month or two, the CDDIS staff will continue to maintain the archive of SLR data on the VAX (host cddis.gsfc.nasa.gov by copying data from cddisa back to the VAX. Users should, however, transition their software to use the UNIX host as soon as possible. Any questions or problems should be directed to Carey Noll (noll@cddis.gsfc.nasa.gov).

-------------------------------------------------------------------------------
                          CDDIS SLR DIRECTORY STRUCTURE
-------------------------------------------------------------------------------
Directory                 Filenames           Description
-------------------------------------------------------------------------------

/pub/slr                  SLR data disk

slr/llrnpt/yyyy           llr_npt.yymm.Z      compressed LLR monthly mini-normal
                                                 point data file for year 'yy'
                                                 and month 'mm'

slr/slrfr/satname/yyyy    satname_v.yymm.Z    compressed SLR monthly full-rate
                                                 data file for satellite
                                                 'satname', version 'v', year
                                                 'yy', and month 'mm'

                 /daily/ssss                  compressed SLR full-rate daily data
                          ssss_yymmdd_v.satname.Z   data file for station
                                                 'ssss', satellite 'satname',
                                                 version 'v', year 'yy', month
                                                 'mm', and day 'dd'

slr/slrnpt/satname/yyyy   satnamev_npt.yymm.Z compressed SLR monthly normal
                                                point data file (generated from
                                                full-rate data) for 'satname',
                                                version 'v', year 'yy', and
                                                month 'mm'
                          satnamev_npt.yymm_sum
                                              SLR monthly normal point data
                                                summary file (generated from
                                                full-rate data) for 'satname',
                                                version 'v', year 'yy', and
                                                month 'mm'

slr/slrql/satname/yyyy    new_qlyymmdd.satcode daily SLR normal point data file
                                                for satellite 'satname' and
                                                'satcode', year 'yy', month
                                                'mm' and day 'dd'

                          new_qlyymm.satcode.Z compressed monthly SLR normal
                                                point data file for satellite
                                                'satname' and 'satcode',
                                                year 'yy', month 'mm' and day
                                                'dd'

slr/slrql/allsat/yyyy     all_qlyymmdd.all    daily SLR normal point data file
                                                for all satellites, year 'yy',
                                                month 'mm' and day 'dd'

                          nasa_qlyymmdd.dat   daily SLR normal point data file
                                                from NASA stations, for all
                                                satellites, year 'yy', month
                                                'mm' and day 'dd'

                          ql_allsat_yymmdd   daily SLR normal point data file
                                                from EDC, for all satellites,
                                                year 'yy', month 'mm' and day
                                                'dd'

Access to GPS Data and Products through the CDDIS -- Update

This is a reminder that users of GPS data and products available through the CDDIS should utilize the new computer, cddisa.gsfc.nasa.gov, operational as of June 01, 1998. In early December, the CDDIS staff made the GPS data and products directories available via host name cddisa.gsfc.nasa.gov accessible via anonymous ftp. During this process, "old" links, such as /gps1, /gps2, /gps3, were eliminated (users should have been using /gps!). Users can now access GPS data and products through anonymous ftp, in the /pub/gps directory tree. Some time in the near future, the CDDIS will discontinue use of the "old" username/password method for accessing these data. The CDDIS staff strongly encourages users to transition their software to use the anonymous ftp access method, or alternatively, through the web (ftp://cddisa.gsfc.nasa.gov/pub/gps). Users can contact Carey Noll (noll@cddis.gsfc.nasa.gov) with any questions or problems.

DATA BITS AND BYTES

This section is designed to give brief notices of special events, new data sets, or problems encountered in recent months. The CDDIS staff believes the user community should be informed of these problems in order to ensure that the best results possible are produced from data issued by the archive.

Permanent GPS Network Update

Since the October 1998 issue of the CDDIS Bulletin, the CDDIS has archived data from the following new GPS tracking sites:

Table 1. New GPS Tracking Sites

IGEX-98 Network Update

Since the October 1998 issue of the CDDIS Bulletin, the CDDIS has archived data from additional sites participating in IGEX-98; this list is shown in Table 2 below.

Table 2. GLONASS Tracking Sites Currently Available through the CDDIS

Since the introductory article on IGEX-98 in the October issue of the CDDIS Bulletin, the IGEX data has been made available via anonymous ftp on host cddisa.gsfc.nasa.gov, in the directory /pub/igex.

Happy Holidays 1998 from the CDDIS Staff: Carey Maury Ruth Laurie