December 1997 Issue of CDDIS Bulletin is Available (05-Dec-97)

The latest issue of the CDDIS Bulletin has been published and is available electronically. Articles include this issue of the CDDIS Bulletin are:

• Cover: VLBI Observatory Network
• Articles:
  • Meteorological Data from GPS Sites
• Data Bits and Bytes:
  • SLR Epoch Timing Corrections for 1997
  • Riga SLR Range Bias
  • Reminder -- CDDIS Web Sites and Anonymous FTP Have Moved
  • Permanent GPS Network Update

CDDIS Web Sites and Anonymous FTP Operational on New Computer (03-Oct-97)

If you are reading this article, then you have found the new home of the CDDIS web sites on cddisa.gsfc.nasa.gov. Read the October 1997 issue of the CDDIS Bulletin for more details.

October 1997 Issue of CDDIS Bulletin is Available (03-Oct-97)

The latest issue of the CDDIS Bulletin has been published and is available electronically. Articles include this issue of the CDDIS Bulletin are:

• Cover: IGS GPS and VLBI and DORIS Sites in the Canadian Region
• Articles:
  • Notice -- CDDIS Web Sites and Anonymous FTP Have Moved
  • CDDIS Bulletin, Volume 12 -- Index
• Data Bits and Bytes:
  • Permanent GPS Network Update
  • SLR Epoch Timing Corrections for 1997
  • HOLLAS Barometer Problem
  • New Range Bias and Time Biases at ZIMLAT SLR Station 7810

August 1997 Issue of CDDIS Bulletin is Available (10-Sep-97)

The latest issue of the CDDIS Bulletin has been published and is available electronically. Articles include this issue of the CDDIS Bulletin are:

• Cover: IGS GPS Network
• Articles:
  • Meteorological Data from GPS Sites
• Data Bits and Bytes:
  • HOLLAS Time Bias in 1988
  • SALRO Time Bias in 1997
  • ZIMLAT Range Bias
  • Permanent GPS Network Update
  • Reminder -- New CDDIS IP Address

June 1997 Issue of CDDIS Bulletin is Available (14-Jul-97)

The latest issue of the CDDIS Bulletin has been published and is available electronically. Articles include this issue of the CDDIS Bulletin are:

• Cover: SLR Observatory Network
• Articles:
  • New CDDIS IP Address
  • New Computer Hardware Delivered
  • SLR Satellite Information on the Web
• Data Bits and Bytes:
  • New Laser Field-Generated Normal Point Format
  • New URLs for CRL WWW Sites
  • New Directory of Daily GPS Broadcast Ephemerides Files
  • Permanent GPS Network Update

New CDDIS IP Address (16-Jun-97)

On the morning of Monday June 16, 1997 (no later than noon EDT), the IP address of the CDDIS host computer will change:

Node Name:	cddis.gsfc.nasa.gov
Old Number:	128.183.10.141
New Number:	128.183.201.162

The node name will not change, just the node number. Users should make certain ther CDDIS access scripts use the node name or this new IP address as of noon June 16.

New Computer Hardware Delivered (02-Jun-97)

The CDDIS staff is pleased to announce the delivery and installation of a replacement hardware platform for the CDDIS VAX system. This system running the UNIX operating system; the system was delivered with thirty Gbytes of on-line magnetic disk storage but will soon be augmented with as much as an additional sixty Gbytes. As can be imagined, a significant amount of the CDDIS staff time will be spent during the next few months learning UNIX and developing data processing and archiving routines for this new system. The staff hopes to have all GPS data activities transferred to the UNIX platform by late 1997.

An area of ongoing concern to the CDDIS staff is the ability to respond to special requests for older, off-line GPS data. Currently, this is a time-consuming activity for the staff since all older data are stored on optical disks in VAX VMS file format and the CDDIS VAX system is equipped with only two optical disk drives. The future CDDIS UNIX system under UNIX will not be equipped with these magneto-optical drives; therefore, a new medium for long-term storage of the historic GPS archive must be identified. The CDDIS staff has decided to utilize CD-ROMs for this archive and a procurement of a CD recordable system will be undertaken in the next few months. This system will have the capability of recording up to five copies of a CD. The existing GPS archive on magneto-optical disks (in VAX/VMS format) will be migrated to CD-ROM. The data will most likely be written to CD-ROM by GPS week. Purchase of a CD-ROM jukebox to further increase the time span of on-line data will be investigated in the hopes of delivery in late 1997.

SLR Satellite Spreadsheet (11-Apr-97)

Information about SLR satellites has been collected and is presented in spreadsheet form. Any comments, questions, or corrections to this information should be directed to the CDDIS Manager, Carey Noll.

April 1997 Issue of CDDIS Bulletin is Available (10-Apr-97)

The latest issue of the CDDIS Bulletin has been published and is available electronically. Articles include this issue of the CDDIS Bulletin are:

• Cover: IGS GPS Network
• Articles:
  • GPS Tracking Data Summary and Access Statistics for 1996
  • IGS Preliminary Orbits Now Available
  • Analyzed Results Recently Submitted to the CDDIS
• Data Bits and Bytes:
  • Time Bias in CRL Tokyo SLR Data
  • Epoch Timing Corrections for NASA SLR Stations
  • SLR On-Site Normal Point Pass Totals for 1996 -- Update
  • Permanent GPS Network Update

February 1997 Issue of CDDIS Bulletin is Available (10-Feb-97)

The latest issue of the CDDIS Bulletin has been published and is available electronically. Articles include this issue of the CDDIS Bulletin are:

• Cover: SLR Observatory Network
• Articles:
  • Global Space Geodetic Site Information
  • Summary of Recent SLR Data Problems
  • SLR On-Site Normal Point Pass Totals
• Data Bits and Bytes:
  • SLR Data from the Starfire Optical Range for 1996
  • MOBLAS-8 Range Bias
  • CDDIS Bulletin Survey Results

Charts of Global Space Geodetic Sites (23-Jan-97)

The Geodetic and Geophysical Sites (GGS) Subcommission has prepared charts listing existing global fiducial or "fundamental" sites and the instruments collocated at each site. The subcommission plans to update and maintain this site list.

SLR Time Bias Functions (TBFs) (23-Jan-97)

Roger Wood (RGO) reports that from January 20 , 1997, TBFs will be distributed via the EUROLAS Data Center (EDC) to a new mailing list called SLRTBF. Anyone interested in receiving TBFs should send a blank message with the subject header "subscribe" to slrtbf@dgfi.badw-muenchen.de. These TBFs are available from the EDC, RGO, the CDDIS. The format for these functions was developed under the aegis of the SLR/LLR Subcommission of the CSTG during the 10th International Workshop on Laser Ranging Instrumentation held in Shanghai

Plans are for this distribution to collect and collate all TBFs currently produced by different providers and mail them as a single file (see example file at the end of the specification) at least once per day. From January 20 the new scheme will work in parallel with present distributions for a trial period of about a month. If all is running smoothly at the end of that period, the existing distributions will be discontinued. A further announcement will be made at that time.

All comments about the new files and the distribution are welcomed and should be sent to Roger Wood at Herstmonceux (rw@gxvf.ego.ac.uk).

IERS Analysis Campaign Call for Participation (03-Jan-97)

Jim Ray (NOAA) has recently distributed a Call for Participation on behalf of the IERS. The IERS Working Group on the ITRF Datum is organizing an Analysis Campaign to collect appropriate products from interested space geodetic data analysis centers and geophysical data analysis centers, and to compare the results. While it is likely that the results of this Campaign will strongly influence any future IERS activity to regularly monitor geocenter motions, participation in this Campaign does not obligate a participant to contribute to any future operational activities. This Campaign does not request the collection of any new observational data not already being collected for other purposes. For further information on the ITRF and the IERS Working Group on the ITRF Datum, please refer to the www site http://schubert.ign.fr:8000/CIAG/WITRF/index.WITRF.html.