|
CDDIS Bulletin - August 1990
Volume 5 No. 5
In this issue:
On the cover: 1990 GPS Campaign in Alaska
T. M. Eubanks (USNO) has recently submitted to the CDDIS their
earth orientation results generated from VLBI data for the IERS annual
report. This analysis was performed on data from the stations participating
in NAVNET (Navy VLBI Network): Gilmore Creek, Kokee Park, Hawaii,
Richmond, Green Bank, and Maryland Point; data from Mojave, Medicina,
and Noto are also included. The NAVNET VLBI data has been analyzed
to produce the USNO 1990-2 reference frame and earth orientation
data and covariance matrix. Source positions and station locations
for the 1990-2 reference frame were also submitted. These data sets
can be viewed through the interactive DIS by using pre-programmed
data base queries. More information about the NAVNET VLBI program
and the analysis of its data is also available in the DIS.
The CDDIS has now received all 1989 VLBI experiments from the GSFC
VLBI analysis group. These data sets are in VLBI data base handler
(DBH) format but can be converted to NGS card-image format upon request.
Users interested in receiving copies of any of these data sets should
contact the CDDIS staff.
Currently, the system portion of the Site Occupation Designator (SOD)
is composed of two numerical digits shared by the SLR and VLBI disciplines.
Numbers 01 through 49 are assigned to SLR systems; 50 through 99 are
assigned to VLBI systems. At this time, all SLR system numbers have
been allocated. It has recently been agreed among Project staff and
science representatives that the full range, i.e., 01 through 99, be
utilized for each scientific technique (SLR, VLBI, and GPS). This policy
will allow the SOD system to expand to satisfy near term requirements.
In recent DIS Bulletins users have been notified of re-releases
of SLR data due to system problems, system configuration flag corrections,
etc. Table 1 on pages 3., 4.,
and 5. lists all known data problems and
data re-issues (already released and planned) for the 1988 and 1989
data sets. By June of this year, all 1988 data (through release C)
and all 1989 data (through release B) will have been sent to the
SLR user community.
This section is designed to give brief notices of special events
or problems encountered in recent months.
It was decided at a CSTG meeting held in April, 1990 that the LAGEOS
normal points generated by the Bendix Data Services group can now
be considered operational. To date, the CDDIS has normal point data
produced from the most recent versions of 1988, 1989, and 1990 full-rate
data. These products can be obtained from the CDDIS on tape or electronically.
The CDDIS has recently received SLR data from the Ondrejov, Czechoslovakia
station. The data currently spans several months in the years 1988
and 1989.
Table 2. SLR Data Release Dates (1988 through 1989)
Received
Year Month A B C
1988 January 25-Mar-88 29-Jul-88 28-Dec-88
February 22-Apr-88 31-Aug-88 31-Jan-89
March 31-May-88 28-Oct-88 16-Mar-89
April 24-Jun-88 30-Nov-88 20-Apr-89
May 22-Jul-88 23-Nov-88 27-Apr-89
June 25-Aug-88 28-Dec-88 28-Apr-89
July 23-Sep-88 31-Jan-89 20-Jun-89
August 26-Oct-88 28-Feb-89 03-Jul-89
September 25-Nov-88 02-May-89 20-Dec-89
October 16-Dec-88 31-May-89 06-Mar-90
November 23-Jan-89 05-Jun-89 06-Apr-90
December 14-Mar-89 07-Jul-89 30-May-90
1989 January 31-Mar-89 31-Jul-89
February 26-Apr-89 07-Aug-89
March 22-May-89 29-Sep-89
April 23-Apr-89 03-Nov-89
May 21-Jul-89 30-Nov-89
June 24-Aug-89 08-Dec-89
July 06-Oct-89 01-Feb-90
August 24-Oct-89 23-Feb-90
September 27-Nov-89 30-Mar-90
October 10-Jan-90 14-May-90
November 28-Jan-90 05-Jun-90
December 09-Mar-90 28-Jun-90
It has been reported by the Bendix Data Services Group that the
TLRS-1 eccentricity value for the up component is only accurate to
0.5 centimeters. This occupation took place from 16-Oct-89 through
12-Nov-89.
All TLRS-4 data from April 1 through 25, 1990 will be recalled
by the Bendix Data Services group due to a processing problem. This
data set is biased by 2.374 meters; users can correct the problem
by adding 2.374 to all range records. The data will be appear corrected
on the B release of the April 1990 data set. This tape is scheduled
for release in October, 1990. Data taken by TLRS-4 since April 25
does not exhibit this problem.
|
