| Date: | 1999-02-04 09:00:00 | |
| Sender: | James Long, Van S. Husson, NASA SLR Program <HussonV@thorin.atsc.allied.com (Husson, Van)> | |
| Subject: | [SLR-Mail] No. 243: New SOD and Eccs for Station 7105 | |
| Author: | James Long, Van S. Husson, NASA SLR Program | |
| Content: | ******************************************************************************** SLR Electronic Mail 1999-02-04 09:00:00 UTC Message No. 243 ******************************************************************************** Author: James Long, Van S. Husson, NASA SLR Program Subject: New SOD and Eccs for Station 7105 by SLRAL2.ATSC.ALLIED.COM with SMTP for SLRMail@dgfi.badw-muenchen.de; Wed, 3 Feb 1999 20:53:15 -0500 by thorin.atsc.allied.com (PostalUnion/SMTP(tm) v2.2 (Build 22008) for Windows NT(tm)) id AA-1999Feb03.205100.1122.2129844; Wed, 03 Feb 1999 20:46:47 -0500 Effective 1 February 1999, the Site Occupancy Designator (SOD) of MOBLAS 7 has been incremented to 71050725 as a result of new geodetic survey conducted by NASA SLR Survey Group. Below are excerpts from this survey report: A new geodetic survey of the MOBLAS-7 telescope reference point (the intersection of the azimuth and elevation axis) and the Goddard Geophysical and Astronomical Observatory (GGAO) calibration piers was completed in relation to the survey control network at the GGAO. Some evidence that one of the GGAO calibration piers had undergone a shift in position predicated the survey. This survey provides new calibration data for the MOBLAS-7 system to each visible GGAO calibration pier and system eccentricities from Station Number 7105. Survey observations were completed using precise conventional Electro-Optical techniques. The effective date for the new MOBLAS-7 eccentricities and calibration data is 12 December 1998. MOBLAS-7 System Eccentricities in relation to Station 7105 North: -0.008 Meters East: -0.032 Meters Up: 3.139 Meters The previous survey of the MOBLAS-7 system was completed in October 1993 and the system has remained extremely stable during the intervening period. The small changes in the system eccentricities of 0.003, 0.002 and 0.001 meters in the N, E and UP eccentricities respectively can be attributed to several factors, such as; newer and more precise survey instrumentation used in the new survey measurements; small settlements and creep in the location of the GGAO monuments; and small changes in the MOBLAS-7 system in relation to Station 7105. The survey did disclose a relatively large shift in the position of GGAO Calibration Pier ”B” in relation to the GGAO survey scheme ( 0.011m North, 0.003m East,-0.028m Up). (Note: As a result of this movement, the range to pier ”B” from the system increased by 5.3mm. Calibration pier ”B” had been used since 1986 as the primary calibration target for MOBLAS 7. Due to the suspected instability of this pier, on 23 November 1998, MOBLAS 7 switched its primary calibration target to another more stable calibration target.) If there are any questions concerning this survey, the calibration data, or the previous surveys of the MOBLAS-7 system, please contact Jim Long at 301-805-3977 or email longj@thorin.atsc.allied.com . From: HussonV@thorin.atsc.allied.com (Husson, Van) ******************************************************************************** |