| Date: | 2004-01-29 23:31:00 | |
| Sender: | Van S. Husson, ILRS CB <Husson, Van <Van.Husson@honeywell-tsi.com>> | |
| Subject: | [SLR-Mail] No. 1180: 7501 HARL Updated System Eccentricities | |
| Author: | Van S. Husson, ILRS CB | |
| Content: | ******************************************************************************** SLR Electronic Mail 2004-01-29 23:31:00 UTC Message No. 1180 ******************************************************************************** Author: Van S. Husson, ILRS CB Subject: 7501 HARL Updated System Eccentricities Dear Colleagues (ATTENTION: ANALYSIS WG), Sorry for the late notice, but there has been a RETRO-active change in the Hartebeesthoek (Station 7501) MOBLAS 6 system eccentricities dating back to day 122 in the year 2000 (i.e. a RETRO-ACTIVE change). To date, 2 surveys have been performed of the NASA MOBLAS 6 system located in Hartebeesthoek. The 1st survey was conducted by HTSI in 2000 and the 2nd survey was conducted in 2003 by an international team composed of the French Institute Geographic National (IGN), HTSI, and the South African Department of Land Affairs, Survey and Mapping. Here are the values of the both system eccentricity measurements: Component 2000 Survey 2003 Survey Delta --------- ----------- ----------- --------- North -0.0030 m -0.0010 m -0.0020 m East -0.0060 m -0.0060 m no change Up 3.2280 m 3.2270 m 0.0010 m There were small changes in North and Up of 2 mm and 1 mm, respectively. Based On Jim Long´s Survey report dated November 12, 2003, the reason for the measured change is due to some shifting and/or settlement of the MOBLAS-6 mount since the initial 2000 survey. Since the exact date of the shifting and/or settlement is unknown, the ILRS CB has decided to BACK-date the 2003 survey to the day 122 in the year 2000. Since the ITRF will be using the 2003 local ties for this site in its network combination solutions, it is imperative that the SLR analysts used the latest 7501 system eccentricities for consistency. The SLR system eccentricity SINEX files (ecc_une.snx & ecc_xyz.snx) on the CDDISA have been updated to reflect these changes in the directory: ftp://cddisa.gsfc.nasa.gov/pub/slrocc/ From: ”Husson, Van” ******************************************************************************** |