| Date: | 2010-02-08 23:52:00 | |
| Sender: | Philip Gibbs et.al. <slrmail@dgfi3.dgfi.badw-muenchen.de> | |
| Subject: | [SLR-Mail] No. 1835: Herstmonceux two laser system | |
| Author: | Philip Gibbs et.al. | |
| Content: | ******************************************************************************** SLR Electronic Mail 2010-02-08 23:52:00 UTC Message No. 1835 ******************************************************************************** Author: Philip Gibbs et.al. Subject: Herstmonceux two laser system Colleagues. Somewhat belatedly we are announcing here that the SGF Herstmonceux SLR is now fully operational using both kHz and 10Hz lasers as dictated by target and conditions. The development of a kHz capability began several years ago with the necessary upgrade to a high-accuracy event timer that replaced in early 2007 the Stanford interval counters. Some technical problems both with the kHz laser, the co-axial optical arrangement of both lasers and losses within the return optical path have delayed progress, but we are now confident that we have arrived at an extremely versatile system. In particular the observer is able from the observing platform to switch in seconds between the lasers using a single command into the user interface; this makes for very rapid switching for example between standard kHz ranging and 14Hz repetition using the ´old´ laser in support of LRO. As we learn more about the capability of the high-repetition-rate laser we continue to revert to the 10Hz YAG when sky conditions are poor or during daylight tracking for some low-signal targets. Crucially, we are confident that we have minimized potential systematic range differences between the two lasers. In particular, for the vital LAGEOS targets our models of the appropriate centre-of-mass corrections agree to better than 1mm, so use of either laser will be seamless from an analysis point of view. A new site log has been uploaded to the ILRS website to reflect these changes, and also to report new site ties between the laser, two IGS systems and the absolute gravimeter. We are particularly grateful to the French IGN team who re-measured the important ties between the laser and the GNSS systems. Regards, The SGF Team at Hx. -- This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. From: slrmail@dgfi3.dgfi.badw-muenchen.de ******************************************************************************** |