| Date: | 1997-07-16 10:00:00 | |
| Sender: | Ch. Reigber <prd@dfd.dlr.de (PRD)> | |
| Subject: | [SLR-Mail] No. 74: GFZ-1 3-day Repeat Cycle Tracking Campaign | |
| Author: | Ch. Reigber | |
| Content: | ******************************************************************************** SLR Electronic Mail 1997-07-16 10:00:00 UTC Message No. 74 ******************************************************************************** Author: Ch. Reigber Subject: GFZ-1 3-day Repeat Cycle Tracking Campaign GFZ-1 3-DAY REPEAT CYCLE INTENSIVE SLR TRACKING CAMPAIGN PROPOSAL -------------------------------------------------------- GFZ-1´s orbit again reaches an important period where resonance effects due to gravitational accelerations in an orbit configuration repeating exactly after 3 revolutions of the Earth will reveal themselves in form of extreme orbit perturbations. These can be measured with the help of the global SLR tracking network. We therefore propose to conduct a 3-day repeat cycle intensive campaign from August 4th until October 6th, 1997, through the 0.5 km band around the resonance altitude. With a best effort amount of tracking data the gravity coefficients mainly in the resonant orders 31 and 77 of a spherical harmonic expansion of the potential can be solved more accurately and reliably from pure satellite tracking data. Back in 1996, from January 22nd until March 18th, the first GFZ-1 intensive campaign which aimed at following the first 8-day repeat cycle orbit yielded a temporary record of 66 passes observed by the global network in week 6, 1996. The overall tracking record with 83 passes is hold by week 23 in 1996. Current tracking efforts on GFZ-1 have a data yield of 10 to 40 passes per week. In the light of these numbers we like to encourage all SLR stations to do their best in achieving a dense coverage of measurements of GFZ-1´s orbit during this unique opportunity period. Because this is the one and only 3-day repeat cycle period GFZ-1 will move through. All time spent by you and us in this job is to the benefit of a further improvement of the knowledge of the gravity field. Also the campaign is suitable to demonstrate the capability of SLR to generate unique data in geosciences. Please feel free to comment on this proposal to rolf.koenig@dlr.de . Good luck and best wishes Ch. Reigber From: prd@dfd.dlr.de (PRD) ******************************************************************************** |