13th International Laser Ranging
"Toward Millimeter Accuracy"
Station Operational Issues (W. Gurtner
and V. Husson)
|Creating a Consolidated Laser Ranging Prediction Format
|Operational Issues from the Stations
| Operational Issues from an ILRS Central Bureau Perspective
|Operational Issues from the Viewpoint of the SLR Data
The session combined three invited presentations about operational issues
as seen from the stations, the Central Bureau, and the Analysis. A fourth
paper dealt with a new prediction format.
1. Operational Issues from the Stations (Werner Gurtner)
The results of a station poll performed prior to the workshop were presented:
Outmoded and failing equipment. Shortage in manpower and funds. Software
shortcomings. Daytime noise. Pointing accuracy. Telescope distortions
during the day. Missing real-time access. Environmental problems. Low
link budgets (GPS, Glonass, Etalon)
- Important recent improvements:
Aircraft avoidance radar. Daily IRVs. Predicted time bias. Realtime
exchange of time bias information. New equipment: CSPAD, counter or
event timer, GPS timing, telescope drives, ...). Improved crew training.
Automation and programmed system support.
Calibration of timing devices against standard.
Web-based collection of hints and tips for devices widely used by ILRS
2. Operational Issues from an ILRS Central Bureau Perspective (Van
- Mundane problems, which can be identified at the sites, persist and
limit performance (e.g. barometric errors, site ties, calibration instabilities).
- LAGEOS daylight ranging capabilities limit the performance and accuracy
of site coordinate determination.
- Need to more aggressively pursue sharing best practices/procedures
through the network.
- Need the user community to develop 'WORTH' functions for the ILRS
approved satellite constellation.
- Need to automate ranging operations and equipment maintenance as
much as possible.
3. Station Operational Issues - an analysis perspective.(G. Appleby)
Laser ranging analysts had been asked to consider a more proactive approach
to operational priority issues faced by the stations in order to maximize
the science that can be obtained from the data. Suggestions were that
observation of segments of passes near AOS, PCA and LOS should be a high
priority for all satellites and that the most able systems should primarily
concentrate on the difficult targets. To achieve best coverage, dynamic
scheduling should be developed, and of prime importance is the minimisation
of systematic bias.
4. Creating a Consolidated Laser Ranging Prediction Format (Randy
Randy presented the rationale for a new Prediction Format and the draft
proposal developed by an ad hoc Working Group during the last few months.
The new format will deal with satellites, lunar reflectors as well as
interplanetary transponders, based on earth-fixed tabulated positions.