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13th International Laser Ranging Workshop
"Toward Millimeter Accuracy"

Station Operational Issues (W. Gurtner and V. Husson)
Session Summary

Title Primary Author
Creating a Consolidated Laser Ranging Prediction Format Randy Ricklefs
Operational Issues from the Stations Werner Gurtner
Operational Issues from an ILRS Central Bureau Perspective Van Husson
Operational Issues from the Viewpoint of the SLR Data Analysis Graham Appleby

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:

  • Shortcomings:
    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.
  • Recommendations:
    Calibration of timing devices against standard.
    Web-based collection of hints and tips for devices widely used by ILRS stations.

2. Operational Issues from an ILRS Central Bureau Perspective (Van Husson)

  • 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 Ricklefs)

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.



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Last Updated: June 17, 2014



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