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Results of 1996 Data Analysis Survey

Note: This information has been updated from the article published in the June 1996 issue of the Laser Ranging Newsletter of the SLR/LLR Subcommission of the CSTG.

A regular question that arises at each CSTG SLR Subcommission meeting is: Are we doing the best we can to satisfy the needs of the science community? Do we understand their needs? In this connection: Are we making most effective use of our SLR station resources? Are we setting priorities correctly and are we allocating tracking time in the most effective manner? Should different stations be tracking with different sets of priorities? Should stations use priorities that are set dynamically?

To begin to address these issues as a community, we have started at a fundamental level to find out

  • Who is using the SLR data?
  • What data are they using?
  • What data is not being used?
  • What applications are being studied?
  • Does the data satisfy the analysts' needs? and
  • What is missing?

In a recent survey of the analysis groups, we asked the following questions:

  • Which satellites are you currently using in your analyses?
  • What are the applications for each satellite (station position, motion, gravity field, Earth rotation, altimetry, etc.) ?
  • Are you receiving sufficient data for your analyses?
  • Are you receiving sufficient geographic coverage?
  • Are the data of sufficient accuracy for your applications?
  • Are there other satellites that you plan to use in the future? For what applications?
  • What else do you need that you are not getting?

Some general comments received from the respondents regarding areas that need attention were:

  • Data quality:
    • Large disparity in data quality among stations
    • Often, data of poor quality are worse than no data at all
    • Too many systems with poor data quality
  • Data Volume:
    • Tracking coverage from some stations is very sporadic and sparse
    • Some stations do not provide a minimum level of contribution
    • Tracking gaps of more than ten days are a problem
    • Weeks with less than 100 LAGEOS passes are sparse
    • Much more data required on ETALON-1 and -2, GPS-35/36, and GLONASS
    • GFZ-1 data is insufficient
  • Geographic Coverage:
    • Better geographic coverage needed in the Southern hemisphere, Russia, and China
  • Temporal Coverage:
    • Tracking gaps over weekends are a problem
    • LAGEOS-1 and -2 data is adequate for three-day resolution, but inadequate for one-day resolution
    • More data on STELLA, STARLETTE, and AJISAI required for one-day resolution of higher order perturbations
  • Local Surveys:
    • More reliable local surveys and more information about the surveys and local eccentricities required
  • Operational Follow-up:
    • Lack of communications with some stations regarding problems
  • Satellites:
    • More satellite targets of high quality needed
Table
SLR Analysis Survey Results
Organization Respondent Satellites by Priority Areas of Investigation
University of Southampton Graham Swinerd STARLETTE
STELLA
AJISAI
LAGEOS-1/2
ERS-1/2		 Ocean Tides
Gravity Field
Long Period Aerodynamics
Gas Surface Interactions
Delft University Ron Noomen LAGEOS-1/2
ERS-1/2
TOPEX
GPS-35/36
STELLA
STARLETTE		 Orbit Analysis
Earth Rotation
Position/Motion
Altimetry
National Aerospace Lab, Tokyo Masaaki Murata LAGEOS-1/2
ETALON-1/2
TOPEX
GPS-35/36
(GFZ-1)		 Position/Motion
Gravity Field
Earth Rotation
Altimetry
Orbital Analysis
RGO Graham Appleby ETALON-1/2
LAGEOS-1/2		 Non-Gravitational Acceleration
Earth Rotation
Position/Motion
Astronomical Institute of Berne Werner Gurtner GPS-35/36
Add'l GPS sat.		 Position/Motion
Earth Rotation
Technique Comparison
Russian Academy of Sciences Suriya Tatevian LAGEOS-1/2
ETALON-1/2
(STARLETTE)
(STELLA)		 Position/Motion
Earth Rotation
(Gravity Field)
NASA/GSFC Erricos Pavlis LAGEOS-1/2
GPS-35/36
STARLETTE
STELLA
AJISAI
ETALON-1/2
GFZ-1
TOPEX
ERS-1/2
GLONASS		 Position/Motion
Earth Rotation
Gravity Field
Altimetry
Shanghai Observatory Tan Detong LAGEOS-1/2
ETALON-1/2
GLONASS-63/67
TOPEX
ERS 2		 Earth Rotation
Position/Motion
Altimetry
Auston University, Birmingham, UK Philip Moore ERS-1/2
TOPEX
STELLA
(GFZ-1)		 Gravity Field
Aerodynamics
Altimetry
GFZ/DLR Heiner Massmann ERS-1/2
GFZ-1
LAGEOS-1/2
(STELLA)
(AJISAI)
(TOPEX)
(High Alt. Sat.)		 Precise Orbits for Altimetry and SAR
Gravity Field
Position/Motion
Atmospheric Density
CSR/University of Texas Richard Eanes LAGEOS-1/2
STARLETTE
STELLA
AJISAI
GFZ-1
ETALON-1/2
TOPEX
ERS-1/2
GPS-35/36		 Position/Motion
Earth Rotation
Gravity Field
Altimetry
Performance Assessment
IfAG/Branch Potsdam Bernt Richter LAGEOS-1/2
ETALON-1/2
GPS-35/36
STARLETTE
STELLA		 Orbit Analysis
Earth Rotation
Position
Velocity
Combined Solution with Other Techniques
GRGS/CNES and OCA Richard Biancale STARLETTE
STELLA
LAGEOS-1/2
AJISAI
TOPEX
ERS-1/2		 Gravitiy Field and Long Period Variations
Ocean Tides
Position/Motion
Atmospheric Density
Altimetry and Calibration
ASI Pippo Bianco LAGEOS-1/2
AJISAI
STARLETTE
STELLA
ERS-1/2		 Position/Velocity
Earth Rotation/Polar Motion
Non-Gravitational Perturbations on Satellites' Orbits
Precise Orbits for Altimetry
Fundamental Physics
Gravity Field and Long Period Variations
Atmospheric Density
University of Padova Alessandro Caporali LAGEOS-1/2
(GPS 35/36)		 Position/Motion
Earth Rotation/Polar Motion
(Earth and Ocean Tides)
(Gravity Field)
MIT/Lincoln Labs Mike Gaposhkin LAGEOS-1/2
ETALON-1/2
AJISAI
STARLETTE
STELLA
ERS-1/2
TOPEX
GLONASS		 Precise Orbit for Calibration of Satellite Surveillance Radars

Updated: October 12, 1996