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Precise Geodetic Infrastructure National Requirements for a Shared Resource (2010) / Chapter Skim
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Appendix C: Glossary
Pages 131-138

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From page 131...
... . Precision contributes to accuracy, but accuracy also takes into account systematic biases arising from calibration errors or imperfect observation models.
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From page 132...
... . • Mean sea level -- A tidal datum computed as the arithmetic mean of hourly heights observed over a specific 19-year Metonic cycle.
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From page 133...
... A detailed definition and descriptions of "error analysis" can be found, for instance, on the National Geodetic Survey Website: http://www.ngs.noaa.gov/CORS-Proxy/Glossary/ xml/NGS_Glossary.xml • Random error -- a statistical quantity that measures how repeated measurements of the same quantity by a single observer or multiple observers yield slightly different results. • Systematic error -- the effect on the result of a measurement caused by a flaw in the mea suring instrument or the measuring procedure.
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From page 134...
... , an SLR station (with some stations having LLR capability) , at least three GNSS/GPS stations to provide local tie information and monitor site deformation, a DORIS beacon, terrestrial survey instruments to determine and monitor local ties to the millimeter level, a superconducting or, preferably, an absolute gravimeter, meteorological sensors, and a variety of other sensors such as seismometers, tiltmeters, and water vapor radiometers (Plag and Pearlman, 2009)
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From page 135...
... -- An international service under the IAG for coordinating analysis and distribution of DORIS data and data products. International Earth Rotation Service (IERS)
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From page 136...
... Mean High Water (MHW) -- Mean high water is a tidal datum computed as the arithmetic mean of the high-water heights observed over a specific 19-year Metonic cycle.
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From page 137...
... Satellite Laser Ranging (SLR) -- A geodetic technique in which a laser signal is transmitted from a ground-based station, reflects off specially designed mirrors (retro-reflectors)
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From page 138...
... Starlette -- A passive French satellite, launched in 1975, used in Satellite Laser Ranging, predomi nantly to measure the gravity field. Stick-slip -- Behavior (often of a fault)
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Key Terms

  • mean sea
  • laser ranging
  • rotation axis
  • reference surface
  • geodetic technique

  • vertical datum
  • data products
  • sea level
  • earth rotation
  • sea surface

  • reference ellipsoid
  • gravity field
  • horizontal datum
  • european space
  • synthetic aperture

  • space agency
  • international service
  • water vapor
  • world geodetic
  • national geodetic

  • geodetic survey
  • satellite laser
  • laser signal
  • international atomic
  • geodetic datum

  • free electrons
  • heights observed
  • datum computed
  • precise orbit
  • nasa satellite


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