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What

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Primary accuracy difference is in UT1 estimation (not relevant for ... at Luxemburg University and distributed on GAMiT/GLOBK ftp site (everest.mit.edu) ... – PowerPoint PPT presentation

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Title: What


1
Whats New ?
  • Better ambiguity resolution
  • LC_AUTCLN now robust for all data with good
    pseudorange from 1994
  • gt 90 resolution after 2004, 80 2001, 70 1996
  • LC_HELP should be equivalent for small networks
  • IAU2000 replaces IAU1980 nutation model
  • Primary accuracy difference is in UT1 estimation
    (not relevant for regional studies)
  • Cannot use g-files created with a different model
    (use SP3 or change nutabl link)

2
Whats New ?
  • Better IGS orbits
  • Can run GAMIT (and GLOBK) with IGSF orbits fixed
    (BASELINE not RELAX)
  • IGSF (from SP3 files) now default, not SIOF (from
    g-files)
  • No discernible orbital error to 4000 km for data
    since at least 2004
  • Reprocessed orbits available later in 2009
  • Reprocessed global h-files available from MIT and
    SOPAC
  • Primary improvement is global ambiguity
    resolution
  • MIT files up to 300 global sites
  • SOPAC files up to 200 global sites plus regional
    networks
  • sh_get_hfiles allows selection of MIT
    reprocessed, SOPAC reprocessed, or SOPAC
    operational
  • Note scale discontinuity at GPS Week 1400
    (November 2008) with current IGS orbits and SOPAC
    operational h-files due to change to absolute
    PCVs

3
Quality of IGS Final Orbits 1994-2008 20 mm
1 ppb Source
http//acc.igs.org
4
Whats New ?
  • Better models for atmospheric propagation effects
  • GPT replaces standard temperature and pressure
    for a priori ZHD
  • GMF replaces NMF for mapping functions
  • VMF1 ZHD and mapping functions from numerical
    weather models available as grid
  • Atmospheric loading ( ATML ) corrections
    available
  • Gridded values available from T van Dam at
    Luxemburg University and distributed on
    GAMiT/GLOBK ftp site (everest.mit.edu)
  • Should be used in conjunction with VMF1 ZHD
  • Sub-daily ( thermal tide ) components not yet
    handled correctly
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