new and future models
DESCRIPTION
New and Future Models. Matt King, Newcastle University, UK. New: Effects of New Models on Tropo Estimates. Several consistent global reprocessing solutions (1995-2007) In turn, examine effect of Abs Phase Centres VMF1 Improved Hydrostatic Zenith Delay Thomas et al (in prep) . - PowerPoint PPT PresentationTRANSCRIPT
3/6/09
New and Future Models
Matt King, Newcastle University, UK
3/6/09
New: Effects of New Models on Tropo Estimates
• Several consistent global reprocessing solutions (1995-2007)
• In turn, examine effect of
– Abs Phase Centres
– VMF1
– Improved Hydrostatic Zenith Delay
• Thomas et al (in prep)
3/6/09
Tropo Estimates
• Respective models influence is location dependant)
3/6/09
Near future: Higher order ionospheric effects
• Examine effect of 2nd+3rd order ionosphere on consistent reprocessing (1995-2007, every 2nd day)
• Also effect of geomagnetic model (simple dipole vs International Geomagnetic Reference Field)
• Petrie et al (in prep), and invited talk at EGU
3/6/09
2nd and 3rd order iono
Transformation to ITRF2005
Effect of modelling terms
Difference between dipole and IGRF modelPeriodogram for dTZ
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2nd and 3rd order
1996-2000
2001-2005
1996-2005
3/6/09
Needed: Improved MP model
• Simulation MP model of Elosegui et al (1995) on long time series
– Static MP field is sampled by time-variable satellite constellation
– Time-variable propagation effect?
3/6/09
Possible MP effect
Presuming clear horizon
3/6/09
Possible MP effect
3/6/09
Conclusions
• Recent models improve GPS TZD estimates dramatically
• Higher Order iono important for global reference frame
• MP simulations
– Gives feel for likely MP effect at each site
– Model too simplistic – e.g., no azimuthal variation, technically only applies in far field
– Need advances here to model and mitigate the effect