GOP near-real time processing background

1
GOP near-real time processing background

• Jan Dousa
• Geodetic Observatory Pecny
• a priori orbits broadcast or
• IGS ultra-rapid orbit predictions
• network 85 stations, 5 clusters
• pre-processing 6h-data batch
• sub-solution normal equations (NEQ) of
  6h batch
• final solution combining 12x 6h NEQ for orbit
  params
• iterative improved orbits 1 day
• final orbits 3 days
• official product 24h fitted, 24h predicted
  precise orbits
• update every 6h, 1h delay

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GOP orbit and ERP improvements
orbits clocks Y,X pole X,Y pole rates lenght of a day
fitted prod. predicted prod. lt5 cm 10 cm - 0.1 mas 0.3 mas 0.2 mas/day 0.3 mas/day 0.03 ns 0.07 ns
new system developed
official GOP contribution (January 2004)
orbit model acc.codes refined (2007/2008)
contribution stopped (2006)
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Processing developments (2006, 2008)

• 2006 (all the parameters improved by factor
  2)
• switched to official Bernese V5.0 (source-code
  modified)
• new routine system consistent with other GOP
  processing
• revised network configuration and processing
  startup
• parallel processing in clusters (4 CPUs _at_ 2 PCs)
• handling unhealthy satellites and manoeuvres in
  the analysis
• satellite exclusions only in final product, not
  in processing
• ionosphere model estimated
• ambiguity fixing (in 6 hour sessions), 70
  resolved
• datum definition fiducial sites iteratively
  checked
• applying new IGS standards
• igs real-time data support
• 2008 (orbits and X,Y-pole improved
  significantly)
• network carefully reconfigured (40 -gt 86 sites)
• refined estimation of the radiation pressure
  parameters
• refined accuracy code assignment
• monitoring the prediction quality, accuracy code,
  eclipsing satellites, etc. http//www.pecny.cz/
  ( GNSS -gt GPS-orbits )