IGS

International GNSS Service

3rd Data Reprocessing Campaign

third full reanalysis of all IGS GPS data collected since 1994

IGS

OBJECTIVE
By the start of 2019, the Analysis Centers (ACs) of the International GNSS Service will begin the third reanalysis of the full history of GPS data collected by the IGS global network since 1994 in a fully consistent way using the latest models and methodology.
VERIFICATION
OF
MODELS
In the leadup to the reprocessing effort we will be attempting to verify the implementation of the different modelling techniques by each AC. This website will contain the results of the inter-comparisons as they progress.

Orbit Modelling

CONVENTIONS
AND
MODELLING
UNDER
CONSIDERATION
FOR
REPRO3
(new
models
highlighted
in red)
IERS Conventions(2010) — generally should be implemented
Mean Pole tide — has been updated from a cubic to a linear model
  • only to be implemented during the reprocessing run. Do not implement this in the operational stream otherwise a discontinuity in the velocities will be introduced
  • There is the possibility of applying this correction at the solution level, rather than at the observation level
Sub-daily EOP model — the exact model is still being investigated, expect this to reduce the spike 14d spectra
Some of the models being tested are:
  • Desai-Sibois(2016)
  • Gipson
Solar radiation pressure models — the recommended model is still being investigated

Earth albedo models
Antenna Thrust
Use of reverse kinematic solutions for satellite attitude
  • Yaw model from JPL

Third body effects — recommend ACs apply all planets into model

Time variable gravity Other ITRF observing techniques are considering the highest fidelity time-variable gravity model, this is not strictly required for GNSS orbits, but it will be important to stay consistent with their implementation.
Loading Models — should be consistent with the TVG model, and again consistent across all observing techniques
use IGS14 reference frame (aligned to ITRF2014)
use updated igs14.atx "absolute" antenna calibrations
Data Products use RINEX3 in preference to RINEX2 Provide solutions in updated SINEX formats that support RINEX3
AREAS
OF
INVESTIGATION

(new
models
highlighted
in red)
Near-field multipath
Improve Radiation Force Modelling
Improve Determination of Attitude of spacecraft especially during eclipse
L5 Antenna Calibrations for satellites and Receivers


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