9:30 AM - 9:45 AM
[G01-1-05] IGS14/igs14.atx: Implications for IGS products
invited
On January 29, 2017, the International GNSS Service (IGS) adopted a new reference frame (IGS14), based on the latest release of the International Terrestrial Reference Frame (ITRF2014), as the basis for its products. An updated set of satellite and ground antenna calibrations (igs14.atx) became effective at the same time. IGS14 and igs14.atx replace the previous IGS08/igs08.atx framework in use since April 17, 2011 and in the second IGS reprocessing campaign (repro2).
The update from IGS08/igs08.atx to IGS14/igs14.atx covers three different aspects, each with different expected impacts on the IGS products. First, the update of the reference frame itself is expected to improve the precision of the alignment of the IGS products to the ITRF, since IGS14 includes more available reference frame stations with more precise and up-to-date coordinates than IGS08.
Secondly, compared to igs08.atx, igs14.atx includes robot calibrations for 17 additional ground antenna types and 19 updated type-mean robot calibrations. These calibration updates are expected to increase coordinate accuracy for stations equipped with these antennas and may also lead to improved repeatabilities of their position time series.
Finally, the radial components of all GPS and GLONASS satellite phase center offsets (z-PCOs) were updated from igs08.atx to igs14.atx. The satellite z-PCOs were changed by about -6 cm on average, changing the scale of the IGS daily solutions by about +0.5 ppb and bringing it closer to the ITRF scale. The update of the z-PCOs of recently launched satellites, from preliminary block-specific values to satellite-specific estimates, is additionally expected to reduce large-scale systematic errors in IGS station positions and in particular to stabilize the scale of the IGS daily solutions.
This presentation will first review the elaboration of IGS14 and igs14.atx. The different impacts of the switch on IGS products will then be quantified and discussed.
The update from IGS08/igs08.atx to IGS14/igs14.atx covers three different aspects, each with different expected impacts on the IGS products. First, the update of the reference frame itself is expected to improve the precision of the alignment of the IGS products to the ITRF, since IGS14 includes more available reference frame stations with more precise and up-to-date coordinates than IGS08.
Secondly, compared to igs08.atx, igs14.atx includes robot calibrations for 17 additional ground antenna types and 19 updated type-mean robot calibrations. These calibration updates are expected to increase coordinate accuracy for stations equipped with these antennas and may also lead to improved repeatabilities of their position time series.
Finally, the radial components of all GPS and GLONASS satellite phase center offsets (z-PCOs) were updated from igs08.atx to igs14.atx. The satellite z-PCOs were changed by about -6 cm on average, changing the scale of the IGS daily solutions by about +0.5 ppb and bringing it closer to the ITRF scale. The update of the z-PCOs of recently launched satellites, from preliminary block-specific values to satellite-specific estimates, is additionally expected to reduce large-scale systematic errors in IGS station positions and in particular to stabilize the scale of the IGS daily solutions.
This presentation will first review the elaboration of IGS14 and igs14.atx. The different impacts of the switch on IGS products will then be quantified and discussed.