Improving GLONASS orbit quality by re-estimating satellite antenna offsets

Abstract Earlier studies performed at the Center for Orbit Determination in Europe (CODE) analysis center have revealed conspicuous signatures for certain GLONASS satellites when comparing their orbits with Satellite Laser Ranging (SLR) measurements. In this study we show that this phenomenon can be significantly reduced when using horizontal satellite antenna offsets that differ from the nominal values used by the International GNSS Service (IGS) for specific intervals and satellites. Analysis of multi-year time series shows instantaneous changes in the satellite antenna offset parameters of several centimeters in the X- and Y-component whereas the Z-component is not affected. In some cases the offsets do not agree with the nominal values during the entire lifetime of the satellite. The magnitude of the deviation may vary between 5 and 15 cm. Using these re-estimated satellite antenna offsets in the orbit determination the residuals with respect to the Satellite Laser Ranging (SLR) measurements are significantly reduced whereas the orbit misclosures for one-day arcs are too noisy to detect a positive or negative impact. It is difficult to reconstruct from the available information what actually caused the observed changes. However, changes in the carrier-to-noise density reported in the observation files in Receiver INdependent EXchange format (RINEX) by several IGS stations suggest an issue with the satellite antennas.

[1]  L. Mervart,et al.  Extended orbit modeling techniques at the CODE processing center of the international GPS service for geodynamics (IGS): theory and initial results. , 1994 .

[2]  M. Rothacher,et al.  Estimation of elevation-dependent satellite antenna phase center variations of GPS satellites , 2003 .

[3]  Harald Schuh,et al.  Troposphere mapping functions for GPS and VLBI from ECMWF operational analysis data , 2006 .

[4]  Leos Mervart,et al.  Combining consecutive short arcs into long arcs for precise and efficient GPS Orbit Determination , 1996 .

[5]  Pascal Willis,et al.  The IGEX-98- campaign: Highlights and perspective , 2000 .

[6]  Peter Steigenberger,et al.  Generation of a consistent absolute phase-center correction model for GPS receiver and satellite antennas , 2007 .

[7]  R. Dach,et al.  Bernese GNSS Software Version 5.2 , 2015 .

[8]  R. Dach,et al.  CODE’s new solar radiation pressure model for GNSS orbit determination , 2015, Journal of Geodesy.

[9]  Z. Altamimi,et al.  ITRF2014: A new release of the International Terrestrial Reference Frame modeling nonlinear station motions , 2016 .

[10]  H. Schuh,et al.  Troposphere mapping functions for GPS and very long baseline interferometry from European Centre for Medium‐Range Weather Forecasts operational analysis data , 2006 .

[11]  R. Dach,et al.  Absolute IGS antenna phase center model igs08.atx: status and potential improvements , 2016, Journal of Geodesy.

[12]  Peter Steigenberger,et al.  The Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS) - Achievements, prospects and challenges , 2017 .

[13]  Peter Steigenberger,et al.  CODE repro2 product series for the IGS , 2014 .

[14]  T. Springer.  Modeling and validating orbits and clocks using the Global Positioning System , 2002 .

[15]  Tim Springer,et al.  GPS, GLONASS and More , 2010 .

[16]  Rolf Dach,et al.  CODE’s five-system orbit and clock solution—the challenges of multi-GNSS data analysis , 2017, Journal of Geodesy.

[17]  Thomas A. Herring,et al.  Effects of atmospheric azimuthal asymmetry on the analysis of space geodetic data , 1997 .

[18]  Grant Hausler,et al.  The International GNSS Service , 2017 .

[19]  Peter Steigenberger,et al.  Impact of the arc length on GNSS analysis results , 2016, Journal of Geodesy.

[20]  Jan Kouba,et al.  A simplified yaw-attitude model for eclipsing GPS satellites , 2009 .

[21]  M. Meindl,et al.  GNSS processing at CODE: status report , 2009 .

[22]  P. Steigenberger,et al.  Satellite laser ranging to GPS and GLONASS , 2015, Journal of Geodesy.

[23]  O. Montenbruck,et al.  Springer Handbook of Global Navigation Satellite Systems , 2017 .

[24]  Michael R Pearlman,et al.  THE INTERNATIONAL LASER RANGING SERVICE , 2007 .