ITG: A New Global GNSS Tropospheric Correction Model

Tropospheric correction models are receiving increasing attentions, as they play a crucial role in Global Navigation Satellite System (GNSS). Most commonly used models to date include the GPT2 series and the TropGrid2. In this study, we analyzed the advantages and disadvantages of existing models and developed a new model called the Improved Tropospheric Grid (ITG). ITG considers annual, semi-annual and diurnal variations, and includes multiple tropospheric parameters. The amplitude and initial phase of diurnal variation are estimated as a periodic function. ITG provides temperature, pressure, the weighted mean temperature (Tm) and Zenith Wet Delay (ZWD). We conducted a performance comparison among the proposed ITG model and previous ones, in terms of meteorological measurements from 698 observation stations, Zenith Total Delay (ZTD) products from 280 International GNSS Service (IGS) station and Tm from Global Geodetic Observing System (GGOS) products. Results indicate that ITG offers the best performance on the whole.

[1]  Yibin Yao,et al.  GTm-III: a new global empirical model for mapping zenith wet delays onto precipitable water vapour , 2014 .

[2]  Jan Kouba,et al.  Testing of global pressure/temperature (GPT) model and global mapping function (GMF) in GPS analyses , 2009 .

[3]  G. Petit,et al.  IERS Conventions (2010) , 2010 .

[4]  Alan Dodson,et al.  Assessment of EGNOS Tropospheric Correction Model , 1999 .

[5]  Richard B. Langley,et al.  The residual tropospheric propagation delay: How bad can it get? , 1998 .

[6]  Sung H. Byun,et al.  A new type of troposphere zenith path delay product of the international GNSS service , 2009 .

[7]  J. Saastamoinen.  Atmospheric Correction for the Troposphere and Stratosphere in Radio Ranging Satellites , 2013 .

[8]  A. E. Niell,et al.  Preliminary evaluation of atmospheric mapping functions based on numerical weather models , 2001 .

[9]  A. Niell.  Global mapping functions for the atmosphere delay at radio wavelengths , 1996 .

[10]  M. Bosilovich,et al.  Evaluation of the Reanalysis Products from GSFC, NCEP, and ECMWF Using Flux Tower Observations , 2012 .

[11]  I. Shapiro,et al.  Geodesy by radio interferometry: Effects of atmospheric modeling errors on estimates of baseline length , 1985 .

[12]  H. Schuh,et al.  Short Note: A global model of pressure and temperature for geodetic applications , 2007 .

[13]  Robert Weber,et al.  Development of an improved empirical model for slant delays in the troposphere (GPT2w) , 2015, GPS Solutions.

[14]  Richard B. Langley,et al.  Assessment of Atmospheric Delay Correction Models for the Japanese MSAS , 2001 .

[15]  H. Schuh,et al.  Global Mapping Function (GMF): A new empirical mapping function based on numerical weather model data , 2006 .

[16]  Yuei-An Liou,et al.  Assessment of ZTD derived from ECMWF/NCEP data with GPS ZTD over China , 2011 .

[17]  R. Simpson.  On The Computation of Equivalent Potential Temperature , 1978 .

[18]  Torben Schüler,et al.  The TropGrid2 standard tropospheric correction model , 2013, GPS Solutions.

[19]  T. Nilsson,et al.  GPT2: Empirical slant delay model for radio space geodetic techniques , 2013, Geophysical research letters.

[20]  Bo Sun,et al.  Validation of ECMWF and NCEP-NCAR reanalysis data in Antarctica , 2010 .

[21]  J. W. Marini,et al.  Correction of Satellite Tracking Data for an Arbitrary Tropospheric Profile , 1972 .

[22]  Wen-yao Zhu,et al.  An Analysis for the Accuracy of Tropospheric Zenith Delay Calculated From ECMWF/NCEP Data Over Asia , 2012 .

[23]  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 .