Positioning Accuracy

Description Processing Software

The demonstration of the algoritms to tune the stochastic model is performed through an adjusted version of gLAB.

As per the gLAB website:

gLAB is a software tool suite developed under a European Space Agency (ESA) Contract by the research group of Astronomy and Geomatics (gAGE) from the Universitat Politecnica de Catalunya (UPC), is an interactive educational multipurpose package to process and analyse GNSS data.

gLAB performs precise modeling of GNSS observables (pseudorange and carrier phase) at the centimetre level, allowing both standalone GPS positioning and PPP. Every single error contributor may be assessed independently, which, in turn, provides a major educational benefit. gLAB is adapted to a variety of standard formats like RINEX-3.00, SP3, ANTEX and SINEX files, among others. Moreover, functionality is also included for GPS, Galileo and GLONASS, allowing performing some data analysis with real multi-constellation data.

The gLAB software tool is quite flexible, able to run under Linux and Windows operating systems and is provided free of charge by ESA Education Office to universities and GNSS professionals

gLAB - Source Code
gLAB - Software User Manual
gLAB - GNSS Data Processing Lab Exercises
gLAB - Frequent Answered Questions
gLUE - Bootable USB stick with a full environment ready to use based on LINUX (Ubuntu) OS.
HTML files describing the standard formats.

The adjusted version gLAB+ encorporates the following extensions to the ‘standard’ gLAB suite:

  • Matlab frontend (Scintillation Assessment Tool) providing graphic user interface to the extended version. Including:
  • Graphic overview of scintillation and other indices provided through the ISMR format in use by Septentrio and Novatel.
  • Calculation of an extended ISMR format (including indices derived from high rate I and Q samples).
  • Geostatistical analyses (variogram and covariance functions) for the generation of scintillation maps.
  • Generation of scintillation maps through Kriging.Graphical user interface to gLAB+ functionality.
  • Graphical user interface for plotting using the binary output file from gLAB+.
  • Variance Component Estimation to optimize elevation based weighting scheme.
  • Ability to process multiple days with selected start and end times.
  • Ability to use stochastic modelling information from a weights file, providing the standard deviations of the measurements.
  • Ability to use C/No information for stoachastic modelling provided by the RINEX observation file.
  • Ability to use scintillation information from a scintillation file, providing the S4 and Phi60 indices, which can be used in screening and Variance Component Estimation (VCE) schemes.
  • Ability to use a phase error file (calculated from high rate I and Q samples).
  • Ability to use elevation weight file providing elevation based model per PRN.
  • Option to create binary output file, including all available information from the processing to be used in plotting interface.
  • Option to create VCE output file to be used in the VCE optimisation based elevation weighting scheme.

The gLAB+ version used in this prototype service comprises a batch processing tool (matlab based) calling the gLAB+ excecutable for the different processing stratagies.