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SOGRA - Supporting Optimized GNSS Research in Africa

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Final rept. 15 Aug 2009-8 Dec 2014

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This effort was a collaborative project between AFRL Air Force Research Laboratory and UBI University of Beira Interior supported by EOARD European Office of Aerospace Research Development. The major initial investment concerning the research done under SOGRA was focused on the development of an integrated system capable of being installed at remote locations. A prototype was developed and installed at some locations in Africa. The next development the upgrade of the network started in 2010 with several missions to survey the feasibility of new stations and the installation of the new station at Zanzibar, Tanzania in July 2010. The final portion of the effort was the daily processing of the observational files for the SCINDA network using the GIPSY-OASIS software package. Scintillation events can cause sudden changes in coordinate positions or even prevent their calculation. They can be misinterpreted as real displacements due to earthquake events. Algorithms were developed to take into account the influence of scintillation events during the processing of the GPS data. The objective was to verify the level of the correlation between scintillation events in the region and abnormal positioning solutions. The positioning solutions were compared in single mode using the GIPSY-OASIS software package with the Precise Point Positioning strategy and in differential mode using TBC, a commercial software. The results were compared to those obtained using dedicated software RINEXHO developed to correct the GPS observables for second- and third-order ionosphere effects. The conclusions are that the improvement is marginal for most positioning applications, namely for surveying, but can slightly improve the accuracy of the derived time series.

Subject Categories:

  • Atmospheric Physics
  • Numerical Mathematics
  • Statistics and Probability
  • Navigation and Guidance
  • Optics

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