Advanced RAIM Scheme and its Evaluation for Non-aeronautical users in Different Environments

J. Simon, J. Vazquez, A. Madrazo, A. Cezon, W. Enderle

Abstract:	The Galileo Services Consolidation (GSC) study, founded by the European Commission, is aimed at identifying new or evolved integrity user needs in different user communities (aviation, maritime, rail, road, LBS and space), including the identification of advanced RAIM concepts that can provide an integrity information for non-aeronautical users in different environments. As a result of these activities, a RAIM integrity scheme called “FDE+PL” has been developed and evaluated within the project based on a prototype. The proposed RAIM scheme is based on two modules, a first one performing Fault Detection and Exclusion (FDE) of outliers and a second one devoted to the computation of Protection Levels (PL) using for that purpose those measurements that passed the FDE module, which in fact can contain outliers depending on FDE module performances. The proposed FDE+PL RAIM scheme, that should be considered as a general methodology for providing integrity, has been particularized with the identification of specific options for the FDE and PL computation modules. As it will be seen after, several options have been identified for the FDE module, like the analysis of navigation residuals or the analysis of navigation signals characteristics. Meanwhile, MHSS RAIM technique [6] has been chosen for the PL computation within the global FDE+PL scheme. Multiple Hypothesis Solution Separation (MHSS) has been selected as it is a RAIM technique that computes a protection level that accounts for possible multiple simultaneous faulty measurements, which is the typical case of non-aeronautical environments. After introduction of the FDE+PL scheme the paper will show performances of the proposed RAIM scheme under different scenarios and with configurations considering Galileo and Galileo+GPS constellations, as it is expected that the multicostellation scenario can improve performances on harsh environments. These performances, that will heavily depend on the severity of the environment under consideration, will allow concluding that in order to increase service availability (while maintaining integrity requirements) on nonaeronautical environments it is necessary to identify reliable mechanisms for the exclusion (and not only for the detection) of outliers on these environments.
Published in:	Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010) September 21 - 24, 2010 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	292 - 300
Cite this article:	Simon, J., Vazquez, J., Madrazo, A., Cezon, A., Enderle, W., "Advanced RAIM Scheme and its Evaluation for Non-aeronautical users in Different Environments," Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010), Portland, OR, September 2010, pp. 292-300.
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