New Tools to Assess the User Domain SBAS Integrity

M. Hernandez-Pajares, J.M. Juan, J. Sanz, F. Toran, J. Ventura-Traveset, C. Lopez, D. Flament

Abstract:	This work summarizes a study performed for the detailed analysis of user domain and pseudorange integrity on Satellite Based Augmentation Systems. Some experimental data of EGNOS and ESTB preoperational service was used for some specific tests, aiming at assessing the new developed techniques, identifying for instance the reaction of the EGNOS checkset subsystem and the way pseudorange errors are translated into the user domain. From this analysis, a new technique for User Domain Integrity Assessment (UDIA) came up. In particular, several complementary tools to asses the EGNOS User Domain Integrity were developed. These tools are inspired in the Stanford-ESA integrity diagram concept presented in a previous work and involve different diagrams to help the integrity analysis. They also include a search algorithm to identify the satellites responsible of eventual Misleading Information events (MIs). Basically, the User Domain Integrity is assessed analyzing the Integrity Ratios XPE/XPL, between the position error (XPE) and protection levels (XPL), for all the possible geometries of satellites, from 4 to all satellites in-view, from a wide European network of monitoring stations. In case of user domain MI or Near MI (NMI) detection, thence the satellites responsible of such events are identified and the EGNOS Check Set (CS) reaction is assessed. In order to validate the technique, this approach was applied to analyze 43 potential UDRE MIs linked to CPF switches, detected with the SREW tool between April to October 2006 on experimental data of EGNOS. When applying this conservative technique to EGNOS operational signal, the safety margins prove to be extremely sound.
Published in:	Proceedings of the 2009 International Technical Meeting of The Institute of Navigation January 26 - 28, 2009 Disney's Paradise Pier Hotel Anaheim, CA
Pages:	894 - 902
Cite this article:	Hernandez-Pajares, M., Juan, J.M., Sanz, J., Toran, F., Ventura-Traveset, J., Lopez, C., Flament, D., "New Tools to Assess the User Domain SBAS Integrity," Proceedings of the 2009 International Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2009, pp. 894-902.
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