An Optimized RAIM Approach and Performance Characterization in the Presence of Non-Gaussian Error Sources

James DiLellio

Abstract:	The objective of this paper is to explore an optimized RAIM algorithm by refining the assumptions of the leading-order fault free error sources observed today and expected in the near future from developing GNSS designs. By revisiting the first principles used to derive standard RAIM fault detection, a modified detection algorithm is developed to more accurately accommodate these new fault-free error distributions. To begin, a modified detection threshold analysis is conducted to encapsulate the new types of fault free error distributions. Protection levels are also re-derived against the new detection threshold for consistency of the RAIM-based approach. Verification of this new approach is performed by employing Monte Carlo simulations that assume non- Gaussian error sources that accurately reflect currently observed system errors. Various categories of non- Gaussian errors are considered to capture current and future system errors generated by the design, operations, and management of modern satellite navigation systems. The results of the analysis and simulation indicate that this optimized RAIM algorithm can provide significant operational benefit by improving the ability to protect the navigation user against system faults. In addition, service availability can be improved and new operational scenarios explored with tighter alert limits supported by the navigation solution, without reducing the effective protection provided to the user. New scenarios that may benefit from this approach could include automobile navigation and intelligent highway applications, autonomous vehicle operations, aviation, and other platforms requiring a trusted navigation solution.
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:	276 - 283
Cite this article:	DiLellio, James, "An Optimized RAIM Approach and Performance Characterization in the Presence of Non-Gaussian Error Sources," Proceedings of the 2009 International Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2009, pp. 276-283.
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