Concepts and Performance Results on the Combination of Different Integrity Methods Using UAIM and GNSS without SA

Erwin Loehnert, Robert Wolf, Juergen Pielmeier, Wolfgang Werner and Theodor Zink

Abstract:	A second generation GNSS has to overcome especially one basic deficiency of present satellite navigation systems as the U.S. GPS and the Russian GLONASS, i.e. the lack of integrity in the Signal-In-Space (SIS). Thus, the European contribution to GNSS-2 (Galileo) requires that the SIS shall provide integrity for Category I precision approach and landing. The integrity of a system refers to the assurance that all functions of this system perform within the operational limits where the integrity risk is the probability of undetected failures resulting in the loss of specified accuracy. Analyses of appropriate integrity monitoring techniques for a GNSS-2 must be performed in order to demonstrate whether or not this performance requirement can be met by the proposed GNSS-2 architectures. The paper discusses basic integrity monitoring concepts as Receiver Autonomous Integrity Monitoring (RAIM) like methods for the Galileo users and the contribution of ground-based integrity monitoring as well as results of an adapted RAIM algorithm availability simulation. Because RAIM alone is very likely insufficient to fulfil all require- ments necessary for a broad spectrum of users (e.g. civil aviation) several techniques have been proposed for combining RAIM with external systems (e.g. LORAN-C, GIC) or independent sensors like inertial sensors, baro- meter etc. Those techniques are commonly known as User Autonomous Integrity Monitoring (UAIM). Firstly, an approach for generic RAIM algorithms to be used for GNSS without Selective Availability SA (GPS since 2nd May 2000, Galileo) is outlined. Then, basic concepts and techniques for user integrity monitoring using RAIM and hybridisation are presented. Finally, a first performance assessment of the combination of different UAIM techniques and concluding remarks will be given.
Published in:	Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT
Pages:	1561 - 1571
Cite this article:	Loehnert, Erwin, Wolf, Robert, Pielmeier, Juergen, Werner, Wolfgang, Zink, Theodor, "Concepts and Performance Results on the Combination of Different Integrity Methods Using UAIM and GNSS without SA," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 1561-1571.
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