GBAS Validation Methodology and Test Results from the Stanford LAAS Integrity Monitor Testbed

Sam Pullen, Ming Luo, Scott Gleason, Gang Xie, Jiyun Lee, Dennis Akos, and Per Enge and Boris Pervan

Abstract:	To verify that the integrity requirements that apply to Ground Based Augmentation Systems are met, testing of GBAS ground facility equipment with injected failures is necessary to demonstrate the effectiveness of the monitor algorithms built into the ground equipment. While it is impractical to generate sufficient independent failure samples to guarantee via test alone that these require- ments are met, testing supplements analysis and simulation to demonstrate that analysis assumptions are valid and that flagged measurements are excluded from the set of broadcast pseudorange corrections. Stanford University is conducting a series of tests in which failures are injected into its GBAS ground facility prototype, the Integrity Monitor Testbed (IMT). Failures are input using a WelNavigate 40-channel GPS signal simulator and by modifying stored IMT receiver packets collected under nominal conditions. In most cases, only a few failure samples are generated to validate detection and proper fault diagnosis and exclusion (functional testing). However, failures that can be generated repeatedly (such as satellite clock anomalies) and failures for which the monitoring analysis is novel and/or unusually complex will be tested with sufficient failure samples to provide reasonable statistical bounds on monitor effectiveness (statistical testing). This paper describes the verification test procedures that have evolved from IMT failure testing and will be used by the FAA to perform Type Acceptance of GBAS ground systems provided by its Government Industry Partnership (GIP). In addition, the results of recent IMT failure tests with injected broadcast navigation data errors (incorrect satellite ephemerides) are shown.
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:	1191 - 1201
Cite this article:	Pullen, Sam, Luo, Ming, Gleason, Scott, Xie, Gang, Lee, Jiyun, Akos, Dennis, Enge, Per, Pervan, Boris, "GBAS Validation Methodology and Test Results from the Stanford LAAS Integrity Monitor Testbed," 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. 1191-1201.
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