Availability Requirements for Local Area Augmentation System (LAAS)

Ted Urda and Navin G. Mathur

Abstract:	Random House Dictionary defines Availability as “Suitable or ready to use“. From an engineering perspective, for any given system, the availability is defined as the amount of time the system is “ready-to- use” by meeting all of the requirements imposed upon it. Any failure in the system causes loss-of-availability until the system is repaired and is brought back to its normal operational mode. A measure of availability is determined by measuring the system reliability and the maintenance practice. Reliability describes how frequent a failure could occur in a system and maintenance practice describes how fast the system can be brought back to its normal operation subsequent to occurrence of a failure. Thus, the better the reliability, the better will be availability (given similar maintenance practice). Further, the more efficient the maintenance practices, the better the availability will be. This paper describes the dependence of availability on the reliability and the maintainability of a system. The paper also addresses the availability requirement evaluation process for a given airport. Further, the paper includes availability requirements for CAT-II/III LAAS along with discussion on GPS satellite geometry availability enhancement using Wide Area Augmentation System (WAAS) Geo-stationary satellites (GEO’s) and Pseudolites.
Published in:	Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002) September 24 - 27, 2002 Oregon Convention Center Portland, OR
Pages:	1924 - 1933
Cite this article:	Urda, Ted, Mathur, Navin G., "Availability Requirements for Local Area Augmentation System (LAAS)," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 1924-1933.
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