Developing and Validating the Loran Temporal ASF Bound Model for Aviation

Sherman C. Lo, Robert Wenzel, Peter Morris, and Per K. Enge

Peer Reviewed

Abstract:	For Loran to be used for aviation navigation, it must meet strict integrity requirements. A key integrity requisite is the ability to bound position errors to a high degree of confidence. This, in turn, means bounding range domain errors and variations. One major source of variation is the temporal variation of propagation delay known as the additional secondary factor (ASF). This paper presents the development and validation analysis of the model for bounding the temporal variation of ASF. It examines the performance of the range and position domain bounds using recently collected data. For each signal, the magnitude and distribution of the bounds into correlated and uncorrelated components is assessed. Position domain bounds and errors are also analyzed. The results show the bounds to be sufficient with exceptions attributable to non-ASF related error sources. The objective is to form the foundation for proving the integrity of the ASF bound methodology.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 56, Number 1
Pages:	9 - 21
Cite this article:	Lo, Sherman C., Wenzel, Robert, Morris, Peter, Enge, Per K., "Developing and Validating the Loran Temporal ASF Bound Model for Aviation", NAVIGATION: Journal of The Institute of Navigation, Vol. 56, No. 1, Spring 2009, pp. 9-21.
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