FAA Loran-C Propagation Studies

G.W. Johnson, C. Oates, R.J. Hartnett, K. Gross, P.F. Swaszek, M.J. Narins

Abstract:	The Federal Aviation Administration (FAA) has embarked on a study of LORAN to evaluate the suitability of this long-range system in serving as an independent radio navigation (RNAV) backup to GPS. LORAN.s potential benefit to aviation hinges upon its ability to support Non-Precision Approaches (NPA), which equates to a Required Navigation Performance (RNP) of 0.3 nautical miles. Through FAA sponsoring, the U.S. Coast Guard Academy (USCGA) is responsible for conducting some of the tests and evaluations to help determine whether LORAN can provide the accuracy, availability, integrity, and continuity to support NPA.s in the National Air Space (NAS). A major part of assessing the suitability of LORAN is understanding the nature of LORAN ground wave propagation over paths of varying conductivities. Propagation time adjustments, called .additional secondary factors (ASFs),. are used to adjust receiver times of arrival (TOAs) to account for propagation over non-seawater path(s). These ASFs vary both spatially and temporally, and unless understood and/or modeled, we lose accuracy and may not be able to guarantee a hazardously misleading information (HMI) probability of less than 1x10-7. The USCGA, as a part of the FAA.s government, industry, and academic team, is striving to improve understanding of both the temporal and spatial variations in (ASF). This paper reports on recent achievement in this program area.
Published in:	Proceedings of the 2003 National Technical Meeting of The Institute of Navigation January 22 - 24, 2003 Disneyland Paradise Pier Hotel Anaheim, CA
Pages:	300 - 316
Cite this article:	Johnson, G.W., Oates, C., Hartnett, R.J., Gross, K., Swaszek, P.F., Narins, M.J., "FAA Loran-C Propagation Studies," Proceedings of the 2003 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2003, pp. 300-316.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In