Recommendations on the Use of the L2 Civil (L2C) Signal for WAAS

Daniel G. O'Laughlin, M. Bakry El-Arini, Michael Tran, Taehwan Kim, Christopher Hegarty, and Swen D. Ericson

Abstract:	In 2001 the WAAS Independent Review Board (IRB) recommended that FAA consider use of the L2 civil signal (L2C) in WAAS and in the National Airspace System (NAS) operations. This paper presents the results of our analysis of the suitability and potential benefits of the L2C signal in the NAS. This paper also identifies the technical and institutional factors limiting the use of the L2C signal for Instrument Flight Rules (IFR) aviation use. The paper shows that there are significant benefits to the use of the signal for both the WAAS ground system and the IFR aviation user. However, there are significant institutional issues concerning IFR aviation use of L2C. Most significant of these is that the L2C signal is not in an Aeronautical Radionavigation Service (ARNS) band as required by FAA and International Civil Aviation Organization (ICAO) regulations for “safety of life” navigation. This, together with the fact that the interference potential for the band appears to be increasing, causes us to recommend against use of L2C as the basis for dual-frequency IFR aviation use, and instead wait until the L5 signal is available. However, for the WAAS ground system, there are significant benefits to the use of L2C. Most significantly are the reduced susceptibility to ionospheric scintillation and the reduced probability of cycle-slips. By adding L2C capable receivers in the WAAS ground system, availability and continuity of WAAS should improve.
Published in:	Proceedings of the 2004 National Technical Meeting of The Institute of Navigation January 26 - 28, 2004 The Catamaran Resort Hotel San Diego, CA
Pages:	121 - 134
Cite this article:	O'Laughlin, Daniel G., El-Arini, M. Bakry, Tran, Michael, Kim, Taehwan, Hegarty, Christopher, Ericson, Swen D., "Recommendations on the Use of the L2 Civil (L2C) Signal for WAAS," Proceedings of the 2004 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2004, pp. 121-134.
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