Generalized Binary Coded Symbol Modulation Theoretical Performance with Multipath and Noise

James J. Spilker, Jr.

Abstract:	The original GPS signals are constant envelope signals, modulated by Pseudo-Noise (PN) codes. The author and many others generalized the earlier Manchester spreading concept of each Pseudo- Noise (PN) chip/symbol to split spectrum (square – wave) spreading, now called Binary Offset Carrier (BOC) that both increases the Gabor Bandwidth as well providing spectral separation. Generalizations of BOC binary square wave spreading techniques include such new families of constant envelope coded symbols as Neuman- Hofman, Barker and Generalized Barker, continuous frequency chirp, Rademacher, and Walsh function codes each of which can be both time multiplexed (TM) and/or operate in I/Q fashion to spread further the PN codes. Each of these signals is transmitted and received after finite rise time filtering and often received with significant multipath and thermal noise, and other interference. Theoretical performance is analyzed using assisted Quasi-coherent Delay Lock Loop (QCDLL) tracking techniques in the presence of specular multipath, and the Cramer-Rao noise performance bound (Gabor bandwidth) is also computed. These new spreading code symbol families permit the autocorrelation function and spectra to be shaped in more general forms than available with BOC alone and can substantially reduce or nearly eliminate the autocorrelation sidelobes and significantly improve multipath performance using QCDLL tracking.
Published in:	Proceedings of the 2010 International Technical Meeting of The Institute of Navigation January 25 - 27, 2010 Catamaran Resort Hotel San Diego, CA
Pages:	750 - 764
Cite this article:	Spilker, James J., Jr.,, "Generalized Binary Coded Symbol Modulation Theoretical Performance with Multipath and Noise," Proceedings of the 2010 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2010, pp. 750-764.
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