The RF Compatibility of Flexible Navigation Signal Combining Methods

T. Fan, V. S. Lin, G. H. Wang, K. P. Maine and P. A. Dafesh

Abstract:	Global Positioning System (GPS) Modernization on Block IIR-M added a new military signal (M-Code) and a second civil signal (L2C). On GPS IIF, a civil signal for aviation users is to be introduced on the L5 frequency. This modernization continues on GPS III with the concept of a Flexible Navigation Payload. This reprogrammable payload is envisioned to be able to modify code schemes, code rates, data rates, and navigation messages on-orbit. An essential aspect of this flexible payload is the ability to add new ranging signals while on orbit. As demonstrated in a prior work entitled, “Study of Signal Combining Methodologies for GPS III’s Flexible Navigation Payload,” the combining schemes used to add these new signals have a great degree of impact on satellite power efficiency and produce intermodulation (IM) signals [6]. These IM signals are products of the other ranging signals such as the C/A, P(Y) and M-code signals and vary with the combining scheme and relative signal power level. In this work, we will study the interference impact of these IM signals on the in-band C/A, P(Y), M-code and Galileo signals as a function of combining methods and number of signals added. These results provide new insights into the RF compatibility impact of flexible signal generation on the GPS III program’s future navigation payload.
Published in:	Proceedings of the 2005 National Technical Meeting of The Institute of Navigation January 24 - 26, 2005 The Catamaran Resort Hotel San Diego, CA
Pages:	810 - 818
Cite this article:	Fan, T., Lin, V. S., Wang, G. H., Maine, K. P., Dafesh, P. A., "The RF Compatibility of Flexible Navigation Signal Combining Methods," Proceedings of the 2005 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2005, pp. 810-818.
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