Code Tracking Loop Performance Including the Effects of Channel Filtering and Gaussian Interference

J. K. Holmes

Abstract:	This report addresses the linearized tracking performance of an early-late type code tracking loop with arbitrary amplitude symmetric code symbols using BPSK modulation, such as is common for GPS receivers. Examples of this type of code symbol include a nonreturn- to-zero (NRZ), a Manchester, and a Binary Offset Carrier (BOC) code symbol. Basically any 1 ± valued symbol falls into this class of code symbols. In addition to the general code symbol shape, the early-to-late code correlator spacing can be anywhere from very small to one code symbol. Since many code tracking systems are faced with the need to operate in a channel in which the filtering is not negligible, the analysis takes into account the filtering effects of the channel, including the transmitter and the receiver. In particular, it is assumed that the composite baseband equivalent filter is complex symmetric. The results apply to any direct sequence code tracking loop system of the type described here and include arbitrary Gaussian interference. In this report the interference is assumed to be composed of the usual white Gaussian thermal noise, plus an interference process which is assumed to be caused by an unintentional interfering signal, and is modeled as a Gaussian random process.
Published in:	Proceedings of the IAIN World Congress and the 56th Annual Meeting of The Institute of Navigation (2000) June 26 - 28, 2000 The Catamaran Resort Hotel San Diego, CA
Pages:	382 - 398
Cite this article:	Holmes, J. K., "Code Tracking Loop Performance Including the Effects of Channel Filtering and Gaussian Interference," Proceedings of the IAIN World Congress and the 56th Annual Meeting of The Institute of Navigation (2000), San Diego, CA, June 2000, pp. 382-398.
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