Folding Techniques for Low Complexity Acquisition of Modern GNSS Signals

摘要

In global navigation satellite system (GNSS) because ofrnthe long pseudo-random-noise (PRN) code period andrnhigh chip rate of the code rapid code acquisition isrnchallenging. The difficulty is how to rapidly detect therncorrect cell from numerous code frequency cells. Tornspeed up the search process several folding techniquesrnhave been proposed in the literature which directlyrnreduces the code phases to be searched by folding eitherrnthe local signal or the incoming signal. Unfortunately allrnthe folding techniques work on the basis of a non-realisticrnassumption that there is no sign transition in the data setrndue to the navigation message bits. In this study wernconsider different variants of the already available foldingrnmethods such as extended replica folding acquisitionrnsearch technique (XFAST) and discuss their performancernin the presence of data sign transition.