Enhanced Differential Correlation Method for the Acquisition of Galileo Signals
Elina Pajala, Elena Simona Lohan, Toni Huovinen, Markku Renfors · 2006
In this paper, we analyze an enhanced differential non-coherent integration method for the acquisition stage of a BOC-modulated CDMA signal in the new European Galileo satellite navigation system. This method, denoted by DN2, offers an improved suppression of any temporally uncorrelated interferers. Background noise is naturally the most obvious source of temporally uncorrelated interference, but, for example, in CDMA systems, also a multiaccess interference is inherently very weakly time-correlated. Here, we carry out a comprehensive comparison between DN2method, the conventional non-coherent integration, and the traditional differential non-coherent integration methods. The correlation methods are compared and analyzed in fading channels, taking into account both ambiguous BOC and sideband based unambiguous technique (such as Betz&Fishman method). We also propose a combined algorithm, which chooses the best correlation method based on an estimation of the coherence time of the current channel