Analysis of the Multiple DLL Architecture: a Novel Solution for Reducing the Multipath Effect in GNSS Receivers

Multipath propagation in urban and indoor environments is one of the factors limiting the accuracy of Global Navigation Satellite Systems (GNSS). The design of modern GNSS receiver will have to deal with the improved theoreticalperformance offered by the new Galileo Signal-In-Space and by the new frequencies and signals of next generation GPS. A large effort has been devoted to identify and reduce the error sources internal to the receiver, and to design proper architecture able to mitigate the effect ofthe external error sources, with a special effort spent onsignal processing techniques for mitigating the multipath effects. In this paper a method based on the use of a multiple Delay Lock Loop (DLL) architecture is introduced, theoretically discussing the achievements in terms of accuracy of the pseudorange estimation. Simulation results for the GPS C/A code and the Galileo BOC(1,1) (Open Access Service) are presented in order to demonstrate the improvements with respect to a single narrow correlator DLL.