Multiple DLL architecture for multipath recovery in navigation receivers

Since the Selective Availability was turned off, one of the major error sources in GNSS user positioning is represented by the deleterious superimposition of the same SIS due to obstruction and ground reflections (multipath). Such an error component is the most critical in case of urban (or indoor) navigation due to the high density of possible scatterers around the receiver. In this paper, a multiple Delay Lock Loop (DLL) architecture for navigation receivers, which is derived from the philosophy of the RAKE receiver for communication, is proposed. In this sense, it is quite different from common multipath rejection techniques already proposed, where the multipath is not tracked. Simulation results of the innovative scheme highlight the increased performance with respect to common multipath rejection techniques.