Turbo architecture for multipath mitigation in global navigation satellite system receivers

In this study a new multipath mitigation architecture for satellite navigation receiver, named coupled amplitude delay lock loops (CADLLs) is presented. This architecture exploits the ‘turbo principle’ to separately track the line-of-sight (LOS) signal and multipath signals in order to mitigate the effects of the multiple reflections. The delay lock loop (DLL) and the amplitude lock loop (ALL) are two basic elements in the structure. DLL is in charge of estimating and tracking the code delay of a specific ray in the incoming signal while ALL is in charge of estimating the corresponding amplitude. A pair of DLL and ALL makes a Unit, devoted to track LOS or a multipath signal. Several Units are incorporated in the CADLL structure, and then able to track the different component rays from the overall incoming signal. The feedback architecture and special working strategy of CADLL boost the performances of the parameter estimation accuracy, the noise tolerance ability and the error mitigation for short-range multipath.