Robustness vs. Accuracy: Multipath Effects on Land Mobile Satellite Navigation

Abstract

Knowledge of performance for different signal options in difficult environments is vital for improving mod- ern satellite navigation systems. Currently, the ac- curacy of the different transmission signals in real- istic multipath environments is still not known in current literature. In this study different classical and advanced signals have been simulated using an urban multipath channel model standardized by the International Telecommunication Union (ITU). For the given multipath channel, signal and receiver ef- fects have been investigated. The performance of GPS C/A and GALILEO open service (OS) signals in this environment has been compared. Additional simulation of wide band navi- gation signals lead to the uncovering of an important conflict between robustness and accuracy in terms of signal bandwidth. This conflict is signal inherent and not associated to a particular receiver. As a result of this finding an improved satellite signal extension for robust urban navigation has been proposed. On the receiver side pure line-of-sight conditions have been identified in which a novel particle filter (PF) based receiver shows a comparable performance as a classical delay locked loop (DLL). In a mixture of line-of-sight and shadowing conditions the particle receiver clearly outperformed the classical DLL. For the classical DLL critical scenarios have been identi- fied that are often causing a loss of lock (LOL).