Demodulation Performance Assessment of New GNSS Signals in Urban Environments

Abstract

Satellite navigation signals demodulation performance is historically tested and compared in the Additive White Gaussian Noise propagation channel model which well simulates the signal reception in open areas. Nowadays, the majority of new applications targets dynamic users in urban environments; therefore the GNSS signals demodulation performance has become mandatory to be provided in urban environments. The GPS L1C signal demodulation performance in urban environments is thus provided in this paper. To do that, a new methodology adapted to provide and assess GNSS signals demodulation performance in urban channels has been developed. It counteracts the classic method limitations which are the fluctuating received C/N0 in urban environments and the fact that each received message is taken into account in the error rate computation whereas in GNSS it is not necessary. The new methodology thus proposes to provide the demodulation performance for "favorable" reception conditions together with statistical information about the occurrence of these favorable reception conditions. To be able to apply this new methodology and to provide the GPS L1C signal demodulation performance in urban environments, a simulator SiGMeP (Simulator for GNSS Message Performance) has been developed. Two urban propagation channel models can be tested: the narrowband Perez-Fontan/Prieto model and the wideband DLR model. Moreover, the impact of the received signal phase estimation residual errors has been taken into account (ideal estimation is compared with PLL tracking).