Assessment on low complexity C/No estimators based on M-PSK signal model for GNSS receivers

In a GNSS receiver the measure of the Carrier to Noise power density ratio (C/No) is not only a measure of the strength of the received signal, but is also used to determine the lock condition of the carrier and tracking loops and to control the channel scheduling. This paper investigates the possibility of implementing various low complexity C/No estimators, properly adapted from the digital communications world in a real GPS/Galileo receiver. After a theoretical analysis, the paper presents the performance evaluation carried out on different C/No estimation techniques, through both simulated and real GPS signals. We used a real-time GPS/Galileo software receiver, that guaranteed a high level of flexibility and helped to analyze and compare the C/No estimators under test.