Global Navigation Satellite Systems (GNSSs) provide essential position, velocity, and time (PVT) information worldwide. Accurate evaluation of GNSS signals and receiver performance requires realistic simulation environments, particularly for the carrier-to-noise-density ratio (C/N0), a critical indicator reflecting signal quality dependent on satellite elevation angles. This paper presents the development of a GNSS testbed specifically designed to simulate and estimate C/N0 values, focusing on GPS L1 C/A signals. The proposed testbed comprises three main components, a satellite simulator that controls signal power accurately according to satellite elevation angles, an up-/down-converter for RF/IF band conversion, and a signal receiver that estimates C/N0 using the Narrowband–Wideband Power Ratio (NWPR) method. The performance of the proposed testbed was evaluated under four scenarios, namely static, dynamic, jamming, and real-signal. In the static scenario, the proposed system achieved a maximum C/N0 estimation RMSE of 0.60 dB-Hz for satellites with elevation angles above 30° and 1.63 dB-Hz for those below 30°. In the dynamic scenario, the corresponding RMSE values were 0.68 dB-Hz and 0.86 dB-Hz, whereas under jamming conditions they increased to 2.08 dB-Hz and 2.12 dB-Hz, respectively. Furthermore, in the real-signal scenario, the C/N0 values estimated by the proposed testbed exhibited trends consistent with those reported by a commercial u-blox receiver processing the same live-sky signals, thereby confirming its reliability under actual GNSS reception conditions. These results demonstrate that the proposed GNSS testbed enables reliable C/N0 simulation and estimation for GNSS receiver performance evaluation.
황용택 et al. (Wed,) studied this question.