Multi-GNSS analysis based on full constellations simulated data

In the near future, satellite navigation will rely on four global constellations. Two Global Navigation Satellite Systems (GNSS), namely GPS and GLONASS, are already in use. In addition, Galileo and BeiDou/Compass systems, with, respectively, 12 and 19 satellites already in orbit, are expected to be fully operational by 2023. However, exhaustive investigations of the joint performance of the four GNSS as well as of the expected intra- and inter-system interferences are still scarce in the literature, due to the incomplete deployment of Galileo and Compass systems and the consequent scarcity of multi constellation data. In our paper, we extract full constellation data at 50000 randomly spread Earth locations of all the four GNSS via a Spectracom GSG-64 simulator. Then, we present a thorough analysis of the Geometric Dilution of Precision (GDOP) and the intra- and inter-system interference in the presence of the four GNSS compared to single GNSS situations. Based on the realistic multi-GNSS data, we verify that a combined utilization of the four systems will significantly improve the satellite visibility and the GDOP. Furthermore, focusing on the E1-L1-B1 band, we notice that the level of intra- and inter-system interference is slightly higher in the equatorial and pole regions and that the interference level to GPS is the highest among all four GNSS. Finally, by investigating the Carrier-to-Noise density ratio (C/N0) degradation for Galileo E1 signal caused by the presence of the four constellations, we show that it is rather small and it never surpasses 2.3 dB.