Development of GNSS Multi-Constellation IF Signal Generator for SSV in Geostationary Orbit

Recent advances in global navigation satellite system (GNSS) technology have led to various research on satellites in various orbits in the space service volume (SSV). Since satellites operating in different orbits have different signal reception environments and characteristics, the development of precise simulation tools that consider the specific conditions for each orbit is required for evaluating and enhancing GNSS performance in SSV. Therefore, this paper presents the GNSS signal generator for SSV. In particular, geostationary orbit (GEO) satellites have a poor signal reception environment than other orbit satellites due to the low C/N0 and the presence of the Earth shadow region. Therefore, the SSV simulator requires the accurate signal generation down to the IF stage, considering the signal reception environment of GEO. However, most simulators are often generating signals at the baseband level for convenience or technical reasons. Therefore, in this paper, we propose an intermediate frequency (IF) signal generator which supports multi-constellation for SSV environments in GEO. After then, the generated signal is processed by a receiver with weak signal processing algorithms to validate and analyze the proposed signal generator. The validation of the implemented GNSS multi-constellation IF signal generator is expected to be used as an accurate SSV simulator similar to the real signal reception environment of GEO satellites.